: 1993 Caddillac Eldorado - Timing Chain Issue



travisj027
09-14-09, 09:39 AM
Okay, so first I would like to start off by saying that this isn't my car. It is a friends. I am just going to give a description of what happened.

It is a 1993 Cadillac Eldorado

4.6 Engine
32 Valve V8 Northstar

Apparently, the timing chain has broken or it is along those lines. He cannot find a how-to guide or anything online and the dealership wants $3600 to fix it.

He said that is backfired and it's throwing the exhaust fumes out of the intake. So it is out of timing.

Any help would be appreciated, a guide on how to replace it. He hasn't tried the Cadillac forums so I figured this be a good place to start. Thanks in advance.

-Travis

Submariner409
09-14-09, 10:51 AM
Replacing timing chains (3), cams, or valve lifters on a 4.6 Northstar, in the car, is a tedious exercise that cannot be explained in a running thread. Too many variables on-scene. Get a Helm/GM Factory Service Manual from www.helminc.com or eBay. Another option is to subscribe the car to www.alldatadiy.com for a year or two.

There's a recent thread, sort of like "Valve lifter ticking" down in the Northstar forum. It involves much of what you're looking at.

The diagrams show basically what you're up against, but that's only the tip of the iceberg.

Submariner409
09-14-09, 10:57 AM
This is a double post, identical to one up in Seville/Eldorado. There is an answer up there.............:thepan: !!

Ranger
09-14-09, 12:05 PM
Merged

travisj027
09-14-09, 12:20 PM
Appreciate merging the threads, wasn't sure where to exactly put it.

So could it be something else? Or is it definitely the timing chain?

Also, for that thread you recommended. Is it a really long one?

Submariner409
09-14-09, 03:32 PM
IIRC it covers 4 pages or so of pictures, starts and stops, and workarounds. Worth finding and reading.

travisj027
09-14-09, 03:39 PM
IIRC it covers 4 pages or so of pictures, starts and stops, and workarounds. Worth finding and reading.

IIRC?

And it is absolutely the timing chain?

Submariner409
09-14-09, 03:54 PM
If I Remember Correctly...............

............backfires and smoke and gas out the intake manifold can be a lot of things, but if the posted dealer diagnosis was timing chain failure, then you're on the right track, otherwise you need to do, or have done, some pretty deep troubleshooting.

If the engine runs at all, timing chain(s) are not at the top of the fault list. BUT, if a chain has let go, there's going to be a real mess to clean up, time and mechanically-wise. When a chain goes, it takes other parts with it.

If a top overhaul is the only option, then so be it. Preferably, find another low-mileage same year (not likely with a 93) engine to swap or go big time and get a new GM long block - Big $$$$$

Ranger
09-14-09, 05:06 PM
The symptoms sound like a chain, BUT they are very reliable and I can't ever recall hearing of one letting go.

Submariner409
09-14-09, 05:11 PM
Ranger is correct and upon thinking back, if a chain had let go at anything other than slow idle there would probably be engine pieces all over the place.............

travisj027
09-14-09, 07:36 PM
If I Remember Correctly...............

............backfires and smoke and gas out the intake manifold can be a lot of things, but if the posted dealer diagnosis was timing chain failure, then you're on the right track, otherwise you need to do, or have done, some pretty deep troubleshooting.

If the engine runs at all, timing chain(s) are not at the top of the fault list. BUT, if a chain has let go, there's going to be a real mess to clean up, time and mechanically-wise. When a chain goes, it takes other parts with it.

If a top overhaul is the only option, then so be it. Preferably, find another low-mileage same year (not likely with a 93) engine to swap or go big time and get a new GM long block - Big $$$$$


Ranger is correct and upon thinking back, if a chain had let go at anything other than slow idle there would probably be engine pieces all over the place.............

I don't think he actually had the dealer scan it, he just asked him how much it would be for a timing chain repair.

I was thinking the same thing, after reading everything wouldn't the engine not start at all if this was the case?

So it could be something else, what else may actually cause this. I would like him not to start doing this long job or buying a new engine until we have definitely confirmed it is the chain.


The symptoms sound like a chain, BUT they are very reliable and I can't ever recall hearing of one letting go.

That is what I've been reading all day. I've searched all over the net and I haven't found anything about one actually breaking.

Is that thread any of these?

Lifter starting to tap and needs replacing
My Rough Idle Story, So Far
Started to hear an intermittent grinding noise?

Thanks again, appreciate the help.

Krashed989
09-15-09, 04:32 AM
If it's backfiring, that means that the spark is firing when the intake valve is still open. It could be caused by one of two things: An Ignition problem (which includes anything that would tell the PCM or ICM to adjust spark timing), or a valve timing problem.

Were the spark plug wires messed with at all? That would be the very first thing to check. Just make sure they are routed correctly. Sub has posted the illustrations thousands of times so I'll just route you to one of his posts: http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/178321-engine-misses-stoplights.html#post1982574