Crash Course In Brain Surgery Replacing Capacitors On ECU - Page 13 -

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post #181 of 292 Old 12-28-2012, 04:48 AM
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Originally Posted by flcracker View Post
Could grounding out the PDC feed back into the ECM and mess it up?? ... I can jump the fuel pump relay and get it to work and it will start after doing that but die within a few seconds. Could I have fried a capacitor??
If something is damaged by grounding it's not likely a cap. More likely a transistor or IC.

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post #182 of 292 Old 12-28-2012, 06:40 AM
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Could the ignition switch have been damaged by this?? It seems like its basically a mechanical switch is it not??
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post #183 of 292 Old 01-23-2013, 10:19 AM
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I broke a lead taking the capacitor out...what should I do?
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post #184 of 292 Old 01-23-2013, 10:34 AM
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Solder the lead of the replacement cap to the lead that is broken if it is long enough. If it is short then you need to get a solder sucker. These video's should help
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post #185 of 292 Old 03-03-2013, 08:39 AM
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I followed your walk through, i now get a cel on start up, but no spark, everything else works great, i have a spare computer but its for a 4.0, and doesnt run my 2.5 very well, but i atleast have spark with it, any idea?
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post #186 of 292 Old 03-03-2013, 11:47 AM
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You have to match the engine to the ecu. Since the other ecu its giving you spark you are going to need to replace the ecu.
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post #187 of 292 Old 03-03-2013, 02:11 PM
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I understand that, I was just wondering if anyone knew the specific circuit that allows ECU to output spark, I am a computer engineer, and I have gone through the capacitors and the transformer, the only thing else that I feel that I should replace is the MOSFETs, but that is a little too much work so I will just buy another
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post #188 of 292 Old 03-03-2013, 03:55 PM
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Not going to be the fets. The drivers are individual. It its probably the micro and it just isn't with the effort.
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post #189 of 292 Old 03-03-2013, 03:56 PM
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Exactly, ill just get a refurb, thanks btw!
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post #190 of 292 Old 03-22-2013, 06:49 PM
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Well, it's a going trend... but here's to the OP!

I picked up a non-running, yet very solid 1995 Rio-Grande that was non-running. I knew it had no spark, but was disappointed when the CKS tested good and I noticed the fuel pump not running. A little net surfing found me here, and sure enough I just replaced the three cap's tonight and I have spark! It's cold and dark, so I will check the fuel system better tomorrow, but it looks promising! By the smell of the fuel, she's been sitting for a while, and I have a few more things to work with still, like the brake lines... but I have spark!
Seriously guys... this is an awesome post!

That on top of finding a very clean set of half doors with the right tan trim panels and mirrors for $250 (for the set) just made my day!

I thought I would add a few more photos to show what I found. Now granted, I don't know just how long the Jeep has been sitting so these may of suffered from age after they stopped working.... but these caps are shot!

I will seal them up after I check the fuel system, it sounded like it came on.. but just to make sure, I want to leave it open.

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post #191 of 292 Old 04-09-2013, 10:40 PM
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Holy tits I just did this and it fired right up! Thanks for the post. I would have bought a new ecu if it weren't for this thread
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post #192 of 292 Old 05-03-2013, 03:55 PM
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Another Success Story

I was having the same issues, 94 YJ 4 Cyl would just turn and turn when it was cold outside. Took it to a couple of mechanics that couldn't figure it out. My wife had me pretty well convinced that it was time to let her go, and I almost let her defeat me. Stumbled onto this post back in November and decided to give it a run.

Never soldered anything in my life - burnt the crap out of my finger, those things get hot. Popped the ECM back in and she started right up. Just to make sure I didn't jinx anything I decided to see how she handled through the winter before posting the success.

Seriously, this thread saved me Jeep, I cannot thank the OP enough for posting this information. My wife, who was not very supportive through this and laughed her *** off after I burned myself, hates your guts.

Here are a couple of pics
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post #193 of 292 Old 06-20-2013, 08:07 PM
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i have been on the fence about being a supporting member of this forum... however this thread sealed the deal for me to pony up!
My 95 always started on the second key turn since I bought it a few years ago.
This winter she sat for several months after the frame swap.
This week, I was starting to see the signs that "brain surgery" was in order, turn the key, no CEL for 45 -90 seconds...
FRANTIC, I started searching the forums and came upon this thread.

I ran out to the local Radio Shack(s) (as I had to hit two of the to get all of the caps) picked up the pair of 220uf and one of the 470uf, about 6 bucks. Then I splurged on desolder braid, 5 bucks and a Rat Shack 35w soldering pen with stand and solder..etc.. you know, the "kit" they sell. Another $13. tube of silicone 5 bucks. All in about $30. Followed the directions here in the thread.
Disconnected the battery, moved the windshield washer fluid container, took out the computer, removed the board, cut away the balastics gel, removed the caps, put in the new ones, filled in the gell holes with silicone, reversed the order to put it all back.
Jumped in the seat, took a deep breath and turned the key. CEL and the other lights came right on, and the engine started on the first crank.


How excited is this guy!

I guess my YJ Is my midlife crisis therapy.....

My 95 YJ cross country (AZ to ME) frame swap thread.
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post #194 of 292 Old 07-15-2013, 09:23 PM
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Thank you so much for the post. Got my YJ about a month ago and have had the problem for about three weeks. Had everyone stumped and like most other have posted, the initial thought was the fuel pump. I Have a 4.0 and had to use 3 220uf capacitors.
I was so nervous about doing it, but glad I did.
Thanks again, I can't thank you enough!
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post #195 of 292 Old 07-16-2013, 01:13 PM
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Hi . I purchased a 1995 wrangler recently. It would crank but not start. It would finally start after a minute or so. I found this thread and figured I didn't have much to loose so I made a trip to Radio Shack and picked up 3 220uf capacitors.

Removed ecu replaced capacitors as noted in this thread and reinstalled ecu. VROOOOM! Started right up.

Total time: 1 hour (not including trip to Radio Shack)
Total cost: $1.49 x3 plus tax for a grand total of $4.86

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