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Hard starting, won't stay running without throttle, intermittent

blistovmhz

NAXJA Forum User
Location
Vancouver, BC
The girls Jeep has had some issues staying running for a while but I just haven't had a lot of time to investigate. The past few times it's happened, I've usually just gone out and messed around with battery connections and the problem goes away, but I'm not sure if that's coincidence.

Usually starts and runs fine, but low idle and stalls. Drives fine as long as you manually keep the RPM's up.
Throw 4 codes simultaneously every time the problem shows up:
* P1294
* P0122
* P1694
* P1391

I know what all these mean individually, but I'm confident they're not separate issues. If I clear the codes when the Jeep is running normally, they all stay gone until the next time it starts lowing idle speed and stalling, and they all get thrown at the same time, every time. I strongly suspect they're all using the same 5V power source and that source is getting weak, but I've got my Jeep in the garage right now while I stretch out the rear wells, so I just don't have the time to trace and probe every wire.

Who's got the answer for all these codes being thrown simultaneously?


(P.S.) The Jeep itself is a 2001 auto. The long block however came out of my 98XJ which was always rock solid (swapped because her 0331 head was cracked). Put the 01 intake, cam position sensor, coil rail, on the 98 long block, and using the 01 ECU. Worked fine when first installed, has worked fine many times since. The issue is entirely intermittent, but seems to be occurring more frequently. I won't be at all surprised when this turns out to be a bad ground.
 
Fix the lowest numbered codes first. Higher number codes are often caused by the malfunction of, or faulty data from, the parts/systems causing the lower numbered codes.

Hard starting, and won't stay running without throttle is a low voltage issue, usually loose/corroded battery/alternator connections, bad battery, or failing alternator.
 
I have the same issue with a cracked head on my 2000 how did you get the 01 exhaust manifold to fit on the 98 head? Or did you use the 98 exhaust manifold.
 
Well damnit. So the girl got towed home and we noticed that with a battery booster attached, it was running fine. Cleaned up all the battery terminals and threw in my yellow top. Ran like a top. Throw in another known good, but currently dead battery, boost it and let it charge, but it's not charging, or if it is, it's real slow. Check alternator coil connector, which is corroded. Clean it up and plug back in, and now we're charging. Threw my good battery back in and again it runs fine, so we go buy a new battery (Delco). Runs like a top with the new battery all day yesterday, but this morning it was hard to start, wouldn't stay running unless I stayed on the throttle a little. When I got home it was running fine again. Then girl goes to start it and again, won't idle normally, but is charging. Starting to think there are a few separate issues, all electrical though.
Not throwing any codes since swapping batteries though, so I doubt any sensors or anything in the motor is at fault. Seems like a purely battery/continuity issue. Am I missing something obvious here? Don't want to troubleshoot any more. Got a 6.0L swap to do this weekend.
 
You may think I am crazy but I just ran across a similar problem and it turned out to be a tranny that was real low on fluid. At an idle it seemed to put a fluxuating load on the engine at an idle. Other than that, it was fine.

I put three quarts of ATF in and the symptoms went away. Go figure.:explosion
 
Turns out there were several problems, all intermittent. Bad battery shorting internally, bad ground wire, and bad IAC. All three checked out fine every time I checked. Finally just threw in MY battery, which seemed to solve it for about an hour, then replaced the ground, which also solved it for a day, then the IAC.
That said though, that was a week ago, and the girl tells me her cel just came back on. Fml
 
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