Check engine (Page 1/2)
itzikbns SEP 03, 05:33 AM
Hi,
I have a 86 SE 2.8 L, no check engine when switch on, and no code blinking when ADLD is shorten.
I replaced the ECM, but it didn't help, might it be the PROMS I was asked to use out of the previous ECM'? the new one arrived with out them (the two units under the opening in the ECM)
Any other ideas?
1985 Fiero GT SEP 03, 07:43 AM
Did you check that the bulb isn't burnt out? That is very common, could also be the wire for that is snipped somewhere between the ECM and the bulb, but check the bulb before replacement anything.
itzikbns SEP 05, 04:39 AM

quote
Originally posted by 1985 Fiero GT:

Did you check that the bulb isn't burnt out? That is very common, could also be the wire for that is snipped somewhere between the ECM and the bulb, but check the bulb before replacement anything.


Hi
Yes, I have new bulbs, but since I have the car, many of the lights didn't work, in fact only the parking brake worked, my main issue is the there was no engine check light and I didn't get the blinking lit for the codes when I shorten the A & B in the ADLD,
I bought a new ECM, and use the previous PROMS, Still no engine check or cods blinking,
I checked the orange line in the back near the bataty and it gives power to the new ECM, the B terminal in the ADLD gets 4.8 volts and the check engine bulb gets zero
armos SEP 05, 07:12 AM
There should be a constant +12V on one side of the Check Engine bulb - the other side is normally open, but the ECM will switch that side to Ground when it wants to turn the light on.
It might be really difficult to probe that though.


quote
Originally posted by itzikbns:
Yes, I have new bulbs, but since I have the car, many of the lights didn't work, in fact only the parking brake worked


Can you be more specific? Which lights do work and which don't? Nothing on the dashboard works except the "Brake" warning light? Which warning lights, illumination lights, and gauges are working / not working?

Check the "gages" fuse.

Do you have a copy of the service manual? It should be on the web somewhere, I don't have a current link.
Check in the "Electrical Diagnosis" - "Instrument Cluster" section for some diagrams of the dashboard wiring. You might find something that would explain the pattern of which lights do and don't work.
I notice a lot of things are grounded to "G201". Does that match up with everything that's not working?
Page 8A-80-7 implies that connector "C3" hooks up a lot of the lights and gauges, and also connects the "G201" ground. I don't know where that connector is or how deeply it's buried, but it's apparently an 18 pin connector tied to the instrument panel.
Vintage-Nut SEP 05, 09:36 AM
Fiero Portable Document Format (PDF) Manuals
https://fieroinfo.com/manuals/

------------------
Original Owner of a Silver '88 GT
Under 'Production Refurbishment' @ 136k Miles

olejoedad SEP 05, 09:39 AM

quote
Originally posted by armos:

There should be a constant +12V on one side of the Check Engine bulb - the other side is normally open, but the ECM will switch that side to Ground when it wants to turn the light on.
It might be really difficult to probe that though.

Can you be more specific? Which lights do work and which don't? Nothing on the dashboard works except the "Brake" warning light? Which warning lights, illumination lights, and gauges are working / not working?

Check the "gages" fuse.

Do you have a copy of the service manual? It should be on the web somewhere, I don't have a current link.
Check in the "Electrical Diagnosis" - "Instrument Cluster" section for some diagrams of the dashboard wiring. You might find something that would explain the pattern of which lights do and don't work.
I notice a lot of things are grounded to "G201". Does that match up with everything that's not working?
Page 8A-80-7 implies that connector "C3" hooks up a lot of the lights and gauges, and also connects the "G201" ground. I don't know where that connector is or how deeply it's buried, but it's apparently an 18 pin connector tied to the instrument panel.



Connector C3 is accessible by removing the trim panel on the back of the instrument pod.
It is located on the right side of the cluster housing rear face and is vertical.
fierosound SEP 05, 10:20 AM
I had this exact same problem with my GT.
Engine would start/stall. Could not read codes.

Connection of D1 to ECM was poor.
I removed the terminal from the multi-pin connector and bent the tangs so it would 'squeeze' harder on the ECM's pin.





------------------
My World of Wheels Winners (Click on links below)

3.4L Supercharged 87 GT and Super Duty 4 Indy #163

[This message has been edited by fierosound (edited 09-05-2024).]

itzikbns SEP 05, 10:56 AM

quote
Originally posted by 1985 Fiero GT:

Did you check that the bulb isn't burnt out? That is very common, could also be the wire for that is snipped somewhere between the ECM and the bulb, but check the bulb before replacement anything.



Hi,
It's a new bulb, and I tested it and it is working fine, I have checked connectivity of all related wires and they are all OK
itzikbns SEP 05, 11:03 AM

quote
Originally posted by armos:

There should be a constant +12V on one side of the Check Engine bulb - the other side is normally open, but the ECM will switch that side to Ground when it wants to turn the light on.
It might be really difficult to probe that though.

Can you be more specific? Which lights do work and which don't? Nothing on the dashboard works except the "Brake" warning light? Which warning lights, illumination lights, and gauges are working / not working?

Check the "gages" fuse.

Thanks for replaying, I think I wasn't clear, I have a ferrari 308 Replica and thus I am replacing the dash to Amida's dash and new SpeedHUT gauges,. I wired the Pisa wiring harness to the previous cluster plugs wires. I tested connectivity with all the wired,and they are OK it's probably not a fuse since the seat belt bulb gets voltage and lights

I tested the orange wire and it provides voltage to the ECM, but there is no voltage going out of the ECM. please see on the images

Do you have a copy of the service manual? It should be on the web somewhere, I don't have a current link.
Check in the "Electrical Diagnosis" - "Instrument Cluster" section for some diagrams of the dashboard wiring. You might find something that would explain the pattern of which lights do and don't work.
I notice a lot of things are grounded to "G201". Does that match up with everything that's not working?
Page 8A-80-7 implies that connector "C3" hooks up a lot of the lights and gauges, and also connects the "G201" ground. I don't know where that connector is or how deeply it's buried, but it's apparently an 18 pin connector tied to the instrument panel.
itzikbns SEP 05, 11:05 AM

quote
Originally posted by Vintage-Nut:

Fiero Portable Document Format (PDF) Manuals
https://fieroinfo.com/manuals/




Thanks, I have the manuals but didn't use it...