Buggy XJ Running ROUGH

[88XJScott]

I swapped in a new trans and this is how she is running now. I put in a new CPS cause I crushed the old wire putting the new trans in. It didnt start with the old CPS, but ran like the videos above with the new one.

This is an 88 cherokee with the non-HO renix motor. Any thoughts? I'm feeling stumped.

 

[1990JEEPXJ]

is the MAP sensor good, plugged in, and the vacuum line connected?

 

[Darky]

Which transmission?

Even though it's on a buggy. this is probably still more OEM tech. Assuming it'san OEM engine and OEM transmission.

 

[88XJScott]

It has an aw4 from a 98, started running like this after the swap.

MAP sensor is plugged in and vacuum line hooked up. When I unplugged the MAP, it wouldnt run at all...

 

[redneck]

Make sure that you have the CPS seated properly. I had the same sorta thing happen to me the first time I changed out my CPS.

 

[avnsteve]

double check the compatibility between 88 and 98 TCU, if that's good then go back and DOUBLE AND TRIPLE check vacuum lines etc

 

[dave92cherokee]

It almost sounds like it's missing from wires being crossed on the cap or a bad plug or two or a bad injector. Mine did the same thing when the wires on the cap were switched around it would be enough to get it to run for a couple seconds then die out.

 

[89xj]

did you do everything from yesterdays post:

http://naxja.org/forum/showthread.php?t=1031467

im unable to view the videos, but i would trace the cps wiring for damage along with the connector/harness.

elctrically speaking, nothing was disconnectd from the engine during the swap except the cps and the tcu?

have you tested the fuel pressure with a gauge? have you checked for a damaged fuel line?

 

[89xj]

looking at my renix fuel injection manual, it appears that the ecu looks for a signal from the shift lamp curcuit. im assuming this comes from the trans or the tcu. not sure if this has an affect on how the engine would run, but could it be the ecu is looking for this signal and not receiving it, causing a missfire??

do you have the renix fuel injection manual?

www.lunghd.com has some great testing info on all the renix sensors along with the manual.

before testing all the sensors, i would test fuel pressure at the rail.

is the ground strap at the back of the head still connected to the fire wall?

edit: i was able to watch the video. is that loud humming before start up the fuel pump? never heard a pump that loud before. the engine sounds exactly like an my gm350 when i was 1 post off with the spark plug wires on the distributor cap posts.

 

[trippled]

def sounds like fire order, but what all did you disconnect to do the swap? how did it run before the swap?

 

[88XJScott]

Fixed it! Faulty CPS from Advance Auto parts was driving my computer nuts.

A new one went in and it fired right up. Thanks for the help guys, I know my jeep motor 10x better now...