How to troubleshoot low power on an A3/B4 engine

TonyJetta

Top Post Dawg
Joined
Sep 15, 2005
Location
Tucson, Az
TDI
'15 Jetta TDI SE / '06 Jetta TDI DSG Pkg0 / '96 Passat TDI
  1. Double check orientation of the control hoses to the N75...trace them back to their source; don't assume color represents the correct function.
  2. Have you verified proper operation of the wastegate actuator? The wastegate should open with 6-8psi applied to the solenoid.
Tony
 

bongolander

New member
Joined
Jan 8, 2012
Location
Washington DC area
TDI
1997 Passat
Vacuum hose leak caused low power

I once had my 97 Passat TDI drop power like mad. I was going up the hill out of Cumberland, Maryland heading west on the Interstate, and could only get going about 50 mph. I assumed since I wasn't having problems earlier in the day that it might be a vacuum line, so I examined some of the ones right on the top of the engine. Sure enough, one looked questionable, so I cut off 1/2 of an inch, and put it back on. Bingo, that solved it!
 

Skeej760

Veteran Member
Joined
Feb 16, 2012
Location
Left Coast USA
TDI
1996 Wolfsburg Passat TDI B4 1Zwagon
N75 fix worked for me-

Mech Brandon at Bob Baker VW in Carlsbad, CA tested for no codes, graphed ECU vs boost, to find an intermittent reading/discrepancy that matched my low power in 3rd uphill complaint, and swapped in a new N75.

Fixed.
 

hockey diesel

New member
Joined
Feb 25, 2010
Location
grant park il
TDI
03 jetta 05 passat wagon 16 audi a6 tdi
Fuel shutoff valve/solenoid

I went through everything on the low power list except VCDS. No luck.I broke down and bought Ross Tech VCDS. Got code 01237 fuel shutoff valve N109 04-00 mechanical malfunction. Replaced solenoid. Problem solved. Full power. I chased this problem for six months. Diagnosed with VCDS in five minutes. Generic code reader did not bring up this code.ID parts - Injection Pump Shut-Off Solenoid $49.95. It comes with new
O-ring. Search threads for change procedure. Simple twenty minutes.
Should mention this problem was on 98 Jetta tdi mt 208k. TDI club is priceless. A big THANK YOU to all who give their time to post information, instruction and support. Thanks again, hockey diesel.
 

nwca

Well-known member
Joined
Sep 28, 2012
Location
North West California
TDI
99 beetle tdi, 2003 golf TDI, 2003 beetle cabrio
My first diesel was a 6.5 Chevy TD. known as a bad motor, I had 300,000+ on mine (original) and I had it loaded down in Wyoming doing 100+ mph (no speed limit there for a short while)...

More to the point though...The only use of a vacuum pump on the Chevy was to control the wastgate. Mine went out and instead of replacing the vacuum pump I built a spring wast gate controller for it.

I have a 1.6 with a tdi gt15 on it and I built a spring (adjustable) waste gate controller for it. I also own a 1.9 tdi (computer controlled).

Spring controlled waste gates are reliable, simple and can be dialed in how you like. I also dealt with a dead n75 once, what a pain.. Sure it might save your engine, but at this stage having a egt/boost gauge is wise regardless (so you know whats gong on). There are even some reasonable price aviation egt gauges that can be set to make a light come on when it gets too high... Were talking less than $100 bucks..

Just thought I'd put it out there..
 

nwca

Well-known member
Joined
Sep 28, 2012
Location
North West California
TDI
99 beetle tdi, 2003 golf TDI, 2003 beetle cabrio
I even thought I'd expand on this..

All diesels should have boost and EGT gauges. Even if its one that sits in the glove box (which my passat doesn't even have!).

They are both motor saving tools and you can use them to "hyper mile" if you like. All for less than a few hundred bucks..

Not to mention you'll know what your car is, and isn't doing...you'll be used to seeing a certain boost/egt reading going up that "normal" hill and it'll make you aware of headwinds/tailwinds and problems...

http://www.ebay.com/itm/DIGITAL-EGT...Parts_Accessories&hash=item2c4defeeb6&vxp=mtr

The above link is one on ebay..I've used it (and just bought a second). Small probe (no problem installing) and you can auto dim the light (with your HL switch) and set up a light to come on (has one built in as well) for high egt's... Not to mention made in the usa (If I remember right).

I don't remember but it even seems like you can set up multiple sensors (although it will only show one at a time) with this one..I'll have to see (when I get the one I just ordered in) as I might put a sensor in the oil pan/coolant) on if it'll read that low (It will, mine now shows ambient temp after its sat and I crank it up).
 
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schltz33

Member
Joined
Sep 23, 2013
Location
wisconsin
TDI
98 jetta tdi ahu
I wish that I had seen and read this before searching/troubleshooting/posting a question for this problem. I indeed have a large crack in the (2h) boost hose. Question now is how can I go about replacing or fixing this without spending $180 which is what the dealer quoted??? are there any other sources for this hose?

Thanks to all of you that have done so much to help those like me!
I have a 98 jetta 1.9 tdi ahu motor with a 2h hose that is used with 50000 miles on it.i bought it new from the dealer, dealer part #1HO-145-838-F HOSE.I can ship it to your door for a reasonable rate,how does $110.00 sound?Call 262 385-1537,nick,located in wisconsin.
 

schltz33

Member
Joined
Sep 23, 2013
Location
wisconsin
TDI
98 jetta tdi ahu
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 have a 98 jetta tdi 1.9, had p1550 limp mode code and dealer charged me to wrongly diaganose it .The cam shaft moves 1/4 inch side to side and timing belt is loose .dealer told me to keep driving it and now car wont run.long story short,i have lots of new parts you may need, let me know 262 385 1537,nick
 

schltz33

Member
Joined
Sep 23, 2013
Location
wisconsin
TDI
98 jetta tdi ahu
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." :(
Try checking you cam shaft for play by slighlty prying on cam sprocket back and forth, under timing belt cover.Also notice if your belt is aligned corectly,my car did the same thing when i took it to the dealer and was told to just keep driving it ,now it wont run.My cam either broke or the berrings went out and then your car valves wont perform correctly.
 

schltz33

Member
Joined
Sep 23, 2013
Location
wisconsin
TDI
98 jetta tdi ahu
98 jetta ahu 2h boost hose

I wish that I had seen and read this before searching/troubleshooting/posting a question for this problem. I indeed have a large crack in the (2h) boost hose. Question now is how can I go about replacing or fixing this without spending $180 which is what the dealer quoted??? are there any other sources for this hose?

Thanks to all of you that have done so much to help those like me!
I bought a 2h boost hose from the dealer and can ship it to you for $110.00 with shipping and handeling,only about 42000 miles on hose schltz33,or call 262 385 1537,nick.pepin wisconsin.
 

jjcsnlynn

Veteran Member
Joined
Nov 18, 2007
Location
Felton, DE
TDI
02 & 03 Jetta TDI,99 Beetle TDI, 04 Chevy Duramax 2500HD 4x4
My Passat supports it....

If you have the latest SW version, the descriptions for each measuring block are automatically populated.

I assume you are trying to measure boost. In vag-com, and almost any car for that matter, it's MAP - Manifold Absolute Pressure.

IIRC, blocks 10 and 11 will give you what you want. If that's not right, just scroll through the blocks until you find the description that fits. There are three possibilities: map requested, map actual, and atmospheric.

HTH

Tony
Tony,
What are good readings? Also, is the 'Manifold Pressure' block relative to the boost from the turbo?
 

TonyJetta

Top Post Dawg
Joined
Sep 15, 2005
Location
Tucson, Az
TDI
'15 Jetta TDI SE / '06 Jetta TDI DSG Pkg0 / '96 Passat TDI
Look at requested vs. Actual map

Tony
Sent from my e-diesel fleet
 

jjcsnlynn

Veteran Member
Joined
Nov 18, 2007
Location
Felton, DE
TDI
02 & 03 Jetta TDI,99 Beetle TDI, 04 Chevy Duramax 2500HD 4x4
Should the actual be more than or less then the requested? I just took mine for a ride after finding my boost problem and mapped it. I couldn't figure out how to save it, so I lost all the info when I tried to scroll through it.
 

TonyJetta

Top Post Dawg
Joined
Sep 15, 2005
Location
Tucson, Az
TDI
'15 Jetta TDI SE / '06 Jetta TDI DSG Pkg0 / '96 Passat TDI
Actual should be ever so slightly less than requested.

Tony
Sent from my e-diesel fleet
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
Should the actual be more than or less then the requested...
Depends....

Actual usually is trailing requested, but can be over with a bad control system.

I like tk see both map and maf request/actual.
 

jcorasaniti

New member
Joined
Dec 19, 2012
Location
georiga
TDI
1997 passat tdi
ok men, I can not get a reading when I plug in to the on board computer.. Its like there is no power there. It is a 1997 passat. Is there a relay some where,I have checked all the fuses and they all seem fine.The car is stuck in limp mood,i use to be able to turn the car off and on and it would fix the problem,but not any more...
Thanks JIM
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
What are you using to connect to the computer? Do you have the normal lights come on with key-on (gp, check engine, airbags, etc)? After-market radio?
 

liliwinski76

New member
Joined
Apr 30, 2014
Location
upstate ny
TDI
96 passat
hey all, i just bought a 96 passat, fuel filter changed and fuel additive put in, so i dont think its a fuel problem, i also dont think its a clutch problem, when im in 4th or 5th gear and have my accelerator past half throttle at 2500rpms it flutters, think of the motor (im going on the sound of my exhaust) like your cellphone ringing on vibrate, on the buzz the car accelerates like it should "waaaa" which lasts about a second, then it bogs "ooo" and doesnt pull as hard again for about a second, then back to accelerating hard "waaa", giving a noise like waaaoooowaaaooowaaaooo....i know it looks stupid over text but its the best i can do to explain it, the car runs great other than that and there is no check engine light on, have any of you dealt with this? im new to tdi's but ive worked on diesel trucks so im mechanical just looking for some direction and some time saving on troubleshooting
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
Put that music on paper - or record it. Sounds better in my imagination that in reality I'd bet.

Can you find someone with VCDS? Might be an IQ (injection quanity, not what you thought) issue, we have some B4 "studder" or "shudder" at certain areas if the amount of fuel is just off of what the computer expects. Would be nice to see what the various sensors say - pressure, airflow, injection quantity... stuff that makes diagnosing easier.

Car is new to you, so some benchmarks should be established. If you're on the northcoast of California with the car some day......

Otherwise, look in your area for someone with a computer interface (VCDS). It makes a difference - worth the $200-300 it costs. Ross-Tech. Not affiliated other than as a serious customer.
 
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super_kev

Active member
Joined
Jun 19, 2013
Location
CA
TDI
'98 Jetta
[snip]

*Edit* I posted this in a stand-alone thread in the A3 forum as I don't think many folks read all the way to page 10 of this sticky, and needed more visibility to help with my problem. :) Here is the link: click

Update 6/19/14: Problem is fixed. Turned out to be an IQ issue, even though the IQ of 4.8-5.0 was fine prior to rebuild, I needed to drop it to around 2 to get rid of my symptoms (ECU codes, loss of boost especially in hot weather, etc.) I'd suggest folks read the thread and see if it helps them. Here is the last post (top of page 4) that gives further explanation of what I found:

Ok, update here, I think it is pretty much fixed...

I called Frank today and spoke to him about what was going on. He suggested that I drop the IQ to 2-3 and see if that helped. I didn't think of doing it as I had an IQ of 4.8-5 prior to the timing belt snapping on me so I figured the rebuild would run just as well. I took a hammer to the pump and brought it do to 3.6 and found the car drove better, so I dropped it again to 2.4 or thereabouts and it drove much, much better.

Then i decided to drop the IQ to 0.4-0.6 but then I found that when blipping the throttle it took longer for the RPMs to come down, and then I got stuttering every 1-2 seconds or so, like a misfire. Group 15 gave me an actual IQ of 0.6mg/str while group 13 (Idle speed smooth running adjustments) gave me Cyl 1 as 0.18mg/str, Cyl 2 at -2.49mg/str, and Cyl 3 at -0.31mg/str. So they were not all lined up, caused by one or more receiving too much fuel (or low compression).

I bumped the IQ back up to 1.4-1.6, throttle blip returned to normal, no stuttering, and Cyl 1 was -0.31mg/str, Cyl 2 at -0.61mg/str, and Cyl 3 at -0.21mg/str so they were all fairly close. Boost builds quickly now, and while I don't get the 1-mississippi-2-missisippi-3-mississippi 35-50mph run in 3rd gear like Frank said to adjust my IQ to (only get to about 45mph in that time) the car runs much better and I am giving it as much fuel as I can without flooding it. I don't know why I needed to drop the IQ so much, but there was definitely a fueling issue caused by the IQ that was not apparent prior to the rebuild. Weird.

Car runs great, and can hold 65-70mph up a decent grade, but I think I still need to tune it so that I can accelerate a little up the grade in 5th. Anyways, thanks for all your help. I would suggest to anyone else that the IQ be dropped as soon as the car is running and timed correctly, prior to any other troubleshooting of a loss of power event. Could have saved me some money and time.
 
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MikeB4

Well-known member
Joined
Apr 18, 2005
Location
Irvine, CA, USA
TDI
1997 Passat TDI Sedan, Candy White
Limp Mode with 00550 and 00560

Hi all,
I'm trying to take care of my unusual limp mode issue on my B4V before I sell it. I've read this astounding thread multiple times, and I see that I may have to go through the EGR troubleshooting steps in detail because my error code is 00550 "Start of injection regulation" and 00560 "EGR" and not the typical 00575. Background: I've replaced my turbo, my N75, and all the vacuum lines (with the silicon lines) five years ago -- including the little one in the ECU. At that time I also cleaned out my intake manifold and intercooler and set the EGR duty cycle to 33768 as recommended. The timing belt, fuel filter, and air filter are about 1 year old. I have the timing slightly advanced and the IQ set to 2.8. So, if I do the hard acceleration up a hill, I will get the loss of power when I hit 3000 rpm or slightly before. I am not sure it is limp mode because it goes back to normal after a short time without rebooting the car.
On my WOT steep hill 3rd-gear test run, note that right around the 56 second mark, the rpm tops out just shy of 2500. The MAP, which peaked at 2019 / 969 mbar (15 psi) earlier, increases it's downward slope there exactly at the same time MAF actual drops off a little.




The codes thrown are 00550 Start of Injection Regulation Control Difference and 00560 EGR control difference. Also, I notice these days that my MAF actual is always over 400 mg/R, not the 370 mg / R listed on the EGR time constant update "how to" file.

After this run, I spent the evening tightening the EGR hoses and clipping, reseating, and clamping the N75 hoses (after some WD-40 through the N75). Today I did another test run, and I got the same symptom, but I haven't read the new codes yet.

Quesstions:
1: When I installed the new turbo, I never "calibrated" the wastegate to 10 psi. Could that be related?
2: Why does the EGR duty cycle fluctuate from 85% when the engine is under light load to 5% when under heavy load? I thought setting the adaptation to 33768 would make it 0%?
3: How come at idle, my MAF actual is always over 400, which is greater than the 370 that the EGR reset instructions said I should see? Could I have an air leak?
I'm going to go back to the troubleshooting document, section 3, as soon as I get a chance. If you have any other ideas, please let me know. (I haven't peaked inside the intake manifold to see if it is clogged again.

Thanks,
Michael Townsend
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
Have you tested the egr? You have vcds, and since the egr runs on vacuum, you can see if it "cycles" when vcds tells it to.

If the N18 isn't working, you will find too much pressure for what the ecu expects, which is why it's telling you there's an egr problem. Note that at 5% cycle, the pressure increases faster than the maf, and that pressure is coming from somewhere.

The adjustment to the egr via vcds is just the legal minimum. To really eliminate it, you'd need to block it off and get a tune (to stop the error codes and to adjust for it's lack).
 

MikeB4

Well-known member
Joined
Apr 18, 2005
Location
Irvine, CA, USA
TDI
1997 Passat TDI Sedan, Candy White
Update

. . . Today I did another test run, and I got the same symptom, but I haven't read the new codes yet.
I checked my codes, and I am no longer getting the EGR error code, so I think tightening those clamps did the trick. I am still getting the 00550 Start of Injection Regulation code, though, which surprises me because my timing is slightly advanced -- right where I thought it was supposed to be:



And here are my MAF values at idle:



I'm stumped . . .
 

MikeB4

Well-known member
Joined
Apr 18, 2005
Location
Irvine, CA, USA
TDI
1997 Passat TDI Sedan, Candy White
Have you tested the egr? You have vcds, and since the egr runs on vacuum, you can see if it "cycles" when vcds tells it to.

. . .

The adjustment to the egr via vcds is just the legal minimum. To really eliminate it, you'd need to block it off and get a tune (to stop the error codes and to adjust for it's lack).
I put a vacuum on it, and then when I release the vacuum suddenly, I hear it slam shut. So, if it was stuck, I think I got it unstuck now. I'll let you know if the EGR code comes back. I hadn't thought about disabling the EGR -- I wouldn't want to make Al Gore angry.
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
It's not just being stuck, it's the N18 valve not doing it's job.

But if that code's gone, you might have fixed it.
 

Simkin

Member
Joined
Oct 16, 2014
Location
Norway
TDI
1994 Audi 80 1.9TDi 1Z
I'm joining the "low power" club on 1Z :p

1994 Audi 80 B4 with 1Z, it has low power and vibrates alot on idle, altough the idle is steady. Every now and then the idle get rough for a split second but otherwise its steady.

What i have done since i bought it is;

New timing belt with new sprocket on crank. No wear on either sprocket or crank, everything was fine.
New Harmonic Balancer.
Replaced all hoses to N75 and replaced the N75 with a brand new one.
Wastegate moves freely.
Checked and adjusted the pump timing to "slightly advanced"
Compression tested every cylinder - OK
EGR blanked off - Intake manifold is clean.

Before i changed the N75, my car would go into limp mode on 3000rpm going uphill, and the VCDS showed 00575 - Intage Manifold Pressure - Control Difference, but this code has not been present since i changed the N75.

On measuring block both turbo pressure and MAF show the correct values. Pressure stable on 1800mbar. Inj quantity also show 35 on full throttle, which is within spec.


Just dont know whats going on. My brother has a A6 with AHU which is basically the same engine as the 1Z, and that car is 70kg heavier than my 80, and still it pulls much better.

My car vibrates alot on full throttle on rpm from 2000 to 2500 and feels sluggish in lower rpm. Is also feels weak 3000 and above, and will hardly go past 4000rpm.
However, measuring block 13 has some weard readings. Im starting to think injectors or even pump? Previous owner had the pump replaced, and according to him the "new" pump had 165.000km on it.


 
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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
The cylinder to cylinder balance is concerning. Have the injectors ever been replaced ir balanced?

Tony
Sent from my e-diesel fleet
 

Simkin

Member
Joined
Oct 16, 2014
Location
Norway
TDI
1994 Audi 80 1.9TDi 1Z
The cylinder to cylinder balance is concerning. Have the injectors ever been replaced ir balanced?

Tony
Sent from my e-diesel fleet
Not that i know of. The car has 320.000km on it, but the pump has been replaced by the previous owner.

Will a bad/dirty pump also give these results on Block 13?
 
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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
Could be. The cylinder - cylinder balance is calculated by the ecu to tell the pump how much each cylinder needs to run as smooth as possible.

Tony
Sent from my e-diesel fleet
 
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