Motor problems- Need help!

[Moses]

One week ago, my SC was starting and running perfectly. On a cold start, the engine would turn over, gather itself briefly, then idle smoothly.

After not driving for 1 week, I attempted to start my car. The engine turned over and idled extremely roughly before quitting. Eventually I was able to get the engine to run at high RPM, but it stumbles badly at idle then stops running.

While increasing the RPM's, the engine backfires wildly. It feels like popcorn under my foot. (I have a pop-off valve)

Even after getting the engine warm, it will NOT idle. It feels like it is missing badly. The last time I drove the car, I added oil. Other than that, uneventful.

Do I maybe have a fouled plug? (or two?) Any help would be appreciated.

On a brighter note, the clock is now running perfectly.

[Jdub]

How's the battery? Is it up to snuff?

Short of this all I can think of is something in the fuel settled down and into the lines and/or filter.

Sorry not to be of more help,
John

[Joe Bob]

Air box leak....even with the pop off valve they can crack from flexing. The 3.0 in my 914/6 had the problem, little rhino snot fixed it up.

[Moses]

Battery is good. Air box appears OK.

Is it possible to cause this by adding too much oil?

[speeder]

As wonderful as the "help thy neighbor" spirit is around here, (especially when the reciepient is named Moses), these posts frequently remind me of a board game, "guess the problem".

All good technicians, whether automotive or otherwise, diagnose problems systematically. Even when they "think they know what it is". Start at beginning, ie. car has fuel, battery good, no banana in tailpipe, etc...

There is nothing wrong with checking your pop-off valve if you have a couple of minutes to spare, but that probably won't be it. Before anyone thinks that I do not appreciate the mechanical help given around here, think again, but for it to be truly effective, the problem-haver must be able to perform at least basic diagnostic procedures and describe results. By 'turn over', do you mean start? Otherwise, it is like (forgive me here) a hot young chick saying, "my thingy is making a wierd noise", and every mechanic from miles around, (plus all non-mechanics), trying to help. Like three monkees trying to f**k a football.

Sorry for the rant, I probably got up on wrong side of bed, and it is not directed specifically at this post, but has been bugging me for awhile. Without some basic common language and skills, AAA and a trusted wrench may be the best option, (and where you are heading anyways).

[Moses]

Sorry, speeder. Yes, it starts and runs roughly and briefly before quitting.

And no, there is no problem with my "thingy" and there never has been or ever will be a banana in MY tailpipe.

[speeder]

It could be anything from a completely plugged fuel filter, (extremely rare), to a very large vacuum leak anywhere from brake-booster in front trunk to cylinder head, bad fuel, (unlikely but possible), to an ignition/electronic problem, (did you check relay under passenger seat?), to etc...

Hard to say w/o looking, basically you want to eliminate the simple things first, work your way up.

BTW, you think that car could be over-filled with oil? It is very important to understand the oil checking procedure on these cars, and do not trust anyone else who is not a Porsche mechanic to do it for you. IF the car was overfilled w/ oil, it could make it run very badly. Check for oil in airbox, it is not supposed to be there. Good luck.

[Chuck Moreland]

Originally posted by Moses
and there never has been or ever will be a banana in MY tailpipe.

Not that there is anything wrong with that


Did the problem start before or immediately after filling with oil?

Open up the air box and see if you have any oil in there.

[Moses]

Thanks. Will check the airbox for oil when I get home.

[emcon5]

Out of they way, I want my turn at the football.

Your car is an 83 right?

Do the dome lights work?

If they do, see if the frequency valve is buzzing.

Tom

[Moses]

Dome lights?

They only wrk in the "manual-on" position. Never have worked when opening the door. What could the dome-light relay have to do with my problem?

[Vipergrün]

Ok Moses,

this may sound really idiotic, but did you replace the oil cap? Leaving this off creates a gnarley vaccum leak. I only know this cuz I've done it

-Brad
80SC

[Vipergrün]

Originally posted by Moses
Dome lights?

They only wrk in the "manual-on" position. Never have worked when opening the door. What could the dome-light relay have to do with my problem?

I believe the dome light is on the same circuit as the thingy under the passenger seat which has a relay for the O2 stuff...... Try pulling the relay out and see if that helps. The clock, buzzer, interior lights, and trunk light (maybe more) seem to all be related and there is a connector for them up near the fuse box.

-Brad
80SC

[emcon5]

Originally posted by Moses
What could the dome-light relay have to do with my problem?

Lamda system gets power from the dome light fuse. With the car running, pull the power relay next to the lamda box under the passenger seat. If the it runs the same, the relay may be your problem.

Does the Frequency valve work (buzzing, or vibrating to the touch)?

Tom

[Moses]

Excellent starting points! Thanks for the help.

Moses (still searching, but no longer aimless )

[Wayne 962]

Yeah, this one:

http://fly.hiwaay.net/~jonlowe/zwart.html

-Wayne