Bad Fuel....I think

[loux951]

My '86 951 starts but idles very hard and immediately dies. I removed the spark plugs to examine and they were covered with carbon deposits. Haynes manual says its a bad fuel mixture. Car ran fine till my brother (never again) used it and put 89 octane fuel in the car. I alway use 92 or greater. I've added an octane booster to the fuel and filled the tank with 93 octane fuel. Last night I put new plugs in and took the car for a drive to burn the fuel. Car would not idle, kill at a stop. It would immediately start and I had to keep the engine reved to get going. Does anyone else have a problem with their 951 with low octane fuel or is this problem something else?

[Weldin]

pretty unlikey about the fuel -- especially if its still doing it -- im pretty sure these car run fine on 89....are you getting spark?? For that matter are you getting gas...youd need to verify those questions first & foremost....

[Weldin]

pretty unlikey about the fuel -- especially if its still doing it -- im pretty sure these car run fine on 89....are you getting spark?? youd need to verify that question first & foremost....

[Weldin]

i tried to delete the first post, because if your plugs are getting fouled its clear your getting gas...

[Dave951]

I've run my 86' 951 on 86 octane with no problems. I didn't even notice any performance drop. I would doubt the fuel is the problem.

Dave

[T86951]

It may be a a throttle position sensor or an O2(Oxygen) sensor. First though, check to see if you are getting vacumn to the 2 fuel pressure regulaters (one on each end on top of the fuel rail, they are round about 2 inches long and 2 inches in diameter and each has a vacumn line going into them). If you don't have vacumn there with the motor running the car will idle really bad and stumble and run bad until you really get the rpm's up under acceleration, plugs black and overrich conditin. The vacumn lines should run to a tee and go somewhere behind the trottle plate for constant vacumn. I had that problem same as you and that was it, no vacumn to the regulaters If you have vacumn there to the regulators, ok, unplug your Oxygen sensor behind the engine on the firewall (big black connector) and see if it helps. If that fixes it, the oxygen sensor may be bad. My problem was that vacumn line off over away from the regulater where it plugged into vacumn.

[This message has been edited by T86951 (edited 11-02-2000).]

[loux951]

I inspected the vacuum lines for the two pressure regulators, and low and behold, the tee going to the constant vacuum is broken. I also discovered that my engine temperature sensor is broken. Darn thing is broken in half! I'll let you guy know how everything works out when I get the parts. Hopefully this is the cure. Thanks for the help!

Tom

[T86951]

I was getting ready to take mine in to the shop, $$$$, when I found I had no vacumn to the regulators. When I fixed my vacumn line and got vacumn back to the regulators it ran perfect again. Between that and your boken temperature sensor, I would guess you are really running rich.

[loux951]

On the road again!!

The vacuum line break was the problem. Thanks for the help!

Tom