XJ Stalls Under Light Accelleration
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Joined: Aug 2011
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
I have not been able to do tip #4 yet. I haven't had any issues with stalling while driving since I started this thread, but it has stalled out a few times after starting. It did it to me today. It started right up on the second try, and the engine held at 1500rpm for 10-15 seconds.
Tip 5 might be enlightening.
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From: Lost in the wilds of Virginia
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
Have you done a fuel pressure test yet? I read through the thread but I didn't see that one.
Thread Starter
CF Veteran
Joined: Nov 2011
Posts: 2,433
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From: Northern MN
Year: 1990
Model: Cherokee (XJ)
Engine: Renix 4.0
The engine actually stalled on me today a block out from the house. I was coasting up to the intersection and felt the steering go stiff, then I realized it stalled. Again, it fired right back up. So far, cool and humid seems to set this off. It was 50F and rainy this morning.
Since it starts, dies, and starts right back up, I haven't looked at the CPS. I've had a bad one and the thing just didn't start to begin with.
Thread Starter
CF Veteran
Joined: Nov 2011
Posts: 2,433
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From: Northern MN
Year: 1990
Model: Cherokee (XJ)
Engine: Renix 4.0
Tips 1,4, and 5 are done. The TPS ground was perfect, and the idle seems a bit smoother. I also pulled the IAT and cleaned it out. I'll report back on the results.
Thread Starter
CF Veteran
Joined: Nov 2011
Posts: 2,433
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From: Northern MN
Year: 1990
Model: Cherokee (XJ)
Engine: Renix 4.0
On another note, my Renduinix from NickNTimes has lit up on the oxygen sensor. It shows 4.98v most of the time. I just replaced it this past fall with an NGK.
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Joined: Nov 2011
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From: Northern MN
Year: 1990
Model: Cherokee (XJ)
Engine: Renix 4.0
Problem unresolved...
It hasn't died on me while starting, though the engine seemed to stumble and catch itself. It did die on me after taking off from a stop light on my way back from walmart just now.
The throttle hesitates just a bit while taking off from a dead stop, but the engine is very responsive once I'm moving. I'm not sure if that will help diagnose anything, but it seemed to be more apparent after getting it started again.
I just tested the CPS and it put out .6VAC while chranking.
It hasn't died on me while starting, though the engine seemed to stumble and catch itself. It did die on me after taking off from a stop light on my way back from walmart just now.
The throttle hesitates just a bit while taking off from a dead stop, but the engine is very responsive once I'm moving. I'm not sure if that will help diagnose anything, but it seemed to be more apparent after getting it started again.
I just tested the CPS and it put out .6VAC while chranking.
Last edited by austinjoe13; Jun 5, 2018 at 02:49 PM.
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Joined: Aug 2011
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
CF Veteran
Joined: Aug 2011
Posts: 10,489
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From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Huh? "Renduinix from NickNTimes" ? And what does the NGK show? I'd still check the CPS here but this one is starting to sound like another problem.
Does it ever backfire out the intake and stumble when you give it gas, but always goes like hell if you floorboard it?
Does it ever backfire out the intake and stumble when you give it gas, but always goes like hell if you floorboard it?
Thread Starter
CF Veteran
Joined: Nov 2011
Posts: 2,433
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From: Northern MN
Year: 1990
Model: Cherokee (XJ)
Engine: Renix 4.0
The CPS tested good at .6VAC. I have had it backfire a couple times, but not recently. The last time it happened was December, I think. It only hesitates a little bit when taking off from a stop, but it's always done that. The power seems to be the same as usual.
I swapped some relays around and things seem to be good today. I also forgot to hook up the monitor again, so I'm not sure what's going on in the system.
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Joined: Aug 2011
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From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
NickNTimes, Cool, .6 CPS ACV, Cool.
There is a problem that comes up that is tough to solve. Goes great past 85% throttle in open loop, but hesitates and backfires out the intake when accelerating normal.
My case that took over a year to solve was unique, but in the end it was for sure one of the wires off the injector harness to the lower sensors shorting to ground.
Was before I joined the forum in 2011, I just repaired the wire and went on my way. Since then I've tried to duplicate the condition by grounding 02, temp and knock sensor wires with no luck duplicating it. (even the brown W white tracer).
A few times that backfiring out the intake on moderate/medium throttle has not been resolved here. Glad you don't have that!
There is a problem that comes up that is tough to solve. Goes great past 85% throttle in open loop, but hesitates and backfires out the intake when accelerating normal.
My case that took over a year to solve was unique, but in the end it was for sure one of the wires off the injector harness to the lower sensors shorting to ground.
Was before I joined the forum in 2011, I just repaired the wire and went on my way. Since then I've tried to duplicate the condition by grounding 02, temp and knock sensor wires with no luck duplicating it. (even the brown W white tracer).
A few times that backfiring out the intake on moderate/medium throttle has not been resolved here. Glad you don't have that!
Last edited by DFlintstone; Jun 7, 2018 at 07:12 PM.
Thread Starter
CF Veteran
Joined: Nov 2011
Posts: 2,433
Likes: 6
From: Northern MN
Year: 1990
Model: Cherokee (XJ)
Engine: Renix 4.0
I think I solved the problem. The engine is running differently after swapping relays around, and my AC compressor is engaging again. I'll buy all new relays tomorrow. Such an easy answer for such a wierd issue... I'll keep this posted in case anything changes.
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Joined: Aug 2011
Posts: 43,971
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Thanks. I suspect your oxygen sensor heater relay was bad or just the connections were dirty and switching them around improved the contacts. Tip 3......