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A question for C4C5

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
I'm working on a buds 92 convertible which he bought at auction... silght front end wreck
the computer was missing.. He ordered a new one from GM AFTER the put a wrecking yard one in... and smoke billowed out of the used ECM.

So Questions

#1 Other than the shop manual( which we don't have yet) is there a GOOD resource for finding the error codes & explanition of the codes... AND YOU HAVE TO JUMP pins 4 & 12 right on the ALDL ?

#2 I think the new ECM ( which has a prom in it )
is not talking.. my Scantron cannot get a connection. What should be the correct ID for the Prom ( 6 speed/ convert/LT-1 ) I still have to check the fusible links.. I think ECM power got toasted, the 92 doesn't have the AUX fuse blocks
correct ?

#3 I have made a GM pellet tool we are trying to get the car to crank...Is the Starter circut part of the ECM or just a VATS thing... in other words
Does the car have the ability to crank ( not start ) without the ECM? We have to wait 5 minutes before attempting the next resistance value correct?

Thanks in advance,

Oh Guru of Guru's

Mike
 
D

Drewser

Guest
vigman said:

#3 I have made a GM pellet tool we are trying to get the car to crank...Is the Starter circut part of the ECM or just a VATS thing... in other words
Does the car have the ability to crank ( not start ) without the ECM? We have to wait 5 minutes before attempting the next resistance value correct?
Mike

As far as the VATS system goes, you only have to wait 3 minutes inbetween interrogations. Or until the security light goes out (about 3 minutes).

Per the ECM, there IS a crank signal that comes from pin 1 (of my ecm that is)(Black connector) to purple wire>> lt blue that goes to the crank fuse (5amp) that goes to the starter solenoid.

I hope this helps till the guru can answer.

Drew :w
 

c4c5specialist

Technical Advisor
Joined
May 29, 2001
Messages
3,682
Location
New Haven, Ct. USA
Corvette
Nope, but someday.
Hi Mike,
Lets get started.
First, no, you must just jump pin A, which is a black with a white tracer, with pin B, which is white, with a black tracer.
You should be in diagnostic mode, your cooling fans will turn on, and your SES light should flash code 12 in 3 sucessions, before flashing your codes.
Just remember, having a check engine light on steady when you first turn on the vehicle is the first thing that you must see. Then, when you jump the terminals, the 12 will indicate that the self test of the PCM has passed.
Second, your check engine light carries power from the Cluster fuse, 5 amp. You ECM main power circuits are carried on fuse link, with a single pin large gauge wire, directly off battery positive. It is not channeled through the fuse blocks.
As for the VATS system, if your PCM is not functional, you will not start the car, at all. As it is not receiving the fuel enable signal from the central control module, so it will not engage the starter enable relay. Yes, time out for the VATS is 5 mins.
Also, check for a SYS light on the dash.
Please keep us posted, c4c5:hb
 
D

Drewser

Guest
Uh, Mr. Guru

I hate to differ with you on this one fine little point but as someone who has interrogated litterally thousands of VATS systems on all makes and models of GM cars, the VATS timeout is only 3 minutes.
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Ok Thank you

There is a sys light on .

When we power up the car... I hear the fuel pump whizzin up ( along with other things )


I will check these items and get back to you....

About the error codes.... any good postings ?

Thanks again Paul


Mike
an re the VATS thing.... it's when the security light goes out...reguardless of the time?????
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Thanks too Drew !

I didn't mean to ignore you

Mike
 
D

Drewser

Guest
sallright

I just get excited when I actually KNOW something. :J
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Bingo

My homemade pass key box worked! yipee!

So Paul...the ECM fuse gone...Main power fusible link gone. After repairs got 12 from the ECM

2 hours later.... VROOM

Now ...just to be correct

The 1992 GM PRELIM manual states 4 minutes... I waited ( counted on my mutant foot...with the webbing).

Talking to those CCM & ECM modules...WHAT A PAIN!

But I got it...Thanks all for your help.

Next Dr.Electronics project

Restoring a 96 colectors electrical system, medium engine fire...

Mike
 

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