ALH TDI problems

B

black3d0ut12v

New member
Sorry to ask a seemingly repetitive question but I'm starting to run out of ideas here...sometimes i get limp mode, other times its just low power but not limp mode. Ive been working on this for almost a year now. first i looked at the vnt actuator. when i pulled it off and moved it by hand a bunch of rust came out so i replaced it. it ran better, then the turbo itself went. i replaced it with a vnt17, replaced the vacuum lines, cleaned the intake, and disconnected the vacuum line to the egr and capped it (surprisingly no check engine light). it ran awesome, then about 4 months later i had this low power/limp thing going on again. i unplugged the maf and went for a drive and it hauled a$$. so i replaced the maf. it still had low power. then i replaced the n75 valve, fuel filter, and cleaned out the fuel canister in the tank. no change. it doesn't spool til around 3000rpm and it doesn't make anywhere near the boost it did when i first put the vnt17 on and if i hold boost like on a hill or hard accel it goes into limp mode. it has never thrown a check engine light for anything since I've owned it and yes the bulb works. the car is a 99.5 jetta manual trans. im running a stg2 rocketchip and pp520 injectors, its straight piped so it doesnt have a clogged cat or anything. and ive read about all i can on limp mode fixes on just about every site out there and ive spent more money on limp mode stuff (if you count the new turbo) than i did on the whole car. any ideas would be appreciated because I'm out of them.
 
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It could be a problem with the IAT/MAP sensor. if they get any oil or junk on them they wont get a correct reading and the car will go into lip mode. Take it out and spray it off real good with brake cleaner then unhook the battery to reset the ecu and see what happens.
 
Cool ill give it a shot, thanks. I just put a new ccv filter on it and it still sucks oil like a pig. I gotta put a catch can on it. I really need vag-com too
 
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wbrown_2009 said:
It could be a problem with the IAT/MAP sensor. if they get any oil or junk on them they wont get a correct reading and the car will go into lip mode. Take it out and spray it off real good with brake cleaner then unhook the battery to reset the ecu and see what happens.
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Could possibly provide pics of where this is located?

Im having limp mode issues all the time now... I have no clue about the stuff on these cars... Mines an 02 Golf.

Mine seems to only do this on the hwy or when leaving a light..Like in between gear shifts.. . It always seems to do it during a low boost situation.. Like on flat ground while cruising on the hwy.. No throttle input really, just when maintaining speed... It'll limp and I'll have to re-key it to get it to go away..

Sometimes it'll drive fine for days and then all the sudden it'll do it three or four times in a day... It's getting to be a PITA!!


My lack of knowlege and lack of wanting to spend a ton of money leaves me wanting to check the easy stuff first..

Any ideas?
 
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if i had to do this whole thing over again, id start by either finding someone who has/knows how to use vag com. or getting the codes scanned and posting them here or on tdiclub and looking at what usually causes those codes but as far as the easy stuff, reach down between the motor and firewall on the passengers side and feel around for the vnt actuator. it looks exactly like a wastegate. see if the rod moves in and out freely. if it doesnt, remove the e clip and pull the rod off and try moving it. if it moves you most likely have soot and carbon built up in the vanes. to fix this remove the turbo, pull the exhaust housing off and clean the vanes out. also check for vacuum leaks. the rest of the stuff is kind of hard to test if you have an intermitten problem. its worth a shot taking wbrowns advice and looking at/cleaning the map sensor. this is located on the upper intercooler pipe. this is on the passengers side and goes from the intercooler to the intake manifold. its the little sensor plugged into the pipe. to test the mass air sensor you just unplug it and go for a drive but if your problem is intermitten you wont know if thats the problem or not i dont think? as far as n75 testing im not entirely sure because i just got so mad at the car i bought one for the hell of it. other than those just the basics like fuel filter, the intake manifold clogs up with soot and carbon and oil and that needs cleaned every so often, and i heard of some people having issues with the fuel canister in the tank clogging up. its located under the rear passengers side seat under a little metal cover. comes out lust like one in a truck.if you do this id reccomend not removing the canister and changing the fuel filter at the same time because i did and totally lost prime and it was a pita getting it started again since tdis dont have lift pumps so id reccomend changing the filter and priming it and letting it run for a while then shutting it down and cleaning the canister so you still have fuel in the filter to get it running.
 
Just after I bought my tdi I battled with it for a few weeks trying to figure out what was wrong and the previous owner said the check engine light had never come on before:bs:. No help there. It would go into limp mode and I would get a maf code and a needle lift sensor code. Replaced the maf (found out they sold me a gasser one and they are different) still got maf code but a different one. Other times it would have low power with no limp mode and it would get worse the further you drove it. Finally figured out the maf was wrong. Finally figured out that the wiring to the needle lift sensor was hacked up. Put all new vacuum lines on. Still got intermittent low power with no codes and no limp mode. Turned out to be the 109 relay. Some call it the 601 relay, depends on how you look at it. Dealer calls it 109. This relay gives power to computer. When it gets hot it melts the relay solder enough to "cold flow" and sometimes break contact. Mine was allowing current to pass, but not enough. Best I can figure is the computer was flickering on and off causing a stuttering feeling and would cause low power especially under load. A new relay from the dealer fixed this problem and I resoldered the old one and carry it as a spare. The relay is under the dash. No problems with this since then. Maybe something to try, its cheap and in my case caused abnormal symptoms for this problem.

Aaron
 
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SOOT4BRAINS said:
Just after I bought my tdi I battled with it for a few weeks trying to figure out what was wrong and the previous owner said the check engine light had never come on before:bs:. No help there. It would go into limp mode and I would get a maf code and a needle lift sensor code. Replaced the maf (found out they sold me a gasser one and they are different) still got maf code but a different one. Other times it would have low power with no limp mode and it would get worse the further you drove it. Finally figured out the maf was wrong. Finally figured out that the wiring to the needle lift sensor was hacked up. Put all new vacuum lines on. Still got intermittent low power with no codes and no limp mode. Turned out to be the 109 relay. Some call it the 601 relay, depends on how you look at it. Dealer calls it 109. This relay gives power to computer. When it gets hot it melts the relay solder enough to "cold flow" and sometimes break contact. Mine was allowing current to pass, but not enough. Best I can figure is the computer was flickering on and off causing a stuttering feeling and would cause low power especially under load. A new relay from the dealer fixed this problem and I resoldered the old one and carry it as a spare. The relay is under the dash. No problems with this since then. Maybe something to try, its cheap and in my case caused abnormal symptoms for this problem.

Aaron
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Excellent ! Thanks!

Under dash on the drivers side?
If you have a pic, that'd be great...

I need to get busy learning this crap...



OH!! btw... I've had my CEL on for the last 3-4 years though... Ever since I bought it, it's had a Coolant Temp Sensor that acted up but it still works and registers the correct temps most of the time... I've just never had it fixed since it never caused any issues... But with the light on, Billysgoat was not able to use his VAG-COM to tweek things after we did the timing belt, EGR delete stuff a couple years ago... So I guess I'm still giving up some power that could be had too...


One more thing... How do I know if it's "Limp" mode or just low power / intermiten like you guys talk about??

When mine goes to low power, it's like a switch was thrown and it will NOT come back until I re-Key it going down the road.... PITA!!!:bang
 
oldestof11 said:
IIRC, there are 2 temps sensors.

I know my 1.6L IDI did.
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Not sure on my 1.9L but my buddy that works at the local VW dealer that does my work for me has only mentioned one...

Soon as I get my truck back up and running, I'm going to let him have it and see if we can get this thing fixed up...
 
Got my codes pulled today:

My cars had the EGR deleted and the little actuator the closes the flapper when you shut it off was broken at the vacum line.. So it was removed.. I never replaced it..

Keep this in mind when looking at my code..

Oh!! And the little wastegate actuator arm was kinda hard to pull down and knly moved about 1/4 inch +\-... Is this correct... I tried to shoot a short vid while holding my phone and a light in my mouth... lol
i'll post it later..


Codes:

P0674 - Cyl. 4 glow plug circuit
P0402 - EGR circuit flow Excessive
P0245 - Turbo wastegate solenoid A Low
P0118 - coolant temp sensor ( been this way since I git it 35k miles ago)
P1538 - Fuel cut off valve Open Circuit


So from this, can anyone tell me where to start first??
I'm thinking the turbo or wastegate or vacum line to it.. But the line looked fine.
 
Heres the vid of me moving the wastegate arm..

Sorry for the bad vid.. But hopefully you can see how little it moves..




[ame="http://www.youtube.com/watch?v=NOiw1FsDrJs"]http://www.youtube.com/watch?v=NOiw1FsDrJs[/ame]
 
P0245 I believe is either the n75 valve or the vnt actuator. P1538 is an open circuit to the fuel cutoff on the I.p. its the single wire around the injector lines that needs power and I think it may be controlled by the 109 relay? Also I've read that the relays themselves aren't always the problem it could be the ground it uses. Hope this helps
 
Big Swole said:
Excellent ! Thanks!

Under dash on the drivers side?
If you have a pic, that'd be great...

I need to get busy learning this crap...



OH!! btw... I've had my CEL on for the last 3-4 years though... Ever since I bought it, it's had a Coolant Temp Sensor that acted up but it still works and registers the correct temps most of the time... I've just never had it fixed since it never caused any issues... But with the light on, Billysgoat was not able to use his VAG-COM to tweek things after we did the timing belt, EGR delete stuff a couple years ago... So I guess I'm still giving up some power that could be had too...


One more thing... How do I know if it's "Limp" mode or just low power / intermiten like you guys talk about??

When mine goes to low power, it's like a switch was thrown and it will NOT come back until I re-Key it going down the road.... PITA!!!:bang
Click to expand...

I don't have a picture of it but it is marked "109" or "601" on the relay and is the only one under there. You have to pull the panel off under the steering column to get at it. Also true limp mode is accompanied by a CEL. Which you would not see since your light is on all the time anyways. Turning the car off and restarting will clear the limp mode until the car experiences the condition again. I would say your actuator is not moving enough. May be time to pull the turbo and clean it up. They get pretty filthy. If the actuator control valve was bad (which it may be) the rod would still move the full amount by hand.
 
Coolant temp sensor code also deals with fueling on these cars. If reading the wrong temp or just bugging out it wont supply "vw correct fueling". You should have updated green sensor in the back of the side water neck. its a 4 wire. Glow plug cyl 4, replace all for glow plugs with Bosch glow plugs, average price around 15 a piece. also call dealer and get your glow plug harness and splice it in place. you either have a 2 wire or 4 wire. check which you have before you order. Also check 409 relay under dash. Should have updated one. last part number is 383 C. Also check and make sure you vacuum pump is supplying over 15 inchs of vacuum on a gauge, if it isnt your vacuum pump is getting weak, this supplys all vacuum for your N75 valve (runs waste gate on turbo) shut down solenoid and other various solenoids on these.

Vag com can be your best friend with these cars. Number one thing make sure pump timing is within spec of vw. How to get into to check this is 01 engine management, 04 basic settings, 00 hit enter on keyboard. now you will have a field of 10 blocks. you have to read field 2 and field 9. Field 2 should read 53 at min and max of 63. i set them at 60 to 63 run the best and wont melt piston. field 9 is fuel temp, not a big concern.

With limp issues. 2.0l AEG maf sensor works best for these. is i remember correctly its 06a 906 461. Ill check tomorrow when i get to shop to double check. yes veins in turbo get sooted up just like 6.0L powerjoke turbos. Another reason they lose power is check to make sure your seals on the fuel filter on return line arent rolled or missing or broken. Also make sure theres no leaks from fuel filter to tank if sucks any air lose of power. have a pin hole in one right at body behind pass wheel one time. Another reason can be fuel temp sensor in the injection pump. have to pull pump head off and replace sensor and reinstall and reset check engine light. In very few cases it was the ECU itself. if newer than 00.5 and have immbolizer you'll have to get that programmed by dealer. If have any other questions let me know. Ill answer them best i can. Oh run a scope if you can into the corner of the intake sometimes hidden soot build up that restricts air flow big time.
 
PDW Power said:
Coolant temp sensor code also deals with fueling on these cars. If reading the wrong temp or just bugging out it wont supply "vw correct fueling". You should have updated green sensor in the back of the side water neck. its a 4 wire. Glow plug cyl 4, replace all for glow plugs with Bosch glow plugs, average price around 15 a piece. also call dealer and get your glow plug harness and splice it in place. you either have a 2 wire or 4 wire. check which you have before you order. Also check 409 relay under dash. Should have updated one. last part number is 383 C. Also check and make sure you vacuum pump is supplying over 15 inchs of vacuum on a gauge, if it isnt your vacuum pump is getting weak, this supplys all vacuum for your N75 valve (runs waste gate on turbo) shut down solenoid and other various solenoids on these.

Vag com can be your best friend with these cars. Number one thing make sure pump timing is within spec of vw. How to get into to check this is 01 engine management, 04 basic settings, 00 hit enter on keyboard. now you will have a field of 10 blocks. you have to read field 2 and field 9. Field 2 should read 53 at min and max of 63. i set them at 60 to 63 run the best and wont melt piston. field 9 is fuel temp, not a big concern.

With limp issues. 2.0l AEG maf sensor works best for these. is i remember correctly its 06a 906 461. Ill check tomorrow when i get to shop to double check. yes veins in turbo get sooted up just like 6.0L powerjoke turbos. Another reason they lose power is check to make sure your seals on the fuel filter on return line arent rolled or missing or broken. Also make sure theres no leaks from fuel filter to tank if sucks any air lose of power. have a pin hole in one right at body behind pass wheel one time. Another reason can be fuel temp sensor in the injection pump. have to pull pump head off and replace sensor and reinstall and reset check engine light. In very few cases it was the ECU itself. if newer than 00.5 and have immbolizer you'll have to get that programmed by dealer. If have any other questions let me know. Ill answer them best i can. Oh run a scope if you can into the corner of the intake sometimes hidden soot build up that restricts air flow big time.
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Wow! Lots of info! Thank you!


Sounds like it might be worth a trip to PA to have you lay your hands on it for me! lol
Call me lazy, I just haven't the patience to learn yet another hot rod..lol
I just want it to run and not limp.

Thanks again. I'll get with my guy at VW and check on some of this stuff as soon as I get my truck back on the road. Just can't have both vehicles down at same time.
 
Not to revive a dead thread but in case anyone is curious, my low power mode actually wasn't low power mode at all. My EGR pipe cracked and caused an exhaust leak and the turbo wouldn't spool. I guess it was cracked all along but I didn't realize it because it was such a small leak that it wasn't annoyingly loud but the other day my buddy drove it and he said "I smell exhaust, you might have a leak" and before the words rolled off of his tongue it must have cracked the rest of the way and the car got ridiculously loud so today we made a block-off plate and I already had an EGR cooler delete kit from diesel geek that I never got around to installing. The car is back to rolling the tires off in second gear now like it used to. now my only issue is trying to find some axles that will live with the torque.
 
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