Newbie here, so please be gentle.
My '94 150 4X (ebay problem child) just got a 306 transplant and it didn't run much better than what came out.
Turned out the TPS was shorted.
New sensor shorted as soon as the engine was started. KOEO, the voltages (feed 5.4 v, sig. rtn. .84). As soon as I fired it up, it was 5 v both ways, lean limit per codes.
I expect the EEC is the problem. I think the truck may have been flooded at some time even tho it cameup OK on CarFax.

I believe the inner fender has to be dislocated to get the EEC out.
Is this correct?

 

Yes remove the screws at the rear fender lip then use a stick of wood, thick broom handle what have ya, to fold the plastic inner fender forward just enough to slide the EEC out of its slot.

 

disconnect batt., remove harness from computer, remove bolts holding computer to firewall, remove lower screws from inner fender, push in a little, remove computer.

 

That's pretty much what I remembered from my days in Navistar engineering - pulled one about 12 yrs ago, but ....memory is the 1st thing to go and I can't recall what the 2nd thing is. Thanks.

 

tell us if that solves your problem.

good luck and welcome to fte.

 

Thanks for the welcome. Got the old 1 out, and as I suspected there are water droplets in the socket where the 60 pin plugs in. Ordered up a replacement, so I'll see what happens.
Just by the by, I didn't see anyplace in the user cp to add a signature. I've been on Corral and FvC for quite a while, and have a lot of 7.3 idi and PS experience.

 

Just on the off chance that I may have damaged the harness during the swap, I decided to pin out the 60 pin to the TPS connector. My truck wiring diag. doesn't show the wire purpose @ the 60 pin, but my '91 'stang diag. does, so between the two I came up with the following:
(it also has to be noted that the 'stang and truck use the same circuit #s and wire colors from the EEC to the sensor)

With the 60 pin disconnected, all 3 wires for the TPS have continuity to them selves from the 60 pin to the TPS connector. I hoped for this result.

However, I have a reading of 4.2 Kohms from the sensor feed (wire 351, brn/wh) cavity 26 on the 60 pin) to the signal return (wire 359, gy/r) cavity 46 on the 60 pin.

Since there are no opens on the wires to themselves, could the other sensors powered by the sensor feed be creating the resistance I'm finding?

 

If the sensor feed, brn/wh wire, is the 5V reference, I can understand the resistance between that pin and the signal return pin. The 5V and signal return wires are used by the TPS, the EVP sensor, and the MAP sensor.

 

yeah, the diag's were telling me those wires were shared, ACT, CTS, and EGR (at least). started pulling connectors messin' around again this a.m. and found out that 1) if I disconnect the EGR sensor, the 4 kohms goes away. I had expected there to be an incremental decrease, but the egr as the only reaction.
2)I took it off and tested it alone (along with another 1) and found out that that's apparently the normal closed resistance. as the plunger goes up (valve opening), the resistance drops.
since i was working with the eec out, battery disconnected, the EGR was not functional.
now I'll just wait for the new eec.

 

Be careful measuring resistance through the MAP sensor, I remember reading somewhere that it can damage that particular sensor.

 

I found that out on my Lincoln project ('90 MK VII, 347, 5 spd, MAF coversion, air ride and ABS replaced w/ springs and 'stang GT brakes etc.) The MAP became the BAP, but in trying to get all the calibrations right, and basically rewiring the car, I hurt it doing just that.
Who woulda' thought it? Not me obviously.

 

So..... the re-manned computer showed up (Auto Computer Exchange - Davie, Fl) {They were $100 under my local parts guys}, plugged it in and NO FIRE !. It'd kick like a pissed off mule, but wouldn't start.
Came with the right coding. WTF?
Plugged my original back in and VOILA!! fired right up and wonder of wonders, the TPS was playing nice (original complaint).
.88 vdc @ idle and the thing acts like it has some torque.
All I can think is that having the EEC out of the truck for a week let it dry out. :dunno:

 

So, .......I thought I had it fixed - - - not figured out, but fixed. ~ 5 mi. from home, after 50+ mi. where it ran OK, the cel came on, it shuddered, had no power from a stop, sounded as though it was backfiring into the intake, but would take off like a big ol' bird WOT.
Got it home, pulled codes KOEO - 172 and 173, O2 sensor rich AND lean, bank 1. Since there is only 1 HEGO in the system, how could it determine BANK 1????
KOER codes, 53 (tps voltage high = WOT),63 (tps voltage too low), 85(cannister purge solenoid circuit failure) and 36, which my Actron or Mindreader books don't even LIST.
Hooked my jumpers back in to the TPS wiring, 5.07v feed, .92v return @ idle -well within range.
Battery disconnected right now. I hate having to re-program my radio!
Any thoughts???

 

You've got to have a broken wire or short somewhere in the TPS wiring. Check the connector for corrosion, and trace back as much of the wiring as you can. The passenger side is tough to follow because of the upper intake, but see if there's anything obvious. The wiring harness runs along the side of the valve cover facing the intake. Also re-check the connector at the EEC for contamination or loose wires.

 

i forgot:

to add signature go to: user cp top of page on left and look in the column on left for add signature.

put in what you want.

i see you like lincolns, me to. which years?