Confused!

[kdubb]

Hello all,
I recently took my car to a local shop for a valve adjustment. The car was running great before I dropped it off. However, when I picked it up, the car has NEVER run soooo bad. It ran REALLY ruff! The problem got worse and worse. The car wont start now. The mechanic insists that the valve adjustment has nothing to do with this current problem. Any suggestions as to what could have happened between the time that I dropped the car off to now? I dont know where to begin. He put on a new fuel filter, and a new coil. The car turns over fast, but won't start. Does anyone have any suggestions? Thanks for you help.

P.S. I had the Fuel Injectors check and they spec'd out fine!

Kevin
85' 911 Cab

[Pingo]

Fuel filter mouted wrong way/upside down???

[kdubb]

Well, the arrow is pointed up. I was just told on this forum that up is correct.

[dfink]

Start with the basics like every thing else. Does it have spark and does it have fuel. Put a used plug on one of the wires and ground it to the engine and see if you have spark. Maybe he didn't get the coil wire pushed on good and it came loose. Take the plastic cover off and make sure it is on good.
Just some ideas.

[Oh Haha]

Check the fuel pump fuse and the connectins ate the rear of the engine compartment. They can be bumped and disconnected when performing work. 3.2 Carrera, right?
Start with simple things first. Spark, Air, and Fuel. Gotta have all three to run right.

Is the wrench willing to look at as it was running correct when you took it in? Seems to me it should be HIS problem.

[pwd72s]

Electrical? Have you checked the spark?

[hatpix]

Check to make sure all the plugs wires run from the distributor to the correct cylinder.

[kdubb]

I will check for spark tomorrow. Thanks for the suggestion. Yes, he is will to look at it. I will take it back to him. My car is supercharged, so air ain't the problem. Can one bad wire stop the car from starting? Or would it have to be more than one wire? Same questions for the Spark plugs.

Kevin

[ned903]

If one wire is incorrect there is at least one other.

[Grady Clay]

Kevin,

Each of the above suggestions are right on.

Here would be my step-by-step:

1) make sure you have spark as above.
2) Insure the spark plug wires go to the correct cylinders with spark.
3) Remove the air filter and carefully lift the sensor plate. Note the resistance when fuel pressure comes up and listen for fuel pump and injector operation. Don't flood the engine.

With these three simple operations, the engine should start. If it starts and runs poorly or starts and dies, please post additional symptoms.

The good news is this should be simple to diagnose and repair.


This is also why you need to be your own expert about your 911. Your mechanic may have the best intentions but not be perfectly knowledgeable about your model. (This is particularly true with MFI.) The solution is to become your own best expert and have the technical information to give your mechanic.

If you don’t want to (or can’t) do this yourself. You are best served knowing everything about your 911 and it’s diagnosis and repair. Only this way can you help your mechanic do correct work for you.

I have spent my professional life training my Porsche mechanics (and vice versa). You can do the same. This Forum is where to start.

Best,
Grady

[kdubb]

Thank you Grady! I am building my knowledge daily. I will post other symptoms when and if they come up.

Thanks again,

Kevin

[bell]

check that the harnesses on top of the engine are plugged in all the way.....i bumped mine loose once while adjusting the valves, if either of the crank triggers are not sending a signal to the DME then it'll crank fast and not fire.
the culprit could be the plate which holds 3 connectors on it on the drivers side of the engine.....