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Topic Review (Newest First)
01-19-2012 12:27 PM
trailblazin Joe My daughters 95 YJ has been doing this exact thing and I suspected that it was the computer going bad. My question is this, AutoZone has a computer for around $240. Is this just a swap out repair job. Someone posted something about matching up with the VIN number. Is this also a job that is hard to undertake? I need to get this fixed ASAP so all help is greatly appreciated.
01-12-2012 04:36 AM
rigger1
Quote:
Originally Posted by patbe View Post
This is weird, although the jeep now starts every time cold, its seems with the capacitor replacement the symptoms have reversed. Now when the jeep is turned off after use and hot, it will not start. Only one red light on in dash cluster and no fuel pump cycle. Let it get cold and all is well again. This has happened the last 2 times I have plowed with it. I never noticed this initially because the jeep is only used for plowing and after shutting it off , it would'nt be started again till next time needed.
Anyone else have this happen? Any ideas?


We replaced the ECM in our Jeep and it starts great on cold mornings (below 30-deg.) When the mornings are warmer, it's harder to start. Like you, I'm stumped!


Chuck
01-11-2012 10:30 AM
patbe This is weird, although the jeep now starts every time cold, its seems with the capacitor replacement the symptoms have reversed. Now when the jeep is turned off after use and hot, it will not start. Only one red light on in dash cluster and no fuel pump cycle. Let it get cold and all is well again. This has happened the last 2 times I have plowed with it. I never noticed this initially because the jeep is only used for plowing and after shutting it off , it would'nt be started again till next time needed.
Anyone else have this happen? Any ideas?
01-03-2012 07:12 PM
sevenservices Im still very pleased w/mine... this 'el be my third winter since replacing it back in 2009. This morning was about 16 degrees here and I still got the fear that it wouldn't start because of how cold it was and whalla... no trouble at all. Of course, I patted the tire and told it "good jeep" on the way in. hehe!
01-03-2012 06:00 PM
sevenservices Right on! Good Job!!!
01-03-2012 02:31 PM
patbe
Thanks

Quote:
Originally Posted by sevenservices View Post
here is a good write up of how to replace the capacitors, not suggesting to try it but the pics may show you where they are on the board.

Crash Course In Brain Surgery Replacing Capacitors On ECU - JeepForum.com
Thanks for posting the above link Sevenservices. I replaced the 3 capacitors in my ECU this weekend and the jeep started flawlessly two cold mornings now, with this morning being 3 below F I suffered through this problem for a winter and a half, what a rush to turn the key and see the red dash lights lit up and hear the fuel pump cycle!!! Thnaks again.
12-22-2011 11:36 AM
patbe I have a bad ecm (which I learned on here). Leave ignition on for 5 or 10 minutres, then finnally the check engine light comes on......then I hear the fuel pump and it starts . But since yesterday, even after waiting with ignition on, fuel pump wouldn't activate. Came to realize I had accidently put the pump relay in the wrong spot. Got it started and plowed. I am going to remove and look at ecm and attempt the resister replacement. Thanks for your response.
12-22-2011 10:15 AM
obidya
Quote:
Originally Posted by patbe View Post
Hi all, can anyone tell me which 2 slots of the 5 for the fuel pump relay you would jumper wire to see if fuel pump is activating? 92 YJ 4 cly. Thanks
turn the key forward without starting and give a listen, you should hear it whirr
12-22-2011 09:54 AM
patbe Hi all, can anyone tell me which 2 slots of the 5 for the fuel pump relay you would jumper wire to see if fuel pump is activating? 92 YJ 4 cly. Thanks
11-29-2011 05:50 PM
rigger1 Correction to my last post. That should have read CPS... not TPS. Sorry for the mis-information.

I'm thinking, we got a 'bad' re-built ECM. Seems as though, from all my searching, ther are no 'new' ECM's available... only re-builts. At any rate, we put my wife's Jeep in the shop today. I'm thinking too, it's either a faulty CPS or ECM... dunno. Thanks in advance for any help or ideas. We have a very open-minded mechanic.


Chuck
11-29-2011 08:11 AM
rigger1 I'm really getting frustrated! Last night, my wife was on her way home from work and her Jeep just quit! She let it set a few minutes and tried to start it and nothing! I got to her and the jeep and tried to start it and nothing. The engine turns-over but it doesn't seem to get spark. It's getting fuel. about 3-weeks ago, we replaced the ECM after having a starting problem on cold mornings and it's been starting fine. She has noticed a slight stutter in the engine while driving. In June, we replaced the TPS. Could it be a faulty (re-built) ECM? This is really getting old. HELP!!!


Chuck
11-15-2011 08:04 AM
rigger1
Quote:
Originally Posted by obidya View Post
hey sorry for the confusion.. the ECM and PCM are the same thing.
When I was saying PCM I was thinking ICV (idle control valve) which helped out on mine as well.

sorry about that, I was apparently suffering from the dumb
No problem! I was getting nervous... I thought there was something else I was going to have to replace. I appreciate you clearing that up.
Got our Jeep out of the shop with the new ECM and it ran great on the way home (20-miles). Got-up this morning and it fired right up. Although it was 50-deg. at the time, I didn't try any tricks just turned the key and it took right off. Looks like we got the problem.
I really appreciate all the help from all who posted here. Thanks, guys!


Chuck
11-14-2011 07:42 AM
obidya
Quote:
Originally Posted by rigger1 View Post
We've been talking mostly ECM, here. The PCM is new to me. What is the difference?


Chuck
hey sorry for the confusion.. the ECM and PCM are the same thing.
When I was saying PCM I was thinking ICV (idle control valve) which helped out on mine as well.

sorry about that, I was apparently suffering from the dumb
11-13-2011 10:30 AM
rigger1 We put the Jeep in the shop, earlier this week to get the ECMreplaced. It was supposed to have taken 7 - 10-days. just to get the part. Our mechanic called us this past Friday at 6:00 PM saying the ECM had been replaced and according to him, 'runs like a top'. I'm going to pick the Jeep up tomorrow. This coming week, we're supposed to have some chilly morning temperatures... that will tell the tale.
I really appreciate everyone's in-put on this matter.


Chuck
11-05-2011 08:39 PM
rigger1
Quote:
Originally Posted by obidya View Post
my cherokee did this exact same thing if it was below 40 degrees. Just wait till the engine light comes on and it fired right up.
I ended up swapping out the ECM and PCM, I was able to get the ECM from the junkyard for like $20 and luckily it worked.
We've been talking mostly ECM, here. The PCM is new to me. What is the difference?


Chuck
11-05-2011 08:35 PM
obidya my cherokee did this exact same thing if it was below 40 degrees. Just wait till the engine light comes on and it fired right up.
I ended up swapping out the ECM and PCM, I was able to get the ECM from the junkyard for like $20 and luckily it worked.
11-05-2011 08:00 PM
rigger1
Quote:
Originally Posted by sevenservices View Post
^ not sure...
I guess, our luck is running out. My wife has been driving the Jeep to work, the last couple days (20-miles, both ways) with no problem. Hold the key on 'Accessory' 10-seconds and it fires right up. Tonight, on her way home, it stalled twice and she told me the needle on the amp gauge was bouncing irratically. I'm assuming, this is related to a bad ECM!?
Thanks in advance, for your help.


Chuck
11-05-2011 07:47 PM
rigger1
Quote:
Originally Posted by sevenservices View Post
^ not sure...
Quote:
Originally Posted by MrRaldood View Post
a pcm like unichip could fix the problem?
We were going to go through Auto Computer Exchange and checked up on them to see what their reputation was like. According to all the complaints... not good. I read somewhere that the original owners sold the business awhile back!?


Chuck
11-04-2011 04:21 PM
rigger1
Quote:
Originally Posted by sevenservices View Post
^ not sure...
I've got our mechanic trying to locate one. What I don't understand is, why they are so hard to find? Do you know of a good source for ECM's? Also, I was told that dealers in my area can only get re-builts. That's fine, as long as they are re-built good.


Chuck
11-04-2011 07:53 AM
sevenservices ^ not sure...
11-03-2011 11:24 PM
MrRaldood
Quote:
Originally Posted by sevenservices View Post
mine did that in 2009. On cold mornings I would turn the key to on and nothing... 5-20 minutes of sitting and the check engine light came on with the fuel pump growling at the same time. Then it runs ok... I replaced the PCM, no problems since.

Turning the key to on and not hearing the fuel pump growl and having to wait anywhere from 1-20 minutes (with the key to ON) is a classic sign it has failed.

I had great luck with autocomputerexchange out of FL. They sent a new one pre-programmed to my VIN. Powdercoated black, new labels, very nice.
a pcm like unichip could fix the problem?
11-03-2011 10:37 AM
rigger1
Quote:
Originally Posted by sevenservices View Post
If you really want to know for sure, pull your ECM off the firewall. Its easy, first remove your washer fluid res. (drivers side) then remove the cable off the front (lay it somewhere clean) and there are only three screws holding the computer to the firewall. Pull it out, bring it in the house and open up the shell. You should find a few capacitors in there that are toast. Either burnt, leaking or otherwise cooroded. Unless its an experienced jeep mechanic you are contacting he's gonna tell you to replace everything you already did. We've seen your symptoms time and time again, each time, its the computer.

Let us know if you attempt to pull it open... or, if the mechanic wants to start throwing more hardware at the jeep that really won't make a difference.

...just trying to help a fellow jeeper experiencing the same headaches I've already fixed. You story brings back bad memories, I was pretty pissed at my jeep when it was doing that. 2009, new computer, never had a prob since. Even down to -18 degrees last winter. Its so common that Im considering adding rebuilding these to the list of things my wifes computer store takes care of. If I can identify the bad capacitors theres no reason I can't solder new ones in.
What great help and information! Thank you! I've checked-out the cost of a Mopar ECM and the average cost is $636.00... Yikes! Have you ever done business with or know of: Automotive Electronics Solutions? They rebuild ECM/PCM's. I want to solve the problem but I'm not made of money, either. I'm tired of throwing new parts at it, too.
I did hold a hair dryer on the ECM, this morning (26-deg.) and the dang thing started! Thanks again, for all your help.


Chuck
11-03-2011 10:07 AM
sevenservices oh, and if you do pull the ECU, disco the battery first and do not hook it back up until the UCE is wired back into the jeep.
11-03-2011 10:04 AM
sevenservices here is a good write up of how to replace the capacitors, not suggesting to try it but the pics may show you where they are on the board.

Crash Course In Brain Surgery Replacing Capacitors On ECU - JeepForum.com
11-03-2011 09:46 AM
sevenservices
Quote:
Originally Posted by rigger1 View Post
This morning, at 7:00, the temperature was 26-deg. I tried starting our Jeep by holding the ignition at accessory, counting 10-seconds and no start. It sounds like when I'm trying to start it, there's no spark. I'm really thinking, the ECM needs to be replaced!? I'm stumped. I'm calling our repair shop and see what he says.


Chuck
If you really want to know for sure, pull your ECM off the firewall. Its easy, first remove your washer fluid res. (drivers side) then remove the cable off the front (lay it somewhere clean) and there are only three screws holding the computer to the firewall. Pull it out, bring it in the house and open up the shell. You should find a few capacitors in there that are toast. Either burnt, leaking or otherwise cooroded. Unless its an experienced jeep mechanic you are contacting he's gonna tell you to replace everything you already did. We've seen your symptoms time and time again, each time, its the computer.

Let us know if you attempt to pull it open... or, if the mechanic wants to start throwing more hardware at the jeep that really won't make a difference.

...just trying to help a fellow jeeper experiencing the same headaches I've already fixed. You story brings back bad memories, I was pretty pissed at my jeep when it was doing that. 2009, new computer, never had a prob since. Even down to -18 degrees last winter. Its so common that Im considering adding rebuilding these to the list of things my wifes computer store takes care of. If I can identify the bad capacitors theres no reason I can't solder new ones in.
11-03-2011 08:15 AM
rigger1
Quote:
Originally Posted by sevenservices View Post
good deal, work it while it still works!!! let us know what it does when it gets down to about 25-27 degrees.
This morning, at 7:00, the temperature was 26-deg. I tried starting our Jeep by holding the ignition at accessory, counting 10-seconds and no start. It sounds like when I'm trying to start it, there's no spark. I'm really thinking, the ECM needs to be replaced!? I'm stumped. I'm calling our repair shop and see what he says.


Chuck
11-01-2011 02:26 PM
rigger1 If, it gets colder than 25 - 27 degrees... I'm not gonna start!


Chuck
11-01-2011 11:57 AM
rigger1
Quote:
Originally Posted by sevenservices View Post
good deal, work it while it still works!!! let us know what it does when it gets down to about 25-27 degrees.
That's kinda what we've been thinking... work it while it works. I'll be sure to post the results when it gets that cold.


Chuck
11-01-2011 08:44 AM
sevenservices
Quote:
Originally Posted by rigger1 View Post
The past two mornings, I've been turning the key to 'accessory', holding it there for 10-seconds then try to start it. It fires right up, idles and runs just great.


Chuck
good deal, work it while it still works!!! let us know what it does when it gets down to about 25-27 degrees.
11-01-2011 05:21 AM
rigger1 The past two mornings, I've been turning the key to 'accessory', holding it there for 10-seconds then try to start it. It fires right up, idles and runs just great.


Chuck
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