We are working on a 1998 TDI Jetta with a complaint of no power above idle.
Floored the engine will not rev above 1600RPM. Here is what we have checked so far: Cam and crank timing is accurate, we went as far as a dial indicator off a valve. Mark is accurate. Basic timing set with Vag. Because this vehicle came with extra parts the injection pump and turbo were swapped with known good units and, the MAf was also replaced. Other things we have looked at:
1. The intercooler was removed and found to be clear and clean.
2. The rubber hose to the ECU is leak free. I tried pressurizing this line and found no engine rpm change at full throttle. Is this normal?
3. Double checked the vacuum line to the turbo wastegate. Pressure moves the linkage.
4. The intake and head was removed and thoughly cleaned.
5. When we unplug the maf sensor, full throttle increases to 2000 rpm and then fizzles.
6. The Cat. converter was removed to confirm that it is unrestricted.
7. There are no engine codes set.
8. The intake pressure is 973mbar at idle and only increases to 1178mbar at full throttle (1500rpm).
9. The injectors are clean and engine compression tests within spec.
Questions:
Could a faulty ECU cause my low/no power condition?
When I pressurize the line going to the ECM should I see an effect on rpm?
What should I check next?
Thanks in advance!!!
Keith
Floored the engine will not rev above 1600RPM. Here is what we have checked so far: Cam and crank timing is accurate, we went as far as a dial indicator off a valve. Mark is accurate. Basic timing set with Vag. Because this vehicle came with extra parts the injection pump and turbo were swapped with known good units and, the MAf was also replaced. Other things we have looked at:
1. The intercooler was removed and found to be clear and clean.
2. The rubber hose to the ECU is leak free. I tried pressurizing this line and found no engine rpm change at full throttle. Is this normal?
3. Double checked the vacuum line to the turbo wastegate. Pressure moves the linkage.
4. The intake and head was removed and thoughly cleaned.
5. When we unplug the maf sensor, full throttle increases to 2000 rpm and then fizzles.
6. The Cat. converter was removed to confirm that it is unrestricted.
7. There are no engine codes set.
8. The intake pressure is 973mbar at idle and only increases to 1178mbar at full throttle (1500rpm).
9. The injectors are clean and engine compression tests within spec.
Questions:
Could a faulty ECU cause my low/no power condition?
When I pressurize the line going to the ECM should I see an effect on rpm?
What should I check next?
Thanks in advance!!!
Keith
