rdkern
Top Post Dawg
- Joined
- May 21, 2004
- Location
- Humboldt Co CA
- TDI
- Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
Some of us are lazy - so if you want help, including a link to your post may get a few more eyes on it.
How to troubleshoot low power on an A3/B4 engine
- Thread starter GoFaster
- Start date
I wanted to add a post.
I have had a low power issue for a week now, intermittent.
My car was hitting limp mode, and diagnosis found all vacuum lines intact, in fact, they were all original, with metal clamps intact.
In order:
Boost gauge indicated that boost pressure was hitting 18psi, and after 3-4 seconds, the car would go into limp mode. No codes were set, and cycling the ignition key would clear the condition.
I checked the vacuum line from the intercooler pipe nipple just before the intake maniold, and it would hold pressure. Removing the vacuum line from the ECU and blowing found the line to be clear. This was confirmed by my SGII and my boost gauge agreeing on manifold (MAP) pressure, indicating that the MAP sensor in the ECU was seeing pressure and able to make a reading.
I Teed a gauge into the blue line (from the N75 valve to the wastegate), and no pressure was present, even when flooring the accelerator in 2nd at 2000rpm. Boost pressure would hit 18psi, but no pressure would make it to the wastegate.
Next, teed the gauge into the red line (boost pressure from the outlet port of the turbo to the N75), and found the pressure reading to roughly mirrror my boost gauge, indicating the line to be clear of obstructions and properly attached.
I then Ohmed out the N75, and found it to be within spec (20-40 ohms, mine read 28 ohms)
I then removed the N75, cut off all the little clamps, and put voltage to the solenoid, expecting a "click", and didn't get one. I did the lip test, and the top supply port was blocked, but the line to the wastegate was open to exhaust (Side-Blue to bottom-black).
Thinking that the solenoid was plugged up, I smacked it with a small hammer a little bit, and used my air gun to blow through the ports. After a few rounds of this, and a fair amount of oilly residue coming out of the n75, I tried putting voltage to the solenoid again, and voila... "click".
Essentially, the N75 was gunked up, and a little tapping and air into the ports cleared it. I hooked everything back up, and now it's back to normal - boosts to 15psi and settles back down to 13 psi.
I have had a low power issue for a week now, intermittent.
My car was hitting limp mode, and diagnosis found all vacuum lines intact, in fact, they were all original, with metal clamps intact.
In order:
Boost gauge indicated that boost pressure was hitting 18psi, and after 3-4 seconds, the car would go into limp mode. No codes were set, and cycling the ignition key would clear the condition.
I checked the vacuum line from the intercooler pipe nipple just before the intake maniold, and it would hold pressure. Removing the vacuum line from the ECU and blowing found the line to be clear. This was confirmed by my SGII and my boost gauge agreeing on manifold (MAP) pressure, indicating that the MAP sensor in the ECU was seeing pressure and able to make a reading.
I Teed a gauge into the blue line (from the N75 valve to the wastegate), and no pressure was present, even when flooring the accelerator in 2nd at 2000rpm. Boost pressure would hit 18psi, but no pressure would make it to the wastegate.
Next, teed the gauge into the red line (boost pressure from the outlet port of the turbo to the N75), and found the pressure reading to roughly mirrror my boost gauge, indicating the line to be clear of obstructions and properly attached.
I then Ohmed out the N75, and found it to be within spec (20-40 ohms, mine read 28 ohms)
I then removed the N75, cut off all the little clamps, and put voltage to the solenoid, expecting a "click", and didn't get one. I did the lip test, and the top supply port was blocked, but the line to the wastegate was open to exhaust (Side-Blue to bottom-black).
Thinking that the solenoid was plugged up, I smacked it with a small hammer a little bit, and used my air gun to blow through the ports. After a few rounds of this, and a fair amount of oilly residue coming out of the n75, I tried putting voltage to the solenoid again, and voila... "click".
Essentially, the N75 was gunked up, and a little tapping and air into the ports cleared it. I hooked everything back up, and now it's back to normal - boosts to 15psi and settles back down to 13 psi.
Starkey
Active member
I am having the typical limp mode issues in 5th gear pulls and hills in my 96 1Z tdi Passat and even after changing all of the lines to and from the N75 it still doesn't want to quit acting up. My question is this, I had a leaky ip and swapped a pump from a mk3 jetta. Now will this cause an issue? I have read that the pumps have different popping pressures for the injector's or something... but could this be fixed with mk3 (non 1Z) nozzles/injectors or if this is even a problem would I be best to look for a 1Z pump?
I am pulling the 5th injector tonight, installing a new air filter and yes I changed the line inside the ecu
Any help would be much appreciated, my gf wants her car back
I am pulling the 5th injector tonight, installing a new air filter and yes I changed the line inside the ecu
Any help would be much appreciated, my gf wants her car back
Starkey
Active member
PS- after replacing the lines to the N75 I am not getting the CEL but before I was getting the typical Internal Control Module Read only Memory (ROM) Error. Also, the N75 is clicking when in the ignition is on but I am still curious how to check it without a vag-com.. or can I? I have read that even if they click they may still be blocked or something? Sorry for all these newbie questions I am new to the world of tdi problems, I like my AAZ much better at the moment lol. Cheers
-Starkey
-Starkey
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TonyJetta
Top Post Dawg
- Joined
- Sep 15, 2005
- Location
- Tucson, Az
- TDI
- '15 Jetta TDI SE / '06 Jetta TDI DSG Pkg0 / '96 Passat TDI
Try cleaning your N75 with some elelctical contact cleaner - it leaves no residue and should be safe for the internals and externals of your N75.
Can you also log MAP requested and actual, then post the log or a graph of the log? Make sure you do the run in 3rd gear, WOT up to ~4000rpm.
My favorite place is to sit at an an on-ramp and set up the log, then go through the gears, getting on the freeway. Short shift 2nd, so that 3rd gear started about 1700rpm, and goes all the way up to 4000 (no more than 4200, just to be safe).
Tony
Can you also log MAP requested and actual, then post the log or a graph of the log? Make sure you do the run in 3rd gear, WOT up to ~4000rpm.
My favorite place is to sit at an an on-ramp and set up the log, then go through the gears, getting on the freeway. Short shift 2nd, so that 3rd gear started about 1700rpm, and goes all the way up to 4000 (no more than 4200, just to be safe).
Tony
Starkey
Active member
I got rid of the 5th injector, cleaned the N75 and deleted the EGR (took the vaccum line off) and the car seems to work great so far and no limp mode...:knock on wood:
Thanks for all your help guys, this thread was great for my tdi learning curve
Thanks for all your help guys, this thread was great for my tdi learning curve
tripl-e
Veteran Member
'97 B4 215,000 miles of which I've added the last 115,000. First thing I did when I got my VAG-COM was re-calibrate the egr values to minimize intake clogging. That was probably 100,000 miles ago.
I've suffered persistent 'limp mode' issues since I've owned the car. One big hill on my daily commute and could never use 100% power or I'd wind up in limp mode half way up. Learned to drive around the problem or reset ignition switch/ecu on-the-fly on the subsequent down grade.
Few months ago began getting 'mil' and 00560 codes and occasionally a 00575. Vacuum hoses were shabby, had never done any intake/egr service of any kind, knew nothing about these systems or their function. Kept resetting the code(s) to extinguish ''mil'. But the 'mil' was coming on more and more frequently and VAG-COM always showed 00560.
Guided by the many invaluable posts here I began:
Started diagnosis/repair with the cheapest item-hoses. New silicone rubber throughout-no change in 'mil' behavior.
Checked egr diaphragm-it held vacuum
Checked vacuum from control solenoid (N75 right?)-20 in. at idle and varying with engine load/speed.
Removed intake air hose at egr and holy darkness!! Intake completely clogged with carbon and soot, couldn't see past the egr actuating rod. Yikes! Removed intake (moderate pita) and the entire manifold was completely clogged up with the accumulated carbon/soot. I picked, scraped, gouged and brushed an entire CoolWhip container full (overflowing actually) of carbon out of the manifold. Then I blocked the 4 intake port openings, added 2 dozen (I counted them 3 times before adding them) 3/8 machine nuts, poured in about a cup of mineral spirits and blocked the intake opening. I let this sit in many different orientations and shook it vigorously from time to time while I cleaned up the intake ports on the head. There I just used a scraper to ease the edge of the accumulated junk to give a smoother transition from the clean manifold runner to the still dirty intake passage. I turned the engine to each cylinder's compression stroke before scraping and then vacuumed/blew each intake port/passage out before moving on to the next cylinder. An hour or so of soaking and shaking with the hardware had cleaned the manifold well (counted the nuts again as they came out) so after blowing it out and air drying it I reassembled everything. Wow, most of a Saturday gone, I'm filthy dirty head to toe but I figure I've seen the last of the danged 'mil' for awhile. And the engine, as you might expect, ran soooo much better. Smoother at small power settings and much, much more power at 100%.
I'm all the next day running errands in my new, super powerful TDI when the 'mil' lights. This being a family forum my exact response in unprintable but you can use your imagination....
Further reading of these truly invaluable posts and the subject of the egr cooler surfaces. Hmmm, didn't look at it very carefully as I moved it aside while taking the intake off. Sooo, removed intake air tube at egr again and ran engine while sucking the egr valve open. Nada, zip, zero. No noise, no visible exhaust nothing coming up through the egr port. Removed flex pipe at egr cooler discharge end, start engine-only the slightest hint of exhaust through the cooler. Oh boy, what now? Dismount cooler again leaving coolant lines attached, lift cooler where I can see into the inlet end and it looks just like the intake did-fully clogged with carbon/soot. I had to use a long length twist drill and drill motor to unclog the cooler's individual tubes. I used great caution not to damage the tube(s) while clearing them and couldn't get to all of them with the drill so the cooler is not completely unplugged. I'd guess it has about 60% of its capacity restored. Reassemble (again!) and now the engine seems to run even better. The idle is smoother and the part power throttle response is better. Drove the car about 10 miles with no 'mil'. Connected VAG-COM, no codes registered. Logged about 3 minutes of MAF data showing egr duty cycle between 19.9% and 64.1%.
No more 'mil' and no more limp mode. Can use 100% power in all gears and have no problem.
Conclusion-intake cleaning/service is probably required in any high mileage 1z and might be recommended as a 100,000 mile routine service item. Your mileage may vary but my results have been dramatic and well worth the effort. On a 1-10 scale this whole project, had I done it all at once, would have been about a 6 pita.
I've suffered persistent 'limp mode' issues since I've owned the car. One big hill on my daily commute and could never use 100% power or I'd wind up in limp mode half way up. Learned to drive around the problem or reset ignition switch/ecu on-the-fly on the subsequent down grade.
Few months ago began getting 'mil' and 00560 codes and occasionally a 00575. Vacuum hoses were shabby, had never done any intake/egr service of any kind, knew nothing about these systems or their function. Kept resetting the code(s) to extinguish ''mil'. But the 'mil' was coming on more and more frequently and VAG-COM always showed 00560.
Guided by the many invaluable posts here I began:
Started diagnosis/repair with the cheapest item-hoses. New silicone rubber throughout-no change in 'mil' behavior.
Checked egr diaphragm-it held vacuum
Checked vacuum from control solenoid (N75 right?)-20 in. at idle and varying with engine load/speed.
Removed intake air hose at egr and
holy darkness!! Intake completely clogged with carbon and soot, couldn't see past the egr actuating rod. Yikes! Removed intake (moderate pita) and the entire manifold was completely clogged up with the accumulated carbon/soot. I picked, scraped, gouged and brushed an entire CoolWhip container full (overflowing actually) of carbon out of the manifold. Then I blocked the 4 intake port openings, added 2 dozen (I counted them 3 times before adding them) 3/8 machine nuts, poured in about a cup of mineral spirits and blocked the intake opening. I let this sit in many different orientations and shook it vigorously from time to time while I cleaned up the intake ports on the head. There I just used a scraper to ease the edge of the accumulated junk to give a smoother transition from the clean manifold runner to the still dirty intake passage. I turned the engine to each cylinder's compression stroke before scraping and then vacuumed/blew each intake port/passage out before moving on to the next cylinder. An hour or so of soaking and shaking with the hardware had cleaned the manifold well (counted the nuts again as they came out) so after blowing it out and air drying it I reassembled everything. Wow, most of a Saturday gone, I'm filthy dirty head to toe but I figure I've seen the last of the danged 'mil' for awhile. And the engine, as you might expect, ran soooo much better. Smoother at small power settings and much, much more power at 100%.I'm all
the next day running errands in my new, super powerful TDI when the 'mil' lights. This being a family forum my exact response in unprintable but you can use your imagination....Further reading of these truly invaluable posts and the subject of the egr cooler surfaces. Hmmm, didn't look at it very carefully as I moved it aside while taking the intake off. Sooo, removed intake air tube at egr again and ran engine while sucking the egr valve open. Nada, zip, zero. No noise, no visible exhaust nothing coming up through the egr port. Removed flex pipe at egr cooler discharge end, start engine-only the slightest hint of exhaust through the cooler. Oh boy, what now? Dismount cooler again leaving coolant lines attached, lift cooler where I can see into the inlet end and it looks just like the intake did-fully clogged with carbon/soot. I had to use a long length twist drill and drill motor to unclog the cooler's individual tubes. I used great caution not to damage the tube(s) while clearing them and couldn't get to all of them with the drill so the cooler is not completely unplugged. I'd guess it has about 60% of its capacity restored. Reassemble (again!) and now the engine seems to run even better. The idle is smoother and the part power throttle response is better. Drove the car about 10 miles with no 'mil'. Connected VAG-COM, no codes registered. Logged about 3 minutes of MAF data showing egr duty cycle between 19.9% and 64.1%.
No more 'mil' and no more limp mode. Can use 100% power in all gears and have no problem.
Conclusion-intake cleaning/service is probably required in any high mileage 1z and might be recommended as a 100,000 mile routine service item. Your mileage may vary but my results have been dramatic and well worth the effort. On a 1-10 scale this whole project, had I done it all at once, would have been about a 6 pita.
BigJohneyK
Veteran Member
I am having the same problem. I haven't checked anything yet except the injection timing, somebody said that could be the issue as well. I could have sworn the link to the diy thread was in here, but Im not seeing it?!
Anybody know the thread im talking about? It walked you through the step by step with or without the service manual...
Yes I did try searching...
Anybody know the thread im talking about? It walked you through the step by step with or without the service manual...
Yes I did try searching...
BigJohneyK
Veteran Member
I found it!!!I am having the same problem. I haven't checked anything yet except the injection timing, somebody said that could be the issue as well. I could have sworn the link to the diy thread was in here, but Im not seeing it?!
Anybody know the thread im talking about? It walked you through the step by step with or without the service manual...
Yes I did try searching...
http://www.tdiclub.com/TDIFAQ/TDiFAQ-7.html#k
7.k Setting Injection Timing
BigJohneyK
Veteran Member
I just wanted to say that my problem was the hose coming out of the ecu. The hose wasn't plugged but I replaced it anyways because it was fairly worn. I believe the problem was in the clamps. Make sure they are super snug, especially the one on the opposite end of the ecu, if you blow into the ecu end of the hose you might misinterpret a leak for just being a smooth flowing hose.
The fuel injection timing advancement helped make it run smoother but the hose replacement cleared the code.
The fuel injection timing advancement helped make it run smoother but the hose replacement cleared the code.
It's now post #19, in that ^^ thread, on page 2 of 7. It is a great guide to tubes and hoses replacement: id & od sizes with McMasters links.
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Old thread, similar problem: my small black "2a" hose is well connected to the small plastic tube that goes into the firewall but is disconnected at the other end-where is it supposed to be attached to?
It was simply coiled onto the metal clip hose holders under the plastic tubing, with the open end just hanging there. Know what I mean? It's like somebody did a vacuum diagnostic and then never re-attached it to where it belongs.
TonyJetta
Top Post Dawg
- Joined
- Sep 15, 2005
- Location
- Tucson, Az
- TDI
- '15 Jetta TDI SE / '06 Jetta TDI DSG Pkg0 / '96 Passat TDI
If I am understanding you correctly, the end of the black hose should connect to the small hose barb on the corner of the boos piping, near the intake manifold.
I'll see if I can find a diagram. Here!
Tony
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soup nazi
Veteran Member
Hi chaps
I bought myself a boost gauge which I fitted today. The thing is my feeling is my car is a little lacking below about 1500rpm, above that she goes fine. Its not very noticeable much on a flat surface but more when going up hill with a little load and on hot days with the A/C running flat out so its torque she lacks. Anyway I did the turbo check from the bentley manual. Disconnect the N75, 2nd gear, WOT and take the reading at 3500 to 4000rpm. No probs she does 8psi on that one. I think the spec is 7.4 to 9.6psi.
Edit: With the N75 connected under the same conditions she does 15psi.
What I would like to find out is whats the boost supposed to do at various throttle settings and rpm's. For instance at 1500rpm in 2nd gear with no load I get about 3psi. Whilst at 100kph steady in top gear at 2000rpm I get about 6.2psi. In 2nd gear from 1100rpm with WOT get no boost at all until it passes 1450rpm and its in this area I think she lacks muscle. Any info is appreciated.
I bought myself a boost gauge which I fitted today. The thing is my feeling is my car is a little lacking below about 1500rpm, above that she goes fine. Its not very noticeable much on a flat surface but more when going up hill with a little load and on hot days with the A/C running flat out so its torque she lacks. Anyway I did the turbo check from the bentley manual. Disconnect the N75, 2nd gear, WOT and take the reading at 3500 to 4000rpm. No probs she does 8psi on that one. I think the spec is 7.4 to 9.6psi.
Edit: With the N75 connected under the same conditions she does 15psi.
What I would like to find out is whats the boost supposed to do at various throttle settings and rpm's. For instance at 1500rpm in 2nd gear with no load I get about 3psi. Whilst at 100kph steady in top gear at 2000rpm I get about 6.2psi. In 2nd gear from 1100rpm with WOT get no boost at all until it passes 1450rpm and its in this area I think she lacks muscle. Any info is appreciated.
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TonyJetta
Top Post Dawg
- Joined
- Sep 15, 2005
- Location
- Tucson, Az
- TDI
- '15 Jetta TDI SE / '06 Jetta TDI DSG Pkg0 / '96 Passat TDI
On the TDIclub, the basic boost test is to short shift 2nd, into 3rd, and drive 3rd gear up to ~4000rpm. If you don't hit limp mode, all is well. However, the turbo could still be over boosting or under boosting a little.
Are you getting any codes?
Tony
Are you getting any codes?
Tony
Johnny_come_lately
Member
- Joined
- Jun 18, 2008
- TDI
- '98 Jetta, 175k of someone else's miles, 50k of mine
Mea culpa - Wastegate controller frozen
Will someone please forgive me?
Seriously, I feel like a dolt. I've been aware there was something "not quite right" with the car since I bought it used and had the TB changed. The local VW mechanic said it was the "turbo and the computer, thousands to fix, with little to be gained"... I think it started, and ran fine, albeit "a bit underpowered"... I think it STARTED in limp mode, I didn't know any different.
Unemployment has me fixing / taking care of things myself now. I read this post, and others like it, and have the car running tip-top now at the cost of a $4 hose and "some time" cleaning. Amazing power up hills, and no perceptable change in mpg yet. I just got it back together and the fuel gauge doesn't move until I've got 100 miles or so on it so I'll have to wait a while.
I've posted my thanks in another thread, but wanted to pass on an essential key to what got me going in this thread.
The nipple on the wastegate controller is just big enough to allow you to insert the little plastic tube on a can of PB Blast, and / or canned air into it. My WGC was locked, and full of gunk. I got it to wiggle a little with a vice-grip on the actuator, but no more with just a bit of effort. Granted, getting the can of cleaner in there (behind the engine, above the axle, laying down in my driveway) was a bit cumbersome, but I was able to flush out the little pot with great results! Free movement again after 3+ years of inactivity thanks to the TB change guys. They tore the blue hose off the WGC, I found the clamp on the nipple. The gunk was in there, but I think it hardened due to its nature / location. I have removed the tee I was using to measure "blue line boost", and have inserted a small fuel filter from a weed-eater to see / catch any more gunk.
I'm not sure what the best stuff to use would be, but PB Blast inside the WGC nipple and a bit of exercise with 20psi compresed air sure worked wonders.... The nipple/ plastic straw fit so tight it actuated with the can of PB blast after a squirt or two. You can't imagine my relief. The PB worked it's way into the diaphram / baloon and unstuck it from itself, PB freed up the gunk, and repeated blasts with 20psi air did a good job of flushing it. Works great now.
Thanks for this awesome writeup, I'd be limping along without it.....
Will someone please forgive me?
Seriously, I feel like a dolt. I've been aware there was something "not quite right" with the car since I bought it used and had the TB changed. The local VW mechanic said it was the "turbo and the computer, thousands to fix, with little to be gained"... I think it started, and ran fine, albeit "a bit underpowered"... I think it STARTED in limp mode, I didn't know any different.
Unemployment has me fixing / taking care of things myself now. I read this post, and others like it, and have the car running tip-top now at the cost of a $4 hose and "some time" cleaning. Amazing power up hills, and no perceptable change in mpg yet. I just got it back together and the fuel gauge doesn't move until I've got 100 miles or so on it
so I'll have to wait a while.I've posted my thanks in another thread, but wanted to pass on an essential key to what got me going in this thread.
The nipple on the wastegate controller is just big enough to allow you to insert the little plastic tube on a can of PB Blast, and / or canned air into it. My WGC was locked, and full of gunk. I got it to wiggle a little with a vice-grip on the actuator, but no more with just a bit of effort. Granted, getting the can of cleaner in there (behind the engine, above the axle, laying down in my driveway) was a bit cumbersome, but I was able to flush out the little pot with great results! Free movement again after 3+ years of inactivity thanks to the TB change guys. They tore the blue hose off the WGC, I found the clamp on the nipple.
The gunk was in there, but I think it hardened due to its nature / location. I have removed the tee I was using to measure "blue line boost", and have inserted a small fuel filter from a weed-eater to see / catch any more gunk.I'm not sure what the best stuff to use would be, but PB Blast inside the WGC nipple and a bit of exercise with 20psi compresed air sure worked wonders.... The nipple/ plastic straw fit so tight it actuated with the can of PB blast after a squirt or two. You can't imagine my relief. The PB worked it's way into the diaphram / baloon and unstuck it from itself, PB freed up the gunk, and repeated blasts with 20psi air did a good job of flushing it. Works great now.
Thanks for this awesome writeup, I'd be limping along without it.....
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Ben28881
Active member
I lost power on the highway the other day, it was -15c that night. I couldn't go over 100 kph. Check engine light came about a minute before. I limped home and parked. Next day temp was above 0c and no limp mode. Next day check engine light went out.
Gotta love self repairs!
Gotta love self repairs!
Ben28881
Active member
Also today thawed and lubed all doors and fixed wire so trunk release works now!
ldogbrass
Member
- Joined
- Jan 25, 2011
- Location
- Denver
- TDI
- 02 Jetta TDI wagon - Bosio 1019's - Lifted and stiff sprung - 2012 Passat TDI SEL
Holy smoke 5 codes!
I just purchased this little jetta 98 TDI with 175K on the dile. It is a basket case. I starded with the body work and paint. Now it is time to get under the hood. The timeing belt was done 30k miles back. The car smokes and has very little power. I can't wait to dig into this thread over the weekend. I don't have a VAG COM yet so I went to autozone to see what the codes are.
P1441
P1550
P1144
P0605
P0380
I just purchased this little jetta 98 TDI with 175K on the dile. It is a basket case. I starded with the body work and paint. Now it is time to get under the hood. The timeing belt was done 30k miles back. The car smokes and has very little power. I can't wait to dig into this thread over the weekend. I don't have a VAG COM yet so I went to autozone to see what the codes are.
P1441
P1550
P1144
P0605
P0380
TonyJetta
Top Post Dawg
- Joined
- Sep 15, 2005
- Location
- Tucson, Az
- TDI
- '15 Jetta TDI SE / '06 Jetta TDI DSG Pkg0 / '96 Passat TDI
You may already know this...Vag Com (now VCDS) is really your best bet for reading codes. Generic is fine, but will only pull some codes: VCDS will pull ALL codes, even factory.
Tony
Tony
Very sudden power lose 2003 Jetta TDI - help appreciated
Last night I was climbing a long steep grade, 4th gear, about 3100RPM, pedal to the floor, suddenly the engine just lost power! It now lacks the torque it had to even maintain 60MPH up a slight grade.
The engine has 157Kmiles, new air filter, fuel filter with about 30Kmiles, I only fill the tank with fuel filtered through a 1 micron filter so I don't think the filter is plugged. The EGR and Flapper Valve have been rendered inoperative for the last 60Kmiles, hence, the MIL light stays lit.
There are no strange sounds and no smoke. I have read the beginning of this post about the various possibilities for my problem.
Any thoughts as to what might cause the very sudden power lose?
Last night I was climbing a long steep grade, 4th gear, about 3100RPM, pedal to the floor, suddenly the engine just lost power! It now lacks the torque it had to even maintain 60MPH up a slight grade.
The engine has 157Kmiles, new air filter, fuel filter with about 30Kmiles, I only fill the tank with fuel filtered through a 1 micron filter so I don't think the filter is plugged. The EGR and Flapper Valve have been rendered inoperative for the last 60Kmiles, hence, the MIL light stays lit.
There are no strange sounds and no smoke. I have read the beginning of this post about the various possibilities for my problem.
Any thoughts as to what might cause the very sudden power lose?
TonyJetta
Top Post Dawg
- Joined
- Sep 15, 2005
- Location
- Tucson, Az
- TDI
- '15 Jetta TDI SE / '06 Jetta TDI DSG Pkg0 / '96 Passat TDI
Sounds like limp mode. Key-off then restart should clear it.
As to why...there are several possibilities.
First, I would change the fuel filter. I know many people change them every 40K, but the original interval is every 20K miles.
Next, I would change the vacuum lines. Here's a good thread with lengths and PN's.
You might also want to start your own thread, so that people that can help, and track the troubleshooting.
Tony
As to why...there are several possibilities.
First, I would change the fuel filter. I know many people change them every 40K, but the original interval is every 20K miles.
Next, I would change the vacuum lines. Here's a good thread with lengths and PN's.
You might also want to start your own thread, so that people that can help, and track the troubleshooting.
Tony
Tony,
Thank you!
You were correct! It was in limp home mode. I drove it today and the engine is back to it's normal peppy self. I guess the ECM designers put some code in it to prevent self destruction. I was running WOT in 4th gear for a few miles before it went into limp home mode. Under that condition I would think it somehow new the exhaust temperature would be too high. How it knew, I don't know. The only sensors I could find in the eBahn shop manual are boost, intake temperature, mass air flow and some kind of sensor that looks at turbocharger speed.
A discussion on how the ECM works would be interesting, how do I start a new post?
Regards,
TDIMoth
Thank you!
You were correct! It was in limp home mode. I drove it today and the engine is back to it's normal peppy self. I guess the ECM designers put some code in it to prevent self destruction. I was running WOT in 4th gear for a few miles before it went into limp home mode. Under that condition I would think it somehow new the exhaust temperature would be too high. How it knew, I don't know. The only sensors I could find in the eBahn shop manual are boost, intake temperature, mass air flow and some kind of sensor that looks at turbocharger speed.
A discussion on how the ECM works would be interesting, how do I start a new post?
Regards,
TDIMoth
TonyJetta
Top Post Dawg
- Joined
- Sep 15, 2005
- Location
- Tucson, Az
- TDI
- '15 Jetta TDI SE / '06 Jetta TDI DSG Pkg0 / '96 Passat TDI
tdidieselbobny
Top Post Dawg
- Joined
- Apr 4, 2005
- Location
- Stafford,NY (WNY)
- TDI
- '03 Galactic Blue Jetta TDI, '15 Silk Blue Golf Sportwagen TDI
I haven't read through ALL the posts in this thread,but thought I would share a "solution" for me. When I had my TB changed last month,the guru offered to change the tube that goes from the egr nipple to the solenoid/valve on right fender(N18?) (it's a 97 B4)....didn't need to,but the PO put this huge rubber line on there,so I thought what the heck,make it look better. The guru put the silicone tube on,good to go. Well,the past few weeks,I've had no problem putting the car in limp mode-2nd gear,just before 3k rpm's,the power was gone until I restarted car. Today while I was tinkering w/ something else,I put other line on it(the one that was taken off during TB change)-no more limping! I was well past 3k rpm's in 2nd & 3rd-didn't go into limp mode at all. I'm not sure the ID of the new tube that was put on,but the old one was quite bigger.
redbeard
Active member
N75 Easy Diagnosis and autopsy - another fixed TDI testimonial
Figured I'd post my limp mode story as well. Thanks to Gofaster's writeup and all the other info in this post, I got started in the right direction.
I had replaced all my vacuum/pressure lines with the silicone 2 years ago, so I knew they were good. Got a click out of the N75 when I applied 12V, so I assumed it was OK (mistake) and went on to try to troubleshoot other stuff because I was too lazy to setup Gofaster's N75 pressure gauge test. Went around in circles for a while finding nothing and finally came back to the N75.
Here is the easy test I used to find out that the N75 was shot. Note: Gofaster's technique is much more thorough, but also kind of a PITA.
This test is so easy and the N75 is so easy to access, I'd recommend trying it first especially if you don't have pressure gauges and VAG-COM.
And now for the N75 AUTOPSY...
I was able to cut it apart without too much damage. It is a dead simple device. The electrical coil pulls a spring loaded cap/plunger one way when energized. Everything was fine inside - no gunk etc, but the spring had broken into 3 pieces due to wear and fatigue. Sorry - no pics. This was not allowing the plunger to move all the way when energized. Just for the sake of trying it, I stretched out the longest piece of remaining spring and reassembled the whole deal with a bit of super glue. To my amazement it actually worked. Who knows how long it would actually last with the almost dead spring and superglue, but it can be done if you are really bored, poor, and would like to risk dropping back into limp land at any time. I put a new one in as soon as it came in the mail. $52 from idparts.com is well worth it.
Hope that helps the next TDI trudging up a hill at 45 mph.
Figured I'd post my limp mode story as well. Thanks to Gofaster's writeup and all the other info in this post, I got started in the right direction.
I had replaced all my vacuum/pressure lines with the silicone 2 years ago, so I knew they were good. Got a click out of the N75 when I applied 12V, so I assumed it was OK (mistake) and went on to try to troubleshoot other stuff because I was too lazy to setup Gofaster's N75 pressure gauge test. Went around in circles for a while finding nothing and finally came back to the N75.
Here is the easy test I used to find out that the N75 was shot. Note: Gofaster's technique is much more thorough, but also kind of a PITA.
- Pull the N75 out. 1 quick release electrical conn and 3 small tubes. If your tubes aren't color coded, note their arrangement.
- a. Blow in the red port -air should come out the blue. b. Blow in the black port - it should be a dead-end.
- Apply 12V to the N75 connector. a. Blow in the black port - air should come out the blue. b. Blow in the red port - it should be a dead-end.
This test is so easy and the N75 is so easy to access, I'd recommend trying it first especially if you don't have pressure gauges and VAG-COM.
And now for the N75 AUTOPSY...
I was able to cut it apart without too much damage. It is a dead simple device. The electrical coil pulls a spring loaded cap/plunger one way when energized. Everything was fine inside - no gunk etc, but the spring had broken into 3 pieces due to wear and fatigue. Sorry - no pics. This was not allowing the plunger to move all the way when energized. Just for the sake of trying it, I stretched out the longest piece of remaining spring and reassembled the whole deal with a bit of super glue. To my amazement it actually worked. Who knows how long it would actually last with the almost dead spring and superglue, but it can be done if you are really bored, poor, and would like to risk dropping back into limp land at any time. I put a new one in as soon as it came in the mail. $52 from idparts.com is well worth it.
Hope that helps the next TDI trudging up a hill at 45 mph.
TonyJetta
Top Post Dawg
- Joined
- Sep 15, 2005
- Location
- Tucson, Az
- TDI
- '15 Jetta TDI SE / '06 Jetta TDI DSG Pkg0 / '96 Passat TDI
redbeard,
Thanks for posting that simplified test! I'm sure it will help others.
Tony
Thanks for posting that simplified test! I'm sure it will help others.
Tony
clowntree
Active member
I'm having the dreaded low power/limp mode with a p1550 code on my 98 Jetta TDI. Here's the symptoms, it drives fine when the weather is 70 degrees or below, except for accelerating up a hill. Also it goes into limp mode when it's between 2000-2200 rpm. Another thing I've noticed is under initial acceleration it feels like it has power, then I hear the click in the dash and it loses power, then it clicks again at around 3000 rpm then it goes fine again. It seems like there's a low power range between 1500-2750/3000 rpm and when in warm weather 75+ degrees 2000-2200 rpm will trigger limp mode. What I've done so far: replaced n75, replaced vacuum lines, replaced MAF, replaced air filter, cleaned snow screen. I'm at a complete loss here and every thread where people have this exact same problem, they just reply back with a simple "fixed" as their last post and don't actually state what the issue was which is absolutely enfuriating. If there's a thread about how to fix something, there should always be an explanation instead of "fixed."