The Top Mitsubishi Galant VR-4 Resource

Join the best E39A 1991-1992 Mitsubishi Galant VR-4 community and document your GVR4 journey.

  • Software Upgraded - Reset Your Password to Login
    In order to log in after the forum software change, you need to reset your password. If you don't have access to the email address you used to register your GVR4.org account, you won't be able to reset your password. In that case, follow the instructions here to regain access to the forum.

Smoke from dash, then car dies, now won't start, help!

JamesFoster

Well-known member
Joined
Oct 14, 2008
Messages
583
Location
ALL
I was driving yesterday, all was well, driving with the A/C on, and smoke comes from the a/c vents, then the car dies, now it won't start.
Had it towed home, now trying to figure out whats going on.

All fuses are good, I thought maybe fuel pump is bad, checked for voltage at the pump wiring and the black wire with the white stripe has no voltage with the key in the on position. I hardwired it to the battery to turn the pump on, and it turns on, but the car still won't start.

Could this be the MPI relay? If so, where is it?

Any other ideas?
 

jmorri15

Well-known member
Joined
Jul 11, 2009
Messages
171
Location
Kemp, TX
pull the ecu and make sure the smoke wasnt from there. you have any idea from which side the smoke came from?
 

SouthCaliVR4

Well-known member
Joined
Jul 31, 2010
Messages
984
Location
North county San Diego
did you have the a/c set to recirculate? the ecu & mpi relay are right by the vent intake when set on recirculate. Ecu is just above the passenger side kick panel the mpi relay is just under the right side of the glove box.

drop em both & check for any odd smell, open the ecu case & check the caps.
 

JamesFoster

Well-known member
Joined
Oct 14, 2008
Messages
583
Location
ALL
I did have the A/C set to recirculate, it's all starting to make sense now. I just pulled the MPI, I think thats what the problem is. I'm going to try and check out the MPI before taking out the ECU because supposedly the caps have already been replaced. Thanks for the help guys. I just put in a new alternator and I think the voltage being up above 14v like it's supposed to was too much for the old electronics.
 

JamesFoster

Well-known member
Joined
Oct 14, 2008
Messages
583
Location
ALL
I popped the top off the MPI and it looked fine, so I just went and pulled the ECU, and it's f***ing fried, I could smell it as soon as I pulled it out, and I took the case off and I can see a few small spots where it looks burned, right next to the caps. Great. Anyone got an ECU?
 
Last edited:

SouthCaliVR4

Well-known member
Joined
Jul 31, 2010
Messages
984
Location
North county San Diego
Sorry to hear that but at least you know what to fix. post up a wanted to buy & someone will set you up. check the IAC motor before you put in a new ecu. as well check all the grounds. A bad IAC can fry the ecu, though I don't know if it would smoke it.

You can also use a 91 up 1g turbo ecu, non e-prom, or a 90 but for the 90 you'll have to swap a couple pins in the connector.
 

jepherz

Staff member
Joined
Aug 8, 2004
Messages
7,877
Location
KC, Missouri
Post up pics of the ECU board so we can determine what actually fried. It may be fixable.
 

chrisfullwood

Well-known member
Joined
Apr 28, 2006
Messages
256
Location
bartlesville, ok
Weird i know, but check the white wire from the O2 sensor. i had it burn up almost completely, and the car wouldn't start. If that isnt it, your going to have to check a lot of wire. If you can be more specific about what works and what doesn't, i would be happy to pull up the schematics and start eliminating stuff (unemployed right now, so i have some free time, and i am an aircraft electrician... cars are much simpler)

oh, something to keep in mind, voltage rarely causes wires to burn out, its amperage... /ubbthreads/images/graemlins/smile.gif
 
Last edited:

chrisfullwood

Well-known member
Joined
Apr 28, 2006
Messages
256
Location
bartlesville, ok
I traced out all the wires connected to the starter relay back, and it touches the MPI relay, CAS sensor, o2 sensor, and there is a direct ground along the way. If one of those components has failed, it will interrupt the path of current to the starter relay. I can take the wiring down further and mark places to check for voltage if you would like.

Below is the image tracing the path from the Starter relay (assuming the relay is good, if you check for voltage there, and don't find it, you will need to start working back to find the point of failure.

 

JamesFoster

Well-known member
Joined
Oct 14, 2008
Messages
583
Location
ALL
Quoting SouthCaliVR4:
Sorry to hear that but at least you know what to fix. post up a wanted to buy & someone will set you up. check the IAC motor before you put in a new ecu. as well check all the grounds. A bad IAC can fry the ecu, though I don't know if it would smoke it.

You can also use a 91 up 1g turbo ecu, non e-prom, or a 90 but for the 90 you'll have to swap a couple pins in the connector.



How would I know if the IAC is bad?
 

JamesFoster

Well-known member
Joined
Oct 14, 2008
Messages
583
Location
ALL
Quoting FavNumber:
Same thing happened to my car and i had a short somewhere (that I still cant find) my ecu was good. Do you need a Socketed/Eprom ECU or non eprom?



I need an eprom
 

JamesFoster

Well-known member
Joined
Oct 14, 2008
Messages
583
Location
ALL
Quoting chrisfullwood:
Weird i know, but check the white wire from the O2 sensor. i had it burn up almost completely, and the car wouldn't start. If that isnt it, your going to have to check a lot of wire. If you can be more specific about what works and what doesn't, i would be happy to pull up the schematics and start eliminating stuff (unemployed right now, so i have some free time, and i am an aircraft electrician... cars are much simpler)

oh, something to keep in mind, voltage rarely causes wires to burn out, its amperage... /ubbthreads/images/graemlins/smile.gif



I checked the o2 sensor, looks fine. The car cranked with the bad ecu just wouldnt actually start.
 

JamesFoster

Well-known member
Joined
Oct 14, 2008
Messages
583
Location
ALL
Thanks for tracing down the wiring for me. I do feel that there is a short somewhere, but I don't know where or what. There's a small gauge wire coming off the alternator harness where the plug plugs into the alternator, that's not connected to anything and is supposed to be connected somewhere I just don't know where. Other than that, the passenger side headlamp ground was showing +12v and the headlight was obviously not working. So I spliced in a wire and grounded it to get my headlamp to work properly, but obviously that means there's a bad ground somewhere or a crossed wire.
 

JamesFoster

Well-known member
Joined
Oct 14, 2008
Messages
583
Location
ALL
So I put in a NON eprom ecu from a 92 awd today, and the car started right up. My ecu was from my 91 vr4 and was an eprom. The car seems to run alright except my tach readout on my safc2 is half of what the actual engine revs are for some reason. I want to get a vr4 ecu because I don't know what is different on the non eprom 92 ecu from my 91 eprom.

Here's pics of the fried ecu. Repairable? I don't think so, but I don't know.

P1050335.jpg

P1050342.jpg

P1050341.jpg

P1050340.jpg

P1050339.jpg

P1050338.jpg

P1050337.jpg

P1050336.jpg
 

chrisfullwood

Well-known member
Joined
Apr 28, 2006
Messages
256
Location
bartlesville, ok
you need to get some denatured alcohol, and a small paint brush, cut the bristles in half, and use it to clean away as much of that burnt stuff as you can. it might be repairable, if you can de-solder the old components, and the board itself isn't damaged to bad. It might be possible to use wire in place of the printed circuit, if its to badly damaged. But clean it up, and put new pictures up, it might be salvageable.
 

chrisfullwood

Well-known member
Joined
Apr 28, 2006
Messages
256
Location
bartlesville, ok
I'm not 100% sure on the differences, I believe they are pretty much the same, i could put up the wiring diagrams if you want.
 

stevep

Well-known member
Joined
Oct 23, 2004
Messages
416
Location
St. Charles, IL USA
Those are original caps and they have leaked. The front 47uf one leaked and shorted out.
If you were having voltage problems from the alternator that might have been the final straw.

Looks like the CPU chip might be blown too. The smudge mark on the top of it looks interesting.
 
Support Vendors who Support the GVR-4 Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications RixRacing RockAuto RTM Racing STM Tuned

Recent Forum Posts

Top