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Need Help: Car starts has rough idle, Does nothing when given throttle.
Hello,
Im trying to fix my brother's new 944 turbo. It's been modified and Im looking for ideas on where to start. The car starts, has a very rough throttle and when given gas or opening the throttle manually its sputters worse and has no power. The only way it actually revs is opening the throttle slightly and it will suddenly start sputtering and pick up power. What could it be? The car was driving fine a couple of days ago.
I had the same problem, except I have a LR MAF. A good couple whacks with a screwdriver fixed my problem. Perhaps your AFM has died? Either that or TPS would be my guess.
Had something to do with the vacuum lines. I found one that was loose. Connected it well and the idle improved greatly. Its still not 100% though. Left it at a shop here in Colorado and they were going to check compression but I don't think they may be looking at the right issue.
Spoke with my local 944 guy
and wire harness to throttle position sensor or sensor itself or if it’s doing a few other things like I said originally DME OR KLR
My car was having some exact issues with an original M-tune setup. After much head scratching..
TPS. I cleaned it, and that made a huge difference. I had a high idle on top of very rough driving. I did tighten up a few minor vac lines, but the TPS was the real culprit.
It's expensive to replace so cleaning it could be worthwhile. Make sure to zip tie, or glue the cover when done.
I would think the TPS sensor first followed by the MAF then DME/KLR then check wiring. Seems the bases have been covered. A new TPS is now outrageously expensive. I bought mine when they were going up in price at $180 years ago.
Thanks for all the help. It's my brothers car. The compression was checked and was low, so now it's probably going to get a full rebuild.
For the record, slightly low compression does not cause the issue you describe. Sure, the engine probably needs to be rebuilt, but I would implore you to diagnose the issue at hand before the rebuild---otherwise you will be fighting the same thing when you try to start it for the first time and will end up washing the cylinder bores down with gasoline, which will make engine break-in/ring seating that much more difficult.
It sounds like you have a giant vacuum leak, have you checked for this?
09-10-2020, 05:49 PM
Need Help: Car starts has rough idle, Does nothing when given throttle.
