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1983 CDV 4.1
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6 Posts
Discussion Starter · #1 ·
Can anyone recommend a mechanic who is experienced in working on the HT4100 engine, preferably in northeast New Jersey? I have an ‘83 Coupe Deville that I’m looking to have worked on - thanks
 

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1984 Eldorado Biarritz, 1983 Sedan deVille
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1,782 Posts
What do you need done? If you have time and basic tools, this site has plenty of material to guide you through doing just about anything.
 

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1983 CDV 4.1
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6 Posts
Discussion Starter · #3 ·
I’m not much of a mechanic unfortunately. The engine races at cold startup and then abruptly settles down a few minutes later, then will randomly rev up again periodically. Was told something is loose in the throttle area coupled with something electrical possibly.
 

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1984 Eldorado Biarritz, 1983 Sedan deVille
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1,782 Posts
Probably just a misadjusted TPS. There are many threads on how to re set that. However, further diagnostic would be needed as several things can cause erratic idle.

It would be in your interests to buy a factory service manual for your year and model and either use it to learn about the car and diagnose & fix the issue yourself, or to provide it to the mechanic you bring the car to.

For what it’s worth, I am in the NYC area and do not know of anyone who is still in business and has experience with this era.
 

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'85 Sedan de Ville, '10 CTS-V
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748 Posts
If something is loose it’s hopefully an easy fix. Take pics around the engine bay and post them. We may be able to see it…


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1983 CDV 4.1
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6 Posts
Discussion Starter · #7 ·
Many thanks - appreciate the feedback. Had the base idle reset and the intake decarbonized a year ago and that didn’t seem to do much. Probably hasn’t made much more than a couple hundred miles since. Occasionally the service engine soon light will appear and go out again. Taking photos and posting is good idea - will attempt tomorrow if weather corporates. Speaking of photos this is her:
Wheel Car Vehicle Automotive parking light Tire
 

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1983 CDV 4.1
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6 Posts
Discussion Starter · #8 ·
Finally got a chance to look under the hood today; I think there’s maybe too much play or loose components in the throttle/accelerator area that’s at least partially causing the issue. Tried to take some photos - appreciate any feedback and of course a very Happy Thanksgiving to everybody!
 

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1984 Eldorado Biarritz, 1983 Sedan deVille
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1,782 Posts
Loose parts aren't going to cause any issues like that-however that spark plug wire should not be wrapped around the throttle body like that as it can get caught in the throttle linkage. Probably not causing your erratic idle, but you never know.
 

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'84 Eldorado and Seville
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2,221 Posts
I'd lean more toward the Idle Speed Controller (ISC). It's the small black thing in the photo below. It has a plunger that touches the throtle. Watch that plunger after you start it and see what it does. If it is irratic (goes in and out) that could be the issue.
Part number 17111169. I see a few listed on eBay for sale.
I would think most repair shops can replace that for you and set it. I'd phone around and find a place. Sometimes that's what you need to do. If there are any local antique car clubs sometimes asking them can be a source.

Automotive tire Motor vehicle Automotive design Rim Automotive exterior
 

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1983 CDV 4.1
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6 Posts
Discussion Starter · #11 ·
Appreciate the feedback - many thanks. Going to talk it over with one local guy I’ve know for years. His place doesn’t usually like to take extensive screwball repair jobs on classic cars but he says he’s familiar with the 4100. Trying to make inroads with Cadillac Club of North Jersey also. This is an annoying issue because I think the motor is more or less fine - just drove it 30 miles last week w. no problem. Maybe I’m just not searching or thinking hard enough about how to approach this :-/
 
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