Trev1006

So it is OEM parts so I thought I'd post it here. I just swapped in a freshened up 98 4.0 into my 92 mj and now all the sudden get no spark? Its also odd b/*** fuel gauge also now says full when I had only 1/4 when i pulled the engine yesterday? I did forget to plug in the CPS and cranked it over a few times but nothing else out of the ordinary tho, ive done abt 10 4.0 swaps and no problems then this! Please help

cruiser54

Which dizzy did you use?

Trev1006

I used the dizzy from the 92 engine that I removed. This engine ran fine except for using oil and a lifter tic. It had 300k on it. I turned it to tdc and pulled the cap and the button pointed at number 4 so I turned the new engine to tdc and installed the rotor with the button in the same position? I though this would be a foolproof way to do it.

cruiser54

I'm gonna say that 99% of the time the reason a transplanted, new, or rebuilt engine doesn't start/run is the dizzy is installed wrong.

Trev1006

I think I did install it wrong......it started sleeting here so I quit for the day hit I hope I can reset it tomorrow. Do you have a procedure that you.use to set it? Ive never switched a used one, only re-install one or.a new one with the pin that holds them at 1

cruiser54

Remove #1 spark plug. Rotate the engine over by hand. With your finger or thumb over the #1 spark plug hole, wait to feel pressure on the finger. When you begin to feel pressure, slowly rotate the engine until the TDC mark on the front pulley is aligned with the pointer. Mark your distributor housing to correspond with the #1 spark plug wire terminal of the distributor cap. Install the distributor and makes sure the rotor points to the mark you made on the distributor housing while the housing is seated and slot of the housing is lined up with the holddown bolt.

Trev1006

[QUOTE=cruiser54;1352913]Remove #1 spark plug. Rotate the engine over by hand. With your finger or thumb over the #1 spark plug hole, wait to feel pressure on the finger. When you begin to feel pressure, slowly rotate the engine until the TDC mark on the front pulley is aligned with the pointer. Mark your distributor housing to correspond with the #1 spark plug wire terminal of the distributor cap. Install the distributor and makes sure the rotor points to the mark you made on the distributor housing while the housing is seated and slot of the housing is lined up with the holddown bolt.[/QUOTE

Ok I will try this in the am, thanks ill post how it works

Trev1006

[quote=Trev1006;1352922]Ok, did this. Can you be out one tooth one way or another or should it be exact on your mark? I also found ckp was damaged so I replaced it still no start. And I still have a leaky injector, does the asd engage under low fuel pressure?

cruiser54

You need to be dead-nuts on if possible.

Trev1006

After all this cranking the number one plug isn't even wet, fuel at the rail but plug dry. So would whatever is giving me no spark is also causing the injectors not to fire?

Trev1006

So i re sealed my leaky injectors and re set the distributor and now the rotor points more at the number one on the cap now. Now I do have a weak spark and fuel at the rail but still no.start?

akita8

If you just reinstalled the engine make sure you have the ground wires connected at the rt rear of the engine block. The grounds can hide back there are can be overlooked.

may pop

Sounds like a ground problem because of many problems. Especially the fuel gauge pegging

Trev1006

There were ground straps on both sides of the engine and i was sure I installed them.but will double check tomorrow.

cruiser54

There are three or four wires that attach at the engine dipstick tube stud.

Follow these instructions to be sure those critical grounds are good:

Renix Ground Refreshing
The Renix era XJs and MJs were built with an under-engineered grounding system for the engine/transmission electronics. One problem in particular involves the multiple ground connection at the engine dipstick tube stud. A poor ground here can cause a multitude of driveabililty issues, wasted time, and wasted money replacing unnecessary components.
The components grounding at the dipstick tube stud are:
Distributor Sync Sensor, TCU main ground, TCU "Shift Point Logic", Ignition control Module, Injectors, ECU main ground which other engine sensors ground through, Oxygen sensor, Knock Sensor, Cruise Control, and Transmission Sync signal. All extremely important stuff.
The factory was aware of the issues with this ground point and addressed it by suggesting the following:
Remove the nut holding the wire terminations to the stud. Verify that the stud is indeed tightened securely into the block. Scrape any and all paint from the stud’s mounting surface where the wires will attach. Must be clean, shiny and free of any oil, grease, or paint.
Inspect the wire terminations. Inspect to see that none of the terminations are crimped over wire insulation instead of bare wire. Be sure the crimps are tight. It wouldn’t hurt to re-crimp them just as a matter of course. Sand and polish the wire terminals until clean and shiny on both sides. Reinstall all the wires to the stud and tighten the nut down securely.
While you’re in that general area, locate the battery negative cable which is fastened to the engine block just forward of the dipstick stud. Remove the bolt, scrape the block to bare meta, clean and polish the cable termination, and reattach securely.
Another area where the grounding system on Renix era Jeeps was lacking is the engine to chassis ground. There is a braided cable from the back of the cylinder head that also attaches to the driver’s side of the firewall. This cable is undersized for it’s intended use and subject to corrosion and poor connections at each end.
First off, remove the cable end from the firewall using a 15mm wrench or socket. Scrape the paint off down to bare metal and clean the wire termination. Reattach securely.
Remove the other end of the cable from the rear of the head using a 3’4" socket. Clean all the oil, paint and crud from the stud. Clean the wire terminal of the cable and reattach securely.
A suggestion regarding the braided cable:
I prefer to add a #4 Gauge cable from the firewall to a bolt on the rear of the intake manifold, either to a heat shield bolt or fuel rail bolt. A cable about 16’ long with a 3/8" lug on each end works great and you can get one at any parts store already made up.
If you want to upgrade your grounds and battery cables in general, contact Jon at www.kelleyswip.com. He makes an incredible cable upgrade for a very reasonable price.