TPS Sensor
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From: Winnipeg/MB/Canada
TPS Sensor
Last spring my '86 F150 5.0l EFI wouldn't start so I changed the TPS sensor figuring it was the problem. I later found out that the timing set was shot. The truck sat for awhile (it was really cold out) and now I finally replaced the timing gears & chain. Tried to start it. No go. Finally with my foot floored it started and runs very rich. The Haynes book says there is an adjustment for the TPS, mine will only bolt on one way. No room for any adjustments. What's the proper way to change a TPS sensor? Or is my problem ignition timing, maybe a combo of both? What's going on, i'm stumpted?
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From: Louisville,Ky.
TPS Sensor
Check to make sure that the vacuum line is hooked up to the MAP sensor. If it is unhooked, it will flood itself out.
The TPS sensor has a slight adjustment, but it wouldn't cause that problem.
Jimmy
The TPS sensor has a slight adjustment, but it wouldn't cause that problem.
Jimmy
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From: Winnipeg/MB/Canada
TPS Sensor
Thanks for the info, Jim. The Map is hooked up, workin' fine & the spec's are in the ballpark. It was -30 below zero when I changed the TPS, and I think I might have had a brain freeze when it came to installing it. Tell me, does the "pigtail" or connector face towards the engine or away from the engine once it's bolted up. I suspect my problem it not timing but rather the TPS because of all the fuel being dumped into the system.
Last edited by fasteddie; Jun 28, 2003 at 11:26 PM.
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From: Dededo, Guam
TPS Sensor
Lookin in my Chiltons manual and it has a drawing of it. The TPS's connector points toward the intake tubes. The pigtail end points toward the manifold.
edit: if you need a picture I can take on tommorrow during the day. Let me know.
edit: if you need a picture I can take on tommorrow during the day. Let me know.
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From: Winnipeg/MB/Canada
TPS Sensor
Thanks big guy, first of all it seems like my problem was largley ignition timing. The sticker said to set it at 10 BTDC. Not true, you gotta bang it up to TDC & then use the timing light to achieve 10 degrees. Not what the sticker said, mine said initial, no wonder it wouldn't start. I've never heard of timing it another way but I thought it was some sort of a computer thing. Next, got an assistant to start it up, found out the new sensor was bad, static resistance was out to lunch. Tomarrow i'll have a new sensor, and i'll let you know.
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TPS Sensor
J.R. the negative from the pic in the manual must have been upsidedown for the 5.0L. The pigtail points away from the T.B. It's the only way it will engage but maybe the 4.9L is different. Got a new sensor, 60 bucks for a glorified rheostat! Rip off city but hey I need it. Installed it & set it at 5V going in & 1V comming out. The resistance was a tad high but not too crazy. Problem is once it's started it runs fine but to start it I still have to hold my foot to the floor until it fires up. Then it seems like it runs loaded up on one or maybe two cylinders. Finally it evens out and runs & starts fine until you shut it off for a long period of time. Then the same hard start thing happens again. Is the PCM still learning? or what.
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From: Louisville,Ky.
TPS Sensor
You might try backing off the tps a little bit, it may be too far advanced giving it extra fuel. I have read that .99v is max. Did you set the timing by removing the spout plug first? if not, you will get way advanced, false readings.
Jimmy
Jimmy
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From: Winnipeg/MB/Canada
TPS Sensor
Now i'm in the stew!! While trying to dial in the TPS, I decieded to turn the idle screw to set the TPS voltage. Turns out that your now supposed to touch that screw. There"s supposed to be a plastic cap with a limiter but not on mine. Can anyone tell me how to set this up again? The truck is hard to start (gotta put your foot to the floor, then once it starts it runs rich untill you wick the throttle and burn up the fuel.) So how to I adjust the TPS, Screw, Throttle adjustments etc. all at once. Any ideas.
Eddie
Eddie
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From: Memphis, TN
TPS Sensor
The EFI throttle stop screw never had a cap - that was the idle mix on carbs. To reset it, run the engine, unplug the IAC, and back the screw out until the engine BARELY dies. It should ALMOST be able to run if you recrank it, but die within ~2sec. Then plug the IAC back in and it should be fine.
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From: Merryland
TPS Sensor
Boy I'm gonna be in for some fun,a guy along time ago broke my idle screw on my truck! It's an 85 4wd 302 fi,i'm not looking forward to setting the timing,i had the distributor out,on the idle set up i have a bolt threw it with a nut on either side,gonna be wild trying to set the TPS!!OH GAWD!!!!
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