Surging problems with early 1999 TDI HELP!!

[Curious Chris]

Hmmm, normal for the car. Did you tell him that you do not start out each day with a plastic bag over your head for 3 minutes?

While I have 99 Golf IV, engine code ALH (you can find out which engine you have by opening the hood, remove the top engine cover(if it has one) then on the left side of the engine there is a black cover that has a label on it), my car has been doing a related thing: hold the pedal steady and it meanders up and down in speed.

What causes mine? I recently purchased Uwe Ross's VAGCOM tool which plugs into the diagnostic port on your car. From this tool I know my car has a flaky MAF (Mass Air Flow) sensor, your car could have the same problem. With luck someone near you has this tool and can help you.

I think in the maintenance forum there is a list of people with the VAGCOM tool. Or you can take the easy way and place a new post with the words "Anybody have VAGCOM tool near <insert where you live>.

Alternately I would suggest changing the fuel filter, air filter, clean the snow screen, check your intake for clogging, verify your EGR valve is working. Search this site for all of these. I have to say I did all of these before I bought the VAGCOM tool, and in many cases changing these could solve your problem too.......

 

[aub]

I have just purchased an old body style 1999 TDI. The car had 143,000 kms on it when we picked it up. The car runs well and we really enjoy it except for one detail. The speed limit in our college town is 30 kph ... and the kids use the streets for sidewalks. When I try to maintain 30 kph in 2nd gear the car will surge or hop. It acts just like a car does when someone is new to a standard shift. The dealer is trying to tell me that this is normal for the vehicle. Does anyone out there have experience with this phenomenon? Thanks

 

[aub]

Thanks for the response Chris. I have changed the fuel filter but will have to check out the other items. My local mechanics might have the instrument you mentioned ... will check.
One other item which I forgot to mention. At those slow speeds, when I go to accelerate, I can depress the accelerator quite a bit before there is any action ... and then the car jerks ahead. In other words there is a delayed reaction. Decidedly uncomfortable when you are trying to manouver around pedestrians who think they own the road!
Thanks again!

 

[Curious Chris]

Aaargh, VAGCOM tool needed.

The press the accelerator and nothing happens for a bit then a jump,hmmmm. The possibilities here are not quite endless, but the first one that jumps into my head is the ECM doesn't know you want to go:throttle position sensor. VAGCOM tool needed.

Good luck!!

 

[aub]

Hi Chris,
Thanks for your reply. I talked to a "TDI Guru" last week. He said there are three possibilities ... 1. The potentiometer on the foot feed needs adjustment. 2. Since my car has 145,000 kms on it, the intake manifold could be coking up. (what would cause this??) 3. There is a problem with the governor ... weak spring, or could even be as simple as a need for lubrication ... fuel additive! I'm doing some more research on it today.
Thanks again,
Aub

 

[Curious Chris]

Aha,

Yes the "potentiometer in the foot feed" is the throttle position sensor, this fault is easily diagnosed with VAGCOM tool. Either in log mode, or with a friend holding the notebook, key on, push down on pedal and have them watch the percent go smoothly from 0 to 100%; in your case it may be not smoothly.

The "coked" intake manifold is a know TDI problem, my car has this problem right now. This problem blocks airflow to your cylinders and can occur after almost any mileage time; some cars very early, other cars never. Verification of this requires removal components to look inside the intake manifold. Search this site for cleaning intake manifold.

Lubrication: Stanadyne Power Formula is my preferred additive; increase cetane, lower gel point, and increase lubricity of fuel to help your injection pump and lift sensor on injector #3.

 

[Coder]

At 9,400 miles my 2001 Jetta TDI had an intermittent surging problem that would happen at various different speeds and gears. The problem was solved by replacing the ECU. The ECU was mistakenly detecting a fault in some sensor (I've forgotten exactly which sensor). When this problem first started, there was no check engine light for the first two weeks. The dealer wasn't able to find the problem until I did finally get a check engine light (by that time the problem was quite a bit worse).

-Coder

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by aub:
I have just purchased an old body style 1999 TDI. The car had 143,000 kms on it when we picked it up. The car runs well and we really enjoy it except for one detail. The speed limit in our college town is 30 kph ... and the kids use the streets for sidewalks. When I try to maintain 30 kph in 2nd gear the car will surge or hop. It acts just like a car does when someone is new to a standard shift. The dealer is trying to tell me that this is normal for the vehicle. Does anyone out there have experience with this phenomenon? Thanks<hr></blockquote>