ECMlink 2G - injector circuit malfunction DTC

[Justin DuBois]

Uuu, well this is a new intermittent DTC for me. What are the typical reasons for an injector circuit malfunction message? Everything has been working fine for over year - now this.

 

[steve]

I have no idea what the "typical" causes are because it doesn't seem that typical. I'm sure you can go down the list of parts involved as well as I can in the injector circuit.

Are there any correlating data points? Does it run funny at the time, is it only when it's hot, are any of the injector clips missing their locks? Which code(s) are you getting?

Tom and Dave would have a better idea of what the 2g ECU is checking as a condition for the fault. The 1g is pretty simple, looking for an open circuit. I had a bad injector that the coil woud go open when it got hot and that threw the fault.

 

[Justin DuBois]

I have no idea what the "typical" causes are because it doesn't seem that typical. I'm sure you can go down the list of parts involved as well as I can in the injector circuit.

Are there any correlating data points? Does it run funny at the time, is it only when it's hot, are any of the injector clips missing their locks? Which code(s) are you getting?

Tom and Dave would have a better idea of what the 2g ECU is checking as a condition for the fault. The 1g is pretty simple, looking for an open circuit. I had a bad injector that the coil woud go open when it got hot and that threw the fault.

Thanks for the feedback. Idle was a bit high, and floating around, but the engine was cold after the battery had been drawn down.

 

[Justin DuBois]

Now consistently popping up injector circuit malfunction cyl 2

drives “ok”

I’m wondering if this is a ECU capacitor leaking symptom.

 

[motomattx]

An ohm meter on the injector two lines at the ecu connector would tell you if its an injector/wiring issue or an ecu issue.

 

[Justin DuBois]

That makes sense.

 

[Justin DuBois]

I have checked continuity between the ecu harness plug to the injector on the Yellow wire, and that checks out ok.

Where does the other pin on the injector go to?

 

[steve]

You can see in the wiring diagram one side comes from the MFI Relay to the Injector Resistors and then each resistor feeds the power to a injector. The other side of the injectors go straight to the ECU. So, the MFI/MPI circuit powers the injectors via the resistor pack and the ECU grounds the circuit to fire them.

 

[Justin DuBois]

Ok, Now I get it. The ecu pulls “down” to provide a ground to the injector coil. So I’m thinking if voltage is not detected at the ecu injector pin, then the ecu throws an error code for injector circuit malfunction.

Since the malfunction is always being reported on the same injector, and I have confirmed continuity between the ECU and the injector, I can narrow down the fault to either the wiring from the injector to the resistor pack, the resistor, or the ecu.

 

[steve]

Have you tried moving the injector to see if the problem moves with it or if it remains on that original cylinder?

 

[randman2011]

I had intermittent continuity issues with several injectors on my GSX and never got this DTC. I did get this DTC on a different car that never had any problems and I never did anything to fix it, so I'm at a loss for what triggers the code.

My GSX was running the 98+ H8 black box ECU at the time but that shouldn't change anything.

Also just want to say that checking continuity isn't enough to confirm that it isn't a wiring problem. My injector problem would register continuity on a DMM but when the engine was running the injector would periodically cut out. I diagnosed my problem by fiddling with the wiring harness while the engine was running to find where the break was. I don't know of an "official" way to be more certain of the wire integrity.

 

[We're on Boost]

Now consistently popping up injector circuit malfunction cyl 2

drives “ok”

For a while I had a 1994 ecu on my 1g that was giving me an injector fault code and the car still seemed to run ok.
I had bought the ecu from DSM chips (Jeff Oberholtzer), with the 1990 conversion to it.
So I sent it back to Jeff and he found "a tiny break in a trace in the injector circuit".
He fixed it. Or maybe he sent me back a different ecu but as I remember he fixed the trace.

 

[Justin DuBois]

The injector resistor pack tests ok with 6.0. ohms for each one, and the injector wire has a connection between the resistor pack plug and the injector on the green wire.

Hmm, well I’ll put it back together and move the injector to see if the error moves to a different number.

I still suspect the injector, ecu, or a heat related failure.

 

[Justin DuBois]

Back as it was and the DTC is back. Ok, well at least it’s consistent. Next we switch injectors

 

[steve]

Jeff found "a tiny break in a trace in the injector circuit".

I think a lot of the PCB were over etched or the electrolyte was eating them. I found a surprising number of broken traces (micro fractures) where the geometry changed, like where a trace met a pad. You could only see them with magnification or measuring. After I found the first I made sure to ohm out a large portion of the boards during repairs. It really slow things down but the good part was they weren't intermittent.

 

[Justin DuBois]

I swapped inj 1 and 2, and the DTC error still says 2. This is pointing to the ECU as the source of the issue. ( not the conclusion I was hoping for )

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[my98gsx]

Download the patch from ecmlinks website. I chased this problem in my buddy's 97 gsx last year, all checked out perfect. Dsmlink offers a free download able patch that eliminates this code from popping up. Again, this is only when you checked all possible voltage issues etc...

 

[steve]

The Injector DTC patch from https://www.ecmtuning.com/wiki/direct_access_changes ?

 

[Justin DuBois]

No codes from the ABS computer, and no way to resolve the injector code that leaves me with any confidence. grrrrrr

Aaaaaaargh!!! ok fine.
ECU is out and now I need to pack it up to go to ECMTuning for some better diagnostics.



And yeah, I looked inside.

If there is something wrong, I cant see it looking at it like this.

 

[my98gsx]

Justin... The board looks fine with no signs of water damage, corrosion or burning... Why would you send this out for repair? Download the patch and it will fix it. This is a common problem that many have faced. Your turning a free fix into something more than it has to be. Steve posted the link for you. It shouldnt take you more than 15 min to resolve this.

 

[steve]

The board looks fine with no signs of water damage, corrosion or burning.

I see several places where the capacitors have leaked and are causing corrosion. I circled the worst parts. Can't say if it's causing any problems yet.

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[Justin DuBois]

Justin... The board looks fine with no signs of water damage, corrosion or burning... Why would you send this out for repair? Download the patch and it will fix it. This is a common problem that many have faced. Your turning a free fix into something more than it has to be. Steve posted the link for you. It shouldnt take you more than 15 min to resolve this.

A patch that turns off the error report, does not solve the issue that is generating the error. The case history indicates a change. Up until recently - no error. Only now, something in the ECU is not happy. Basic diagnostic logic has pointed the finger at the issue - so I'm sending the component with the issue to the experts to get more information.

 

[my98gsx]

I'm going to be curious how this turns out - please post the results. If an issue is found by ecmtuning I would like to send my buddys ECU out as well. Looking forward to the results.

 

[Justin DuBois]

Well - Its in the hands of the US postal service now...

 

[fourgsixty3]

Well - Its in the hands of the US postal service now...

You're a gambling man.