CLUTCH or INJECTOR? Help!

Porsche9xxlover · 03-09-2005, 08:33 PM

O.K. guys, I need your help...

I took my car in today for a complete check after buying it on eBAY last month. The listing stated the car has a leaking fuel injector--read previous post yesterday--and that it causes the car to not start right away, idle rough, etc. Nevertheless, I noticed that while driving, if I let off the throttle, the car jerks a bit--as if someone hit you from behind.

I called the previous owner's tech in Chcago and he swears it has to do with the injector(s), where as my tech found the rubber hub cracked!! My tech thinks it is the clutch that is causing the jerking, but is not ruling out that the injector (if that is it) may be contributing.

I asked my tech to not look further into the car becasue I am now turned off that I will need to pay $600 for a clutch + 8-10 hours of labor. He also said that it may be a fuel regualtor or something else and not the injector(s) causing the rough idle and hard start. He also said it is running rich... no fouled plugs.

These cars seem to be more complex than my 911! What do you guys think? I have always LOVED this car but I am being turned-off quick...thanks for your time!

AFJuvat · 03-09-2005, 08:42 PM

You violated the cardinal rule of buying a Porsche - You get a PPI on it before you buy.

The jerking is probably fuel related - Check your injectors regulator\dampener and replace as necessary

Your tech should be able to diagnose this fairly quickly.

Start saving for a clutch, the clock is ticking on it self destructing.

AFJuvat

DannoXYZ · 03-10-2005, 11:36 AM

"He also said that it may be a fuel regualtor or something else and not the injector(s) causing the rough idle and hard start. He also said it is running rich... no fouled plugs."

This could be as simple as a broken or disconnected vacuum line to the fuel-pressure regulator or dampener. Manifold-vacuum reduces fuel-pressure at idle when the throttle-body is closed. If you don't have sufficient vacuum, you'll end up with too much fuel-pressure and a rich mixture.

You want to hook up a vacuum gauge to the hoses going into the vacuum-activated parts like the FPR, fuel-dampener, heater-valve to see if they all get 18-22 in.Hg of vacuum. Then use a vacuum pump and test those parts to make sure they hold vacuum without leaking. if they do, they may be sucking vacuum away from some other part. The entire vacuum hose system is a mess, they all share the same vacuum-source and T it off into a bazillion connections. If anyone of those connections is bad or a T is cracked, you're going to have running issues that needs lots of troubleshooting to hunt down.