just replaced the caps on ecu and worked great....

[acebrooks44]

then a day later went to crank the car and it started doing the same thing.I finally got it to crank and idle right but ten minutes later I went to cvrank it again and now it will not fire. The problemm was the infamous chattering coming from the dash and the car dumping fuel into the engine as fast as it could. What the heck could it be now.

 

[babell2]

Matt
Check the solder connection on the top side of the ECU board. I couldn't even drive mine about a week after I replaced the Caps. Found a bad solder joint on the top next to the botom of the caps. Same symptoms dumping fuel like no tomarrow and flooding out. Thought it was ignition at first.
Brice

 

[laserblue]

Who replaced the caps? Did you do it yourself? Now, a week later it is doing EXACTLY what it did BEFORE you changed the caps? The problem could be something other than the caps... or you messed up the cap change. Like said above --> the soldering is important. The solder MUST flow from the bottom of the board, thru the 'holes' to the top of the board. When I changed my caps, I mounted them a scooch 'up' from the board so that I could see under them to make sure that the solder connections were good. Also, if there was any leakage from the old caps, there might be crud that ate away at the copper traces in that area. Sometimes the break is so small that it's difficult to see with the naked eye. I would take the caps out again, clean the area with rubbing alcohol and a q-tip or very small stiff brush, inspect the area carefully, repair if necessary, then re-install the caps. Be careful... Repeated heating of a circuit board may cause the copper traces to lift off and break. If you find a break it can usually be fixed by bridging over the area with a thin wire. If you are not an experienced solder-person, seek out help -- like from a VCR repairman, etc.
Like I just said...... you may now have 2 problems... the original, and the one that you made. Take your time and check it all out carefully............. and GOOD LUCK.
Let us know what you find!

 

[rebuilt65]

Someone had a problem that caused them to change an ecu and it later turned out to be fuel system related, ie filter, dirt, water, etc... If these are eliminated, the ecu may still be the culprit. I changed the caps in one ecu, and it didn't fix a thing. Changed caps in another one for the same kind of symptoms, and that ecu is still working after a year. When changing caps, use a cotton swab and alcohol to gently remove the electrolyte fluid from the circuit board. Some of the protective coating may come off a little as well. the fluid will run down the board to other components and circuit traces as well. Check all soldering connections. I think the ecu is shot though.
regards

 

[acebrooks44]

I had my father in law do it. He owns a computer store and is a jack of all but a master of none kind of person so he may not have gotten the solder all the way through. I have a spare awd though and installed it and the car still did the same thing. So I believe the ecu is ok. Could the fuel pump relay cause this?

 

[laserblue]

I don't understand the last post.
• Do you mean that you took a known good ECU from another car and installed it into the problem car... and that problem car STILL had the same problem, so you ruled out a defective ECU problem?

[Boy, there are alot of "problems" in that sentence!!]

So there is still chattering from behind the dash?

And did you take the ECU that you did the cap job on, and put it into the spare car? If so, what happened?

 

[acebrooks44]

there is no chattering behind the dash after the cap replacement. It just dumps too much fuel into the car and the car cant even start. If I pull the injectors out and try to start it it starts with what fuel is left in the cylinders. then dies. With the injectors in it cant do it. What about a fuel pressor regulator. I didnt put the cap repl ecu in the other car cause I recently took the throttle body off of it.

 

[mitsutuner]

It sounds like you're not getting spark, but you're getting fuel & could be flooded. The ecu can cut the spark, so if you had the ecu out to replace the caps, it's possible that 1 or more of the circuit tracings on the bottom of the pc board may be broken, especially the skinny trace that runs very close to where the 100uf cap solders to the board--mine was--it's easy to damage because of its location & flowing resin from the solder joint. A visual check with good magnification will give good clues, but to know for sure, use your digital voltmeter to check for continuity between the solder joints along the trace. if the trace is open, bypass the broken part of the trace with a small jumper wire between the 2 solder joints. this is somewhat delicate soldering work--first prepare the jumper wire by stripping off only 1/8 inch on insulation. twist the ends of the wire strands ,then heat the ends of the wire & run some solder into the tips of the wire. Then hold the ends of the wire on the solder joints on the trace & heat just enough to make the solder flow.
Having replaced the caps 5 times & then still having the ecu chattering & engine stalling, earlier today I emailed Tom Stangl to see if he would check my ecu & he replied that first I should check the ecu power relay, but where exactly on the car is the ecu power relay? (can't seem to find it in the 1000FAQ or chilton or google.)
)

 

[Bostedquest]

It sounds like you're not getting spark, but you're getting fuel & could be flooded. The ecu can cut the spark, so if you had the ecu out to replace the caps, it's possible that 1 or more of the circuit tracings on the bottom of the pc board may be broken, especially the skinny trace that runs very close to where the 100uf cap solders to the board--mine was--it's easy to damage because of its location & flowing resin from the solder joint. A visual check with good magnification will give good clues, but to know for sure, use your digital voltmeter to check for continuity between the solder joints along the trace. if the trace is open, bypass the broken part of the trace with a small jumper wire between the 2 solder joints. this is somewhat delicate soldering work--first prepare the jumper wire by stripping off only 1/8 inch on insulation. twist the ends of the wire strands ,then heat the ends of the wire & run some solder into the tips of the wire. Then hold the ends of the wire on the solder joints on the trace & heat just enough to make the solder flow.
Having replaced the caps 5 times & then still having the ecu chattering & engine stalling, earlier today I emailed Tom Stangl to see if he would check my ecu & he replied that first I should check the ecu power relay, but where exactly on the car is the ecu power relay? (can't seem to find it in the 1000FAQ or chilton or google.)
)

The main power relay in beside the ECU, the big black top motha.

 

[steve]

Where exactly on the car is the ecu power relay?

It's normally referred to correctly as the MPI relay. It's bolted to the inside of the passenger center console support. It's usually a gold colored case about half the size of a pack of cigarettes.

Steve

 

[mitsutuner]

Correcto, the MPI relay--took it apart, contacts looked like new--I sent my ECU off to Zdoctors in orlando fla., They charged me $410 to rebuild my board--the cost was high bec the pc board was unusable & so had no core value. Anyway, the rebuilt ECO, (ok, truth is these cars are never totally fixed).

I appreciate your good intention, but hey, that was 19 months ago.
I sold that car last December for $2500 & got my social life back.
At age 50 & having owned 36 cars, the DSM is at the bottom of the list in terms of reliability--I'll leave it at that--no offense intended towards anyone.
FYI, it's reassuring to know that the Acronym Police,(AP), are reminding us what is correctly normal, heaven forbid that we should slip into the sloppy habit of using easy to understand common generic terminology & aka's, etc.

 

[steve]

I appreciate your good intention, but hey, that was 19 months ago.

FYI, it's reassuring to know that the Acronym Police,(AP), are reminding us what is correctly normal, heaven forbid that we should slip into the sloppy habit of using easy to understand common generic terminology & aka's, etc.

Sorry, I didn't dredge the post up and I didn't notice how old it was.

I wasn't really correcting you. It's a lot easier to find information in the manuals and on line if you use the terms Mitsubishi gave to the parts and it didn't sound like you knew what it was called since you couldn't find it.

Also sorry you got raped by the rebuilder. Nineteen months ago a clean EPROM ECU could be had for about $200

Steve