How to fry an ecu?

rareusername · 09-16-2005, 03:40 PM

Hi. I might need a new ecu for my 1987 turbo. Could anyone give some advice on what to check before plugging the new unit in?
I never had a Supra before (never had a Toyota for that matter), but in any other car I had I never burned an ecu. I did not burn this one either, I bought it this way. I thought may be there are some known issues with this car’s ecu.
In case it matters, what I have on my ecu is:
AD
Engine Control
Toyota
89661-14140
175000-0561 12V
Denso Made In Japan
10P 18P 24P
7MGT A/T

Thanks for your help.
Alec

SupraMan1784 · 09-16-2005, 06:11 PM

ive never heard of anyone messing up their ecu, rather than trying unsuccessfully to reflash it, but when u mean check for something...did u mean check to see if the ecu is still ok? or how to install?

rareusername · 09-16-2005, 06:48 PM

I meant the cause that possibly (not certain yet) fried my ecu might still be there and it will fry the new (well, probably used) one just as well.

mrnickleye · 09-17-2005, 03:10 AM

I would not just plug in another ECU if the one in there is bad. I would run a full system diagnostic check to see if the first one is really bad.

We had a 89 Cressida in the shop for last month. It would hard start, intermittantly of course, when it was hot. The ECU was bad. But it turned out that the distributor was the culprit, with ultra-high resistance when it got very hot. Somehow the ECU got overloaded and fried from the bad distributor. We replaced both units with ones from the wrecking yard.

Point is...it took the tech quite some time to test all the circuits to narrow it down. Plugging in the ECU may just burn it up if the cause is not found first. ECU=$175...Distributor=$125 Labor=4hrs.

SupraMan1784 · 09-18-2005, 06:03 AM

interesting...my guess was gonna be that it might just be electrical...maybe a short thats heating the wires up to a point where its just bustin up that ecu

rareusername · 09-19-2005, 09:45 PM

I just wanted to make sure that there is no COMMON problem with this engine/ecu (like trunk lid leak is common to Supra, because of dried rubber gaskets).

mrnickleye · 09-21-2005, 03:34 AM

Well...after reading all these supra forums (like 4-6 on the net), for the last 3 years, and all the old threads (like 3-4 years back), I can say that the ECU does not appear to be a regular 'problem' (like BHG, radiators, turbo oil leaks).
It seems that neither are the TPS, ISC, cold start system, temp senders, oil pressure senders, water pumps, alternators, power steering pumps, wheel bearings (seem to be very tough), and ABS system.

I think that most electrical problems are caused by (1) eventual component failure, and (2) by someone working on the car that was not very proficient with Supras (human error with assembly/disassembly).

You gotta figure, these cars have probably had 3-4 owners, and several repairs before you got it.

lethalwithasupra · 09-23-2005, 12:09 PM

hey its impossible to fry the ecu of a supra. mine shorted injector wires to the manifold and it still works after the short was taken away. ages and ages spent fault finding just to find that there was a massive short circuit every time i tried to fault find. those ecus are electronic tanks.

09-16-2005, 03:40 PM	#1
rareusername Stock Join Date: Sep 2005 Posts: 11	How to fry an ecu? Hi. I might need a new ecu for my 1987 turbo. Could anyone give some advice on what to check before plugging the new unit in? I never had a Supra before (never had a Toyota for that matter), but in any other car I had I never burned an ecu. I did not burn this one either, I bought it this way. I thought may be there are some known issues with this car’s ecu. In case it matters, what I have on my ecu is: AD Engine Control Toyota 89661-14140 175000-0561 12V Denso Made In Japan 10P 18P 24P 7MGT A/T Thanks for your help. Alec

09-16-2005, 06:48 PM	#3
rareusername Stock Join Date: Sep 2005 Posts: 11	Thanks for reply. I meant the cause that possibly (not certain yet) fried my ecu might still be there and it will fry the new (well, probably used) one just as well.

09-18-2005, 06:03 AM	#5
SupraMan1784 SP58GT Join Date: Jun 2005 Location: Dirty Jerz Posts: 691	interesting...my guess was gonna be that it might just be electrical...maybe a short thats heating the wires up to a point where its just bustin up that ecu __________________ Now: Saving for an MKIV Broken Rides: (Sold) 91 supra turbo 5speed with a 1jzgte motor 421whp 400(399) ft*lbs of torque on tap @ 15 psi "Always outnumbered, never outgunned."

09-19-2005, 09:45 PM	#6
rareusername Stock Join Date: Sep 2005 Posts: 11	Thanks. I just wanted to make sure that there is no COMMON problem with this engine/ecu (like trunk lid leak is common to Supra, because of dried rubber gaskets).

09-16-2005, 06:11 PM	#2
SupraMan1784 SP58GT Join Date: Jun 2005 Location: Dirty Jerz Posts: 691	ive never heard of anyone messing up their ecu, rather than trying unsuccessfully to reflash it, but when u mean check for something...did u mean check to see if the ecu is still ok? or how to install?

09-17-2005, 03:10 AM	#4
mrnickleye 1000whp postwhore Join Date: Jun 2005 Location: Mojave Desert, Calif. Posts: 1,705	I would not just plug in another ECU if the one in there is bad. I would run a full system diagnostic check to see if the first one is really bad. We had a 89 Cressida in the shop for last month. It would hard start, intermittantly of course, when it was hot. The ECU was bad. But it turned out that the distributor was the culprit, with ultra-high resistance when it got very hot. Somehow the ECU got overloaded and fried from the bad distributor. We replaced both units with ones from the wrecking yard. Point is...it took the tech quite some time to test all the circuits to narrow it down. Plugging in the ECU may just burn it up if the cause is not found first. ECU=$175...Distributor=$125 Labor=4hrs.

09-21-2005, 03:34 AM	#7
mrnickleye 1000whp postwhore Join Date: Jun 2005 Location: Mojave Desert, Calif. Posts: 1,705	Well...after reading all these supra forums (like 4-6 on the net), for the last 3 years, and all the old threads (like 3-4 years back), I can say that the ECU does not appear to be a regular 'problem' (like BHG, radiators, turbo oil leaks). It seems that neither are the TPS, ISC, cold start system, temp senders, oil pressure senders, water pumps, alternators, power steering pumps, wheel bearings (seem to be very tough), and ABS system. I think that most electrical problems are caused by (1) eventual component failure, and (2) by someone working on the car that was not very proficient with Supras (human error with assembly/disassembly). You gotta figure, these cars have probably had 3-4 owners, and several repairs before you got it.

09-23-2005, 12:09 PM	#8
lethalwithasupra 3" Exhaust Join Date: Sep 2005 Location: south cantebury Posts: 112	hey its impossible to fry the ecu of a supra. mine shorted injector wires to the manifold and it still works after the short was taken away. ages and ages spent fault finding just to find that there was a massive short circuit every time i tried to fault find. those ecus are electronic tanks.