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PKRWUD · 08-09-2001, 01:44 AM

The ECM determines whether or not you are at idle right at the 1 volt point, in the TPS circuit. If at idle your reading is 1.04, the ECM thinks you are driving, not idling. This could have something to do with your timing. loosen the screws on the TPS and try to rotate it far enough to get a voltage reading of .95, or close to it. Some might suggest getting it as close to 1 volt as possible for more performance, but they are idiots. There is no noticable difference in performance, but the closer you get to 1 volt, the more likely you are to confuse the ECM. The other test you should do with your TPs, that most people don't, is to unplug the connector, and hook up a DMM with a bar graph across the reference wire and the ground wire and set it to ohms. Then watch the bar graph while slowly turning the throttle. It shouldn't back step once. If it's nice and smooth, you're good, but if it jumps back and forth, the potentiometer has worn spots in it's travel (usually right after idle), and must be replaced. This can be done with a voltmeter with the connector plugged in, and by back probing the wires, and turning the ignition on, but it's much more acurate unplugged and by resistance. Anyway, once you have the TPS set, disconnect the battery, turn on your headlights for 2 seconds, reattach the neg. bat cable, pull the spout connector and start it up. Check your timing. Set it at 10 degrees BTDC. reinstall the spout and go for a drive. Post your results.

Take care
~Chris

------------------
Retired Moderator
MustangNet

My site: JimPorterRacing

RACECAR spelled backwards is RACECAR

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08-09-2001, 01:44 AM	#5
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	The ECM determines whether or not you are at idle right at the 1 volt point, in the TPS circuit. If at idle your reading is 1.04, the ECM thinks you are driving, not idling. This could have something to do with your timing. loosen the screws on the TPS and try to rotate it far enough to get a voltage reading of .95, or close to it. Some might suggest getting it as close to 1 volt as possible for more performance, but they are idiots. There is no noticable difference in performance, but the closer you get to 1 volt, the more likely you are to confuse the ECM. The other test you should do with your TPs, that most people don't, is to unplug the connector, and hook up a DMM with a bar graph across the reference wire and the ground wire and set it to ohms. Then watch the bar graph while slowly turning the throttle. It shouldn't back step once. If it's nice and smooth, you're good, but if it jumps back and forth, the potentiometer has worn spots in it's travel (usually right after idle), and must be replaced. This can be done with a voltmeter with the connector plugged in, and by back probing the wires, and turning the ignition on, but it's much more acurate unplugged and by resistance. Anyway, once you have the TPS set, disconnect the battery, turn on your headlights for 2 seconds, reattach the neg. bat cable, pull the spout connector and start it up. Check your timing. Set it at 10 degrees BTDC. reinstall the spout and go for a drive. Post your results. Take care ~Chris ------------------ Retired Moderator MustangNet My site: JimPorterRacing RACECAR spelled backwards is RACECAR HEY !!! Are you ASE Certified ??? If you are, ask me about iATN. The best tool you'll ever have, and it's free !!!