[gemarsh]

Got a new Autoxray 6000 scan tool Friday. Found the reason behind the MIL light glowing on the 3.8. MAF low input. Changed the MAF out and it took care of the problem of dieing right after starting the first time in the morning. Sometimes it took three or four times to stay running. Also smoothed out the entire rpm curve.

But my problem now, that I didn't even know of, is this scanner is reporting the timing advance is at -22 at idle and goes to a -28 as you rev the engine. I have no idea how to adjust the timing on this machine. Can't even see a timing mark on it let alone a distributer! :&gt

Any insight on what to check or adjust? I'm an old school mechanic and I can't believe it's runing this retarded. If I get this repaired I'm sure the fuel mileage will skyrocket. Car's info center is saying 18-19 mpg. I was under the influence these should get above twenty.

Thanks,
Gayle

[gemarsh]

Got a new Autoxray 6000 scan tool Friday. Found the reason behind the MIL light glowing on the 3.8. MAF low input. Changed the MAF out and it took care of the problem of dieing right after starting the first time in the morning. Sometimes it took three or four times to stay running. Also smoothed out the entire rpm curve.

But my problem now, that I didn't even know of, is this scanner is reporting the timing advance is at -22 at idle and goes to a -28 as you rev the engine. I have no idea how to adjust the timing on this machine. Can't even see a timing mark on it let alone a distributer! :&gt

Any insight on what to check or adjust? I'm an old school mechanic and I can't believe it's runing this retarded. If I get this repaired I'm sure the fuel mileage will skyrocket. Car's info center is saying 18-19 mpg. I was under the influence these should get above twenty.

Thanks,
Gayle

[george kujanski]

Welcome. Yep, seems hard to believe that it's after TDC. Are you misinterpreting the data? Perhaps it displays BTDC as negative and after TDC as positive numbers. From an engineering point of view, that would make sense, but it's contrary to old school mechanics.

Check the instructions or contact the mfr to verify. my opinion is that it's fine, and negative numbers are BTDC.

George

[gemarsh]

Thanks for the reply. I had already thought of that so I plugged it into my 97 454 suburban. It is reporting 25 degress advance. Knock retard = 0.00.

The Pontiac is also reporting 0.00 knock retard. I would think the scanner would report the same -/+ settings for GM 97 OBD11, no matter what engine.

Does this thing have a cam postion sensor or just a crank sensor? I think I will throw a new sensor at it if it's not hard to do.

Test drove the car with the check engine light on. The dealer cleared the codes and repaired the drivers side window and horn before we bought it. Horn doesn't work again. So, I don't know what the codes that were set before then.

Thanks for the help,
Gayle

[meanolegoat]

Gayle, dont replace the crank or cam sensors. their pretty much "dumb animals". They work or they dont, really didn"t have any issues with them on these year models. As fo the scanner readings it may very well be an anonomly with the scanner. Try re-setting the fuel monitor, it should be re-set after every fill as it is cumulative. In other words if it hasn't been re-set in forever, it will not reflect true mileage under your driving conditions/habits.
"mean"
ps.. probably just the horn contact is bad in column (ie broken)

[gemarsh]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">"mean"
ps.. probably just the horn contact is bad in column (ie broken) </div></BLOCKQUOTE>

I guess I need to buy a repair manual for this vehicle.

When you refer to the horn contact are you in fact talking about the ring and brush as used for many years that is under the wheel? Or is this horn contact something else?

Ebay a good place to find GM repair manuals?

Thanks,
Gayle

[george kujanski]

I highly recommend factory manuals for any late model car you intend to keep. I buy a set whenever I get a new vehicle. For GM's manuals nowadays will cost you about $125; on my Yukon it consists of 5 books! Well worth it, tho.

If you can find a set on ebay for less, go for it.

George

[meanolegoat]

Gayle, Yes its the same slip ring deal...But for some reason they tend to come un-plugged or break where the horn contact wire twist locks in....
"mean"

[gemarsh]

Well I just got the GM Techline Service and Diagnostic CD program off ebay. Man what a change from reading a book. Anyway, the timing should be at a -20 and variable on this engine. Atleast that is what the GM's Tech 2 scan tool should report. So I guess the Autoxray wasn't lying to me.

Oh got the horn fixed also, ice/snow must have accumilated on the wiring and unplugged the horn under the passengers front fog light. As good as GM's weatherpacs are, you'd think they would have used a better connection for the horn/wiring connection in this area.

Won't tellya how long I looked for the damn thing!

Thanks guys,
Gayle