I've got a 1993 xj with a HO 4.0, and I put in a 1989 xj 4.0 motor temporarily until I get the original motor back from the shop. Everything from my 93 bolted right up, I bought a new cps, coil, plugs, wires, complete distributor, fuel filter, and a starter. It's been done for over a month and I still haven't gotten it to run. Everything works, but it seems like the timing is off. But you can't adjust the timing manually. I'm completely stumped on this one.

2 things come to mind. did you use the intake gasket for the 93 manifold or the 89?

I'm betting you have the dizzy in there wrong.

Setting Your 4.0 at #1 TDC
　
With #1 spark plug removed, turn the engine over clockwise using the 3/4" front crankshaft bolt. You will see the degree marks on your front cover. Mark the 0 with chalk or white-out.You will see the timing mark on the balancer. Mark it with chalk or white-out. While turning the engine over, put your finger/thumb over #1 spark plug hole. As the mark on the balancer approaches the marks on the front cover, if you are coming up on #1 TDC, pressure in the cylinder will push on your finger. If there's no pressure, you're at #6 TDC and need to crank the engine over until you see the marks coming together and you get pressure. Set the mark on the balancer to the 0 mark on the front cover.

http://www.angelfire.com/my/fan/dist_index.html

that has been done over and over again. i just replaced the entire distributor, after that i got it to run for about a minute and it even idled for a few seconds. i have replaced everything that has to do with the start-up process. im getting very frustrated trying to get my jeep running.

and i used a new intake gasket for the 93 manifold. i double checked to make sure everything lined up. it actually lined up better than what the 89 manifold did. i just dont know what else i can do.

Did you use the torque plate from the 93? The 89 torque plate might not work with the 93 CPS. Have you got spark?

i must also say that i did not swap the flexplate from the 93 engine. #17 from your renix thread states you should swap flywheel/flexplate when going from renix to HO. im guessing it would be the same when going from a HO to renix? if so then all the time and money i have spent trying to figure this out have been a complete waste of time.

might be a stupid question since im right in the middle of the issue. but what kind of problems would surface if you forgot to swap the flywheel/flexplate?

That's Cruiser's #17. Well,,,he will be back around 5AM Pacific time. Plenty of time to swap flex plates.

Boy, BUMMER... I don't know personally, but I'd bet Cruiser has it right. That may well be it. Do you have spark?

i did not swap the flexplate from the 93 engine. #17 from cruisers renix thread states you should swap flywheel/flexplate when going from renix to HO. im guessing it would be the same when going from a HO to renix? if so then all the time and money i have spent trying to figure this out have been a complete waste of time.

yea, but if the flexplate is different then the spark and fuel timing would be off, giving me the problems im having now. almost as if the timing is off.

There was a change in the way the CPS works between 90 and 91. I gather the gaps that it uses in the flex plate changed as well. The CPS tells the puter when to spark and fire the injectors.

ok, well i think i found my problem. have to get my 93 flexplate from the shop tomorrow. ill give you guys an update as soon as its done. thanks for the help.

I had missed this post. MMMMMMI really don't know. It ran eh?

I'm sacking out...


There is a brittle little tube. It comes out of a rubber plug, low on the engine side of the throttle body. It runs back to the firewall, then up to your MAP sensor sort of high up there near center on the firewall. CRUCIAL!! The MAP will tell the ECU to dump fuel with less/no vacuum. Any crack or blockage and it will be pig-rich. (black smoke, fouled black plugs). You can pull the line off the MAP and feel for vacuum with your finger. If it runs!

Well I don't know, maybe catch Cruiser in the early AM. Best of luck.....

OK, I took a moment to nail it down. The Renix has 12 gaps between a wider one. The OBD has just 4 small gaps spaced at 120*. Got me how it started and ran at all, but the flex plate is likely at least one of your problems. They are both at 1/3 if the diameter, (120*). Guess maybe your HO CPS was able to make just a little sense out of what it got from the Renix flex-plate.