So I am having idle problems with my 75 1.8. At initial startup the cold start doesn't work. However it starts up no problem. I keep it idling manually. Once it warms up, it idles perfectly. If the story stopped here I would be a happy camper. However, after driving till the engines reaches operating temperature. The idle starts surging. It surges from 200-900 rpm. It doesn't stall. I don't think it is a vacuum leak since it does idle perfectly when it is not cold and not hot.

I have replaced every vacuum and fuel line, Injector seals, the elbow has no leaks.

I am stumped as to what the problem could be? I am off this week and would like to fix it! Any ideas on what my strategy should be?

Regards

James

I idle hunt could be caused by a too rich condition. The cold start valve maybe leaking fuel or the air flow meter is set incorrectly. Being that you live in a hot area at the moment, the fifth injector should not engage till temps drop below 30 degrees. Pull the spark plugs and post the pics on here

I have replaced the cold start valve with a new one. I'll look for the pics of the plugs

Here are the plugs

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I'm viewing the pics over my phone but it looks like the car is not running rich. Erratic idle can also be caused but excessive grooves on the carbon track inside the air flow meter. Can you post a pic of that?

While it may appear erratic, from my perspective it is not. It consistently idles perfectly after initial warm up until it is driven a while (miles or thirty mins or more) and is hot then the idle surges. Otherwise runs great

Sure seems temperature to me

distributor advance plates ever been cleaned and re-greased?

Rich

Not since I have owned it (7 years). How do you clean and regrease the plates?

I read your post. I Have pertronix kit I didn't install anything special I need to do?

I had a similar problem and had the throttle body rebuilt by a machine shop. All 75's have this issue. The valve sticks and doesn't return because the shaft is probably bent. Might want to check that out.

Well I removed the dizzy. Not sure what to do next... Concerned about reinstalling the pertronix unit. I don't have instructions and appears to have a gap between the unit and the ring on the shaft. I also have a gaping whole where I guess the fi trigger went I assume I should some sort of cover over it?? Thoughts

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This piece fell out when I turned the dizzy upside down???
Any ideas on what this is???

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So I took my dizzy out to clean it. I followed the directions from Rich's post. The first thing I noticed was that I have a dizzy for a D-Jet!! The trigger points for the injectors was removed. In its place was just an open space!! I was surprised that there wasn't more crap in there than their was. I used hvac foil tape to seal the gap. It will be interesting to see how it holds, but a day/night difference from a gaping whole!!

The next thing I found was a a round depression on the roller ball path. With all the dirt I didn't see how it was moving much less functional. I am excited to see how the new plate improves engine function.

As everyone has stated about the pertronix adapter plate's fit. I tool my Dremel and craved it to fit perfectly!

Next step is to see if it actually works!


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post a want to buy for the correct dist.

I was shocked to see dent in the bearing track. Look at how it shines. Looks like the bearing spent most of its time in that spot!!

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All finished

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