1996 GMC Jimmy SLT 4×4

[Cyphercrash]

Although the information states 1996, I believe that the motor may have been switched for the 95 or al the least the heads were changed for whatever reason. My clue was that whenever I would want to change the spark plugs the ones listed for the 96 were not the ones that fit. The plugs from the 95 had the proper length and thread depth and pitch.

So here is my dilema... Do I gap the plugs as if this was the 95 motor or do I gap the plugs for the specifications of the 96 ECM?

[95 S_Trucker]

Can you take a pic of the engine? There are major differences in the pre 96 engines(tbi or CPI) and the 96 and later engines. The cylinder heads are not interchangeable between the 2. The intake manifolds have different bolt patterns.

The 96 and newer call for platinum or iridium plugs. Never gap an iridium plug. It will chip and ruin it. Just make sure the plug wasn't dropped or damaged.

[Cyphercrash]

What is it you want to know. It has a Single fuel injection spider, with a plastic upper intake manifold, the plugs that fit are the AC Delco 803, the plugs listed are like the 809 the entire motor was replaced pre ownership according to the previous owner.

[95 S_Trucker]

There's no possible way for a 96 and newer intake manifold to bolt to 95 and earlier heads. Your motor must be a 96+. I'll look at some plugs when I get to work.

[95 S_Trucker]

I see 41-803 for a 95 and down, I see 41-979(double platinum) and 41-993(iridium) for 96+

So do the 96 plugs not fit? or did it have 95 down plug installed in it previously? Its possible the last person to due a tune up put the wrong plugs in it.

[Cyphercrash]

Originally Posted by 95 S_Trucker

I see 41-803 for a 95 and down, I see 41-979(double platinum) and 41-993(iridium) for 96+

So do the 96 plugs not fit? or did it have 95 down plug installed in it previously? Its possible the last person to due a tune up put the wrong plugs in it.

THE 41-979 is a long plug , thin, fine thread. If I put them in my Jimmy they do not go in properly and if I start it they get blown out of the holes.

The 41-803 is the only plug that fits the treads in the head.

[Cyphercrash]

Originally Posted by 95 S_Trucker

There's no possible way for a 96 and newer intake manifold to bolt to 95 and earlier heads. Your motor must be a 96+. I'll look at some plugs when I get to work.

The motor is 95 the body and ECM are a 96

[95 S_Trucker]

Can you take some pics of the motor? Especially of the intake manifold and bolts.

The 96+ intake manifold only has 8 bolts holding it down, and they are straight up and down.

95 and earlier have 12 bolts, and they are angled.

Its not physically possible to put a 96+ intake on older heads.

[Cyphercrash]

Originally Posted by 95 S_Trucker

Can you take some pics of the motor? Especially of the intake manifold and bolts.

The 96+ intake manifold only has 8 bolts holding it down, and they are straight up and down.

95 and earlier have 12 bolts, and they are angled.

Its not physically possible to put a 96+ intake on older heads.

Missing the point..... I already stated that the entire motor was replaced, I'm assuming they put as much from the original back ass possible (jiffy Lube left the oil plug out on previous owner.) No I can't post pictures because there is no place for me to post them and then link to them. But the 95 and 96 vortec blocks are exactly the same the heads however have major differences. My question is if they put the 95 motor into a 96 body with a 96 computer, the values returned to the computer could effect the running of the vehicle. There's a big difference between the 96 and 95 spark plug, the 96 has no real alternatives like platinum and iridium from what I see where as the 95 was much more choice. Or visa versa, I have memory issues from Parkinson's. If they just bought a 95 block, heads intake manifold and transfered everything to it from the 96 the question still exists that the 96 computer receiving different values than expected will cause issues. Plugs have different resistances, use different amounts of amperage to fire, so this will confuse the cuter as well. Bottom line, the Registration says 96, but the block heads intake and who knows what else were taken from 95 because of jiffy lube

[95 S_Trucker]

You are saying the entire motor was replaced and a vortec intake manifold was installed. I am saying that it's not possible to put a vortec intake on 95 heads.

The intake manifolds are different between 95 tbi, cpi, and 96 vortec. They bolt in differently and they look very different, and they inject fuel differently.
R
Posting pics is easy on this site. You can upload them from your computer or phone. No need to link them from a third party.

[Cyphercrash]

Originally Posted by 95 S_Trucker

You are saying the entire motor was replaced and a vortec intake manifold was installed. I am saying that it's not possible to put a vortec intake on 95 heads.

The intake manifolds are different between 95 tbi, cpi, and 96 vortec. They bolt in differently and they look very different, and they inject fuel differently.
R
Posting pics is easy on this site. You can upload them from your computer or phone. No need to link them from a third party.

No I'm saying g they took a 95 vortec and stuck it in a 96 body with a 96 computer

[95 S_Trucker]

Th first year for the plastic plenum intake is 96. You said that's the intake you have.

[Cyphercrash]

Originally Posted by 95 S_Trucker

Th first year for the plastic plenum intake is 96. You said that's the intake you have.

Well, lets review the facts. The engine only accepts the 803 plugs. It has the plastic upper intake, is it possible that they drilled out the spark plug holes and Re tapped them for the other plugs? I'm just trying to figure the gap out.

[95 S_Trucker]

I am trying to find what the facts are. I am trying to figure out what kind of parts were used to put the engine together.

It's more likely that they re drilled the intake manifold. That's why I wanted to see pics. Just put the plugs in that fit. If you have the newer "crab" style distributor, you can gap them at .060".

[Cyphercrash]

Originally Posted by 95 S_Trucker

I am trying to find what the facts are. I am trying to figure out what kind of parts were used to put the engine together.

It's more likely that they re drilled the intake manifold. That's why I wanted to see pics. Just put the plugs in that fit. If you have the newer "crab" style distributor, you can gap them at .060".

Horizontal cap

[95 S_Trucker]

Then look at the last sentence in post 14.

I would like to help you find out what engine you have pieced together, but I cant do that without more info or pics. I am done posting in this thread until that happens.