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09-16-2012, 11:36 PM #1
Anybody have to troubleshoot a 7m swap w no spark?
So made a ton of progress this weekend, wired in everything needed to start my 88 7mgte swapped 82, no spark. I spent all of today troubleshooting, wanted to give a shout out to see what it might be going on here.
My Wiring is as follows-
C1 plug- Black wire yellow tracer has constant fused power. This is verified on the BATT pin of ECU.
This was all I thought I needed on this plug according to this- http://www.supracharged.com/tech/wiring/c1.shtml
but through my trouble shooting I realized ecu pins B+ and B+1 didnt have switched power, so the black wire red tracer got switched power and that fixed this.
B1plug- my starter is hooked up to the 7m harness wire, and I spliced into the chassis wire by the ecu, I have verified the STA pin knows when it is cranking.
The rest is followed on the website I posted above. Small ga black wire red tracer, both big & small ga black w orange tracer all got switched power.
So what Ive checked-
All of these have power- Coil packs, ignitor, fuel injector resistor, and all necessary pins on the ECU
The fuel pump is on by jumping stock MAF pins 1&2, it runs.
Some things that concern me-
The injectors actually have 12v power on both wires, both turn on a test light.
On ECU pin E1 (engine ground) it does not show as ground. but my grounds should be in order, continuity checks out okay, body to engine, ect. and the sensor ground pins ground properly. There are a couple plugs on the engine harness that arent plugged in, there are 2 small two pin white connectors, one long on the left side that I assumed went to an auto trans, and another higher up by the head. Any help is appreciated, and will be awarded by the much needed video of this beast finally firing up
09-17-2012, 06:55 AM #2CelicaSupra.com Member
- Join Date
- Jan 2010
- Pittsboro, NC
are your injectors actually clicking open and closed? you said your CPS doesn't have power but everything else does? check the wiring harness in between the CPS plug and the pice of plastic that goes over the valve-covers. the wires right there tend to get heat-cycled and break apart.
Are you sure you tapped into the right Acc power? i spliced into the wrong one and it caused me a whole boatload of problems. the one i used showed 12v with the key on (thus all my accessories showed that they had power) but when i turned the key from "run" to "Crank" position it would cut off the power signal to the ECU (No fuel or spark when actually trying to start it) when i had it hooked up that way the car would start and run with an "ignition bypass button" but it wouldn't start with the key. that shit boggled my mind...The Supra is gone... What a fun project!
Living the Wagon Life! 86 X72.
New family member, 89 MX83. (temporary DD)
09-17-2012, 07:57 AM #3
09-17-2012, 05:18 PM #4CelicaSupra.com Member
- Join Date
- Jan 2005
Pull the CPS out and spin it with the ignition on. You should hear injectors clicking, fuel pumps turning on, and coils firing. If not, the signal is not getting all the way back to the ECU through the ignitor.
Last edited by johnb7; 09-17-2012 at 05:52 PM.77 Celica: GT coupe (SOLD)
82 Supra: L Type Terra Cotta Hardtop 7MGTE
82 Supra: L Type Terra Cotta (PARTS)
83 Tercel: 4WD (SOLD)
91 Mercedes 300SEL: Eternal Project
95 BMW 318TI: Daily Driver
09-17-2012, 06:26 PM #5
If you look on the pinout of the ecu, there will be an FC wire. It is the wire that goes to the piggy's stock relay(Circuit Opening Relay) to turn the pump on. If that wire goes to ground when spinning the CPS, then you know the ECU sees the cps spinning.
If all is well with the CPS, the coils will make a clicking sound, along with the injectors, like John said.
09-18-2012, 09:10 AM #6
Great info thank you. Ill get right on this and see what's up
10-05-2012, 10:29 AM #7
I haven't had a lot of time on this... what i was able to find is-
my coil packs were not grounded
injectors/coils DO NOT click with cranking.
my oil pressure sender is bad
Ill pull my cps this weekend spin by hand.
10-05-2012, 10:56 AM #8
grounds! coil pack bracket to head. block to neg on battery. head to body. neg on battery to body. and make sure the cluster of grounds in the engine harness are bolted to the intake manifold properly. if these are not all done it will not run. check the grounds on the engine harness to the intake manifold. those can cause the injectors to not fire as well.
if all of that checks out. peel the insulation off the wire on the harness that goes to the cps all the way across to the intake side. i bet the 4 wires inside have lots of cracks. tape them all up individually and then put the shielding back over them and tape the whole thing back up. ive had to do this on mine and several other 7mgte's ive worked on. helps get rid of alot of the popping misfires at idle ive noticed.
11-05-2012, 11:17 PM #9
Last edited by mk2 supra; 11-05-2012 at 11:29 PM.
11-06-2012, 06:03 PM #10
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