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1G Help kind of stumped very hard cold starts than frying ECU's back to back

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moboostin

Probationary Member
18
2
Feb 3, 2018
LA, California
hey guys hoping maybe I can get some insight.. got a 92 talon awd turbo 6 bolt motor minor bolt ons big16g 2g maf full exhaust & 550cc injectors. Thing doesn't start on its own unless I spray starter fluid.. I fixed most of the boost leaks changed the maf still no change. might start up once after 20 cranks if I catch the revs till it warms up. long story short I took my ecu out to look inside to see maybe if something was off from the starting issue nothing seemed burnt? so I put it back than it started smoking and drivers IC106-108 fried. I had another ecu laying around so I swapped in but this ecu also started smoking and the same drivers got fried. The car starts up on its a lot better with this ecu but still after a few cranks if im lucky. I don't know if there is a short or if a wire popped out the harness for the ecu causing it to keep frying? I also try to unplug the maf but nothing really happens besides a slight rise in the idle.. It does not have dsm link its got an safc I bought the car like this.. first the no start and now 2 ecu got burnt.. once it runs it idles fine and I can rev it no problem got 14+ volts from the alternator
 
Definitely something is wrong in the circuit. I think you have bad or incorrect wirings for the SAFC or/and for the 2G MAF conversion. Don't keep burning ECUs. Check everything first.
I also try to unplug the maf but nothing really happens besides a slight rise in the idle.. It does not have dsm link its got an safc I bought the car like this..
This. The SAFC or/and the MAF is not working properly.
 
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Thanks for your input guys Alright i’ll try and check the wiring in the harness worse case i’ll put 450s back in and try to remove the safc. It just hadn’t done this ecu frying thing before till i unplugged the ecu idk i suck with wiring it might be over for me.. just curious how would i even know i even fixed anything without putting another ecu in and possibly frying that too ? Sorry for the noob questions literally dont work well with wiring unless told what to do
 
Don't give up, wiring is just another part of the puzzle. If you have questions post them here and we can try to help walk you through things as long as you're willing and able to do the leg work.

It definitely sounds like the safc wiring is pooched, or was done poorly and the disturbance of the ECU harness may have caused the issue.
Trace the safc wiring and ensure nothing is cut/exposed or directly shorted.
Check the ECU pins themselves to make sure none are bent.
Check the MAF wiring to make sure it's done correctly (an adapter would be better) and it's integrity isn't compromised.
Lastly, check the injectors to see if they are high or low impedance, and verify if your injector resistor pack is still present.

Report back, good luck :thumb:
 
Thanks for your input guys Alright i’ll try and check the wiring in the harness worse case i’ll put 450s back in and try to remove the safc. It just hadn’t done this ecu frying thing before till i unplugged the ecu idk i suck with wiring it might be over for me.. just curious how would i even know i even fixed anything without putting another ecu in and possibly frying that too ? Sorry for the noob questions literally dont work well with wiring unless told what to do
Looks like you completely ignored the link that Gary took the time posting. Test your ISC with a multimeter, if it fails it will blow those drivers in the ECU. Also, It's possible to plug the injector resistor pack into the ISC connector. They are both identical 6-pin connectors and relatively close to each other in the engine bay and doing so could damage the ISC drivers in the ECU.
 
Alright will do ill check the wiring out and everything, and I didn't ignore the link I checked It out I had just woken up haha ill test out the isc and see what's up, the maf is also using an adapter plug. I looked up the injectors they are some new ebay 550cc high impedance and I still have the resistor box plugged in. Weird but with this newer ecu that I fried last the car starts up first try on a cold start now without giving gas or anything and will idle on its own (surging) and not die but it will not turn back on if I shut the car off while its hot.. Im going to check the link, trace wires & test the isc and take it from there! Thanks guys appreciate the help
 
So i checked the isc plug it’s in the right spot. I checked with a multimeter i got like 2.0 ohms on it outside the car guessing it’s bad i found another one laying around i tested it got 29 ohms i plugged the harness and left it out and turned the key to see if the sensor would move but it didn’t (guessing cause the drivers were fried)? so i unplugged it and tested it out the car it read 0 ohms this time ?
 
Please refer the pic to check the ISC.
The second pic is my old ECU that got the 106 driver burnt. This was somehow caused by a bad installation of SAFC and/or MAFT. It never happened again after I fixed their wirings, .

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Thanks a mill for that, will check using that way. Also that’s odd same driver blew on mine. You think i should just remove the safc and connect the maf sensor wire back in the harness ? I wouldn’t know how to fix the wiring i can remove it and going off the forums i can connect it back to how it should be without safc? Thanks again!
 
Thanks a mill for that, will check using that way. Also that’s odd same driver blew on mine. You think i should just remove the safc and connect the maf sensor wire back in the harness ? I wouldn’t know how to fix the wiring i can remove it and going off the forums i can connect it back to how it should be without safc? Thanks again!
If you have the stock 450cc injectors, you don't need the SAFC for now. But anyways you may already have a short in somewhere, so I suggest to check the ISC/its wirings, the SAFC wirings around ECU and the 2G MAF conversion wirings around the MAF sensor to see if there is some suspicious part. If you don't know the wiring just take some good pics and post them here. More people would chime in to help you.
 
2g maf harness looks good, i’m uploading the isc plug wires(it looks good?) Also here are the ecu harness wires not sure if it’s possible to see anything out the norm?
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2g maf harness looks good, i’m uploading the isc plug wires(it looks good?) Also here are the ecu harness wires not sure if it’s possible to see anything out the norm?
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You have a lot of quick splices. You should insulate all wire ends that are coming from quick splices like the green circles in the pics below. Those would cause a short easily. And also should check loose connection/contact failure/burnt mark on the harness and in those quick splices. In my case when I burnt a driver was, some of quick splices had a contact failure.

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Okay I see what your talking about I really hope that's the case with this too! First thing tomorrow I'm on it, ill check the isc the way I was told as well as opening those blue things to check the connections and get those open ones covered and check the harness. Hope to find my issue there! THANK YOU!
 
You have a lot of quick splices. You should insulate all wire ends that are coming from quick splices like the green circles in the pics below. Those would cause a short easily. And also should check loose connection/contact failure/burnt mark on the harness and in those quick splices. In my case when I burnt a driver was, some of quick splices had a contact failure.

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Whoever did that deserves to be murdered.
 
If he has stock injectors, the safest or the best way would be to remove everything and going back to stock and make the car running as it should first, then reinstall everything properly. Most of time, that would save time finally.

Whoever did that deserves to be murdered.
The 12v wire in the pic makes me nervous.
 
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Did the fact that he has 550 HI Z injectors but has the resistor pack make any sense or did I just read it wrong? Not that it might harm the computer but......WTF? Doesn't that require the deletion of the resistor pack?
 
Did the fact that he has 550 HI Z injectors but has the resistor pack make any sense or did I just read it wrong? Not that it might harm the computer but......WTF? Doesn't that require the deletion of the resistor pack?
Hence why I was asking what kind of injectors he had. I've seen a few sets of low-z 550s, but they're rare.
 
I know, it sucks wish I saw that before I bought it! Okay so that's what ill do than. ill just remove all those shitty wires cut them and connect the green and blue wire back right? As I have hopefully read correctly on the forums to get the maf sensor to work back to normal? This car also has that avc-r device if I remove the safc will it effect that and its wiring as well? or can I just remove the safc and be done? Yeah I bought the car with those injectors they had no label I took them out they came up at 440cc Ebay injectors but the owner claims there 550cc Im waiting for a buddy to mail me some 450cc and ill start getting rid of this connectors!

Based on your guys help, Im going to get a new isc and get the wiring sorted out to normal but what about the ECU with the burnt drivers what do I do about that? Do I buy another somewhere or does someone repair these? Weird but with the old ecu the car didn't start cold unless I sprayed starter fluid but with this ecu it starts right up on cold starts on its own but doesn't start back when hot LOL
 
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I know, it sucks wish I saw that before I bought it! Okay so that's what ill do than. ill just remove all those sh**ty wires cut them and connect the green and blue wire back right? As I have hopefully read correctly on the forums to get the maf sensor to work back to normal? This car also has that avc-r device if I remove the safc will it effect that and its wiring as well? or can I just remove the safc and be done? Yeah I bought the car with those injectors they had no label I took them out they came up at 440cc Ebay injectors but the owner claims there 550cc Im waiting for a buddy to mail me some 450cc and ill start getting rid of this connectors!

Based on your guys help, Im going to get a new isc and get the wiring sorted out to normal but what about the ECU with the burnt drivers what do I do about that? Do I buy another somewhere or does someone repair these? Weird but with the old ecu the car didn't start cold unless I sprayed starter fluid but with this ecu it starts right up on cold starts on its own but doesn't start back when hot LOL
You don't need to cut any wires. Just remove the quick splices and wires of the SAFC and the AVC-R (If you also wish to remove) from the ECU harness. And then reconnect the green wire (The MAF signal, the green circles in the pic below) that is already cut to be connected to the SAFC pink and orange wire. As for the ISC, if the check result is bad, replace it. But always it's better to have a spare. As for the ECU, ask ECMTuning or somebody who can repairs ECUs. If not possible to repair, no choice, just find a working ECU.

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Hey guys my apologies haven't been able to get back to y'all or the car, I was swamped wit school and exams. I did get a change today to mess with it so I removed the quick splices and took out the safc and avc-r out the harness and connected the green/blue wire back and FIRED right up Tried a few on and off starts she takes a few tries but she starts no matter what. Thank you guys so so much. Im waiting on the stock 450 injectors to come in the mail to put them in. Will do a boost leak test and clean some things up. Would there be any reason it takes a couple cranks before it fires up? Thank you guys again


*** Weird but I went to start it today wouldn't start for nothing. I don't know what even happened it started yesterday back to back five times. Today nothing.. Started once idled and than she wouldn't start back up hot. Changed the coolant temp sensor and threw some new plugs in there. Its not like it isn't getting spark or fuel like it starts but when it feels like it and than it won't start back up unless I let it sit for awhile or unless I spray starter fluid. When I took out the acv-r electronic boost controller I left the solenoid alone do I have to take out those vacuum lines and run a manual boost controller would that effect any start ups ?
 
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Figured i’d update everyone, i replaced the coolant temp sensor wires at the sensor they were a bit brittle and threw the 450s in there so far she starts up aboht 20 times back to back while fully warmed. I think she’s good now i haven’t repacked the iac yet or repacked the ecu with the burnt drivers but she starts up still so i guess once i get those replaced she should be 100%
 
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