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General Forums => The Mess Hall => Topic started by: calvinh on October 16, 2011, 10:53:37 PM
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Here's the problem... When my jeep (92 YJ 2.5) has been sitting out overnight on cold days, when I get in and turn the key, there is no CEL on and it will just crank forever. However, if you wait 5 minutes or so, or warm up the ECU with a hairdryer, it makes a clicking noise and then starts up.
Does this sound like bad capacitors in the ECU? or could it be my fuel pump? the fuel pump relay is what makes the clicking noise.
Also, sort of off topic, but would an exhaust leak hurt performance? I've got a pretty bad exhaust leak, but I'm wondering if it is really worth fixing it right away or just waiting until next summer... thoughts?
Thanks!
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I had a pretty bad exhaust leak in my car and I noticed that once I fixed it I got a bit better performance. Depending on how bad it is depends on the back pressure and back pressure is needed. In my car though the setup is headers and catless. Runs much better without the cat. I also do not have smog checks!!!
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Can you hear the fuel pump prime when you turn the ignition to ON?
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The exhaust leak I had was really hurting my performance. But it was right at the head too.
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Unless the bulb is burnt out, no cel when the key is turned to run pretty much means the ECU has a problem. It is supposed to turn on as a bulb check, it doesn't depend on anything besides the ECU itself. I went through this a few years ago. You might want to check the power and ground to the ECU, but it will most likely be a waste of time.
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Unless the bulb is burnt out, no cel when the key is turned to run pretty much means the ECU has a problem. It is supposed to turn on as a bulb check, it doesn't depend on anything besides the ECU itself. I went through this a few years ago. You might want to check the power and ground to the ECU, but it will most likely be a waste of time.
Yeah, the CEL light should come on for a few seconds then turn off when you turn the key to ON. It's not only a bulbcheck but a sign that the ECM is doing a quick diagnostic check.
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with this hairdryer heating up thing: could also be a connection issue at the PCM connector, if that's not it then it's the PCM/ECU most likely.
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Strange that it's starting up at all though.
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Strange that it's starting up at all though.
just as a test i would try moving the connector a bit instead of the hair dry thingy and see if if it works, if it does could be a bad pin
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Mine acted the same way, working better in warm weather than in cold and then slowly getting worse until it would no longer start at all.
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sounds like capacitors going bad just as you described to me. i had the same issue...no cel and would crank forever, wait a few minutes, and it would start right up. there is write up floating around somewhere (i think it is on ju) about how you can dissect your ecu and replace the capacitors for about $5 in parts at radioshack but i was a little leary and elected to buy a remanufactured one on ebay that came with lifetime replacement. as soon as i swapped the ecu out ...problem solved.
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here is the write up
http://www.jeepforum.com/forum/f12/crash-course-brain-surgery-replacing-capacitors-ecu-492597/ (http://www.jeepforum.com/forum/f12/crash-course-brain-surgery-replacing-capacitors-ecu-492597/)
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Well, I got around to taking apart the ECU today and taking a look at it, and just by looking at it it was obvious that one of the caps was bad (bulged head on it) I didn't even have to put any new solder on the board, just warmed up the stuff that was on there, slid the old ones out and slid the new ones in. Turned the key to ON and it primed right away. Problem solved! I'd recommend this to anyone with these problems... cost $10 in parts (including a soldering iron) and it was surprisingly easy. The whole process took about a half an hour.
Thanks for the help!
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wow, good job on saving that one
good to know for future, i thought the caps on these would be high grade and not blow up like on the cheap electronics, i guess the dealer price for one of these does not account for the low grade capacitors in them :yikes:
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Great job! I'll have to try this first if I ever have problems with it again.
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Congrats on the fix. Did you do all three caps or just the one? Also, did you use the 220 uf 35wvdc cap recommended or find one that matched the original value? Take any pictures by any chance?
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Congrats on the fix. Did you do all three caps or just the one? Also, did you use the 220 uf 35wvdc cap recommended or find one that matched the original value? Take any pictures by any chance?
Yeah, I got some pics. I can try to make a writeup for it if anyone is interested.
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Yeah, I got some pics. I can try to make a writeup for it if anyone is interested.
that would be cool.
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It would be great to see a writeup.
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It would be great to see a writeup.
Sorry for the delay, I'll try to get it up this week. I've just been extremely busy with school and work (full time college student +full time job) :rage:
Its been a few weeks since I've done the repair, and its gotten below freezing almost every single night. Still fires right up on the first try!
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sure is cheaper than buying a replacement. I did mine some time ago for about 6$ in caps from Radio Shack.