1981 ECM question

[vigman]

The check eng. light on my friends 81 is dead.
1) Who has a factory schematic?
2) The check engine light driver module is located where?
3) The 5 pin connector ( under the ashtray ) It states to jump pins d & e but nothing happens ( I'm assuming the key needs to be on for this)
4) the bulb is good and there is 12 volts to the circut.

So brave one's
HELLLPPPPP!

Mike

 

[Nut]

Mike, I have a full schematic at home but I'm at work now. If you have no satisfactory answers by this evening I'll dig it out and have a look. Stay tuned.

......... Nut

 

[vigman]

Thanks Nut

Standing By........
Mike

 

[Yoda]

Mike,
I didn't have a chance to check in last night, I was having computer problems at home.. ad

I'll get back to you tonight once I have a chance to take a look at the schematics and wiring diagrams..

 

[Nut]

Mike,

I've got my shop manual at work today and I'm going to try and get the whole schematic scanned into MSWord. If it doesn't come out I'll mail you the copies. Send me an Instant Message with your home address and I'll get it out this weekend. It's REAL hard to follow that particular run. Took a while to even find it in the schematic. Sorry it took so long to respond.

......... Nut

 

[vigman]

Thanxs

Wilco!

Mike

 

[vigman]

Nut......

You DA MAN!

Got the package last night

THANKS SOOOOO MUCH

Now if I can get out of work I can help my poor british buddy.'


MIKE

 

[RonG]

Vigman,

Have you got things working yet?

FYI - On my 1981 I kept getting a code set. Turns out the diode in the EGR solenoid circuit shorted out and blew the driver chip in the ECM.

Since the EGR parts are no longer available, I hand repaired the old one.

After running all tests and still getting the ECM code set, the shop manual states to replace the ECM. I it with a rebuilt unit (about $90) and all is well.

 

[Rob81]

Were you able to get another PROM chip for your new ECM?Didn't you state before that your Prom was shorted out by your EGR problem. I'm probably wrong, but I didn't think that EGR was related to the ECM electrics. I thought that the ECM was only regulating the M/C Solenoid, TPS, Coolant Temp,.
I'm having some drivabilty problems, getting codes. My mechanic has looked the car over twice and can only think that it is ECM and/or Prom chip. I hate to buy and install a new ECM only to have it shorted out by something else. Cars???

 

[RonG]

Rob,

You stated: . I'm probably wrong, but I didn't think that EGR was related to the ECM electrics. I thought that the ECM was only regulating the M/C Solenoid, TPS, Coolant Temp,.

If you look in the 1981 Shop Manual pages 8A-82 & 8A-83, you will see the ECM diagram and all that it controls.

As for the EGR, there is a relay controlled by the ECM that controls vacuum going to the EGR valve.

One other thing to remember, the ECM has two functions:
1) Monitor certain signals
2) Control certain functions

The ECM monitors the TPS and Coolant Temp, but does not control them.

Controls:
=======
AIR control valve
AIR switch solenoid
Ignition module bypass
Spark timing
MCC
EGR
Torque Converter (automatic tran only)

Montiors:
=======
Vacuum sensor
TPS
O2 sensor
Dist pulse ref
Coolant temp
Vehilce speed (automatic tran only)
Park/Neutral Switch (automatic tran only)

I think that's everythin.

As for your other questions on the PROM, that must have been someone else posting.


Regards,

RomG

 

[Rob81]

Thanks..It sounds like I need to find one of those shop manuals.

 

[Yoda]

1981 Shop Manual

Rob,
Check out Ebay 1981 Corvette.

I'll get that chip sent out this weekend