Tan wire w/black stripe???

[rob67gmc]

Does someone have a pic of the tan wire w/black stripe that you disconnect when you check timing? I've looked for it on the '89 camaro and can't find it. I've also looked for it before on my '97 silverado and on my dad's '89 silverado and have never been able to find it. It's got to be there somewhere.

Thanks,
Rob

[Morley]

The wire is either back by the firewall on the passenger side. It comes up out of the big wire loom, has a single pin connector on it and then goes back into the loom.
Or it is by the passenger fender, near the strut tower. Same wire with a single pin connector. They say it is tan/black but it is closer to brown/black.

[rob67gmc]

Found it. More brown than tan, next to the strut tower. Timing is at about 9*. What should it be set at?

[Morley]

Originally Posted by rob67gmc

Found it. More brown than tan, next to the strut tower. Timing is at about 9*. What should it be set at?

Timing should be 6* BTDC in drive, parking brake on and wheels blocked....resist the temptation to rev the engine while doing the timing check until AFTER you get done and put it back in park.

[rob67gmc]

Can't put it in drive since it is a 6-speed. Should it still be at 6* BTDC in neutral? I just read in a book that it should be between 8*-12* BTDC on a TPI engine, but you haven't steered me wrong yet.

[Morley]

Yep, put it in neutral on a manual. I don't know who would print it up as 8-12* but that can cause detonation. The "base" timing is programmed into the PROM chip, meaning that the ECM "knows" that it is starting from 6* and from there uses its timing tables. Now, if the timing were set to 12* then the entire timing table would be skewed to the high side by 6*. Running that much timing can and will cause detonation problems in several places throughout the spark curve. If you have a scanner that can data log you could try advancing it 2* from factory, take it out for a run and see what the data logs look like. You could keep doing this until your knock counts go up. Then back it off the last 2* increase you did and 2* more for safety (hotter weather, lower octane gas, etc).

Originally Posted by rob67gmc

Can't put it in drive since it is a 6-speed. Should it still be at 6* BTDC in neutral? I just read in a book that it should be between 8*-12* BTDC on a TPI engine, but you haven't steered me wrong yet.

[rob67gmc]

Set the timing at 6* and drove it for about 30 miles. I think it it needs to be tweaked a little. Engine lugs a little when you start off.

What would be a good but not too expensive scanner or would it be better to use a laptop?

I got the 8-12* timing info from the book "How To Tune & Modify Your Camaro 1982-1998". It said "1985-1992 TPI cars generally respond well to base timing of 8-12* BTDC".

[Morley]

The "best" scanner would be a laptop. The cable can be made for about $4, the scanning program is free and laptops can be found for $50 on E bay.
If you want/need the schematics for the cable and want the program, let me know and I'll E mail them to you.

[chadis]

Originally Posted by Morley

The "best" scanner would be a laptop. The cable can be made for about $4, the scanning program is free and laptops can be found for $50 on E bay.
If you want/need the schematics for the cable and want the program, let me know and I'll E mail them to you.

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i have a 1987 irocz was wondering what this scanner u speak of is all about???