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Discussion Starter #1 (Edited)
I'm stumped. I can't get my car to start as it keeps fouling plugs from being way too rich sine I switched over to my 36# injectors and my 80mm C&L (it has the proper sample tube). I checked my TPS voltage after noticing my Crane Interceptor was displaying the throttle position as WOT during the cranking cycle. I hooked up my multi meter with the key in the run position, throttle closed and the voltage is reading on the TPS is 4.56 volts WTF? I tried another TPS and I get pretty much the same number. What's going on here? The first time I started it with the 36's it ran OK and I even drove it around the block. I went to go start it again and no go. Pulled all the plugs and they're all black and wet so I'll clean them before I re-install them (autolite 3923's)The car ran without flaw until I switched to the big injectors.
 

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Sure they are....that's why a lot of people just take a drill and slot the sensor so that you can adjust it more. Trust me, it's a lot more common than you think! :)
 

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94 Cobra R said:
Sure they are....that's why a lot of people just take a drill and slot the sensor so that you can adjust it more. Trust me, it's a lot more common than you think! :)
Sigh!!!!!!!!!!!!!!
Plus, you have a 94/95. SAD, sad, sad, sad, sad.
Do a search.
 

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From Ford:
http://www.veryuseful.com/mustang/tech/engine/images/TPSTypes.jpg
NOTE: Two types of TPS are used on EEC-IV system. "Level C" Type is adjustable and "Level D/RD" type is nonadjustable. Throttle position sensors without slotted mounting holes are not adjustable. If voltage reading on nonadjustable TPS is not .9-1.1 volts at idle, and greater than 4 volts at wide open throttle, replace throttle position sensor.


From Probst page 89: Recent Ford systems, all EEC since 1988, use a Rotary TP. The potentiometer increases resistance as the throttle shaft rotates. It is not adjustable, but the control-module programming compensates for any differences in sensors, readjusting to a base voltage when the throttle is closed.

Also, see Probst Page 302.

End of discussion on the TPS.
 

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94 Cobra R said:
Why not just adjust it? It's not uncommon for them to be off from the factory.
And the basis for that statement?
In fact, NO 94+ could leave the factory if the TPS was not in spec. It would set off the check engine light.
 

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stangplus2birds,
you seriously confuse me. One minute we agree, the next we don't. No engine check light is set off when the tps is off from the factory...you know better than that. :) Anyway, if the guy wants to find out the real answer, let him try it. Or atleast do a search so that you and I don't have to post our message a couple of dozen times a week...right? Have a good one....I'm going to bed....(BTW - Don't you owe me a beer from previous conversations we have had? Or do i owe you one?)
 

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Discussion Starter #10
Did a search here on Corral for related topics and was able to diagnose the problem based on those findings. Turns out that somehow during the course of my injector swap I must have damaged the ground wire for the TPS as there was no ground present when I tested it at the TPS connector. I connected a wire to ground it and sure enough that fixed it as the voltage returned to .97 volts. Didn't try starting it yet since it's 1:30am in the morning but I'm pretty confident that will fix my problem.
 

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Discussion Starter #12
Yes. When I first diagnosed the voltage problem, I had 4.56 volts on the green wire with the key in the "run" position when it should be reading under 1 volt. I clued in to check it because my Crane Interceptor was diplaying the throttle position as WOT during cranking. I did a continuity test on the black wire between the neg terminal on the battery and the black wire of the TPS.....no ground. Grounded it with a wire and the green wire now reads .97 volts.
 
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