Last week my son and I installed a newer (90k) engine in his 89. Yesterday we got it buttoned up and cranked it over. Idled a little rough but smoothed out once it got up to normal temp but I went to give it some throttle it fell on it's *** and would backfire out the exhaust. I checked the firing order and it is correct. Can the timing be adjusted on my 89 model? I'm going to pick up a new CPS and see if maybe it went bad during the swap. Any other ideas? Thanks for the help and support

Ed

 

no timing is non adjustable,ive heard of the dist being moved just a little never tried ,

 

Can a bad computer cause the jeep to backfire?

 

wondering if you changed the computer too?

or was the engine from the same year?

did you ensure you connected ALL the sensors in the engine electrical harness?

IAC, MAP, Knock sensor, TPS, coolant temp, etc etc etc.....

check the engine you pulled out of the car and match up the number of sensors on the block and head etc to the one that you installed.

maybe not having one of the sensors plugged in is driving the computer crazy

or..........the timing is 180 degrees out. I have seen that on chevy 350's and ford 360's all the time...

just my two cents


cpnwrench

 

I double check all the sensors again and going replace the ECM and icm. If none of this does it I'm thinking the engine or head is bad.