OldSchoolFresh said:
Well my 98 Jetta TDI has been really underwhelming lately. It seems that in December that the power output has been decreasing gradually. Now in January my car doesn't want to rev past 2000 when cold and not over ~2600 when at normal operating temperature, as well boost pressure seems to top out at about 5 psi. When idling and I rev it a bit it seems to sputter or misfire at about 2000 rpm, but idles perfectly. I checked with my VAG com and boost pressure is definitely low. I suspected the N75 valve so I replaced that with a new one but still no change at all, and wasn't the N75 supposed to click all the time when the engine is running, it's silent for me.
It's gotten to the point where I can out accelerate a semi trailer or a city bus so it's getting hazardous now. Any help would be great. Oh and the air filter is clean, the fuel filter has about 10,000 kms on it and I always fill up with V-Power diesel. The car starts fine in cold temperatures without being plugged in but just no performance at all.
OldSchool, sounds exactly like the problems I was experiencing a few months ago. I opened up the hood, and replaced every vacuum line possible. Two to the turbo, the ECM line, the one going to the EGR, the other one coming off the N75 Solenoid, the brake booster, etc...etc...I didn't use pretty silicone hose like posted about in the forums, but if I had to do it again I would. If you want to go that route do some searching here, and you will find it. Do you have access to VAG Com? oops just saw you did my bad! I wasn't so lucky. Is your check engine light on? When I had these issues I had a " Charge pressure deviation " code, so I knew my turbo wasn't getting full boost. I could push the car up to a bit, and then SLAM!!! the power would stop, and it would go into limp mode. I could cycle the key on and off, and it would refresh the ECM, power was suddenly back!!! Yeah, but annoying to have to do that.
I lifted the car, and rigged an air nozzle up to the blue turbo hose. I verified that the waste gate actuator rod moved. As I was applying air to the blue hose I heard a POP!!!, and that must have been the release of oil, and crap from the diaphragm. That did it for me. You may have more constrictions in the intake system.There is always pulling your intake to see how much soot is built up. And then you can have a buddy with VAGcom change the duty cycle of your EGR Valve, so that you wont ever have to clean it again
Anyhow hope this helps it sounds exactly like my situation. I think you will benefit greatly by changing vacuum lines, and verifying that your wastegate rod moves freely. If it doesn't apply penetrant oil, and go out for a beat while getting the turbo hot. That may free things up.
I hopefully can get my car back tomorrow. Waiting on parts...The shifter lever that sits under my clutch cables stripped out, and cause the Jetta not to engage gears. I could get it to budge in 3rd but not always. Hopefully (fingers crossed ) I get the parts tomorrow. I need a reverse switch too, and that's on order. Does anyone know if these are common wear items???
On another note how's the weather in Calgary???
Cheers,
Bart