MustangWorks.com : Ford Forums - View Single Post

PKRWUD · 08-11-2001, 12:33 AM

You didn't go read it, did you? I'm not concerned with the voltage at the TPS, although yours is dangerously close to 1 volt, which is where the ECM determines whether or not you are at idle. .95VDC is really much better. There is no noticable performance increase between .95 and .99, but .99 is alot more risky, but that's up to you. I want you to disconnect the TPS from the harness, and hook up the leads from a DMM (with a bargraph) across the VREF and TP Sig (grn & orange) wires from the TPS, not the harness). Set the DMM at ohms, and watch the bar graph as you turn the throttle. There's a good chance that you will find a flat spot, where the bar momentarily stops progressing, or even back steps. I've had that happen before. When I tested it for a smooth voltage increase, it wasn't as evident as it was testing it for resistance. My bar graph jumped significantly in both directions while I slowly rotated my throttle. I replaced the old TPS (only had 60k on it!), and the problem was solved.

I'm not saying for certian that's your problem, but your description sounds similar to what my experience was when this happened to me.

As far as checking your injectors goes, try and duplicate the miss in your garage. Then, one at a time, disconnect an injector until you find one that doesn't make as big a difference. Then inspect that injectors harness, and if you don't find something wrong, pull that injector and another one, and swap them. Now try and see if the problem cylinder moved with the suspected injector. If it did, you've found your problem. If it remains in that first cylinder, then there is a problem with the circuit. You should also measure the resistance of all your injectors.

Or, find a shop with a MotorVac, and have them professionally cleaned.

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 !!!

08-11-2001, 12:33 AM	#4
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	You didn't go read it, did you? I'm not concerned with the voltage at the TPS, although yours is dangerously close to 1 volt, which is where the ECM determines whether or not you are at idle. .95VDC is really much better. There is no noticable performance increase between .95 and .99, but .99 is alot more risky, but that's up to you. I want you to disconnect the TPS from the harness, and hook up the leads from a DMM (with a bargraph) across the VREF and TP Sig (grn & orange) wires from the TPS, not the harness). Set the DMM at ohms, and watch the bar graph as you turn the throttle. There's a good chance that you will find a flat spot, where the bar momentarily stops progressing, or even back steps. I've had that happen before. When I tested it for a smooth voltage increase, it wasn't as evident as it was testing it for resistance. My bar graph jumped significantly in both directions while I slowly rotated my throttle. I replaced the old TPS (only had 60k on it!), and the problem was solved. I'm not saying for certian that's your problem, but your description sounds similar to what my experience was when this happened to me. As far as checking your injectors goes, try and duplicate the miss in your garage. Then, one at a time, disconnect an injector until you find one that doesn't make as big a difference. Then inspect that injectors harness, and if you don't find something wrong, pull that injector and another one, and swap them. Now try and see if the problem cylinder moved with the suspected injector. If it did, you've found your problem. If it remains in that first cylinder, then there is a problem with the circuit. You should also measure the resistance of all your injectors. Or, find a shop with a MotorVac, and have them professionally cleaned. 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 !!!