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1981 Eldorado Distributor issue

Started by Tonyv_73, September 16, 2017, 09:17:41 PM

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Tonyv_73

Okay so I have a 1981 Eldorado Biarritz with 70k miles on it. When I first got the car it ran fine, I had a tune up done and while having the plugs, wires, cap, rotor and coil replaced now the car sputters and every once in a while almost stalls.  I decided to check the timing, and while doing so I noticed that the strobe for the timing gun didn't flash consistently. So I then checked a few wires for spark and it was not getting consistent spark to any of the plugs, it looks to be pretty weak. The engine at idle shakes and sputters but I've been driving the car like this for quite a while.  I feel the issue has to be with the distributor, but my mechanic says I need new injectors. I would like some feedback and some suggestions as to what I should do first to check this issue. My injectors look to be spraying evenly, i dont think they were ever changed, so eventually I will but I would like to rule out whether this is a bad cap or coil before hand
1963 Series 62 Convertible
1965 Eldorado
1966 Calais Sedan
1970 Fleetwood Brougham
1970 Wildcat
1970 Coupe Deville
1973 Eldorado Convertible
1974 Coupe Deville
1976 Coupe Deville
1981 Eldorado Biarritz
1985 Eldorado Commemorative Edition
1991 Brougham
1993 Eldorado 4.9
1996 Fleetwood Brougham
2006 XLR
2006 DTS
2014 XTS

James Landi

Keep checking for ignition issues--- weak, inconsistent spark is your problem...and from what you describe, it may likely be a NEW part that is at fault.  A strobe that shows inconsistent timing after a bunch of parts were just put in tells the tale.  Your mechanic is not paying attention to what you're describing.  I feel your pain--- you shouldn't have to endure this/   James

TJ Hopland

Even at this age injectors are not a real common issue.   What is often a fuel related issue at this age that wasn't even when these were only 20 years old is aging seals and gaskets in the throttle body, shot fuel pressure regulator, and general crud build up.   Refresh kits are available and fairly inexpensive and easy to install.   IF you can do a carb 'rebuild' you can do one of these.  These have fewer parts.   There is a screen around the outside of the injectors that at this age tends to have a lot of crud on them.

Does the 8-6-4 still work?   If no can you tell how it was disabled?   The right way to disable it is to disconnect one wire from the transmission.   All the other methods tended to confuse the computer and cause other issues which then also needed creative workarounds that often were not successful.

Did they get the correct cap?   It looks like the normal HEI that fit every GM V8 but for some reason they made these slightly different and used regular screws to attach it rather than the spring clamp the rest had.   I once saw one in a junkyard that had the regular cap fitted to it that looked terrible inside.  Don't know if that was because its shorter or taller or something or if it was just a neglected car.   This cap was only used on some Cads and maybe a year or two on Corvette so especially now days its a special order item. 

Is the coil assembled correctly?  The button goes in first then the rubber washer.   It works the other way but not for long.    When it correct the button sticks up out of the cap.   When its wrong its slightly recessed.    While you are checking that look to see that you don't have the issue I had recently with an 81 cap were there are nubs on the bottom of the coil that rub on top of the cap.   On mine I caught it fairly quickly and just ground the nubs down but if you kept running one like that I bet it would damage the rotor.     How do things look under the cap?   If its not like new it may be worth taking apart and cleaning all the electrical connections.  IF you remove the module you will want to clean and remove the heat transfer compound.   You can buy a tube of the stuff at parts stores or stores that sell computer parts. 

The ignition modules in these didn't tend to be intermittent like you describe so that is why I was first focusing on the basics above.  The intermittent failure mode of these is no spark then it cools off and works fine till the next time you completely loose spark which is often the final time.   The module is located under the rotor. 

There isn't anything to odd about the distributor.  There wasn't any spark saving features or anything like that.   Its like all the other GM's of the era.   It sends a tach signal to the computer and receives a signal from the computer for the desired timing.   Its not like some later systems where the computer is actually sending the pulses to the coil.   The actual 'work' is being done in that internal module.   IF it looses the signal from the computer it still works it just goes to a default fixed timing setting.

In these the pickup coil does not move so you don't have the likelihood of cracked wires like in the ones with vacuum advance.   
 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason