electrical gurus unite! for the love of sup help!

[morganson]

Im 5 days into this electrical nightmare. First the fuel pump left me then after I got it fixed I drove it home. I turned it off like normal idle was good then suddenly it just cut like I pulled the plug. (Yes I have a turbo timer) tried to start it back up and its spins over but never catches. No poot, pop, nothing. Noid light shows no pulse. Test light shows power at the injector on both pins. I have spark. I have continuity from the ecu to the injector however what strikes me as odd is I have continuity from one pin across all pins??
Ex. Probe pin 2 on ecu (inj no1) and have continuity on injector 2??
I have been through all the different diagrams but cant find the smoking gun here. Have checked with two ecu and both do the same thing. Some explain to me whats going on here. Whats right and wrong and why.

 

[morganson]

Bump. Come on guys. Ive done fuses and noid lights I can assure you the injectors (all of them) are not firing and I have spark. I have voltage on both sides of the injector connector. Checked all relays and fuel pump runs.
Help me out here. Plz

 

[z287mgte]

If the injectors are not firing then, cps , maybe a loose wire for the fuel injectors. My ecu had a loose connection in the plug itself

 

[3p141592654]

Well, I'd say you have either a wiring problem from the injector circuits to the ECU, or the ECU is bad.

Everything you are measuring is perfectly normal for the injectors in standby. Since they all get powered from the same source, and are low impedance seeing continuity of a few ohms between injectors is normal.

Try grounding one of the injector circuits (#10, #20 or #30) at the ecu. You should see your noid light flash and hear a click if the ignition is on. Do it fast so you don't overheat the injector coil.

 

[morganson]

I have swapped ecu already (spare) no change. Im trying to understand what tells the ecu to engage efi. Can the circuit open relay be bad on one of the pins but still engage the fuel pump? Cps is perfect with continuity back to the ecu. No odd ground talk. And spark is fine as well. It just isnt telling the injectors to fire. Thoughts or facts?

 

[3p141592654]

If its sparking and the injectors are not firing then the ECU inputs are fine (CPS etc). That's why I said its the wiring or an ECU fault.

COR is only for the fuel pump control. Jump the FP in the diagnostic box and try to start to verify the COR is not the issue. Given the fact as presented, I would say the recent fuel pump work has the highest chance of being the problem. However, you state the injectors are not firing (I'm skeptical of your claim). To test that....

Try my test.

 

[morganson]

So I just want to say that I ran across the problem. The information I was looking for was the N1 talks to the ecu for the injector pulse. However if it so happens to cross talk to the Ne it will spark but you will not have injector pulse. (But will still have power)
So after pulling the harness apart and repining the connector with a new connector (I just happened to have lying around) she busted right off and purrs like a kitten.

 

[jetjock]

Why I decided to pass on unification...

 

[3p141592654]

N1?

 

[morganson]

Sorry. This one refers to it as the g- and Ne
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=IG&P=16
those are the two that fused together.

 

[3p141592654]

G- is the ground for all 3 CPS coils. So you had no NE signal since it was shorted to ground. No NE signal means you get no ignition or injection. Your original claim to have spark was therefore false.

 

[morganson]

No sir. I had spark. Tested every single cylinder. You can pick it apart if you want but this was the problem and the solution. I thank everyone who helped.

 

[jetjock]

He's right. Can't have spark with NE hard to ground. Even Supra owners can't change the laws of physics. That means there must be another explanation...

 

[Piratetip]

morganson aren't you running 6 individual aftermarket coils wired in series?

 

[morganson]

Yes the dg500 mod.

 

[3p141592654]

NE is used by the ECU to compute RPM and crank position. Without it you get no spark and no injection. There is no point debating it.

 

[morganson]

So she did it again. Kinda. This time after turning it off just decided she didnt want to start again. Same symptoms, no injector grounding pulse, ignition is firing fine. My question is am I supposed to see earth ground on g-? I can unplug the ecu and looses the continuity plug it back in and now I have ground again. From what im looking at g- is dedicated. All four wires grouped carried in a shielded cable. So im thinking cps is off the table. Cps talkes to ecu ecu talks to injectors. Common sense says the ecu is the problem but it persists no matter the ecu I put in. So what tells the ecu its ok to fire the injector during startup?

 

[3p141592654]

Its not the CPS if you have spark.

 

[morganson]

Hey guys.....ive poked this thing for the last 2 day and still nothing. No codes either. At this point you could tell me to unplug my dome light and I would be on board to try it.

 

[morganson]

Can someone tell me what this B1 connector goes to.
http://www.supramania.com/forums/sh...ta-Supra-Turbo-Body-plug-Pinout-s-with-colors
also pin 17 has continuity to the 12v B/o wire (pin 12). Is it supposed to have a little continuity or not?