i have an 89 jeep wranger 2.5 that will not fire

[Timberjack86]

last year the transmission went out. I bought a used one and replaced it, we had to weld bolts in the frame to hold the skid plate. when we got it together the jeep would not fire. i bought a cpsand it didnt work. then a coil and router cap and button, then a ecm out of a 91(was wondering if there is any differents in a 89 ecm to a 91). it didnt work so i bought an ignition control module, and still nothing. Was just wanting so ideas of where to go next, i'm getting 12.3 v to the coil and though the other side too. but no spark at the plug nothing. thanks.

 

[JPNinPA]

Test for spark. Place your Jeep in neutral (or park if it's an automatic). Be sure to chocked the wheels to prevent it rolling. Pull the coil wire from the distributor and put an extra spark plug in the end you removed from the distributor. Ground the spark plug and have someone turn the key over like they are starting the engine. Keep your fingers/hand away from the metal; part of the plug. There is a high chance for getting a hard electrical shock!!

If you got a nice blue spark as you turn the engine over, no need to investigate farther. If the spark is orange or some similar color. Either the coil is weak and is going bad or you do not have proper voltage going into the coil.

The battery should be 12.6V the 12.3V seems low.


Sent from my iPhone using Jeepz.com mobile app

 

[Bounty__Hunter]

Big difference between the '89 and '91 ECM, you should find an '89 ECM before going further.

 

[greg92jeepxj]

Agree with all the above . Spark should be determined if present and injector pulse confirmed using a noid light on an injector harness plug.
but the problem seems to be more than that . A 1991 PCM won't work on a 1989.
'91 and up is Chrysler and '90 and down is AMC . Two different engine management systems .
chrysler uses their house brand sequential port injection system and ignition system using a different flywheel or flex plate than AMC .
chrysler flywheels have notches in three separate parts with six notches each.
The flex plates are similar but use Windows . This is how the crank shaft position sensor reads for injector pulse firing order and ignition firing order.
Your AMC uses a similar system but it is of RENIX design ( Renault bendix ) .
The flywhell would have notches a and the flex plate would have windows around the entire circumference . This would mean AMC and Chrysler are two different engine management systems . The engine wiring may seem to fit but the sensor feed back won't agree with the programmed engine map . Crank sensors will obviously not send the signal at the right timing and won't be properly interpreted . Cam sensor readings are likely to be different too .
On obd 1 Chrysler , the cam sensor is similar to RENIX but won't do any good if the crank sensor dosen't relay correct signal at the correct time . Obd 2 cam sensor is different and may not work altogether with obd 1 AMC .
This is a lesson I learned the hard way back in the '90's when a brother asked if I can help do a motor swap on a Cherokee . Don't remember what year XJ to receive ( pre or post '96 , the first year of obd2 ) but the donor was a RENIX jeep . My brother compiled a hodge podge of RENIX and Chrysler obd 1 & 2 parts . We couldn't figure out what was wrong and why it didn't start after assembly . I guess I didn't read directions ? No , we didn't stay genuine to manufacturer .
thankfully , the engine , trans and t-case stayed RENIX so at least the flex plate was right . Whew ! After research , he and I got it right since we figured it must have been the mix of parts .
I learned this the hard way and thankfully I did . His then wife was threatening to pull the project from us and take it to a local mechanic . We saved her from getting robbed $$ , excess assembly time aside .