Diagnosing and Fixing Limp mode for A4 1.9TDI [low power troubleshooting]

bmccrea

Veteran Member
Joined
Jan 5, 2008
Location
Winnipeg
TDI
'13 Golf TDI Wolfsburg, '10 Touareg TDI
Me again.

Still investigating.
Finally got under the car to take a look at the turbo and actuator and i have a few questions.

I tried moving the lever that the actuator connects to on the turbo. It was difficult to move, but moved thru the entire length that it should (according to the video clip on drivebiwire's vnt repair procedure). I noticed when pulling the lever it would spring back to its original position. Sometimes it would stick when going back and i'd have to give it a hand for it to go back to its original position.

My questions are:

- is this stiff movement normal for the vnt mechanism when the actuator is hooked up (moved full length, just showed resistance, like it was spring loaded)?

- being sticky as described above, it is is either the vanes are clogged up and not moving freely, or the actuator is catching or not working properly... is there a simple way to disconnect the actuator arm from the lever on the turbo? (i searched for a bit of direction on this and couldn't find much) This would let me flip the lever on the turbo and see if anything is catching in the turbo (clogged vanes). If not, i would assume my actuator is bad.

I don't have a mityvac or equivalent to test the actuator (yet).

Any feedback is greatly appreciated!
 

rosher

Well-known member
Joined
Feb 23, 2007
Location
Salinas, CA
TDI
'99 Golf, '83 Caddy
I don't think so. You'll notice in dbw's video how easily the vanes move after they've been cleaned. When I took my turbo out there was some carbon build up but the main problem was rust on the inside of the housing that prevented the plate from rotating freely.

Once cleaned (as per drivebiwire's and speedster's instructions: http://pics.tdiclub.com/data/517/8078TurboRemovalHOWTO.pdf ) it was remarkable how easily the vanes rotated. So smoothly that I thought I'd put the turbo back together incorrectly (in retrospect, I think if you mate the housing back together incorrectly, it will not move at all - someone, please correct me if I'm wrong). Like butter. Good luck.
 

bmccrea

Veteran Member
Joined
Jan 5, 2008
Location
Winnipeg
TDI
'13 Golf TDI Wolfsburg, '10 Touareg TDI
Yeah, i noticed they flip back and forth easy.
Does the actuator provide any resistance to moving the lever when its hooked up?
Is it easy to disconnect ?
 

rosher

Well-known member
Joined
Feb 23, 2007
Location
Salinas, CA
TDI
'99 Golf, '83 Caddy
There's a bit of resistance from the diphragm but I don't think what you describe. I'm trying to recall taking it off - it's pretty tight in there. Take a look at speedster's photo, p. 6. There's an 'e' clip that you can remove if you're careful to disengage the actuator arm from the VNT.
 

bmccrea

Veteran Member
Joined
Jan 5, 2008
Location
Winnipeg
TDI
'13 Golf TDI Wolfsburg, '10 Touareg TDI
I don't see the pic on pg 6 you're referring to.
I'll keep searching, but i think that is the next step (remove the actuator arm from the vnt lever) in order to see if there is resistance in the turbo, or if the actuator itself is whats causing the resistance.

It squeaks a fair bit when moving it.

I'll try to post a video i took of me moving the lever later. Its still on the camera at home.
 

churp

Member
Joined
Mar 16, 2008
Location
essex, england
TDI
2004 audi a4 1.9 130bhp
whats happens if you have sticky vanes and you disconnect the vac pipe to the actuator that adjusts the vanes. will it act as if a fixed vane turbo??
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
Disconnect the vac pipe and the vacuum can's open the turbo up. Depends on where it's sticky - you just might have no turbo function, or always turbo function, or always some turbo function. You will get a CEL and limp mode eventually if you try to use the power.
 

P3Mike

Member
Joined
May 18, 2008
Location
Waldorf, MD
TDI
2004 Jetta TDI (BEW)
Just a generic thought since we are all talking about diesels. It's possible to get bad diesel if you go to a gas station that doesn't sell much diesel. This diesel will normally accumulate some water, so if you put in in your car.......water will make its way to the fuel filter and possibly cause limp mode. If the ignition resets it, not likely water in your fuel. If the ignition does reset it, then take a philips head screwdriver and loosen the mount around the fuel filter. Pick it up and unscrew the plug on the bottom (should be able to do this by hand). If possible, drain it into a clear container and see if there is a "layer", water will be at the bottom. Try it, if it works...great! If not, well, see the above troubleshooting steps.
 

BudsBug

Veteran Member
Joined
Dec 9, 2005
Location
Trenton NJ
TDI
2000 New Beetle (Buglet)
Great writeup. I had a big problem with the 2 exhaust Flex pipes attached to the EGR cooler 1 had broken completely apart the other had a crack about half way through one of the accordian folds I inserted 3/4 copper pipe with muffler sealant to start with. I also wrapped the repair with Tigertape and 2 hose clamps on the cracked one. The broken one got another piece of 3/4 copper tubing, the same tiger tape, followed by a 2x around peice of stainless steel and 4 hose clamps. I now can get 31+ on the MAP. I had black smoke when I got on it and went into limp very often after it got warm I would loose it on the highway in 5 minutes :-(

Now it is fun again
This also was filling up the air filter quickly with black soot. just thought I would add to the post with my Negative devation issues.
 

rpony

Active member
Joined
Sep 17, 2008
Location
Regina
TDI
2002 Jetta GLS TDI
Problems with 2002 Jetta GLS TDI

Hey Everyone

I'm new here.
I have a problem with power and throwing code P0234 always at the same time in the same place (80kms/h and 3000rpm's)
Code generally doesn't come on unless I'm on the power.

Here are my symptoms
-Car seems to run fine and fast between 0-80kms/hour with MAF hooked up.
-When it hit 80kms hour and 3000rpm's the car seems to go nowhere and holds steady until after I let off the gas. At which point it seems to hit high gear (by the way this is automatic) but everything upward of that seems to go fairly slow. As far as passing another car I better make sure I got lots of room. Exceleration is poor. When I hold it out at 3000rpm's and 80kms I always throw trouble code P0234.

2002 Jetta GLS TDI-144000kms (to my knowledge the MAF has never been changed.

Here's what else I've done so far.
Checked vaccum lines and replaced some that appears to be damaged.
(I know before tells me to change them all that is where I'm heading next but wanted to know if there was any point.

Swithced N74 valve.

Cleaned snow screen-totally plugged probably a quarter of a sandwich ziplock bag.

Unplugged MAF-(things seem to remain the same as far as the hold out on the 80kms/3000rpm's. Power seems more or less the same.

I have a new MAF on order-does anyone really think it's this?


Your help is appreciated.

Thanks
 

rpony

Active member
Joined
Sep 17, 2008
Location
Regina
TDI
2002 Jetta GLS TDI
Sorry

I didn't mean to highjack anyone's thread
I've moved my posting to a new thread under TDI 101
Sorry
 

lukejedi

Active member
Joined
Sep 30, 2008
Location
Katonah, NY 10536
TDI
'06 Jeep Liberty CRD, '09 Sportwagen
quoting from first post on this thread:
"Most problems with the turbos are simple leaks in the vacuum lines. It is hard to see on the cloth covered stock hoses and if your car is past warranty it is best to simply replace all the lines. Here is a link of what you need… http://forums.tdiclub.com/showpost.php?p=1566427&postcount=30

When you do it, be very systematic. Pull off one hose, cut new one to length and replace that one hose and so on."

Which of the vacuum tubing is to be replaced with the 4mm inside diameter tubing and which is to be replaced with the 3mm inside diameter tubing?


thanks grizzly. this is a great post! with this board, i'm getting a little closer to knowing my car every day.:D
 

windigo

Active member
Joined
Feb 6, 2006
Location
near Indy
TDI
none but looking
Hi,
I have replaced all vac lines.... still low boost and limp home often..
Did the mighty vac test... 27inHG.. engine running... ok
ran vac line from brake nipple to n75 vac... ran same 5psi... here is the
kicker... pluged the line from the air filter and got 23psi on the boost gage.
Ran like a rocket...
Will it hurt it to run like this?
I am running a K&N filter charger cone style element... the vac line from
the old air filter box is stuck in to the flex tube just past the MAF... The hole in the flex pipe has gotten a little big and I feel it does not fit well...
I replace the vac lines to the brake nipple and it ran really bad.... unpluged the air filter box vac line put it back into the flex pipe and it was better but not right yet...
 

JimNM

Active member
Joined
Mar 21, 2007
Location
Las Cruces, NM
TDI
98 NB
CG - thanks for taking the time to write this uip. I'm one of the many with limp mode and I will be referring to your tutorial until I get it fixed.

Thank you *:D*
JimNM
 

SnowCub

Veteran Member
Joined
Jun 6, 2005
Location
Bedford, MA
TDI
2013 S350 BlueTec
Been getting limp mode and my boost gauge read 28 psi yesterday, yikes! I replaced all the vacuum hoses with silicon McMaster hoses a couple of months ago so it should not have leaks. Tried replacing the MAF last night to no effect.

Scan with Vag-Com shows
17965 - Charge Pressure Control: Positive Deviation
P1557 - 35 -10 - - - Intermittent

Canadian_Grizzly said:
Even if the N75 is good, it it doesn't have solid vacuum getting to it (top hose 'vac' ) it will not send vacuum properly out the 'out' port just below the vac port. It is also important that the vent port is clear. It's on the same side of the valve as the connector.

2 test options posted by Anut:

1. disconnect the 'vac' hose. Connect a mighty vac to the hose. Start the car. You should get >25 inHg vacuum.

Got the vacuum, yay!

Canadian_Grizzly said:
Faulty N75 solenoid

You can also check that the N75 is working and moving the actuator on the turbo.... It should cycle and move properly. As in diagnosing many things on these cars a vagcom comes in very handy as you can ask the computer to cycle the N75 while you watch the actuator. With the engine running, in VAG-COM go to Group 011. Down in the lower left of that VAG-COM page is "basic settings." Click this on.
My Actuator arm seems to be moving, but I'm not sure if it's 3/4". After watching it for a few minutes it stopped moving! Is that supposed to happen? I shut off the engine, checked the vag-com, restarted the engine and went back to group 11 basic settings and watched the actuator arm move for the next few minutes with no stopping.

Canadian_Grizzly said:
Faulty Actuator
If this doesn’t solve then you either have a faulty actuator or stuck vanes in the turbo. If you can get your hands on a vacuum pump attach it to the actuator and see if it holds vacuum.
It doesn't hold any vacuum. But I'm confused, why would the actuator arm work when hooked up to N75 if it can't hold vacuum with the mighty vac. What's the difference?

I took the mighty vac and attached it to N75 and <bam> right up to 25inHg. Attached it to the hose going to actuator and still couldn't hold any vacuum :confused:
 

windigo

Active member
Joined
Feb 6, 2006
Location
near Indy
TDI
none but looking
I hit 28psi a couple of times yesterday... not sure if it could go higher as I backed off when I saw it... I have been driving by the boost gage and shifting at 20psi... If I am reading the Vag right about 23psi is the upper limit.. May be bad to drive it continously in Test mode...

Decided to replace the N75 and EGR solenoids... priced both for a 99 Bug...
$420.... Ask how much for a 2003 jetta... $210.... Had the same problem
with my Miata when it turned 10years old they doubled the price of parts...
The 03 is the same engine... part looks the same... I am going to try it...
Also I am on my 3rd check valve...
jeff near Indy
windigo
03 jetta tdi 102k mi
99 bug tdi 219K mi
83 Kubota B7100 diesel
 

Stevie D.

Member
Joined
Mar 20, 2007
Location
New Albany, IN
TDI
2005 Golf TDI and 2002 Jetta TDI
Wanted to know if when you unplug the MAF and it performs the same or better does that mean better, but it still shows the same symptoms ie still goes limp @ high rpm's? I disconnected my MAF to see and it runs about the same, I want to say it even runs better but it still hesitates in 4th right around 3000RPM's...I'm guessing that stutter/slugish BS is what we're calling limp.

If you unplug that connector should the symptoms disappear alltogether and then you know you need a new MAF?

Sorry if the answer was already stated in this thread and I've overlooked it. I'm just a bit impatient at this point. Been trying to sort out this "Limp Mode" problem w/ my car for over a month.
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
Sluggish isn't "limp mode".

Limp mode is when you're accelerating, and you no longer have power. At any rpm since the ecu saw something it didn't like, so it cuts fueling to keep you from grenading the turbo.

If it's better without the MAF, the problem is likely the MAF.

You may also have other problems, such as air restriction or fuel restriction, bit if better with no MAF, MAF is not good.
 

mk4gasm

Veteran Member
Joined
Dec 21, 2007
Location
VA BCH, VA
TDI
01 Golf
Canadian_Grizzly said:
If it doesn’t seem to work then swap the EGR solenoid (same looking part just to the left of the N75 and with black top not grey) with the N75 and try again.
Are these essentially the same piece?

Will I be able to turn my engine on and drive with the EGR solenoid in its place?

....Can I save $60 and just use the EGR solednoid? :D:p
 

Stevie D.

Member
Joined
Mar 20, 2007
Location
New Albany, IN
TDI
2005 Golf TDI and 2002 Jetta TDI
I unplugged the MAF and it runs just the same or maybe a touch better. Here's my question. Should the CEL be on since I just disabled the MAF? I got no CEL. Is that another symptom of a crapped out MAF or does that present another possible issue...like a toasted ECU? I really have no idea and I am only relaying the thoughts of other friends that work on gassers, so any info would really rock.

Also does anyone know the part number for a proper MAF or a link to a decent priced one that will work for a 03 Golf 1.9? I've found them all over the net anywhere from 69.99-139.00.

Thanks as always and happy holidays!!
 

GTTDI

New member
Joined
Jan 5, 2009
Location
Stroud uk
TDI
Golf mkIV GTTDI
Power loss after 40 min

Great thread i have a golf iv 1.9 pd engine 115 bhp with a power loss problem only after 40 min of reasonably high speed/load (80+) no matter how you drive, even booting it proper will not trigger shutdown initially.

It will reset by cycling the ignition but the problem comes back much sooner and then will when triggered again until it will not reset. It also appears that the vents deliver hotter air as the temp in the car suddenly feels much hotter at the point of turbo shutdown! the car has a/c. this is at freezing outside temperatures

I have read loads and tried some things, new vacum hose to actuator which appears to be moving fine and not leak, i tried pressurising it with a bike pump and found it held pressure and couldnt detect leaks. new air filter and maf as i initially tried cleaning it which only resulted in immediate consistently reduced power so i guess i killed it, back to great power until shutdown.

Could it be a clogged intercooler? appears fine externally, egr appears to cycle fine, took airbox off and pipe to clean, doent seem to have any snowscreen, would always reduce power not just after a while anyway. Is due a service/oil change but this cant cause turbo shutdown can it?
Anything i am missing to try before i have to pay to have the codes read?

Dont think its related but have had slight shudder under braking inconsistently but appears better at the moment, no probs with braking power/stiffness though.

did have to drive on some flooded roads a while ago, no disloged pipes as far as i could see, just cant figure the heat/delay factor out.

thanks for all the hard work here, the willingness to help others here helps to restore my faith in humanity
 

highender

Veteran Member
Joined
Oct 8, 2006
Location
Northern California
TDI
2012 Jetta TDI
I think most cars, while they can benefit from an intercooler cleaning, would not have a clogged intercooler. Sounds like you are driving it correctly, at high speeds when possible.

If you checked snow screen, air filter, MAF ( maybe you need to change it), then check and make sure turbo actuator is working. How about intake manifold ? When was it last cleaned ? Also, check fuel system.
 

highender

Veteran Member
Joined
Oct 8, 2006
Location
Northern California
TDI
2012 Jetta TDI
One other limp mode rreason::


If you are carrying a heavy load, or towing a trailer, and go up a steep hill in 5th gear, then car may go into limp mode to protect engine.

Simple way to fix this is to keep the car in lower gears...and never use the 5th gear if you are towing or carrying heavy loads. USe only up to 4th gear.


This happened to me when towing a U Haul with tons of stuff.
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
GTTDI said:
It will reset by cycling the ignition but the problem comes back much sooner and then will when triggered again until it will not reset.

When did you last change your fuel filter?
 

moparmatty

Active member
Joined
Oct 14, 2002
Location
Priceville, Ontario, Canada
TDI
2002 Black TDI Jetta
ERICandMilousTDI said:
Here is something interesting that might pop some lights on:
I just bought a 99 Jetta TDI with 260K on it.
Took it down to Florida from Canada: no problems at all.
On the way back all good UNTIL I hit New York State and Snow!!!
50 miles from the border: lack of power.
Stopped and had a coffee: got back in: All good until 45 minutes away from Ottawa: same thing.
I thought my Turbo was gone but after letting the car rest overnight: All good.
This issue only happens when there is snow!
Any of you guys realized this also?

Thanks

That problem sounds to me like the snow screen or more than likely the air filter are getting clogged with snow/snow dust. I have this roblem from time to time when driving down unplowed roads early in the morning and pushing snow over the bumper. Snow gets sucked right into the airfilter housing, and blocks off all the air flow, resulting in no power until I clear out the snow.
 
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