1G What fried my ECU

[And_44]

Hello,

Well I just toasted my 1st ECU in my 1990 Talon TSi. When I purchased the car a little over a month ago the ECU (original 20 year one) had one torched area on board and interior of car smelt of ozone, had no experience with car before while it was running. I was able to purchase a used one hooked it up and car was running great. BUT when I installed the used ECU and put the car in the On position I would get a rapid clicking noise from either the ECU and now guessing the MPI (don't know which) This was the case from day one of the install. On cold starts the clicking would happen for 3-5 seconds and stop, I would wait for the clicking to stop before starting car. On a few occasions not often the clicking in the On position would not stop and I would have to go back to the off position and try again and it would click for the 3-5seconds and stop. I had no drivability issues when the car was running (up until the end, had a slightly higher idle). If I drove the car for a while and turned it off and started it back up a few minutes after turn off the ticking wouldn't occur. The night my ECU fried I drove up to Marysville about a 20mile drive from home turned off car let it sit for little over 5min. I came out to turn on car put it in the on position and I wasn't paying attention to the clicking (asked sister later she said it was still clicking when I started car but stoped when started), about 1mile later I hear a pop hiss fizzle and car just dies, and the smell of ozone burning our eyes and noses.

When I opened the ECU i purchased and compared it to the original the damage to the board was at the same place. Using this link and going to post #7 ( http://www.dsmtuners.com/forums/newbie-forum/75929-fried-ecu.html ) The little rectangle circuit almost a 1/4 inch up and to left of (47uf @ 50v) That same circuit on both ECU's appeared to be ground zero of my malfunction. Now it was said and asked by a few people in that post that they experienced the same ground zero location, but the area was never named.

My question in this post is what is that area responsible for? And what would cause it to fry itself on my 2 ecu's at the same spot. I am planning on just purchasing a ECU from ( Mitsubishi Eclipse Talon Laser Tracker Sidekick ECU ECM Computer Repair Service and Rebuilt Parts ) but before I install and drive and fry another, I would like to know if that area can help me limit my relay and sensor replacements.

OR did I just get lucky and purchase a ECU that was taking a tank and happen to fry itself in same spot because of just being a faulty ECU?

I appreciate any time and input anyone could offer. Although I do enjoy working on my Beast I don't enjoy spending money to replace perfectly good parts, when something else is at fault. Not complaining about my used ECU, was expecting issues with it being used but hoped to last longer. And little confused for the same burn location in 2 ECU's.

Thank you again.

Andrew

 

[Dewayne Waldron]

Sounds like the capacitor's leaked onto the board. I've dealt with this quite a few times.

 

[dented_coffee]

im on my number 2 ecu as well and i think that mine might be going again. maybe we have faulty wiring in our cars. im thinking of swapping all of my stuff to a 91 or a 92 wireharness to avoid the problems all together. can you post a picture of your bad ecus so i can see if mine is in the same spot and so i can get the info on what that part is suppose to be controlling.

 

[Dewayne Waldron]

I doubt it has anything to do with any wiring or anything. This is common with our ECU's. I've personally repalced 3 and even installed new capacitors in an ecu one time. Don't buy an old, used ECU, It's a glutten for punishment.

 

[And_44]

Unfortunatly I don't have a picture of my own 2 ecu's. BUT I did include a link in my first post ( Fried ECU ) to another thread on this forum with a great picture of our board and gave the location to where the Fry occured. If you follow that link and go to post #7 my ground zero for destruction was at the area circled in blue almost a 1/4 inch up and to left of (47uf @ 50v). And yes Dewayne Waldron I know buying a used ECU is just counting the time. But I was expecting it to fry else where not the expact same spot. OR if it is common for the ONE area to fry itself on a bad ecu or if something else would cause it to over work itself.

 

[1983gsp]

The isc is known to take out ecu's.....just a thought.

 

[steve]

If you follow that link and go to post #7 my ground zero for destruction was at the area circled But I was expecting it to fry else where not the expact same spot. OR if it is common for the ONE area to fry itself on a bad ecu or if something else would cause it to over work itself.

I assume your talking about the black chips in the red circled area. Those are driver chips for the ISC and solenoids. A bad ISC is the more typical cause I see when repairing ECUs but people who disconnect the various solenoids have also blown the drivers for them when water gets into the loose connectors.

If you never fixed the cause of the original damage then any new ECU is going to also burn up.

Let me know if you need a good ECU.

 

[And_44]

I thought the ISC was the culprit so I unplugged for a week and still had the clicking coming from the ECU area. With it unplugged I would imagine it not clicking at all, but it still did. So plugged it back in.

I've also found that the ISC drivers are not near the location where the board fried itself. ICS drivers are circled in red in the link I provided, post #7 ( Fried ECU ) in my first post. Those are in great condition no leakage or damage near them.

Ahh Steve the ECU wiseman No my problem area isn't near the red circle but the blue one labeled as 47uf @ 50v

And yes most indubitably I do need a new ECU. I'm down to one car right now and extremely difficult for fiancee and I to do our daily errands and work. I was going to go through motorguys and pick up one for 199 well 299. I have two core's I can give but they only take one;(

 

[steve]

90 ECUs have this bad tendency for the 47uF capacitor to short out and burn if you don't get the caps replaced. More so than the later ECUs.

If you note there are part number on the board. Using them where you describe your problem will help us figure out what your referring to.

Do you need a MD145903?

 

[And_44]

Yep MD145903/E2T34478/0508 is the number on the case.

Also the original ECU was an EPROM with the E742 chip installed on board;(

 

[steve]

Send it in and I'll see if I can revive it. If the 47uF cap burned through the board it might be done for. Same goes for any bubbling or cracking of the black square chips (the CPU, port expander, and interface chip) That an indication of an internal failure usually because of a voltage spike.

 

[And_44]

Well damage is just located on the C37 and C38 and the 47uf capicators. The 3 chips I believe your reffering to appear to be in good shape.

 

[DSM1G90]

Interesting on the read here, for after a simple oil change, my car decided to go totally crazy on me. First, thing wouldn't fire up at all until I shot some starter fluid in the throttle which it did fire up immediately - but would not run up to a high idle on cold, but sit at a nice 750rpm idle and would run find afterwards.

Then, the CEL came on. I did the beep test and came up with the temp sensor malfunction. Did the hot water test on the thing and it was functioning normally - high resistance when cold and drops when gets hot. Undid the battery to clear out the code and restarted the motor. Soon, the CEL came back on again with the same code as before.

Then, my radio began to go nuts with squalls and static, and my interior lights fuse blew. What has mentioned to the member above smelling some ozone, I did smell a bit of ozone-come to think of it after reading the above post. Car still being weird on the CEL display with four codes saved with three of them pointing to the MAF section and still this temp sensor code.

Now, the thing finally has an issue with the idle with oscillation between 600 and 1000 rpms. I havent checked the IAC unit, but on my next agenda for maintenance..

I think my ECU took a dump. Now, when I eventually get another ECU (MD128625, and if this is the problem), what are the precautions that one can take so another ECU doesn't head south on any of us, I wonder?

Would stock fuel pumps cause ECU issues if they're getting tired, or going out?

I need to get this car going good again (it can run okey, but you can tel it's a sick one...) - it's my DD vehicle where I normally go. I love it and it's been very reliable.

Any help is great on my end here - love this site for all of the info one can use to get our vehicles running again.

thx-DSM

 

[And_44]

Hey there if was curious if a JDM Galant VR4 ECU would work in my beast found one locally and cheap. 10/89-7/90 MD150427/E2T36173/E769. I have 3/89-6/90 - MD145903/E2T34478/E742 for the stock ECU.

 

[steve]

I though I had pictures from the ones (MD150427) that I had worked on before but I can find them. The JDM ECUs have different code/maps in them and additional circuits for cyclone manifolds.

I believe the EPROM versions can be converted to US specs but I don't know if all of them are EPROM or remember exactly what the board looked like.

The Galant VR4 has a different MAF than a DSM, it's like a factory hacked 1G MAF that reads lower aircounts than a DSM would with will cause that ECU to run richer in a DSM the JDM versions don't have the same emissions equipment, and different fuel and timing maps.

 

[DSM1G90]

I was doing a bit of study on these M5269L drivers and wonder if a glass, 1.5A quick blow fuse could be placed somewhere so if the amp draw suddenly gets greater than the 2A max these drivers can handle, it would pop the fuse and save these drivers and our ECU's when sensors desides to act up or suddenly fail.

 

[steve]

Find a fuse than till pop in less than 2mS and you'll be good.

 

[yokotabrat]

A fuse could work if you're willing to wire it in to the harness.

The better solution is to switch to the newer style ISC (black housing). The few failed ones I've seen had 10 ohms instead of the nominal 40 ohms from the coil. I suspect Mitsu designed them with an internal 10ohm resistor in series with the coil to limit current when/if the coil fails.

 

[DSM1G90]

..wonder if you could add this resistor to the plug side of the circuit....

Ya.. did check my ISC and got 28 to 29 ohms on all of the 4 test points on the connector. Before my problems began, I had a very smooth 750rpm idle.

.. and I've got the original metal cased, lateral mounted version (being the car was built in June of '89) with the attached cord, where I have to take the throttle body off to remove the ISC and make the extention harness to connect the new black designed ISC unit to the plug.

 

[And_44]

Well, after some thought I think I'm going to bring my ECU down to Pina Motorsports here in Washington. It's a 40 mile drive from my home so relatively close. They said they could most likely revive my EPROM MD145903. Would want to try to stick with the EPROM because I plan on chipping this year sometime. Andrea qouted a round figure of 50-150, up to 200 if I see the EPROM being worth that much. They inspect it first give a qoute and if I find price acceptable they start work and final price isn't changed from qoute. Also he said most repairs are done in 1 business day.

 

[steve]

Say hi to Andre, He's a good guy and we've done a lot of business.

 

[And_44]

Will do Steve Glad you approve of him. You were my first choice but need to get my Beast on the road as soon as possible. Didn't even know about Pina until Arsenal here in Everett referred me down to Andrea saying "He does wonders". Also pretty impressed they've been in business for over 8 years here in Kent, and mostly work on DSM's. Though they do cater to other client's.

 

[DSM1G90]

K, got my ECU back from repair, stuck it in, hooked up the battery and hit the key.

Thing fired right up, took it for a spin to warm it up, then do the ISC/BISS adjustment steps to get it at the right idle RPM's of 700 to 800 RPM (which it settled in a very smooth 750rpm).

Dang, like having a new car now ...

Good luck all - DSM

 

[And_44]

Turned out that what fried the ECU was just bad leaky capacitors. Made the capacitor blow. Happened to 2 ECU's.