Stallacrew
NAXJA Forum User
- Location
- Cullman, Alabama
Ok, so I've looked over every bit of the Cruiser54 and lunghd.com website sensor problems and I still can't get my AW4 2WD 1989 4.0 Renix MJ Eliminator w/278k miles to run well. I used to be a paid naxja.org member but I've been without an XJ/MJ until recently. I'll re-up on my membership once this new job starts.
I bought it in this poor running condition and I've gotten it to at least idle decently well and crank up when I turn the key without having to fool with the map sensor vac line. Previous owner would crank it and it would then die shortly and then he'd pull the vac line and it'd crank and "lope" hard while it idled. Runs like dogcrap aside from idle.
Things I've checked:
-All the grounds are good.
-New plugs and wires from previous owner.
-Previous owner replaced fuel pump and filter recently so the pressure should be acceptable but I haven't been able to check it yet.
-Previous owner installed a new distributor (which I'm suspicious of)
-I've tried new Map Sensor and still runs the same.
-New coolant temp sensor changed nothing
-TPS was set to 10% and I adjusted it to the recommended 17%
-IAC is working well.
-CPS swapped out and works fine (I did read where one guy used washers to space it out to make it read under load, it was cutting out because the flex plate was bending out of the CPS plane)
-No vacuum leak I can find, previous owner replaced the major lines and tidied it all up. I am missing the vac bulb in the bumper but maybe I'm not supposed to have one?
-EGR is disconnected from the vacuum lines and they are plugged, I'm making an EGR delete plate to get rid of it (no emissions here)
-Battery reads right at 12.02v at the terminals(no cranked) but reads 13.1 on my MT2500 scanner.
-Input voltage to MAP AND TPS are 4.95v each.
-At idle, injector pulse is 6.9 to 7.9 mS, goes up to 27+ as it bogs down under partial and full throttle. It backfires through the exhaust at 50-100% throttle.
-Spark advance at idle is 14 degrees, goes up to 35+ degrees with throttle.
-MAP sensor voltage is 1.8v at idle on the scanner
-O2 sensor is at 4.98v and does not change according to the scanner, I'm sure it's fouled with such rich running recently.
-Idles at 800 rpm, won't go over 1500 and it shoots soot out the tailpipe and backfires and pops in the intake.
-I put a spark tester light on and it cuts out with partial/wot. Replaced the coil with a known good one.
Has tons of blow-by gasses coming through intake boot (I've been running it with everything disconnected and just an open throttle body because the gasses kill the engine if I move the boot back onto the intake)
Ive checked and replaced everything I know to do other than the O2 sensor which I feel is fouled and bad but shouldn't cause this (don't have the cash for another week).
I feel like it might be a tooth off on the distributor that the PO installed, but I haven't tried to check timing yet.
Any thing else to check? I'm out of ideas and I've read over this forum for bog down issues. All the critical sensors seem to be ok unless it's the CPS not reading under throttle because the flexplate is bowing out.
Someone knowledgeable please help, and thank you.
I bought it in this poor running condition and I've gotten it to at least idle decently well and crank up when I turn the key without having to fool with the map sensor vac line. Previous owner would crank it and it would then die shortly and then he'd pull the vac line and it'd crank and "lope" hard while it idled. Runs like dogcrap aside from idle.
Things I've checked:
-All the grounds are good.
-New plugs and wires from previous owner.
-Previous owner replaced fuel pump and filter recently so the pressure should be acceptable but I haven't been able to check it yet.
-Previous owner installed a new distributor (which I'm suspicious of)
-I've tried new Map Sensor and still runs the same.
-New coolant temp sensor changed nothing
-TPS was set to 10% and I adjusted it to the recommended 17%
-IAC is working well.
-CPS swapped out and works fine (I did read where one guy used washers to space it out to make it read under load, it was cutting out because the flex plate was bending out of the CPS plane)
-No vacuum leak I can find, previous owner replaced the major lines and tidied it all up. I am missing the vac bulb in the bumper but maybe I'm not supposed to have one?
-EGR is disconnected from the vacuum lines and they are plugged, I'm making an EGR delete plate to get rid of it (no emissions here)
-Battery reads right at 12.02v at the terminals(no cranked) but reads 13.1 on my MT2500 scanner.
-Input voltage to MAP AND TPS are 4.95v each.
-At idle, injector pulse is 6.9 to 7.9 mS, goes up to 27+ as it bogs down under partial and full throttle. It backfires through the exhaust at 50-100% throttle.
-Spark advance at idle is 14 degrees, goes up to 35+ degrees with throttle.
-MAP sensor voltage is 1.8v at idle on the scanner
-O2 sensor is at 4.98v and does not change according to the scanner, I'm sure it's fouled with such rich running recently.
-Idles at 800 rpm, won't go over 1500 and it shoots soot out the tailpipe and backfires and pops in the intake.
-I put a spark tester light on and it cuts out with partial/wot. Replaced the coil with a known good one.
Has tons of blow-by gasses coming through intake boot (I've been running it with everything disconnected and just an open throttle body because the gasses kill the engine if I move the boot back onto the intake)
Ive checked and replaced everything I know to do other than the O2 sensor which I feel is fouled and bad but shouldn't cause this (don't have the cash for another week).
I feel like it might be a tooth off on the distributor that the PO installed, but I haven't tried to check timing yet.
Any thing else to check? I'm out of ideas and I've read over this forum for bog down issues. All the critical sensors seem to be ok unless it's the CPS not reading under throttle because the flexplate is bowing out.
Someone knowledgeable please help, and thank you.