Delco EST distributor issue

Don S

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Re: Delco EST distributor issue

I think your carb is probably causing your surging at low rpm. Have you checked your timing at 3500 rpm to see where it's at?

How much of this was a problem with the points distributor?
 

cj7ole

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Re: Delco EST distributor issue

26 degrees from 1000 to 3500 rpm. The surging coincides with the advance jumping, I can see it with the timing light. Surging wasn't a problem before.

Does anyone have a timing curve for the EST? How it is designed to advance?
 

cj7ole

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Re: Delco EST distributor issue

Well, after two years I solved my problem of rpm loss. And this should be added to the checklist for WOT problems: Distributor wires crossed. It took a second mechanic to find it. Apparently I crossed the wires when I first replaced the distributor after fixing the heads after the overheat. When I installed the EST unit, I just switched wires, one at a time from cap to cap, so I perpetuated the problem. What fooled me is that it ran as smooth on 6 cylinders as it would if it were a V6. Figured that switched plug wires would cause a horrible vibration. Not so. I still get the quick jump of 200 rpm in idle speed around 900 rpm, but I can live with that. All is well, I get 44 mph at 4700 rpm.
 

Bondo

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Re: Delco EST distributor issue

Well, after two years I solved my problem of rpm loss. And this should be added to the checklist for WOT problems: Distributor wires crossed. It took a second mechanic to find it. Apparently I crossed the wires when I first replaced the distributor after fixing the heads after the overheat. When I installed the EST unit, I just switched wires, one at a time from cap to cap, so I perpetuated the problem. What fooled me is that it ran as smooth on 6 cylinders as it would if it were a V6. Figured that switched plug wires would cause a horrible vibration. Not so. I still get the quick jump of 200 rpm in idle speed around 900 rpm, but I can live with that. All is well, I get 44 mph at 4700 rpm.

Ayuh,... The threads, 'n help here, Assumes that such basics as plug wire installations are within the abilities of the posters...
And,...
It IS covered by # 14,...
"14. Engine timing and ignition system operation"
 

Don S

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Re: Delco EST distributor issue

With two crossed wires, a Chevy V8 will have an obvious miss when running, even at idle, and you should have been able to hear it. Had that been mentioned, your problem would have been found long ago.
 

cj7ole

Seaman
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Aug 17, 2009
Messages
74
Re: Delco EST distributor issue

With two crossed wires, a Chevy V8 will have an obvious miss when running, even at idle, and you should have been able to hear it. Had that been mentioned, your problem would have been found long ago.

Well, that is exactly what I ASSUMED. Had the engine been running rough, I would have double checked the wires. This is why I made the post, in case someone else has the same issue. My ear is probably not as fine tuned as yours, but the idle with 2 and 4 crossed was very smooth IMO as was the engine at WOT, except for the loss of power. I am sure there is an explanation as to the firing order with 2 and 4 out of commission. After all, the new Gen IV GM V8 engines run with only 4 cylinders firing under a light load and the engine is smooth. Now I am certainly no professional mechanic, I could NEVER make a living at this but I really respect those that can. But I do have some shadetree experience, I am just now working on my 3rd engine swap, this one being a 5.3 LMG engine out of an '07 Tahoe into my CJ7. Look, we all make mistakes, and I don't appreciate the condecending manner noted in the last 2 responses, particularly by moderators. I am active in several other forums and I can see the professionalism and empathy moderators bring to those forums when trying to help folks with less experience than themselves. I encourage you to do the same.

"14. Engine timing and ignition system operation." is a pretty broad topic, I was just suggesting that adding one short comment regarding crossed wires might help the next guy. After all, isn't that what this forum is all about, helping people?

I am still surprised that no one is able to adequately explain the workings of the EST distributor. I am beginning to think that they are really intended to run with some type of ECM. The 2nd mechanic, who works for one of the largest ski boat dealers in the United States, and that found my problem, seemed impressed that I chose to upgrade the ignition with the EST distributor. So even he isn't too familiar with the issues.
 
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