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Cadillac Deville 1990
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266 Posts
Discussion Starter #1
Hey all it has been a while but glad to be back. The question I have has to do with a misfire I am experiencing on my baby. Recently I notice a slight backfire through exhaust and when it warmed the puttering and hesitation got allot worst. I had also been having bad mileage even after I replaced the plugs.

Since this was my dads old car I knew he had never replaced or cleaned the rotors and distributor cap since he bought the car and this is what I thought was the problem to the gas mileage. So I bought a new rotor, new cap, new wires and new plugs to fix this issue and yesterday I started to work on it. Yesterday I pulled the cap and rotor and noticed a few things that proved I was right. When I got the cap off I noticed the ignition coil wire plug was hard to remove and when I finally removed it it was scorned badly and allot of black carbon buildup was on the connection. So I ran to the parts store and got me a new ignition coil. When I did pull the cap off I notice the rotor was all black from the contact point of the ignition coil plus the rotors contact end was a bit smaller about a mm when I compared to the new one. plus on the underside of the cap I noticed the contact ends where the rotor contacts the cap were rusty and corroded.

Figuring I had found the issue for my misfire I replaced all the parts to the distributor and put the car back together to see if this was the issue on my car. When I started the car, though, the misfire was allot worst and from the start. I ran the car around the block to see if it would adjust itself but no cigar. Hence why I am here. Did I miss something in the stuff I fixed? I am planning the recheck my work today but is there something I have to reset, readjust, or flash?
 

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1990 Deville 4.5L
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57 Posts
My car has been having misfire issues for awhile now. It's usually worse cold and gets better as the engine warms up, though. I've replaced 2 injectors already, each of which has improved the misfiring. I'm buying a set of 8 and replacing all of them. It seems that the factory Cadillac injectors aren't too good and often have issues.
 

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2011 Crown Vic LX, 2009 Chevy Malibu 2LT
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5,607 Posts
My car has been having misfire issues for awhile now. It's usually worse cold and gets better as the engine warms up, though. I've replaced 2 injectors already, each of which has improved the misfiring. I'm buying a set of 8 and replacing all of them. It seems that the factory Cadillac injectors aren't too good and often have issues.
The original Multecs aren't as bad as everyone makes them seem. Mechanically, they are actually a superior design to even the later Bosch injectors. You'll rarely find a Multec that leaks, has a degraded spray pattern, or is restricted.

However it's unfortunate that the coils were a problem and they shorted electrically.

ANYWAY, the symptoms are changing as your playing with the ignition system, so you must be in the ballpark. Corroded connectors to the distributor is bad.

Specifically, what did you replace?
 

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Registered
1990 Deville 4.5L
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57 Posts
The original Multecs aren't as bad as everyone makes them seem. Mechanically, they are actually a superior design to even the later Bosch injectors. You'll rarely find a Multec that leaks, has a degraded spray pattern, or is restricted.

However it's unfortunate that the coils were a problem and they shorted electrically.

ANYWAY, the symptoms are changing as your playing with the ignition system, so you must be in the ballpark. Corroded connectors to the distributor is bad.

Specifically, what did you replace?
Well, I was going to buy the set of 8 reman injectors from the Precision Injector guy who sells on ebay. He has great ratings, and I spoke with a couple people on the board last year who used his parts and had positive results. It's about $130 for a set of Bosch 4 hole injectors, or $34 per injector for GB reman Cadillac Multecs from my local auto parts store. What should I buy?

OP, sorry for thread hijack...

OP, did you pull codes? You may get some info from those...either bad sensor or a particular cylinder that's misfiring.
 

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Cadillac Deville 1990
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266 Posts
Discussion Starter #6
Thanks for all the responses guys but I figured out what the problem was. This must have been an issue since I got the car from my dad, when I pulled the cap I marked the cables and the position of the cables to the cap and replaced them as I marked them. When I was looking at the FSM I notice two wires were in the wrong place and once I fix that the car is running like a champ now. I still have a slight back fire but that should get corrected with the plugs and wires I am putting in now. So far the car revs up nicely and not putter plus no lose of power when I rev high.

I don't think I crossed the wires myself which is why I think it was the last mechanic that worked on the car when my dad had it. Now if this heat comes down I could finish the plugs I did the front 4 yesterday and I was soaked from head to toe:helpless:
 
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