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4G61T ecu replacement http://4g61t.org/forum/viewtopic.php?f=6&t=39256	Page 1 of 1

Author:	aluma scoupe [ Thu Nov 13, 2014 10:19 pm ]
Post subject:	4G61T ecu replacement
Hi guys, 2 of my 1.6t ecus are blown, and not the capacitors which have been replaced. My injector driver circuit iare blown on both boards. I believe one of my cars has an intermittent short on one of the ecu power circuits and foolishly I plugged one of my other 1.6t ecus into that car to move it, it fried the 2nd ECU also. My computer rebuilder has fixed this under warranty twice before ( problem is intermittent ) but now says he needs spare injector drivers to fix mine and he has none ! So 2 of my turbos are possibly "un-fixable" my question is does anybody have their old 1.6T ecus available for parts or know of a fix or way to work around this without swapping to a 1990 2.0T ecu and slowly killing the engine through improper fueling tables ?

Author:	CaptainTonus [ Thu Nov 13, 2014 10:38 pm ]
Post subject:	Re: 4G61T ecu replacement
I don't have a great recommendation about repairing your 4g61t ECU's. Frankly, I've never heard of someone having that problem before. Why do you think a 2.0T ECU would kill your engine? Lots of people use them and don't have issues. Just have to use the right combination of airflow meter and injector size, and if it's an EPROM ECU, you can program it to run just about whatever you want.

Author:	j2dapo [ Fri Nov 14, 2014 8:54 am ]
Post subject:	Re: 4G61T ecu replacement
No need to slowly kill anything. Get an eprom 90 ECU and put an 89 CSM chip on it. Most of the parts from a 90 DSM ecu should swap over to the 89 ECU. My swapped car is running an 89 ECU with an E931 (DSM) bin.

Author:	Flying Eagle [ Fri Nov 14, 2014 9:53 pm ]
Post subject:	Re: 4G61T ecu replacement
What these guys say. ^^^ I had a 1.6 T running with a 90 ECU. I could have run a 1.6t airflow meter and 390's with a proper chip but I converted everything to 90 DSM turbo stuff. MAF, 450's and chipped ECU. Injector drivers can be had from any 4g61, 4g63, 4g67, and likely 4g64 ECU from 1989-94. I'm not sure if being turbo or not will matter because I think it is only the injector resistor and injector resistance that was different on turbo boards. Maybe your rebuilder can confirm part numbers to look for in this regard. Tons of spare boards on EBay that need a new home.

Author:	ColtiXim [ Sat Nov 15, 2014 10:33 am ]
Post subject:	Re: 4G61T ecu replacement
My original 4G61T ECU has capacitor's replaced and nice board, good working condition, let me know where i ship this thing if you are interested ? You pay shipping only

Author:	Flying Eagle [ Sat Nov 15, 2014 6:34 pm ]
Post subject:	Re: 4G61T ecu replacement
Just make sure to trace out the wiring to make sure it won't blow parts again. Super nice of you Remy! Be sure to check for case grounds where the case bolts to the RF A-pillar. Missing grounds will stress components. Also make sure to check the injector resistor pack for problems and wiring issues. Lots of manuals at www.lilevo.com/mirage/

Author:	aluma scoupe [ Sun Nov 16, 2014 1:57 am ]
Post subject:	Re: 4G61T ecu replacement
thanks for the help guys, 2 of my ecus are at the rebuilder for over a month now with injector driver issues and the guy first said it was the drivers and they are specific to that model number ecu only and very hard to find. I gave it a month, called him to get the driver numbers as I have tons of bad dsm/csm/hmc ecus for spare parts, and now he said the drivers are fixed but there are still issues with the boards. The car both ecus were plugged into when they died has been probed (with a multi meter ) several times for proper injector resistance , and all ecu grounds and power wires have been tested multiple times over the 3 years this problem has been occuring. I run the car once maybe twice a year and so far I get the computer rebuilt, it runs awesome 2-3 starts and pop its done. I'm sure its an issue with the vehicle somewhere but I've yet to catch it " in the act" with a test meter to verify the problem. Rest assured the car won't have an ecu plugged into it again until I root this problem out. If/when I get the 2 ecus back I lose my warranty if I open them so I am unable to say if they have e-prom or not. But if I can manage to get just one chip from my 3 ecus I could get the bin files flashed to another chip and use a 90 board, never thought of that ! Remy, the offer to ship your ECU is quite generous, If my rebuilder is unable to fix my ecus I'm interested and would certainly pay you more than just shipping ! I guess its just a waiting game to see if my rebuilder will fix them. Any news and I'll post it up. Thanks everyone

Author:	Keane [ Sun Nov 16, 2014 2:19 pm ]
Post subject:	Re: 4G61T ecu replacement
Just a quick thought...dont bad isc motors cause shorts in the ecu like that

Author:	aluma scoupe [ Sun Nov 16, 2014 6:30 pm ]
Post subject:	Re: 4G61T ecu replacement
supposedly yes, ISCs can fry ECUS, I have yet to confirm or experience this but, I'm currently in contact with Thomas at ECM link ( who has been very helpful ) and there is a plethora of information on their site including the ISC thing, my current next things to test (once its warm enough ) are the ISC, possibility the ISC and injector resistor wiring is transposed, a bad ecu case ground, or several of the pins and associated wiring that leads to those drivers, Monday when my rebuilder gets back into his shop I'll try to get him to identify which exact driver keeps blowing since I now a have a decent list of which wires actually interact with those drivers thanks to ECM link. Up until now I've been in the dark as to which wires to test other than the actual injector wires, and the main ecu power circuits. Previously that was as far as my rebuilder could direct me. I almost hope its ISC as that seems the easiest to test and replace.

Author:	aluma scoupe [ Mon Nov 17, 2014 11:38 pm ]
Post subject:	Re: 4G61T ecu replacement
Update : the drivers are mitsubishi ML5269L , and while hard to source new they're available in various mitsu ECUs. My Scoupe ECUs even have 2 each so I've had tons of replacements here the whole time, kinda wish my rebuilder had taken me up on my offer of several spare dsm ecus for parts when I sent him my 2 Mirage ecus over a month ago !! I got outside to test my ISC resistance and all 4 coils are 27.1-27.3 ohms on the car in question so OK there. 89-90 ISCs are waaay harder to test with the probes than the later style 91-94 plug. And it is sketchy removing plastic parts in these temps, but I ruled out the ISC and also there is no way I plugged the ISC into injector resistor because they're several feet apart on this wiring harness vs the DSM one so thats ruled out too. I might just wait till spring to tackle the other driver wire leads so I dont destroy plastic plugs, harness and insulation, plus working 2 test probes like chopsticks with frozen hands and with your arm jammed in a hole is not the most productive thing I can do right now, so problem will have to be solved at a later date I guess, I should've started this sooner not November.

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