Distributor to coil rail conversion?

[KCsTJ]

Can a 97 or 98 2.5L or 4.0L jeep distributor engine be converted to a coil rail system ?
I'm sure the wire harness would need modification.
Is this done or could it be done without major modification ??

 

[Jerry Bransford]

I wouldn't expect that'd be an easy thing to do, not at all.

 

[Chris]

You'd need a different wiring harness, a different PCM, and likely a lot of other components as well.

Possible? Sure. Worth it? Not a chance.

 

[KCsTJ]

Gotcha, that was what my gut was telling me. Just thought id get confirmation from the experts.

 

[GASnBRASS]

Is there a problem with your current distributor?

 

[mrblaine]

Can a 97 or 98 2.5L or 4.0L jeep distributor engine be converted to a coil rail system ?
I'm sure the wire harness would need modification.
Is this done or could it be done without major modification ??

Sure it can be done. Lot of work though because you would basically be converting the entire underhood harness to be a 2000 along with the year equivalent sensors. The coil rail is a waste fire system. It has only 3 trigger wires out of the PCM and fires 2 cylinders at a time. You would also need the camshaft synchronizer but that plugs directly into the hole for the distributor so no change in that regard. Another challenge is the pre-00 heads do not have the threaded bosses to attach the coil rail. That can be overcome with some small sheet metal brackets off of the valve cover bolts. You could very likely just stab the boots on the plugs and they would never pop off.

 

[KCsTJ]

@GASnBRASS I think so, 175k miles and I got a cyl #1 misfire along with a too rich condition last week. Runs terrible when cold, think it's a timing issue
So I'm replacing the timing chain and gears, prob should replace distributor as well

 

[KCsTJ]

Sure it can be done. Lot of work though because you would basically be converting the entire underhood harness to be a 2000 along with the year equivalent sensors. The coil rail is a waste fire system. It has only 3 trigger wires out of the PCM and fires 2 cylinders at a time. You would also need the camshaft synchronizer but that plugs directly into the hole for the distributor so no change in that regard. Another challenge is the pre-00 heads do not have the threaded bosses to attach the coil rail. That can be overcome with some small sheet metal brackets off of the valve cover bolts. You could very likely just stab the boots on the plugs and they would never pop off.

Cool, thank you. Knew it would be involved but thanks for breaking it down to explain the process.

 

[PatMc]

@GASnBRASS I think so, 175k miles and I got a cyl #1 misfire along with a too rich condition last week. Runs terrible when cold, think it's a timing issue
So I'm replacing the timing chain and gears, prob should replace distributor as wellView attachment 124796

That seems like quite a bit of work without having tested anything to prove what's wrong. Run the crank around to TDC, pop off the distributor cap, and see how much crank movement you have before the distributor starts turning the other direction.

 

[KCsTJ]

That seems like quite a bit of work without having tested anything to prove what's wrong. Run the crank around to TDC, pop off the distributor cap, and see how much crank movement you have before the distributor starts turning the other direction.

Hey thanks, @PatMc I knew there was a way to check for timing chain slack but just didn't know exactly.
I will do that first thing tomorrow in fact.

 

[KCsTJ]

@PatMc it seems there is slack in the chain.
However I'm not sure if it is normal for 175k miles or not. How can i tell how much slack is too much slack?

 

[PatMc]

There will always be some slack, but shouldn't be much more than a degree or 3 of slack. How many degrees are you seeing?

 

[KCsTJ]

I don't have a good way to measure the degrees , ill have to figure that out. But going by what I can see, it seems more than 3 degrees.
I'll research that and check the degree of slack. Thanks for your help

 

[KCsTJ]

There will always be some slack, but shouldn't be much more than a degree or 3 of slack. How many degrees are you seeing?

I figured it out. The timing chain shows consistently 7.5-8 degrees slack. I checked it several times.
So the new gears and chain are going on, ill check the slack tolerance in the FSM
Thanks for the tip @PatMc