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-   Ford 67-96 F-Series, 78-96 Bronco (https://forums.off-road.com/ford-67-96-f-series-78-96-bronco/)
-   -   TPS (https://forums.off-road.com/ford-67-96-f-series-78-96-bronco/48725-tps.html)

**DONOTDELETE** 12-10-2000 03:29 AM

TPS
 
My air filter smelled of gas when I changed it today and wondered if the TPS can cause a truck to run rich?


Steve83 12-10-2000 09:22 AM

Re: TPS
 
Yes, but there should never be gasoline anywhere near the air filter. It's injected less than 2" from the intake valve and the airstream pulls it straight in. The only way would be if the rings are shot, the engine is really rich, and the blowby is carrying fuel thru the crankcase, backward out of the breather filter in the airbox. But it would carry a LOT of oil with it; is the breather filter fouled? Pull the hose from the valve cover to the breather filter and check how it smells. Is the PCV valve (on the other valve cover) working properly? Is its vacuum hose to the plenum OK? Is there fuel leaking out of the fuel rail putting the smell in the whole engine compartment?

Steve
83 Custom w/95 4.9L EFI, 78 NP435, 83 NP208, 83 D44IFS 3.07, 87 Ford 8.8ABS 3.08, Michelin LTX AT 31x10.50R15

**DONOTDELETE** 12-10-2000 07:16 PM

Re: TPS
 
Well, for the PCV, i changed that yesterday cause it was messing up and the grommet on the valve cover was messed up too, so all that is changed. everything is good on that side.

2. AIR BOX, changed both filters in there, so that is done. cleaned the pipe going into the valve cover/

3. No oil in the air filter...

4. no fuel leaking anywhere that I can see, however I think it is running rich. timing seems to be on, however I need to get the TPS changed before I can get it accurate. (TPS is on order, getting in a couple of days)
Anything else?




Steve83 12-10-2000 07:50 PM

Re: TPS
 
You say in 2 that you changed the breather filter (the little one below the air filter) and cleaned the pipe; Were they oil-fouled?? How did you determine that the TPS was bad? If the PCV system was not working, the oil might have gotten thin enough to damage the rings: do a compression test. Did you check the timing with a light? The TPS won't affect the timing - why can't you set it?

Steve
83 Custom w/95 4.9L EFI, 78 NP435, 83 NP208, 83 D44IFS 3.07, 87 Ford 8.8ABS 3.08, Michelin LTX AT 31x10.50R15

**DONOTDELETE** 12-10-2000 10:47 PM

Re: TPS
 
1. They were not oil-fouled, just regular dirt and crud. Where the PCV plugs in I had a lil oil around there, cause the grommet had a tear in it.

2. TPS, I tested it the way the haynes book says and it came back negative.

3. Will try the timing, again, tommorrow. However, when I timed it last week, the RPM's kept going really high and then really low. Thats when I started looking at the TPS. Wouldn't that effect the timing?
Thanks for your help and time!



Steve83 12-10-2000 11:04 PM

Re: TPS
 
The TPS doesn't directly affect timing, but as RPM increases, timing is advanced by the computer. Remember to unplug the SPOUT connector the way the book says when you time it. BTW I keep a stock of TPS's I've collected from junkyards - it's cheap insurance.

Steve
83 Custom w/95 4.9L EFI, 78 NP435, 83 NP208, 83 D44IFS 3.07, 87 Ford 8.8ABS 3.08, Michelin LTX AT 31x10.50R15

**DONOTDELETE** 12-10-2000 11:14 PM

Re: TPS
 
One last thing! To replace the TPS, do I have to follow all the steps given in Haynes? Or can I just screw and plug it in?
Thanks


Steve83 12-11-2000 12:21 PM

Re: TPS
 
I don't recall what Haynes says, but the later TPS is spring-loaded and the adjusting slots have been filled in, so there is no adjustment possible. Just make sure the throttle shaft is lined up in the TPS before you crank the screws down and crack it.

Steve
83 Custom w/95 4.9L EFI, 78 NP435, 83 NP208, 83 D44IFS 3.07, 87 Ford 8.8ABS 3.08, Michelin LTX AT 31x10.50R15

**DONOTDELETE** 12-11-2000 01:23 PM

Re: TPS
 
The tps is adjustable. It shoul be set at .98v with the key on and engine off. This provides the best throttle response. The TPS will be able to be adjusted a little bit but to get the desired reading, you will have to take the TPS and ":drill out" the mounting holes and make them bigger. This will allow for more adjustment. You have to use a voltmeter hooked up to the green and black wires, that run from the TPS.


**DONOTDELETE** 12-11-2000 01:29 PM

Re: TPS
 
Here is a better step by step....it is for a mustang but it is the same procedure.
1) Get a digital voltmeter
2) Turn the key on, engine off
3) Pop the hood locate the TPS sensor on top of the throttle body (black thing with 2 screws on it, 3 wires)
4) Probe the black wire on the TPS with the ground from the voltmeter, green wire with the positive lead. You should get some reading between .95-.98 volts. If not, loosen the 2 screws, clockwise to increase, cc to decrease. Tighten the screws back down and recheck voltage. You may have to enlargen the holes slightly with a drill bit to gain more adjustment.
4) Probe the black wire again and the orange wire with the positive lead. It should read between 4.9-5.1 volts with "key on engine off". If there is voltage here and no voltage on the green wire from above, the TPS is bad. If there is no voltage on the orange wire, you have a short somewhere.

I think you will have to take the throttle body off to adjust it on a Bronco.
Hope this helps,
Rich



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