TPS Testing

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Apr 23, 2002 | 11:28 PM

whaynes

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TPS Testing

I ran the codes for my 93 4.9L and it came back with 13 34 in the KOEO and KOER 129 126 225. I tested the TPS as per the Haynes manual and did not see a change in resistance. I pulled the TPS off and tested it on my workbench and this time I did notice the proper decrease in voltage as I simulated throttle change. What is the deal? Is it still good or does it need to be installed on the truck to test properly? As for the other codes I have some intermittent pinging I don't have a Vacum actuator to test the MAP sensor. Are there any other ways to test the MAP Sensor?

Thanks,

WHaynes

Apr 25, 2002 | 10:40 PM

madman666

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From: Buena Vista

TPS Testing

Go to this page for testing the TPS: https://www.ford-trucks.com/articles/code124.php

May 4, 2002 | 03:05 PM

whaynes

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TPS Testing

I put a new TPS in today and there was a huge improvement in Idle response, smooth acceleration, and less throttle needed to maintain constant speed. I have just filled up both tanks and I will advise as to any changes in MPG. I was doubtfull as the TPS seemed to test fine outside the vehicle but there must have been something wrong with it.

On to the MAP Sensor. I picked up a vacuum pump and backprobed the wires as per the haynes manual. The voltage reading was 2.5 with no vacuum. When I applied vacuum to the sensor the voltage did not change. Could I be doing something wrong? I was getting a 129 code from the PCM.

Thanks,

WHaynes
93 F150 4.9L 4x4
4" ProComp StII Lift
BFG 33in 4.10's
Detroit TrueTrac's

May 6, 2002 | 09:02 AM

kwing

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TPS Testing

I think you should have 5.0 volts at the MAP (KOEO). The voltage won't change. You need a frequency counter(tach) to read any changes to the MAP with different vacuum. Just unplug the electrical connectors to the MAP with engine running and if RPM changes it would seem it is working properly. On the other note, get your fuel pressure tested at the fuel pressure regulator. Sounds exactly like vapour lock due to improper priming pressure. Maybe check the Charcoal canister vacuum solenoid. It may be dumping fuel vapours into the engine on a hot start.

May 6, 2002 | 09:04 AM

kwing

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TPS Testing

Sorry, ignore my reply regarding fuel pressure. Wrong post.

May 12, 2002 | 06:55 PM

pancake

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From: utica n.y., u.s.a.

TPS Testing

May 13, 2002 | 07:13 PM

ront

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From: Pacific NW

TPS Testing

"I put a new TPS in today and there was a huge improvement in Idle response, smooth acceleration, and less throttle needed to maintain constant speed. I have just filled up both tanks and I will advise as to any changes in MPG. I was doubtfull as the TPS seemed to test fine outside the vehicle but there must have been something wrong with it".

Hi whaynes,
I have been wondering about my TPS also. Some of the symtoms you had sound like some of mine. It feels like I am either giving my truck alot of gas or if I let off just bit, it's like I have completly taken my foot off of the gas. This is really noticeable if I am driving along at around 30 miles/hour. Some times it seems that there is a choke that is stuck(I know there is not one).