1996 Fleetwood Brougham Shudder

[alfredgee]

Hi Gang,

My friends Fleetwood is experiencing a shudder/stumble under very light acceleration and the dealer is at a loss at what the problem could be.

The car has no codes right now and it all started after they replaced the waterpump and the distributor.

To try and cure the problem, they have also replaced the EGR and the O2 sensors.

Can anyone comment on where he should look next?

Thanks!

Alfred Gee

1996 ETC

[Bruce Nunnally]

What year Fleetwood (with which engine)?

[KHE]

Hi Gang,

My friends Fleetwood is experiencing a shudder/stumble under very light acceleration and the dealer is at a loss at what the problem could be.

The car has no codes right now and it all started after they replaced the waterpump and the distributor.

To try and cure the problem, they have also replaced the EGR and the O2 sensors.

Can anyone comment on where he should look next?

Thanks!

Alfred Gee

1996 ETC

If it started right after the distrubitor was replaced, that's where they should look for the problem. Was the distributor replaced due to a problem with the optispark unit? Maybe the dealer did not get the plug wires fully seated in the distributor.

What year Fleetwood (with which engine)?

Bruce, It's a '96 and has the LT-1 350 engine.

[alfredgee]

They replaced the distributor because according to the dealer, there is a sensor in the unit and once coolant gets on it, the car will not run correctly and there is no way to clean it.

I'll see if he checked the wires, but I'm sure he has since he has been at it as well as the dealer. Most frustrating part is the dealer is telling him it's they way he drives!

Thanks!

Alfred

1996 ETC

[KevinW]

It is evident that either the new distributor (internal defect), or the process of changing the distributor (improperly seated ignition lead(s), as mentioned; damaged lead(s); incorrect connections resulting the wrong firing order) is responsible for the observed problem.

The dealer changed an (expensive) distributor that did not require replacement, and created a new problem in the process that they are unable to diagnose and repair! What a rip-off!

[Ranger]

How old are the wires? The '95 - '97 Northstars were recalled to R & R the fuel rail. In the proccess the wires must be moved. We have found that a misfire as you discribe is a common problem afterwards. Perhaps a new set of wires is all that is needed.

[Cadillac Jim]

It's not always easy to get good help these days. Sometimes a dealer is hostage to a horsy technician. The service manager telling you that "It's the way you drive" is the biggest of red flags that he has no confidence that the technician can fix the problem and is hoping that it will go away. I would take the car elsewhere to get this problem fixed – perhaps to another Cadillac (or Pontiac, or Buck, or Chevrolet, or Saab, or Hummer or whatever GM) dealer.

The whole thing sounds very much like arcing in the distributor cap, wires, or plugs. I had that problem once on a bow-tie V8 and found that about half the plugs were finger-tight, and one was over-tightened so that the gasket wouldn't seal anymore; I changed all the plugs myself and the problem went away. Most times this is caused by condensation in the distributor cap or arcing in the plug wires. I once had arcing plug wires that caused this problem, and traced it to a technician using an ice pick to puncture the plug wire on No. 1 to time the car.

Also, look for the vacuum line to the distributor and make sure that it is hooked up properly. A lack of vacuum advance can make the throttle response of any car with a distributor go all funny, and the timing will likely be way off.

Two things you can do yourself are to inspect and clean the distributor cap, and check for outside arcs. Pop the cap and look inside. If you see fingerprints or grease stains, that either is your problem or will cause a problem soon, and I would just replace the cap with a new one myself. To check for sparks, just raise the hood at night in the garage, turn off all the lights, and look around while a friend blips the throttle a little (don't rev the engine over 3,000 rpm).

[KHE]

It's not always easy to get good help these days. Sometimes a dealer is hostage to a horsy technician. The service manager telling you that "It's the way you drive" is the biggest of red flags that he has no confidence that the technician can fix the problem and is hoping that it will go away. I would take the car elsewhere to get this problem fixed – perhaps to another Cadillac (or Pontiac, or Buck, or Chevrolet, or Saab, or Hummer or whatever GM) dealer.

The whole thing sounds very much like arcing in the distributor cap, wires, or plugs. I had that problem once on a bow-tie V8 and found that about half the plugs were finger-tight, and one was over-tightened so that the gasket wouldn't seal anymore; I changed all the plugs myself and the problem went away. Most times this is caused by condensation in the distributor cap or arcing in the plug wires. I once had arcing plug wires that caused this problem, and traced it to a technician using an ice pick to puncture the plug wire on No. 1 to time the car.

Also, look for the vacuum line to the distributor and make sure that it is hooked up properly. A lack of vacuum advance can make the throttle response of any car with a distributor go all funny, and the timing will likely be way off.

Two things you can do yourself are to inspect and clean the distributor cap, and check for outside arcs. Pop the cap and look inside. If you see fingerprints or grease stains, that either is your problem or will cause a problem soon, and I would just replace the cap with a new one myself. To check for sparks, just raise the hood at night in the garage, turn off all the lights, and look around while a friend blips the throttle a little (don't rev the engine over 3,000 rpm).

There's no "distributor cap" pre se on the LT-1 350 - it is a self contained unit. I am betting on bad wires or the wires are not seated properly on the distributor. An ignition scope would be able to pinpoint the problem in short order.

[Cadillac Jim]

Almost any filling station with a good service area will have an ignition analyzer. Look for "State Emissions Inspection" sign or something like it at a shop near you. If you're picky, look at one of the Goodyear Service Center, Pep Boys, or mall service centers that have a chain behind them, and look on the wall for mechanic certifications. If you see one on emissions or tune-up, note the name and ask to talk to him to make sure he's still there.