I'm hearing an audible knock under heavy acceleration. When this happens I get code 42 & 43. I tried another ESC module and it didn't help. Any ideas? Timing is at 6* with 93 octane gas. Compression is around 9.5 and it has a ZZ4 cam. Its a L98. Also, I have a plug that is unplugged comming from the ESC module. See pic. I've been unable to find a home for this wire. It seems like this is causing my ESC to not retard the timing with knock. One wire is pink with black stripe and the other is black. Where does this wire go?

See pic? Can you try again to attach it or at least post a link? Remember that an attachment must be under 100K, so it the file size is larger your have to reformat the graphic.

The only connector on my ESC is a four-wire WeatherPack containing a pink/black, black, brown, and blue wire. The brown and blue wires route off to engine ground (brown) and the knock sensor (blue), and the pink/black and black wires route through a separate plastic conduit to the ECM harness for power (pink/black) and the Retard signal (black). If the latter two waires aren't connected, the ESC will have no function (just as if the EST bypass connector were disconnected).

The oddity is that my '86 does not have any other connectors in the pnk/blk and blk wires that you dscribe, and the '87 models use the same harness and '165 ECM.

whoops, i completely forgot to attach it

yea, i have that four wire connector, then the pink/black and black wires end at the pictured connector

dosent that go to the back of the distributor?

Yeah, I think that goes to the ignition module on the distrib.

Matt

After looking at some wiring diagrams that does not go to the distributor. I'm still trying to figure out where it does go.

It eventually goes to the intake temp sensor located on the bottom of the upper tpi plenum, There should be about a foot long extension wire harness that actually connects the sensor to that plug.

Are you sure about that? Different colored wires. And maybe a wrong wiring diagram in my book.

There are only two plugs that look like that in a Typical TPI harness that are near the firewall, one of them which I mentioned above, which I have found typically to be on the driver side rear area of engine. The other is near the passenger side rear and goes to the egr control solenoid. So unless someone routed his EGR plug to the drivers side, I am very sure that is where it goes. However if EGR is not functional, it could very well explain the knock he is getting. Unless the sensor I First mentioned somehow effects EGR as well.

IAT? You mean the MAT on the bottom of the plenum?
My connectors on my 88 for both the MAT and the EGR are different than the connector pictured.
I'll be ripping into my bird again today. I'll see if I can find that plug on my car.

Yes, I meant the MAT sensor. I apoligize I am at work, trying to stay awake and couldnt remember the correct name of it.

AFAIK the names are interchangeable.

Correction. My connector to the MAT does look like that but it has tan and black wires going to it. I still haven't found any pink and black/pink wires with a connector on that side of the block.

EGR is functional. I have the wire connected into the EGR solinoid. It doesn't go to the dizzy, it doesn't fit, and i have both wires connected there anyway. I'll check MAT once the engine cools down a bit, as i was just testing my new thermostat, which didn't correct my overheating problem. However, I think I have it plugged in. On my chilton's manual it indicates that these wires go the ECM, but it obviously won't reach the ECM. Any ideas with code 42 & 43? Seeing as how both are related to the ESC I would assume this wire is related to the codes, do you agree?

87,

I'll agree to one thing - that connector is probably supposed to be plugged into something.

Although I don't have 1987-specific schematics, my '86 diagrams reveal a couple items that might interest you:

1. The pnk/blk wiring is probably from the GAGE fuse or other ignition power circuit, which is used to power a lot of ECM loads on the engine, and a few information sensors;
2. The wiring between the 4-wire connector and the ECM has no other connectors - it is directly wired to the ECM connector;
3. The IAT/MAT (or whatever term you want to use) usually has a tan wire and blk wire, not a pnk/blk;
4. The extra connectors at the distributor are pnk/blk (coil power) and wht (tach) wires. The rest of the connections are in the 4-wire flat connector;
5. The EGR solenoid uses blk and gry.

Now I'm getting confused, too....

1. didn't know that, but interesting

2. my chiltons agrees, except for some reason my car isn't like that

3. i agree

4. i agree

5. i agree

i have some photos of mine the wire lots identical but i cant post them because they are to big who can post them i will email them and they will get posted, or ho ever wants them tell me

3 pics of the driver side corner of the engine bay where the clip in question is clipped in and has pink black wire and black wire out of it

Yea, could you shoot thoose pics to me? Can you see where this wire goes?
Thanks
JP
jpgolf14@excite.com

sent them.

This should be interesting...

These pics are provided by blackgold84, thanks dude
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I started a thread a while back about the same connector I came across on my '87 L98 roc. Here is a link:

http://www.thirdgen.org/techbb2/show...readid=119433.

Unfourtunatly there is no solid conclusion to be found here. The fact is though that no one that found THIS conector on THIS car has found it connected to anything. My opinion is that our harness was most likely used on other vehicles that did have something connected here in an attempt to minimize the parts bin and lower production costs. To lower production costs even more, GM just didn't eliminate it from the harness at the factory and just left it dangling and unconnected. You'd think they could of still somehow included it in the wiring diagrams to keep us from wondering though, ba$tards.