JDM trueno not starting. need help!
03-09-2017, 03:54 PM
Post: #1
JDM trueno not starting. need help!
OK, so some might have seen my build thread. just got everything back in and its not starting..

Car is a 1985 JDM Trueno. Car DOES NOT have diagnostic plug.

so story so far: the gets spark, and gets fuel (kinda) and will crank over and over. Have followed the guide and set crank to 0Deg TDC for piston 1, check intake cam mark and set the dizzy to the correct markings also so timing SHOULD be good. fuel is getting to the rail but i don't think the injectors are firing. swapped over to injectors that i know work and still nothing.

Now given that I've only done about 50miles in the car i didn't really know what the fuel pump sounded like on ignition start up. i bridged the yellow 'T' plug and switched on to ignition and the pump started pumping. turned over but nothing (i do think this is down to the battery going down)

I flashed the EML light and it came up with 4 and 6. now being early spec i believe there is only 11 codes meaning that the codes are 4- coolant temp sensor signal and 6- RPM signal


1 All systems normal
2 AFM meter signal
3 ignition signal
4 coolant temp sensor signal
5 O2sensor signal
6 rpm signal
7 tps signal
8 air intake temp signal
10 starter signal
11 switch signal (AC switch on. ECU faulty) * ( INFO FROM CLUB4AG)

Earths I have taken of to clean are 2x gearbox, 1x head earth, 1x block earth, 1 x intake earth and 1x earth behind engine bay fuse box.

EFI rely in engine bay is working fine and so does the 2nd one in the drivers footwell.

im not any way electronically minded but am sure I've covered the areas needed done.

Any suggestions?
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03-09-2017, 04:28 PM
Post: #2
JDM trueno not starting. need help!
Check the ignitor for any faulty wires.... =)
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03-09-2017, 05:36 PM
Post: #3
JDM trueno not starting. need help!
Might be a dead ECU.

Never heard of a 4AGE without a diagnostic plug though, that would be the easiest way to diagnose it.

FABRICA MI DIEM, PVNC!
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03-09-2017, 07:39 PM
Post: #4
JDM trueno not starting. need help!
I got a electronic screw driver (Light up thing) and disconnected the plug in the boot for the fuel pump, turned on to ignition and the screw driver didn't light up. I then bridged the 'T' plug, turned on ignition again and the screw driver lit up.

pump/ground issue?
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03-09-2017, 11:17 PM
Post: #5
JDM trueno not starting. need help!
Is your engine/ECU Map or AFM controlled?

AE86 ex-daily
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03-10-2017, 01:25 AM
Post: #6
JDM trueno not starting. need help!
Couldn't honestly. Say. MAP at a guess.
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03-10-2017, 01:43 AM
Post: #7
JDM trueno not starting. need help!
no rpm signal probably means the pickup in the dizzy is knackered, of you have a break in the cabling between there and the ECU (maybe where it runs through the timing belt cover). Can't imagine that the code 4 temp has anything to do with your problems.

No rpm signal also means no injector pulse. Some of the older ecu's also used the rpm signal as a fuel pump cut, so in a crash when the engine stopped the fuel pump would shut off as well.

Check the resistance of the coils in the dizzy pickup, should be 140 - 180 ohm.
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03-11-2017, 06:38 PM
Post: #8
JDM trueno not starting. need help!
what nakilad says is true, i know for sure that a really early 4a-ge (the one without O2 sensor) uses the rpm signal for the fuel cut. Not sure about the later models off course, but on my early 4a-ge the fuel pump relay is powered by the ign switch (start position) or the rpm signal.

"It's all about the heart, the people who focus on parts, turbo's and all that stuff...they're just losers."
-Shinji Minowa
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03-12-2017, 05:05 PM
Post: #9
JDM trueno not starting. need help!
Ok so my mate came round and checked out for me. He tested everything. Grounds, continuity, current, Volts, fuse, relays etc you name it, it was tested. Everything is ground and getting power as it should be. So there is no reason why it should start.

We know the injectors are getting power so Have ordered a 'Noid' tester to test the injectors to see if they are getting power when ignition is on and cranking. multimeter is to slow to pic anything up.

Error code 4 & 11 are still present after reset. So if the Noid test comes back fine then next step is to try another ECU. If that STILL doesn't work then I'm lost. Also changed Dizzy for my old one and one from an MR2 incase it wasn't getting a pickup on ignition.

At least it's not something I've done (from investigations) from being stupid and not connecting something etc.
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