Won't idle

[jamieg74]

Hello,

I have a '79 fiat spider that won't idle. If I give it some throttle it will run but stalls on it's own. The car was running fine and this problem just came on suddenly. I tested and cleaned the idle solenoid, as well as looking over all the vac. lines.

Any suggestions?

Thank You,

Jamie

[TulsaSpider]

Check for vacuum leaks.

[bobplyler]

Does it do it both cold and warm or just one or the other.

[jamieg74]

Does it do it both cold and warm or just one or the other.

It does it hot and cold.

[jamieg74]

I may have found the problem.?. maybe. I took off the distributor cap and the rotor had contacted one of the posts and bent it 90 degrees so it was about 1/4" out of place. that one cylynder would have been firing way late. Could that have caused the idle issue? Has anyone else ever seen this happen?

If I can figure out how to post pics I will.

Jamie

[So Cal Mark]

if the rotor is broken, all cylinders would fire late. This seems to be a common problem with the replacement parts that are available now for the distributors. I don't think the tolerances on the parts are very good

[jamieg74]

It was only one post in the cap that was bent 90 degrees. All the others, along with the rotor, were intact. Is there a better source for quality parts than advance auto and the likes?

Jamie

[So Cal Mark]

hard to imagine the rotor isn't broken too if the cap is damaged. Usually the rotor breaks as soon as it contacts the cap contacts.

[mdrburchette]

You could try the Fiat vendors to see if their parts are any better. They are most likely better in price, but they may be the same quality.

[bobplyler]

A broken post won't affect the timing (that's from the points or electronic module). But it will make that cylinder possibly not fire. Which would affect the idle.

[jamieg74]

OK, the saga continues.... I replaced cap and rotor and it still doesn't idle.

On further investigation I found a jet on the inboard side of the carburetor totally missing! I found it and screwed it back in (it was laying on top of the intake runners). I figured I was all set but it didn't change a thing. I'm not sure what this brass screw does but I tried it all the way screwed in and 5 turns out in 1/2 turn increments and it didn't work.

Any takers?

Jamie

[manoa matt]

Do you still have the stock 28/32ADHA carb? If so, look under the housing for the water activated automatic choke. There is a white plastic piece under there. If its broken or missing it will affect the idle.

[jamieg74]

Found the problem! I sprayed starter fluid around the intake manifold gasket and the RPM's increased. So now I have to replace the gasket. Is there a kit with all the gaskets I need?

[majicwrench]

Hmmmm, spraying starter fluid around intake will ALWAYS make RPM go up, vacuum leak or no, as the fumes get sucked into the carb. Possible, but not common to have an intake gasket leak. Get a long hunk of vacuum hose and stick one end in your ear. Now stick other end into carb and hear the sucking sound. That is what a vacuum leak sounds like. Now move end of vacuum hose around intake gasket and see if you hear the same sucking sound. If you indeed have a intake gasket leak you should be able to locate THE SPOT with a vacuum hose.

[So Cal Mark]

sounds like the secondary idle jet fell out. Since you tried turning it out without any result, try the same thing with the primary low speed jet. Turn it out about a qtr turn and see if it affects the idle. As Keith suggested, it's rare to get vacuum leaks at the manifold flange. If you did have a leak there, it should only affect one cylinder so you'd have a rough idle