Author Topic: Glow plug problems and accelerating problems (Read 5813 times)

CaddyTDI · « **on:** April 10, 2008, 05:26:10 pm »

Hi all,

I have two problems with my Caddy TDI from 1998:
1) It does not start because the glow plugs does not work correctly.
If I disconnect the temperature sensor the glow plugs work and I can start the car. I've bought a new temperature sensor and it didn't do any good. I have also placed a new relay 109, measured the connections to the glow plugs (these are OK because it will start when I disconnect the temperature sensor).
What could be wrong? I think I have to look at another direction. The needle lift sensor gave an error when I read the errors. Could this be the problem?
I've also read something about a reverse-drive sensor. I will give this a look. I think the switch at the door for the glow plugs is OK.

2) The car have enough bhp, but when braking and speeding up again it does not respond to the gas pedal, only a bit (very low power). Also there comes a LOT of grey smoke out of the exhaust. When I put the gear in free and wait a while I can speed up again. Making lots of RMP is no problem at all. Making low/medium RPM gives problems. We have found a leak in the turbo circuit and fixed it: the car was a bit quicker but it didn't fixed the problem.
Looked at the air supply and looks good. Took the air filter out, the car was a bit quicker but same problem. I think the car gets enough diesel because of all the grey smoke.

Who can help me? Thanks in advance!

truckinwagen · « **Reply #1 on:** April 10, 2008, 06:50:24 pm »

poor timing?

CaddyTDI · « **Reply #2 on:** April 11, 2008, 05:06:57 am »

Could that be poor timing because of the needle lift sensor is not working properly and the computer gets the wrong information?
My buddy thinks the catalysator is also broke. I read that you should check first other things of the motormanagement before you replace the katalysator.
Things to check I've read:
- Lambda Sonde
- The mass flow sensor is new
- The timing
- Failed exhaust valve
- Worn injectors

truckinwagen · « **Reply #3 on:** April 11, 2008, 01:51:53 pm »

I am not super familiar with all the sensors in a tdi, but poor timing on an idi will give you those symptoms.

hope you figure it out!

CaddyTDI · « **Reply #4 on:** April 11, 2008, 02:47:50 pm »

Thanks,
Do you mean the timing of the distribution belt? Or...?
I've read it's quite a difficult problem. It's actually the new car of my buddy who knows a lot more about cars then I do, but he can't find the problem.

truckinwagen · « **Reply #5 on:** April 11, 2008, 04:14:36 pm »

im not sure how one would adjust the injection timing on a tdi, but if it is injecting at the wrong time, not all the fuel will get burned resulting in smoke and loss of power. in the higher rpm range it is less of a problem, so if you rev it you get your power back.

smoken u · « **Reply #6 on:** April 11, 2008, 09:43:19 pm »

I've had some experience with the TDI's here could be some issues

1. the MAF sensorcoulkd be one for a gasser, the gasser one does not work in a TDI, sends the wrong signal to the computer

2. turbo wastegates are notorious on TDI's, the small pins that slide in the exhaust side of the turbo sieze, causing no low end power, and lots of smoke, cause there is no air.

if its a 98, I can,t see the injection timing jumping. even if it did it would display a DTC.

3. The car may be temporarily be putting itself into limp mode, which cuts power, and runs low boost. the coolant temp sensor will affect the limp mode, when it is unplugged, senses an overheat, or stops working the car will switch into limp mode.

CaddyTDI · « **Reply #7 on:** April 12, 2008, 01:36:30 pm »

Quote from: "smoken u"

2. turbo wastegates are notorious on TDI's, the small pins that slide in the exhaust side of the turbo sieze, causing no low end power, and lots of smoke, cause there is no air.

3. The car may be temporarily be putting itself into limp mode, which cuts power, and runs low boost. the coolant temp sensor will affect the limp mode, when it is unplugged, senses an overheat, or stops working the car will switch into limp mode.

Thanks man, I will check these things.
Do you also have an idea why the glow plugs won't work correctly when I connect the (new!) temperature sensor?

CaddyTDI · « **Reply #8 on:** April 14, 2008, 06:39:47 pm »

I've saw another TDI and the glowing is exactly the same as with the Caddy TDI. It looks like the glowing is okay with the Caddy. The reason why it doesn't really glow is because the computer only let it glows under 5 degrees Celcius.
The starter motor is also weak. We will try a new one, we think this is the problem of the starting problems. Maybe in combination with a bad accu.

We still don't now what the other problem is. The MAF is OK, we have to check the wastegate because there is maybe a leak.

CaddyTDI · « **Reply #9 on:** April 18, 2008, 07:03:29 am »

OMG, we think the previous owner has used benzin (gasoline in english?) in stead of diesel! :evil:
It smells like gasoline...

burn_your_money · « **Reply #10 on:** April 18, 2008, 11:31:07 am »

old diesel smells like gasoline to me. If you get some on your hands is it slippery (diesel) or dry (gas)?

CaddyTDI · « **Reply #11 on:** April 20, 2008, 05:13:10 pm »

Don't know. I've put diesel in it and it didn't helped. We think the injectors maybe are worn.

CaddyTDI · « **Reply #12 on:** April 23, 2008, 06:53:10 am »

Sad to say but the fuel pump is probably broken

RIP

C A Veman · « **Reply #13 on:** May 04, 2008, 11:20:00 am »

The symptoms you describe sound like my 2000 TDI jetta plus some. I bought used with 145k mi and replaced Inj pump at 150k as it was leaking. The car has now 200k and I was getting codes for MAF and having the same glow plug issue (started when really cold-rare in ca). Limp mode the same but does allow some driving when on the floor but gets poor mileage. MAF error and emmissions control error. My course of action so far and not solved completely.
Glow plugs don't kick in even though the dash light is on!!! I ran a diagnostics wire from the GP harness to a trouble light so I could see when power was applied to the plugs. The power is applied only when the temp sensor is unplugged or when its below about 45degree F. Once started the plug power cycles on and off with the temp plugged in until the engine warms up.
Question: Can the ECU be reset to lower the point at which the plugs are powered? Who makes the best tool for reflashing/resetting the ECU values?
I have a bypass as I got tired of unplugging the temp sensor. I am thinking of putting a button on the dash to over ride the solenoid with a light powered by the GP harness output on the solenoid so I can see if it is working and can ovewride from the drivers seat. Has anyone done this? worried about triggering some error message.

The other low power issue: Since the car had a lot of miles and I knew the intake was plugged (Pull the hose and look in), I opted for a complete manifold cleaning. The turbo did not fully engage (applied vacuum directly) so I opted for a new turbo at the same time (turns out the diaphragm was leaking and the turbo was OK it's now new - need a good turbo?). The MAF error which can be triggered by both issues, still comes on and triggers limp mode. New MAF sensor is ordered. I am also getting the error on emmissions control from time to time. not sure if it is cause or effect.
Warning on the intake manifold cleaning. There is a lot of how to do this but beware that you can damage the manifole by soaking in lye. The threads in the manifold will be dissolved. If you choose to do it this way do a mechanical cleaning first then pour the lye inside where the carbon is. It will dissolve some of the manifold but won't destroy threads. I would put the steel bolts in the threads with silicone on them to keep the lye from the threads also.