New thread...EST/ESC and knock sensor questions...

Ok...I think I've identified the burned up pigtail coming off the back
of my HEI.

Again, this is an '86 K5 Blazer, with the weird-ass 5-pin ignition
module. On the back of the HEI enters a small pigtail/wiring harness.
It plugs into 3 of the pins on the ignition module.

Does this go back to the Electronic Spark Timing / Control? I know it
shouldn't have a real "ECM" because it was carbureted, but I believe it
does have the EST. I don't know to what degree electronics played a
part in the original Quadrajet. That carb is off the truck and it's
running an Edelbrock Performer 600cfm. There ARE a couple of unused
wires/connectors that end up in the vicinity of the carb that I assume
would've been attached at some point.

If the harness I'm referring to does indeed go to an EST unit, is it
necessary to get the truck to run? Can it be bypassed in any way?

The pickup wires connect in between this connector and the actual
ignition module. A picture of all the parts can be seen here...
http://www.absolutepickens.com/K5/Damage/Distrib_guts.jpg

Thanks,
~jp

Jon Pickens wrote:

Ok...I think I've identified the burned up pigtail coming off the back
of my HEI.

Again, this is an '86 K5 Blazer, with the weird-ass 5-pin ignition
module. On the back of the HEI enters a small pigtail/wiring harness.
It plugs into 3 of the pins on the ignition module.

Does this go back to the Electronic Spark Timing / Control? I know it
shouldn't have a real "ECM" because it was carbureted, but I believe it
does have the EST. I don't know to what degree electronics played a
part in the original Quadrajet. That carb is off the truck and it's
running an Edelbrock Performer 600cfm. There ARE a couple of unused
wires/connectors that end up in the vicinity of the carb that I assume
would've been attached at some point.

If the harness I'm referring to does indeed go to an EST unit, is it
necessary to get the truck to run? Can it be bypassed in any way?

The pickup wires connect in between this connector and the actual
ignition module. A picture of all the parts can be seen here...
http://www.absolutepickens.com/K5/Damage/Distrib_guts.jpg

Thanks,
~jp

Yes it is the ESC pigtail. Yes your truck does have a ECM. You can
convert to the older NON-ESC module and pig tail by using a NON-ESC
magnetic pick-up. With out the CCC, ESC isn't doing you one bit of good
(not that it ever did with a vaccume advance distributor)
Charles

Just sent you an email to your Yahoo account...

~jp

If you want to simplify things, scrap the ESC distributor! Get a regular
HEI and drop it in. Less to go wrong.


"Jon Pickens" <jonrpick (AT) yahoo (DOT) com> wrote

Ok...I think I've identified the burned up pigtail coming off the back
of my HEI.

Again, this is an '86 K5 Blazer, with the weird-ass 5-pin ignition
module. On the back of the HEI enters a small pigtail/wiring harness.
It plugs into 3 of the pins on the ignition module.

Does this go back to the Electronic Spark Timing / Control? I know it
shouldn't have a real "ECM" because it was carbureted, but I believe it
does have the EST. I don't know to what degree electronics played a
part in the original Quadrajet. That carb is off the truck and it's
running an Edelbrock Performer 600cfm. There ARE a couple of unused
wires/connectors that end up in the vicinity of the carb that I assume
would've been attached at some point.

If the harness I'm referring to does indeed go to an EST unit, is it
necessary to get the truck to run? Can it be bypassed in any way?

The pickup wires connect in between this connector and the actual
ignition module. A picture of all the parts can be seen here...
http://www.absolutepickens.com/K5/Damage/Distrib_guts.jpg

Thanks,
~jp

Well, simple is always better...but a replacement pigtail is on the
way. I did manage to piece one together using a replacement connector
and new pins with the other original (unmelted) connector. I don't
feel good about using it though. I know the actual electrical
connections will be fine, but it's designed to fill the square hole in
the back of the HEI and I'd have to figure out a way to duplicate that
part first.

Charles found the pigtail in his stash. I may try mine just to verify
connectivity and all but, again, I'd feel better about using a factory
part.

It's 9:30am now, and I'm just making the first cup of coffee.
Hopefully I'll get a good deal done today. Sucks though, cause I have
to walk to a parts store if I need anything...

~jp

Jon Pickens wrote:

Just sent you an email to your Yahoo account...

~jp

Got it. Ill send it out tomorrow (since I have to ship stuff then anywho).
Charles

Thanks again...

~jp

Ok, I've been screwing with the truck, trying my damndest to get the
heater / a/c harness out from the dash. I've damn near disassembled
the whole dash. Not fun, considering I'm sick.

Anyhow, was doing some thinking on the ignition module situation. It's
the 5-pin module made to connect to the ESC to detect spark knock and
then retard timing as needed. The 3-pin side connects to the pickup
coil via a pass-thru connector (which only uses 2 of the 3 pins). The
3 pins "pass through" this connector, which allows the ESC harness to
be connected.

I have a new 4-pin module already. Would using the 4 pin module and
just not connecting the ESC allow the truck to run until I get the new
5-pin module and harness?

~jp

Never used an ECS HEI. Any vehicle I ever had that had one, I installed a
standard HEI. so I'm not 100 sure if not having every wire hooked up would
be fine or not. Sorry.


"Jon Pickens" <jonrpick (AT) yahoo (DOT) com> wrote

Ok, I've been screwing with the truck, trying my damndest to get the
heater / a/c harness out from the dash. I've damn near disassembled
the whole dash. Not fun, considering I'm sick.

Anyhow, was doing some thinking on the ignition module situation. It's
the 5-pin module made to connect to the ESC to detect spark knock and
then retard timing as needed. The 3-pin side connects to the pickup
coil via a pass-thru connector (which only uses 2 of the 3 pins). The
3 pins "pass through" this connector, which allows the ESC harness to
be connected.

I have a new 4-pin module already. Would using the 4 pin module and
just not connecting the ESC allow the truck to run until I get the new
5-pin module and harness?

~jp

Well I found bypass instructions for the ESC.

Apparently the ESC was such a POS that Chevy released a service
bulletin on doing that exact thing. But that procedure still involved
the 5-pin module.

I'm suggesting switching to the 4-pin module.

However as likely as it is, there's no way of knowing if my module is
toast till I try to start it. I have my home-made ESC harness until
the replacement from Charles arrives. It's not perfect, but it would
let the truck run at least. So we'll see.

~jp