vw tdi poor acceleration

[howe719]

Hello i am new to this site but not to diesel motors. I have a good bit of experience with the dodge cummins motors but not so much with these TDIs. i just bought a 1997 vw passat with the tdi with 150000 on it and i cant really here the turbo spooling up and i dont have good power on hills or off the line. Could my turbo be bad since i cant hear it or could it be the EGR valve getting build up. I need imput so i can get this fix because i know its cutting into my fuel miliage. Could someone please direct me what to do and how i go about cleaning the EGR since i never have on these TDIs before. thanks

 

[howe719]

Can anyone tell me what might be causing the poor acceleration? also i am not hearing the turbo is there a safety switch that shuts it down need its not working right? thanks

 

[Bopper]

I am having same problem.. Start by looking in the TDI 101 section or search "power loss", tons of possibilities. When there is a problem it is always good to let us know Year, Make, Model, etc. I added mine to my signature to always have that part covered.

 

[bayshorecs]

Sounds like "Limp mode". I bet you have a boost hose with a small hole in it. I would start by replacing them.

Very common problem on the A3/B4 platform.

 

[Herm TDI]

I have som hope for you guys...a leaking EGR valve.
To verifi this problem you'll need to temperoraly install a blank-off plate where the EGR inlet pipe attaches to the intake manifold.

Since the A-3 / B-4 EGr valve is an integral part of the intake manifold there is no simple way to replace just the valve.

Anyway install a blank-off plate and then test drive the car.
If power / performance is restored you found the problem

The problem is the EGR valve face has become corroded and the internal spring is old (weak) which results a leaking EGR valve.

 

[Bopper]

I have a $20. scan tool called a memo-scan it is telling me that I have Fuel Shut Off Valve problem. I get a engine REV on startup and low power as only symptoms, NO CEL. I looked up the shut off sensor in the archives here, could possibly be my o-ring on the sensor. How do you get the sensor out without taking all the fuel injector lines and various other stuff apart.

 

[howe719]

so i just need to install a blank piece of metal between the egr valve and the manifold and if i get my power back i need to replace the EGR valve correct??

What about the turbo lines. do they cost much and if i get under the car will i be able to see them attached to the turbo??

What is the chance that my turbo is shoot since i cant hear it spool up.
What is limp mood and how do i fix it..


This weekend i am going to have the egr valve and manifold off for cleaning because i just bought the car and dont know if or when it has been done.. this could be causing the problem too.

 

[dieseldorf]

This just happened to somebody else I chatted with (A3 cars) and he too found leaking EGR valves which killed the cars' performance.

 

[bayshorecs]

I would think the EGR leak problem is rare though. Go with the 1,000 member strong problems first. Plugged intake/EGR and boost hoses for an A3.

You should "hear" an EGR leak.

 

[kooyajerms]

Herm when you say an EGR leak. You are not speaking of a a leaking EGR pot right? Or is that what you are referring to?
-An EGR that is leaking, is shown by a pot that leaks oil down the weep hole and also does not hold vacuum when the nipple is attached to the mityvac? Is this the performance stealing type of egr? Does it effect anything else? blowby, consumption etc?

 

[Herm TDI]

Egr

so i just need to install a blank piece of metal between the egr valve and the manifold and if i get my power back i need to replace the EGR valve correct??

What about the turbo lines. do they cost much and if i get under the car will i be able to see them attached to the turbo??

What is the chance that my turbo is shoot since i cant hear it spool up.
What is limp mood and how do i fix it..


This weekend i am going to have the egr valve and manifold off for cleaning because i just bought the car and dont know if or when it has been done.. this could be causing the problem too.

We're talking about the A-3 AHU engine. This EGR valve is an integral part of the intake manifold. If you find that this blank-off plate solves your problem then you have two options.
1. Replace the EGR / intake manifold
2. Leave the blank off plate in place and then get your ECU chipped and have the EGR map modified (by your chipper).

 

[Herm TDI]

EGR diaphram

Herm when you say an EGR leak. You are not speaking of a a leaking EGR pot right? Or is that what you are referring to?
-An EGR that is leaking, is shown by a pot that leaks oil down the weep hole and also does not hold vacuum when the nipple is attached to the mityvac? Is this the performance stealing type of egr? Does it effect anything else? blowby, consumption etc?

What you are discribing is the famous EGR oil leak. This oil leak is NOT what I'm talking about.

What I'm talking about is an internal EGR leak letting the exhaust gass flow almost constantly which causes poor over all performance, poor acceleration.

In your situation try the blank-off plate anyway. Simply unbolt the EGR flex pipe to the EGR valve and insert the blank-off plate between the EGR valve and flex-pipe

 

[howe719]

ok once i do the blank plate and my power is restored then i know its the EGR valve correct? and i need to buy a new one and replace it?... thats it.


What if i still have poor power.. I am replacing all the turbo hoses this weekend to and if i still have no power what else could it be....bad turbo??
let me know thank you all for all your help..

 

[bayshorecs]

start with the simple stuff first.

hoses
intake
fuel filter
N75
MAF

before you get too excited.

 

[Herm TDI]

I agree

start with the simple stuff first.

hoses
intake
fuel filter
N75
MAF

before you get too excited.

I agree with you to keep things simple ...a simple blank-off plate is quick ,easy and will tell you alot about the operation of your EGR system.

 

[bayshorecs]

I agree the block-off plate is simple, but how many cars has that really happened to that have been posted about?

Honestly, this is the first time I have heard of the EGR issue on the A3 causing bad performance. And, that would have been one of the last things I checked unless it have obvious damage to it.

 

[Herm TDI]

As these manifolds/ EGR valves are getting older(12 yrs on the B-4) they are failing more frequently in this manner. The springs are getting weaker and the valve seats corroded deeper making a secure seal unlikely

 

[kooyajerms]

Exactly what Bayshores said. It was just new to me that an EGR would cause the poor acceleration that is why I asked. Good to know Herm. Thanks.

 

[Bopper]

Well it seems my car has possibly fixed itself. I did the "Cage Mod" (Dielectric Grease) on all the connectors I could easily reach. I never was able to get the Fuel shut off valve out in order to check that o-ring. After the Cage Mod I had one High rev start and then the power returned. Done about 5 normal starts in a row with normal power. I find it hard to believe that the cage mod fixed it or maybe it did.

 

[bikeprof]

bayshorerecs:
"start with the simple stuff first.

hoses
intake
fuel filter
N75
MAF

before you get too excited."

I second this note...

Check the hoses, the N75 and the intercooler hose that is probably with oil in it(so use a container to catch the oil...) FIRST.

If you have a tunnel or a high barrier, drive there and accelerate while you are close to the cement barrier, this will echo the sound of your engine back to you.
Listen for the :
turbo
or blowing air/whistle that has a low sound.

If it is that, it is the turbo having a leak, or then, the hose(s) that are split and need replacement.

My .02cents...

 

[howe719]

OK here is what was done. I replaced ALL hoses. took off Manifold intake/EGR and clean that all out.. SHE WAS CAKED SHUT check pictures out... Also i pulled the exhaust manifold and the Turbo out to check it all. I even tore the turbo down to make sure it was clean and fins where moving freely.

It helped alittle bit but i still cant hear the spooling of the turbo and i get some boost but not like i should... when i was pulling a hill in 5th the speed starts to fall and i have to down shift and with it to the floor there was a time or two when the power just stop got soft like and i had to let off of it and down shift.

What do you guys think is wrong... Could the turbo be shoot

I didnt replace the N75 should this be done??
I dont think its the MAF because when i unhook that the car still drives the same...

All hoses are new and all pipes are cleaned out new filters on everything.


Any help thanks alot all you guys are awesome on here and really know your stuff. here is a link to some pictures of the car and of the cleaning i did..

Also i just bought this car from a small dealer with 153000 on it so i am just trying to get it to run right because my Dodge Cummins eats the fuel on long trips. thanks

http://s191.photobucket.com/albums/z5/howe719/VW/

 

[Foiled]

I had low power issues that slowly got worse. It turns out the CAT was totally plugged. The CAT was gutted and now all power is back. I was thinking it was the IP or turbo or something else - but it was the CAT so get it checked out by an exhaust shop that can check back pressure to see if the CAT is the problem.

I forgot to add.... yes, replace the N75 valve because that could very well be your problem. When I replaced mine a couple years ago, it made a huge difference.

Good luck!

Kurt

 

[bayshorecs]

Didn't think about the CAT. Good point. With that kind of build up, the exhaust side is in question if everything else checks out good.

Time for a straight pipe!

 

[bayshorecs]

Oh, and if you did not replaced that intake to turbo pipe that is completely trashed, you will always be in limp mode too. The intake system will not be able to hold pressure.

 

[howe719]

I fixed that with some 2in silicon tube and put clamps on it. Its all Air and psi tight i checked it. actually think its better sealed then the factory pipe... I will check cat out this weekend and put the new N75 on it.. thanks alot guys..

 

[bayshorecs]

Unplugging the MAF does not work on the A3/B4 platform. Only the A4/B5+ cars. Only way to really test it for you would be with a vag-com. Might consider getting a replacement MAF too if you have no way to check it.

But, that is just throwing parts at it without knowing if they are good or not so it is up to you.

 

[jkwalker]

my 2 cents...

plugged cat... for sure cavitate the core out... will see good improvement in power but still not all you expect.

With those miles replace the nozzles.... bingo

bargin nozzles = http://www.dieselvw.com/
best nozzles http://kermatdi.com

 

[bayshorecs]

Might sound like a stupid question....but you did check the air filter, snow screen and fuel filter right?

 

[howe719]

Alright here is the outcome. I have cleaned the intake manifold, all new hoses even the one INSIDE the ECU. New N75. Snow screen cleaned, air filter cleaned and a new fuel filter which i did first thing. I also Deleted the CAT. I pulled the turbo off while i had the intake manifold off just to check it out and everything seemed ok. Now i can hear the turbo spooling up and i got boost. ****but i didnt have very good boost UNTIL I CLEARED THE CODES OUT***** after i did all the work i then found a buddy that had a scanner and we hooked it up.. I had 3 codes. 1. glow plug circit "A" 2. Manufactor spec error. and 3. the Little hose inside the ECU. Cleared them and i just took it on a 170 mile trip and the boost seems to be there. Seems to be running ok i guess with the codes cleared it helped and with me doing everything to it before clearing the codes.

The only thing i can notice is if i go through the gears fast there is boost from the start of acceleration in every gear. If i stay in a gear for little bit and then shift (only in 3rd 4 th and 5th) it will take about 3 seconds or so to kick in I have to push the padel all the way to the floor then it kicks in so cruse control cant keep me at 70mph unless i push the pedel to the floor so the boost kicks in. so there is a delay caused by something but the boost does work. 1st and 2nd will work all the time 3rd 4th and 5th have a delay if i drive in the gears for alittle bit and then shift..

you think of anything.. if not its running good enough for me 18gal fuel tank and there is 3 left in the tank and i just hit 750 miles.. thats good enough for me 50mpg. thanks for all your help everyone but if anyone has any last thoughts please share.

thanks alex

 

[howe719]

just wanted to ask this questions to see if anyone has any ideas. Like i stated in my last post back in september i got my boost and the car has been running well. Here is my question.

I am pulling a hill with the cruise locked on at 75mph the car is doing fine but then the turbo goes into lump mode and the speed starts to drop and all i have to do is push the accelerator in some and then the turbo will kick back in and get me back up to 75mph. then it will do it again in about 10 seconds.

The turbo only holds for about 10 seconds then i have to push the accelerator.
This does not happen on flat roads only when pulling a hill when the turbo has a load against it.


Any ideas when would cause this. it has always did this but i am just wondering if anyone knows what is causing it. thanks