Car idle problem

Kevin Lewis · 01-19-2005, 01:34 PM

In the morning my car starts up and idles ok approx. 1000 RPM. By the time I get a block away and stop at a stop sign the idle will not fall below 2000 RPM's, but if I stomp the throttle a bit it falls right to 1000 RPM's. Does anybody know what's going on with the idle. I have a 1973 914-4 1.7L with the original fuel injection system. Help me please, this is flustrating.

mikey · 01-19-2005, 01:47 PM

It sounds like a lean condition. There are many previous threads regarding this. Check head temp sensor, and check for vacuum leaks...and aux air valve.

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Sounds like it could be a number of things.

Check for vacuum leaks. Almost always a good idea anyway.
Check to see if the throttle valve is hanging up. When it's doing its "high idle" bit, reach into the engine bay and push the throttle bellcrank in the "closed" direction.
Check the vacuum advance and retard mechanisms; the diaphragm in the dashpot could be leaking or the mechanism could be sticking.
Check the centrifugal advance in the distributor, it could be sticking.
Check the decel valve, make sure it doesn't hang open.

--DD

Kevin Lewis · 01-20-2005, 07:02 AM

Thanks for the info, I'll trouble shoot using your suggestion this weekend when I get some good light and time.
K

bpgreer · 01-21-2005, 09:29 PM

I had a similar problem which turned out to be the accel cable. The old ones eventually stop allowing the cable to glide freely through the outer sheathing. When it starts idling at 2000rpms, open the engine lid and take a look at the throttle area. See if a little tug on the accel cable makes it close back up. It's a relatively simple repair. Good Luck.

Brian

Peter_Hinkle · 01-22-2005, 06:25 AM

What Dave said about the vacuum leaks and you really need to MAKE CERTAIN that you check really good. I don't know how many times someone in my local 914 club has called and said that they have an idle problem and that they checked for leaks. After them screwing around and throwing money at the problem, they bring it over and we find a leak. Use a good vacuum leak detector kit or make one. It is worth the time. As a matter of fact, I seem to remember Dave himself just saying on the mailing list the other day that his shop found a vauum leak that he was sure was already fixed. So there, as you see, even very knowledgeable people can overlook them.../peter

Dave at Pelican Parts · Dave at Pelican Parts's Garage

It was more than one, Peter... >blush!<

--DD