blondejoncherokee
NAXJA Member
- Location
- sacramento
brand new filter. I had the airbox and stuff like that off at least 20 times in the past few months.
Another MJ build thread ...
- Thread starter blondejoncherokee
- Start date
brand new filter. I had the airbox and stuff like that off at least 20 times in the past few months.
- Location
- Patterson, Ca
I just pull the stock bs resonator and airbox and put a spectre cone filter right on the throttle body in the wifes wj. Put a nipple out of the end for the pcv line. Works great and we run the same tuner as well.
blondejoncherokee
NAXJA Member
- Location
- sacramento
Damn MJ died on me again this weekend. I thought it was all fixed, been fine for months.
Just acted like it had no fuel, just dying , finally got it to start by having to rev it up a ton. After doing that 5 times in a row, it ran fine for the rest of the day. Weird . I ordered a new Bosch fuel pump and I have a new filter and well - I want to rule out a intermittently clogged pump screen or a pump that could be occasionally cutting out. All of my fuel pressure tests have been fine, but I've never been able to test it while it was acting up. so I am going to make sure the screens are not occasionally clogging, maybe if the main strainer is clogged/full of crap.
If thats not it, I already have replaced every sensor, and cleaned every ground every few months, and it only does the crap once every 4 months...so its really hard to diagnose.
I have no checked for corrosion at the ECU, that might be worth it.
the fact that it only acts up once every 3-4 months is making it really hard to figure out, and I keep thinking I've fixed it.
Just acted like it had no fuel, just dying , finally got it to start by having to rev it up a ton. After doing that 5 times in a row, it ran fine for the rest of the day. Weird . I ordered a new Bosch fuel pump and I have a new filter and well - I want to rule out a intermittently clogged pump screen or a pump that could be occasionally cutting out. All of my fuel pressure tests have been fine, but I've never been able to test it while it was acting up. so I am going to make sure the screens are not occasionally clogging, maybe if the main strainer is clogged/full of crap.
If thats not it, I already have replaced every sensor, and cleaned every ground every few months, and it only does the crap once every 4 months...so its really hard to diagnose.
I have no checked for corrosion at the ECU, that might be worth it.
the fact that it only acts up once every 3-4 months is making it really hard to figure out, and I keep thinking I've fixed it.
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thanasi85
NAXJA Forum User
- Location
- Sacramento, CA
When I had a similar issue where it would die and take lots of cranking and being on the gas pedal it was an issue with my fuel pump ground needing a clean up. Maybe something to look into. The fuel pump ground on your MJ is behind the drivers side taillight housing.
blondejoncherokee
NAXJA Member
- Location
- sacramento
good call. Ill do that.
- Location
- WA state
Also, consider running a check valve, if you think the fuel pressure drop in the line is an issue was well.
I think I need to install the BMW check valve that is sitting in my tool box in my MJ.
I occasionally have long crank issues, mostly when it's warm after she sits at work for hours.
I think I need to install the BMW check valve that is sitting in my tool box in my MJ.
I occasionally have long crank issues, mostly when it's warm after she sits at work for hours.
831_xj
NAXJA Forum User
- Location
- Santa Cruz
My mj does the same takes a long time to crank lol
blondejoncherokee
NAXJA Member
- Location
- sacramento
yeah mine just dies randomly while driving, not a long crank. It always starts right up.
- Location
- WA state
My XJ used to cut out at speed and then go back to running okay. If I was stopped or going slow enough it would die. But I could fire it back up. Since I have bypassed ign. switch and ballast resistor. It has no issues of that sort.
blondejoncherokee
NAXJA Member
- Location
- sacramento
Vote for my MJ for rig of the month!
blondejoncherokee
NAXJA Member
- Location
- sacramento
Vote for this MJ in ROTM!
blondejoncherokee
NAXJA Member
- Location
- sacramento
So its still ranomdly dying, even after another night of work on it. damn.
Johnnie,
How exactly did you bypass the ignition switch ? Mine is brand new but I am at my wits end. I might even run a 12v power wire straight to the ECU too just to rule out weird stuff.
I fixed the fuel pump ground, replaced the fuel pump, cut out the c101 and soldered everything back, soldered the cut o2 sensor wires (from a twist connection) and soldered the sensor ground connections together in the harness.
Other things I have done that are new:
CPS
injectors(ford 19lb)
FPR
ground refresh multiple times
upgraded grounds
new battery connections
new plugs
new wires
new dizzy cap and rotor
new ign coil
new alternator
new sign switch
TPS is newer, maybe ill try swapping that out, maybe it was bad out of the box
jumped the TPS ground so it has its own chassis ground
cleaned the NSS(it was all fubar and dirty and previous owner had bypassed it with a switch)
swapped the MAP out
installed a cleaned up, Bored out throttle body
c101 delete
cleaned relay connections
The only things I can think of now:
swap out the TPS (again, luckily i have like 10 of these, including another brand new one)
bypass ignition switch
swap out the dizzy (maybe cam sensor is going out?)
swap in another ECU ?
swap out 02 sensor just for fun ?
run 12v to ECU from battery (add a switch in line as a theft deterrent too)
check for corrosion at the ECU ?
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- Location
- Sacramento, CA
I still have that ecu that you gave me from the last part out rig if you want it back
blondejoncherokee
NAXJA Member
- Location
- sacramento
what year was that rig though? wasn't that a HO? the HO computers are way different than the renix. Or was it a renix? If I cant find a renix ECU in my stash (which I haven't been able to find yet) maybe I could borrow it for an extended period of time?
- Location
- Sacramento, CA
It was an 89 I thought. It's the silver box that goes under the dash
blondejoncherokee
NAXJA Member
- Location
- sacramento
oh ok. let me see what I have lying around. I might take you up on that then. Thanks man .
- Location
- Sacramento, CA
Anytime. Text me or get me on facebook, I should be around all weekend.
blondejoncherokee
NAXJA Member
- Location
- sacramento
OK cool thanks Casey
blondejoncherokee
NAXJA Member
- Location
- sacramento
SO I swapped out the O2 sensor. looked like crap when I pulled it, and have a ton of renix o2 sensors lying around, and at first it did not seem to do much. But then I found a vacuum leak (left over from previously trying to diagnose the random dying) and then I decided to swap in a ECU I had found in the attic, that seems to be from a 89-90 renix. So far, the jeep it running a lot better.
I also swapped out the fuel pump and o2 sensor relays too as well, just for the hell of it. And I readjusted the TPS since upon deleting the c101 and soldering the ground splices the input/output voltage ratio was a tiny bit off.
The rig is running way better, idling better, and no longer wants to die , well at least for now. Prior to doing all of this tonight it was dying after idling for a little while . Maybe I got lucky and nailed it.
Hoping maybe this was it.
I also swapped out the fuel pump and o2 sensor relays too as well, just for the hell of it. And I readjusted the TPS since upon deleting the c101 and soldering the ground splices the input/output voltage ratio was a tiny bit off.
The rig is running way better, idling better, and no longer wants to die , well at least for now. Prior to doing all of this tonight it was dying after idling for a little while . Maybe I got lucky and nailed it.
Hoping maybe this was it.
- Location
- Fort Collins, CO
Damn Jon! You've been busy with that thing. Sounds like you've narrowed it down. Did you check your sensor voltages going into the computer at the computer connector?
