1G MPI relay help, (ECU not switching it to ground)

[gto1150]

Hey, Having a bit of trouble with my car. I have posted on many forums about it but no one has said anything that resolved the issue.

First off the car is a 1991 Mitsubishi GTO twin turbo RHD (from Japan).

The problem I am having is with the MPI relay. I am getting power to all the wires that are supposed to have it, but when I check the wire that comes from the ECU that is supposed to switch to ground and turn the relay on, it is not switching. (it stays positive).

If I ground that wire manually than the relay will turn on and the car will start. Would that part of the ECU circuit be fried, not letting it turn to ground when supposed to? I'm pretty sure the part that switches it back and forth is IC110 in the ECU. any help is greatly appreciated. (I dont want to go and buy a new ECU if its not the problem)

Thank you.

 

[boostd_mitsu]

i'm thinking that something shorted out in your ecu, if it is suppose to ground the relay and it has power there then the ecu is junk. open it up and see if there are any burn marks on the board.

 

[gto1150]

I have had the ECU out and nothing seems fried. The wire is supposed to have a bit of power when the key is off (it keeps the relay off) but when you turn the key to on it is supposed to switch to ground and turn the relay on.

But its staying positive. I'm thinking of buying another ECU but I don't want to spend the money unless i know for sure .

 

[steve]

If the caps have leaked it's a rather common problem. I also see the output transistor failing on IC110 often.

 

[gto1150]

the caps all look fine, thats what i was thinking about ic110. so if thats gone i may as well buy a new ecu than.

 

[steve]

Getting a 6G72 turbo ECU for a GTO (3000GT VR4 or Stealth RT/TT here in the US) could run upwards to $400.
Getting your fixed should be cheaper. If all that's wrong is the transistor, a lot cheaper.

 

[gto1150]

wheres a good place to send it to have it fixed. i also know a place that imports the cars and they have ecu's and i could get one for 200. but if its cheaper to have it fixed than i might go that way. also i have a turbo timer installed and its not working now (did before) so i didnt know if that would cause this problem or not. thank you

 

[steve]

I don't know anybody in Canada that repairs them. I get them from all over the world but it seems that sending them back to Canada is a PITA and I never know if they are going to show up or get lost in customs somewhere.

 

[gto1150]

ok, thank you anyways. I will give the place i know a call tomorrow and see if i can pick one up.