Wiring/ECU Issues

campbell.w03 · 11-05-2009, 12:25 AM

I have an 87 7mgte that I bought off a kid in Richmond, and he had pretty much mangled everything under the hood of the car. About a week ago, the EGR cooler plate blew out, caught a coolant hose on fire, and toasted my wiring harness. Picked up a new harness from a local junkyard, and soldered in the new chunk to replace the burned chunk. Anyways when I finished everything and went to start the car it wouldn't catch. I have spark and I have fuel coming through the fuel line, I dont know yet if the injectors are getting a pulse. The computer is giving me code 22, water temp sensor failing, and code 32, MAF sensor failing. Now I have 2 questions. One, would either of those 2 codes cause the car not to start? But what I am thinking is that when the wiring harness melted some wires crossed over and shorted out the ECU, but theres no way in hell I'm going to shell out cash for a new ECU if thats not the problem. So question number 2, does anyone here know if there is a breakout box that toyota made for this car, and does anyone know where I could find a chart with each pin, which wire runs from it, what its voltage is at acc, idle, low rpm, high rpm, normal operating range, etc.? If i could find the chart the breakout box could probably be made after a trip to radioshack anyway...

cre · 11-05-2009, 02:23 AM

Here's a guide of mine on the diagnostic box in the engine bay: http://www.fadingworld.com/CRE/_Auto...mystified.html

Here's Toyota's Electronic Wiring Diagrams for the Supra all digitized and nicely formatted... you're in for hell...

HINT: Test for a break in E2 between the ECU and the TPS, temp sensor and AFM connector.

EDIT: Nevermind about the FC switch, that's N/A specific. On the GTE it's controlled by the ECU.

campbell.w03 · 11-05-2009, 07:54 PM

Thanks alot cre, I'll be checking into that friday when I'm off. I found another 87 turbo/manual car at a junkyard in MD, so if I cant get it running I might just pick up the ecu, the guy said he'd let it go for $75 but I hope it wont have to come to that. Also is it just me or is there no link to toyotas wiring diagrams? Yeah that's exactly what my dad said. After spending like 6 hours soldering I put the key in the ignition, went to crank it, all you heard was the starter grinding away. my dad just looked at me and said "yup. this just became REALLY hateful"

11-05-2009, 12:25 AM	#1
campbell.w03 Stock Join Date: Jun 2008 Location: NoVa Posts: 3	Wiring/ECU Issues I have an 87 7mgte that I bought off a kid in Richmond, and he had pretty much mangled everything under the hood of the car. About a week ago, the EGR cooler plate blew out, caught a coolant hose on fire, and toasted my wiring harness. Picked up a new harness from a local junkyard, and soldered in the new chunk to replace the burned chunk. Anyways when I finished everything and went to start the car it wouldn't catch. I have spark and I have fuel coming through the fuel line, I dont know yet if the injectors are getting a pulse. The computer is giving me code 22, water temp sensor failing, and code 32, MAF sensor failing. Now I have 2 questions. One, would either of those 2 codes cause the car not to start? But what I am thinking is that when the wiring harness melted some wires crossed over and shorted out the ECU, but theres no way in hell I'm going to shell out cash for a new ECU if thats not the problem. So question number 2, does anyone here know if there is a breakout box that toyota made for this car, and does anyone know where I could find a chart with each pin, which wire runs from it, what its voltage is at acc, idle, low rpm, high rpm, normal operating range, etc.? If i could find the chart the breakout box could probably be made after a trip to radioshack anyway...

11-05-2009, 02:23 AM	#2
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Here's a guide of mine on the diagnostic box in the engine bay: http://www.fadingworld.com/CRE/_Auto...mystified.html Here's Toyota's Electronic Wiring Diagrams for the Supra all digitized and nicely formatted... you're in for hell... HINT: Test for a break in E2 between the ECU and the TPS, temp sensor and AFM connector. EDIT: Nevermind about the FC switch, that's N/A specific. On the GTE it's controlled by the ECU. Last edited by cre; 11-05-2009 at 02:26 AM.

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11-05-2009, 07:54 PM	#3
campbell.w03 Stock Join Date: Jun 2008 Location: NoVa Posts: 3	Thanks alot cre, I'll be checking into that friday when I'm off. I found another 87 turbo/manual car at a junkyard in MD, so if I cant get it running I might just pick up the ecu, the guy said he'd let it go for $75 but I hope it wont have to come to that. Also is it just me or is there no link to toyotas wiring diagrams? Yeah that's exactly what my dad said. After spending like 6 hours soldering I put the key in the ignition, went to crank it, all you heard was the starter grinding away. my dad just looked at me and said "yup. this just became REALLY hateful"