Howdy y'all,

My 93 2nd Gen's ECM is apparently on it's deathbed. It runs OK for a while (sometimes 15 min., sometimes an hour), then the ECM relay starts clicking, and the engine hesitates, and then it shuts off. It cranks but no dice. I clip on the test light to the diag plug, switch it on, and the light stays on solid. I turn it off, the ECM relay clicks off, and I switch it back on, and I get the constant pulse that sez the ECM is OK, and the engine works normally again for a while. WTF?!?

Anyone run into this before? Any ideas? Is my ECM possessed? Anyone have a good used (cheap) ECM lying around willing to sell?

Thanx!

My 93s ECM pretty much caught itself on fire a few months ago. Whole cab filled with smoke. Little black thing inside burst and had black marks around it. Atleast yours died peacefully. From what I experienced those are pretty rare. You can get a rebuilt one for around $300. MS recycling had a stock nonrebuilt one from a running truck for $350. I told them I could get a rebuild one cheaper and they said that is their price. I did not buy from them.

Well, this is her second ECM. The first died in 2006 after a few ants decided to hoard in it. Bought this one rebuilt for about $225, and I found a local seller asking $275 for a good used one. To think one just closed on eBay for $80, and I was outbid.

I pulled the ECM out about an hour ago, and smelled it. Smells OK, but the intermittent clicking starts after it runs about 15min, and stops when it cools down.

I checked the ECM relay, opened it up, filed the contacts a little with an emery board to remove any crud (very little), and tested it. Works fine.

I'm starting to think my ECM needs an exorcism.

<img src="/forums/images/graemlins/angry.gif" alt="" /> <img src="/forums/images/graemlins/angry.gif" alt="" /> <img src="/forums/images/graemlins/angry.gif" alt="" />

The big capacitors are usually the culprit when an ECU goes bad. Check closely if they are leaking.

Ditto, The caps are gone. $2 of parts and an hour or so if you can use a soldering iron.

Just to clarify, I'm not saying to just remove them. You need to replace them with new ones if they are starting to go south. If they are already bad and leaking fluid, then you may need to repair the board since the fluid is corrosive and may destroy either solder runs or components if it's leaking.

That's what I was gonna do in a while, take the ECM apart and check the caps.

Can I get them at Radio Shack? Is there a specific amp rating that I should replace them with? Has anyone posted a write-up on this?

I'll post some pix on my findings.

Thanx for all the help!!

There was a write-up done but it's for the earlier model ECU's, not the gen II models. The write-up is still relevant however. You can find a copy of it in the tech/faq section of the mitsu club site at http://www.geocities.com/mitsubishifourwheeldriveclub

The cap ratings probably differ depending on the ECU year/model.

Typically they're not available from Radio Shack but are available from a real electronics supply house. You can usually find them by doing a Yahoo search for the cap ratings.

If you're not sure, post pictures and I'm sure we can tell you which ones might be bad, and what spec's they are so you will know what to look for.

Yep, I opened up my ECM and just as I expected...one cap had blown and spread its jolly goodness over the PCB.

I'm going to replace both caps, and try to clean up the PCB.

Wish me luck.

I removed and cleaned the offending caps, but a large strip of the PCB that corroded came off in the process.

Here are two pix of the damage:





Can I repair this? How do I go about doing this?

The leaking caps are rated 50V 47microF, and 16V 100microF. Where can I order them online?

Thanx in advance.