'97 GLT - Dash warning lights staying on after key is turned off. Topic is solved

[abscate]

I wonder if there is enough capacitance in the IAC to keep 12 volts for a few seconds on power down. You’ve made some pretty big changes to ignition and the wiring that might be impacted by that.

That’s speculation on my part, the good news is I don’t think it will be a running issue

[xanthefin]

Went to go through your diagnosing out of interest.

TP3932202 schematics i followed.

(4/46 - ECU pins)
A12 Wake up or Ignition ON (+12V) from Terminal 15


A41 (GND - OUT) 2/32 (Main Relay Fuel Injection - Relay 106) (Command)
A26 (+12V - IN) 2/32 (Main Relay Fuel Injection - Relay 106) (Parallel with the Ignition input Terminal 30, ECU gets power via 11B/1 fuse)

Relay 106 has Diode on pins between A41 and A26.



As General Injectors gets all time +12V and ECU gives GND as command to open.



I try on bench M4.4


"When I touched on A24 and A25 (Control signals to injector #3 and the IAC) it would beep. After messing a bit, if I kept one lead on A26 and touched A24 or A25 and had it beep, and then touched A12...it would beep for half a second."

A24 and A25 and between those and A26 no beep, nothing happened.

Beeping between and A26 and A12 made my relay to engage.




Note:
My Bench Not good enough to test things. I had add relay with diode to simulate more closely what is happening.

Note 2: When i turn "ignition switch" ON it switches relay. But when i turn Ignition OFF my relay stays ON still.. so some mishap happening on my bench still now

Slight update: Relay does turn off but with big delay. Can be due my relay actually is 9V and i have resistor series with it so it takes less current than real 106 relay..(?)

[Chuck W]

I wonder if there is enough capacitance in the IAC to keep 12 volts for a few seconds on power down. You’ve made some pretty big changes to ignition and the wiring that might be impacted by that.

That’s speculation on my part, the good news is I don’t think it will be a running issue

I did the same conversion to my T5 last year and didn't have any oddities like this. I didn't cut into any existing wiring for the COP conversion, and did the exact same thing I did to my car, so I doubt it's to do with that. The biggest modification was adding the resistors in the ECU, but the issue remained even after swapping to an un-modified ECU.

The 12V isn't coming from the IAC, but from A26, which is full-time battery power. If A26 and A12 connect, that 12V is passed through for a half second.

All of the "Beeps", either between A26 and A24 or A25 and A26 and A12 after that are only a half second. It's not sustained.

After that half second connection between A26 and A12, if I go directly back and check that again, I get no continuity. However, if I go back and touch A26 to A24 or A25 and then A12, I get continuity.

I agree that it doesn't appear to be an issue while the engine is running, but something weird is happening. I'll be prepping the car this evening for the upcoming trip tomorrow, so I'll probably take a second to disconnect injector #3 and the IAC and see if either/both are a culprit.

[xanthefin]

I get continuity only ever between A12 and A26 if ever and i can trigger "106" relay on and off via beeping there. Only weirdness on my setup plus that if i turn ignition switch off the "106" relay turns off only with big delay.

No beeping on others. But to be noted. I have not real 106 relay but 9V relay one. It has as real 106 relay a diode between legs for protections. I don't have any injectors there or IAC valve. Injectors i have leds instead just to testing purposes.

[Chuck W]

Well, unplugging the IAC and injector #3 didn't change any of the behavior.

Just going to roll with it for now.

[misha]

At this point...i would start pulling fuses and see what is happening.

Also...b+ cable from positive battery terminal to fusebox,where it is bolted under the fusebox,should be checked.

[abscate]

What colour is it Chuck! Not green , I hope.

( favourite response from Click amd Clack when they were stumped)

[Chuck W]

The only fuse involved in this is #1, which is the one in the back-feed to the 106 relay.

I didn't think the B+ cable was an issue on the 850s. Only thought that was for the S/V/C/X70s with the relay/fusebox in the engine bay.

[wizechatmgr]

What happens if the ignition switch is totally unplugged with the car otherwise having power?

[wizechatmgr]

They make signal injectors for finding wires that are shorting to each other or ground. You may need to pick one up unless you wish to go over the entire harness.