tps ground problem

[fordnut71]

i just happened to check my tps today an i came up with the same valves as 1.00 at rest an 3.80 at wot.
i would be looking at the egr also as it will cause a bog or a feel like a miss fire. could be the valve is stuck open, so even if the electonics of it checks ok id take it off to see if it moves with vac or has carboned up an not letting it close.

 

[richrd]

Last fall the engine codes were 335,spressure feedback egr signal voltage and 327, egr valve position
.

I had to drive the thing out of town last weekend. 160 mile, 62 mph. 12 mpg and one quart of oil.

Is it burning oil because the engine is shot or is something causing the cylinders to be "washed"?

It needs a new hinge pin in the drivers door, a new battery cable, and the radio quit.

I think I'm going to take it to a good mechanic to tell me whether to fix the radio or junk the truck.

 

[fordnut71]

i think u should take off the egr valve an check it to see if its in the open postion or letting exhaust gas by. that would be part of the problem for bad mpg

 

[X-North]

THE solution

I also have the same problem. Heres the test you must do for it with the key to Run. Unplug the TPS and measure the voltage between Brown/White wire and the Grey/White wire you are supposed to have 5.0 volts.On mine i have only 4.93 volts. Plug it back and backprobe Grey/Red wire and Grey/white wire you are supposed to have less than 1.5 volt. Turn it to wide open throttle and it supposed to have 5.0 volts again but also there i had only 4.93 volts. When it was unpluged i measured it but instead of putting it on grey/white wire i did it on the negative of battery it gave me the 5.0 volts i needed. Made the same with other tests and it gave me the good voltage. So thats why we say that there a lost of voltage du to ground resistance and in this case what is could be considered as a ground even if it go back to EEC is the Grey/white wire. Just to be sure thats not the TPS that was more resistant than it supposed to be i unplugged the connector behond the alternator..the one with lot of wires. The one with male pins is the one that the voltage come from so again i tested it the Brown/White wire plugged on the negative of battery gave me 5 volts but on the Grey/white wire on the same plug that go back to EEC it gave 4.93 volts again. Now like that we are sure that its not other wires or tps that have too much resistance. Problem solved its the Grey/White "ground" wire that is more resistant than it should be. Lots of first gen explorer have the same problem. For my part it gave me 3 codes. First a TPS out of range, second is a HEGO, and third is a false pcm EEC signal. In ford manual shop for first gen explorer and other 4.0 OHV its written a faulty tps or tps circuit out of range will make the engine run richer and give a HEGO oxygen sensor signal at the same time. This problem will be solved when the tps problem will be solved. For the faulty pcm signal it come from the wrong voltage that is sent back by the TPS grey/white wire. For my part i will cut the grey/white wire at the connector start a wire from there pass it through the firewall cut the other end of the original wire at the EEC pcm and put my new wire there. Problem of "Ground" solved without having the problem to take off all the wires and their protectors. I dont know why but from 1991-1994 they had all the same grey/white wire problem. :frustrate

 

[MrShorty]

Good writeup SexyFantome, especially when English isn't your first language. The only thing I might add (and it might already be there and I missed it) is to measure the voltage drop across the PCM grounds, to make sure the 0.07 V drop isn't on that side of the PCM.

 

[X-North]

every voltages has been tested from everywhere and they give correct voltage within specs when you use the battery negative as ground. The problem is when you use the Grey/White wire. Theres two place to measure it. The first is at tps the other is at the connector box just behind the alternator.You masure it first at the tps connector.Whoops it have less voltage so you are sure it come from somewhere in the wires because at this test the tps is unplugged.You disconnect the connector box and you measure it at the male pins connector because its them that give the voltage. So if it give you the same problem you know that the voltage drop is not between the tps and the female pins connector its between the male pins connectors and the pcm. I call it "Pinpoint" an electrical problem. You separate every parts of a wires system coming from the sensor and then you go back to the pcm that is why you test sensor first. But sometimes sensors are not faulty so you go back to the source the ECC-pcm.
You see i made it all those tests and when i made the male pins test it gave me 5.01 volts on the Brown/White wire when it was probbed on the battery negative and 4.93 volts when it was probed on the Grey/White male pin that go back to the pcm.