Electronic spark control module

saeedbeck

saeedbeck

Member
I have been tracking this problem ever since I bought my black 92 Typhoon with 62000 miles. The idle is terrible because of a noticeable "miss" in the engines operation. This shudder happens at any rpm. I have replaced the distributor completely. The spark plugs, plug wires, and ignition coil have all been replaced. The funny thing is, when I was finished replacing the distributor and started it up, my truck ran smooth as astroglide. I pulled it out of the garage and left it running when I went in to get my coat. I came back out about a minute later and my problem returned. I think it might be my electronic spark timing module. I pulled the wire on my knock sensor and nothing changed. I want to diagnose the electronic timing module but I can't find it. The knock sensor is supposed to be attatched to it but I followed the wire up into a bundle and lost it. Can anyone tell me where it is, and if I am on the right track?
 
myclone

myclone

Donating Member
Re: Electronic spark control module

saeedbeck said:
I have been tracking this problem ever since I bought my black 92 Typhoon with 62000 miles. The idle is terrible because of a noticeable "miss" in the engines operation. This shudder happens at any rpm. I have replaced the distributor completely. The spark plugs, plug wires, and ignition coil have all been replaced. The funny thing is, when I was finished replacing the distributor and started it up, my truck ran smooth as astroglide. I pulled it out of the garage and left it running when I went in to get my coat. I came back out about a minute later and my problem returned. I think it might be my electronic spark timing module. I pulled the wire on my knock sensor and nothing changed. I want to diagnose the electronic timing module but I can't find it. The knock sensor is supposed to be attatched to it but I followed the wire up into a bundle and lost it. Can anyone tell me where it is, and if I am on the right track?
Click to expand...

The ESC module is internal to the ECM on syty's so its gonna be tough to find ;) . Regular S10s have the module mounted on the firewall.
 
saeedbeck

saeedbeck

Member
Re: Electronic spark control module

How about that. It is in the ecm. I will try to work some magic, but I will probrably need a new computer. I will double check the map sensor and make sure the wiring going to the ESC is correct and then switch out the ECM. Thanks for the help.
 
nightdiver

nightdiver

Active member
Re: Electronic spark control module

you need a datamaster or a scan tool to monitor the values of the sensors. if you ground the esc wire then the ecm wont pull any advance, if you just pull it from the knock sensor the ecm will pull all the timing can pull
 
saeedbeck

saeedbeck

Member
Re: Electronic spark control module

I found the computer. It appears to be the original because the little "void warranty sticker was still on it. I found one black wire that was missing some of the insulation on it, but the actual wire was still intact. I just covered it up with electrical tape. The only other thing that I found that was strange was that he connector that contained the black wire looked like it had been shaved off on the corner like it was dragged across the ground at a high rate of speed or something. I don't know. I am worried because when I bought this truck, I found a small mouse nest between the valve covers. I took most of the intake off and looked for any nibbled wires and found only 3 that connected to the idle air control. I soldered in some replacements. I am worried that these mice got as far as the computer and maybe the connector was nibbled on and not dragged across the ground. Maybe there are more nibbled wires. I will remove the dash one more time and check for nibbled or stripped wires and if I find none, I will probrably change out the computer. One more thing, I replace the park/ nuetral/ safety switch because my truck would not start in Neutral. It worked for about a month and now the same thing is happening. Could that be my computer? I am positive the switch is still positioned properly, but I will doublecheck. Any thoughts?
 
gjp

gjp

another post whore
Re: Electronic spark control module

my truck does that too. its driving me nuts. Only when its warm????
 
saeedbeck

saeedbeck

Member
Re: Electronic spark control module

I wish. It happens all the time. The only time it stopped is when I swapped out the distributor. It cleared up for about 30 seconds and came back.
 
Loeryder

Loeryder

New member
Re: Electronic spark control module

The ESC module is actually in the blue memcal case, plugged into your ECM.
I think it is the chip that has the clear epoxy layered over it.
It will be located behind the VOID tag and under 2 sheet metal screws inside the ECM case itself.

Try just swapping memcal (chips) and see if that helps.
There were updates applied to the BIN files for the different year trucks so look for a 93 Ty memcal to experiment with.
Also, you can swap out jsut the ECM without having to pull the whole dash again.

Id try some component troubleshooting before pulling the entire dash again...
That has to be a pita.

Best of luck getting all the bugs, or mice worked out!
 
saeedbeck

saeedbeck

Member
Re: Electronic spark control module

Thanks for the advice. I will take all I can get. You did mention getting at my ECM without removing the dash. HOW?
 
Loeryder

Loeryder

New member
Re: Electronic spark control module

Just remove the plastic fromt eh passenger side footwell area.
Looking up at hte bottom of the ddash you will see a triangle shaped metal bracket with a single screw.
Remove that screw and the entire ECM drops down as a unit.
There is a box bolted to the ECM that will run out of wire before it hits the floor.
You can remove that module form teh ECM bracket and jsut tuck it up in teh dash by itself.
This gives you enough wire to let the ECM sit in the pass side floorboard.
Some folks relocate them to the glovebox for easy access.

In most cases you arent dropping teh ECM on a regular basis so its up to you.
To get it back in it will take some practice.
You can pull the pass side dash speaker to see if the upper bracket is sitting in the right spot or not.

It will make more sense once you have it out and in your hands.

Best of luck getting it worked out.
 
saeedbeck

saeedbeck

Member
Re: Electronic spark control module

NIGHTDIVER. Hey, you mentioned that if the esc wire is grounded, then the computer will not pull any timing. Did you mean the wire going from the knock sensor to the ecm? I grounded that wire ?and the truck ran the same except the temperature gauge pegged out. Did I do it right?
 
saeedbeck

saeedbeck

Member
Re: Electronic spark control module

Wow! Thanks for getting back to me so fast. I know exactly what you mean. I should have removed the plastic from the footwell first. I would have saved myself alot of trouble. I know the little box that you are talking about too. You mentioned the memcal chips. Do you know where I could get one?
 
Loeryder

Loeryder

New member
Re: Electronic spark control module

No prob man, you gotta learn somewhere, right.

Best thing you can do right now is search and learn.
Try not to just start buying stuff just to bolt on some more horsies.
Do some research find out what works with what and who has had luck with what combos.
It'll save you a bunch of headaches as well as bad investments later down the road.

The Memcals are still available from GM I believe.

ScanID Delco ID GM Part #
3051 AXXA 3086 16163085
3961 AYBM 4053 16164052
3971 AYBN 4175 16164174
8581 AWXJ 9137 16159136
831 BBZA 1576 16181575
841 BBZB 1580 16181579
copied from www.sytyauthority.net under part#s

Highest # being the most recent revision.

It's always nice to have an extra for troubleshooting sake.
 
nightdiver

nightdiver

Active member
Re: Electronic spark control module

saeedbeck said:
NIGHTDIVER. Hey, you mentioned that if the esc wire is grounded, then the computer will not pull any timing. Did you mean the wire going from the knock sensor to the ecm? I grounded that wire ?and the truck ran the same except the temperature gauge pegged out. Did I do it right?
Click to expand...

yes thats the wire . that means that the knock sensor is fine and the problem is somewhere else.
The temp gauge has nothing to do with it though :roll:
How about the ecm engine temp sensor ? its located at the front of the intake. A bad sensor will give wrong information to the ecm , so wrong fueling. Just and other idea...........
Oh did you clean up the iac valve ?
 
saeedbeck

saeedbeck

Member
Re: Electronic spark control module

Yes, I cleaned the idle air conrol sensor out. I never checked the output of it though. I will check the output of the temp sensor too. It can't hurt. I grounded the knock sensor wire on the ground that the windshield wiper motor motor is grounded to and have no idea why the temperature gauge went crazy. Go figure.
 
nightdiver

nightdiver

Active member
Re: Electronic spark control module

if you wont ground the esc wire the ecm will pull all the timing it can. The gauge sensor is located on the left head
what about the O2 sensor ? is it working right ?
 
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