Anyone have testing specs on T.P.S, I.A.T., and coolant temp sensors?

 

Oldfuelinjection.com is a good resource.

 

Article speaks of an adjustment of the TPS in relation to initial setting of throttle stop. Problem: What is the initial throttle stop adjustment. No-one seems to have this info. It had to have a starting point when assembled at factory. I can find specs for GM and Chrysler feed-back carbs. but not Ford. Have any info on this?

 

I set mine by warming it up, unplugging the IAC and then setting it to run at ~600-650rpm warm. Then hook the IAC back up and check the TPS again. The base idle is NOT supposed ever be touched on these motors, that's why it's not listed.

 

But what happens if it has been adjusted? It has a screw on it; so, therefore, it can be adjusted. I'm not the only one who has worked on this truck.

 

Another problem: While trying to check TPS (voltage between voltage reference and signal return), I could only get .02 volts at WOT. What should the voltage input be at the TPS? I'm assuming 5 volts. Also, are there bench test specs on the TPS?

 

TPS stuff from the Ford book on my Photobucket albums:

TPS stuff from 1986 Ford Engine-Emissions Diags Photos by ctubutis | Photobucket

You will need to read from the last picture to the first, haven't figured out how to re-order the things.

 

Thanks again.
On page 21-57 at the bottom of page is a step that I need. It says if voltage is less than 4v or greater than 6v go to pinpoint test step C1 . Do you have that (C1)?
Also hate to keep bothering someone for info on this. Vehicle is becoming so frustrating. Currently testing all sensors and have done a thorough inspection of wiring harness. Going to check everything before installing new ECU.
Have discrepancy: two sources of info (Mitchell's and Ford FI.com) state that this vehicle has a heated O2 sensor (HEGO). This one doesn't. Any input on this?

 

OK, go look at what are now the first 7 images in that photobucket album but, once again, read from right to left.

You are interested in C0 thru C6, and C4, 5 and 6 are actually from B.

For Hutch Photos by ctubutis | Photobucket

Given the problems you're having and what you're doing, I'm hoping you'll go buy your own book sometime real soon now.

My 1986 DD Tempo doesn't have a heated sensor, and I seem to recall Ford didn't start using heated sensors until sometime in the early 90s but of course that's just my memory and I very well could be wrong. My brother's 1993 Taurus SHO 3.0L has two HEGOs.

BUT... I just looked in the Fuel Control section for EFI (in this book) and only found reference to EGO, not HEGO. So, perhaps the aftermarket stuff is wrong. Just go look at your own 02 sensor and count how many wires are on it... in my experience, 1 or 2 wires = EGO, 3 = HEGO.

 

85 and 86 5.0 EFI engines have the O2 sensor in the rear of the right exhaust manifold and it is a one wire unheated sensor. I think 87 is the start of Ford using heated sensors. There is a minimum airflow adjustment on the later systems, on yours, the adjustment is to get the TPS to .9-1.1 volt at closed throttle. 1.0 is what you really need for that early system to behave. It should go to right at 5 volts at WOT, if it doesn't it's probably bad.

First and most important do not use anything other than a Motorcraft TPS, if you don't believe me ask Archion, his 86 kicked our butts for over a year due to an aftermarket TPS. To really check one you need an analog meter and a breakout box.

 

Thanks for the info. I know I have a 1 wire non heated O2 sensor and also know they are the most primitive design--relying on engine ground to complete the circuit.
Gripe I have is all the conflicting and erroneous info I've obtained from repair manuals and other sources. Two sources say the 85 has heated O2 sensor. Could not find a correct wiring diagram for this truck. One source says to set TPS at .6v-1.0v, another says .9v-1.1v and on and on.
At full throttle (stop screw backed off with plates closed) TPS voltage is .88v, WOT is about .489v-.492v. Adjusted screw until I got .92v. Starts and idles OK. Haven't test drove it yet.
This is not my vehicle. Belongs to a relative and I'm trying to fix something 2 shops failed to do. So I'm not willing to purchase break-out boxes and other expensive equipment. Just have to improvise.
Thanks for all the info. If I have any driveablity problems, I'll kick voltage at TPS up to 1.0v. May have to experiment to get it right.

 

A breakout box makes it easier to test continuity & resistance in harness wires but it's not always needed, those pins are numbered the same. I don't have one but I sometimes wish I did.

 

Hutch, I assume you are measuring it at the correct lead? It should probably be a dark green with light green tracer wire. I don't have the 85, but do have the 86 EFI wiring on my website. Go there, on the left side you will see "downloads and links" the downloads will have a red "NEW" beside it since I added some files recently. Look for the "86 Ford EFI" those are scanned from my 86 EVTM. If that doesn't help you enough, I can get the 85 stuff from my Alldata.

If you are on the correct wire and only get .489-.492 volts (be sure if you have an autoranging meter it isn't 4.89-4.92 which is great) you probably need a TPS. Those are not fun to change on a 5.0/5.8L engine.

 

I'm not going by color codes. Color codes on this vehicle do not match any wiring diagram I can locate (Mitchell's, Alldata and other online help). I'm measuring voltage by location of pin. 85 has the round 3 pin connector. Instructions say to measure between TPS terminal & signal return. 3rd pin is VREF (voltage ref.).
I'm using an accurate auto digital multimeter. You need to be careful with analog meters, not all of them are computer safe.
TPS works smooth throughout the range. Vehicle has only 60K miles, so TPS should still be in good shape. Am going to test drive for a few days before turning over to owner.
Proper test for most TPS units is to see if they function smooth, no jumping of meter through entire range of travel. Also, info I have obtained says test voltage at WOT is 4.538 with 5.0 only obtained on over travel. If the vehicle runs smooth and accerates OK, I'm going to call it good. So far it seems OK.
Yes, a lot of components on that vehicle are in hard to reach places. Easy way to remove TPS is to remove the throttle=body. May have to replace gasket though.
Really have appreciated all the help. Would have had to give up a long time ago. Just hope that his is the end.

 

Well, since you obviously already know everything, I won't clutter this thread any more with an attempt to help.