According to the Haynes manual my Throttle Position Sensor (1995 F-150 4.9L 5 speed) should have 3.0-4.0K ohms when closed and @ 350 ohms when full open. This is checked between the ground (Return) and the TPS Signal connections on the sensor with the connector unplugged. I seem to be getting about the opposite? On the volt meter's 20k scale, I get 00.87 ohms closed and 03.70 ohms open. Isn't this 870 ohms closed and 3,700 ohms open? To compound my confusion I have a Mustang intake laying around with a TPS on it and it reads just about the same!?!? Is the Haynes manual backwards, am I reading the voltmeter correctly or is my TPS bad? Thanks

Oh yeah TPS voltage ranges are spot on.

 

Why are you setting the OHMmeter to the 20k scale?

 

Because the 2k scale (next smaller scale) is to small for the 3-4k measurement I am looking for.

 

when you put your volt meter in the 20k position it says 0.87kohms wich is the same as 870ohms. same as for your 3.7 kohms. wich is 3700ohms.
if not wright might be easier with a picture and the specs of your volt meter

 

Voltmeters don't measure ohms - ohmmeters (or multimeters) do.

 

It is a multimeter. Has anybody tested TPS resistance and had the opposite readings, as the Haynes manual calls for.

 

Have you looked at a different manual to see what it says? It wouldn't be the first time Haynes screwed something up.

 

Forget resistance - resistance is futile! Ford specifies voltage:

 

I guess I was just hoping that I had found an issue. My truck has a barely rough idle and intermittently falls on its face when I take off in first gear. Literally falls on its face, it hesitates so bad sometime that it feels like just the front brake are being applied! I have done hours of searches on forums and hours of trouble shooting. I was really excited when I found a bad canister purge solenoid and no fuel pressure increase with the vac line removed. Replaced both of them and all I gained was new parts.
I have done:
-new plugs, wires, rotor and cap
-new Idle air control valve
-new fuel pressure regulator
-tested fuel pressure
-pressure tested all vac lines
-tested the TPS, MAP, coolant temp sensor, IAT sensor,
-EGR restriction installed
-Tested the EGR valve, EVP sensor and EGR vacuum solenoid
-Replaced throttle body gasket and upper intake gasket
-Pulled codes (no codes)
-Tested coil resistance
-Tested ICM ground
-Check for frayed wires near the ICM and spout splice per the TSB
If I blindly throw parts at the problem, I am leaning towards:
-fuel pump (mine is very loud). Even though my high rpm, under load drive-ability is great and an on the way out fuel pump usually acts up when they are working harder than just taking off in first gear.
-The Ignition control module, just because I am reading that it is so heat sensitive that it should be put on a regularly scheduled, mileage determined replacement cycle.
-The distributor PIP sensor, just because it is cheap.

The only other Haynes manual check that failed was the Ignition coil primary circuit continuity check. When I check from the coil connector neg side (TACH) to ground I get 7,100 ohms and Haynes says that it must be greater than 10,000 ohms. So it says I should check for a short in the harness. 7,100 is really close and as I am finding out, Haynes numbers are not spot on. I really don't know if this test failure should be perused?? Did I miss anything that would cause my problem?

Oh yeah I have not had a professional fuel injector cleaning yet. I am saving that as a last resort because a good cleaning is expensive. I have run in tank fuel system treatment. Thanks

 

Go to "User CP" at the top of the page & put your truck's specs in a signature so they appear with every post. You can omit "F150" and "19.." since we assume that. But put the year, engine size, transmission model, trim level, cab/bed configuration & wheelbase, transfer case model (if 4WD), gear ratio, tire size, miles (or KMs), mods, maintenance, damage, repairs, etc. If you don't know all the truck's details, read this caption & follow the links in it:



If there are any terms you don't understand, read this: Automotive Terms & Abbreviations

The CANP is hardly ever used, and has no impact on driveability. Read this for fuel pressure specs, and leave the gauge attached while driving so you can see it:



What does "pressure tested all vac lines" mean? You didn't apply air pressure to the vacuum system, did you? How much pressure? Did you disconnect everything & ONLY pressurize the lines?

How exactly did you test the MAP, and what was the result?

Undo whatever you did to the EGR so it works as designed.

What does "no codes" mean? Even with no faults, you should still get a code or 2.

Don't throw part$ at it - it's the slowest & mo$t-expen$ive way to fix it.

No, the ICM isn't on the maintenance schedule because it doesn't need to be. You're confusing it with the pre-'92 distributor-mounted ICM.

The PIP itself is cheap, but installing it involves disassembling the distributor, and then you have almost no warranty. To get a warranty, you have to buy a reman dist, which bumps the price up to ~$90, so it's not cheap. And if it was going bad, you'd have much more severe symptoms, and the Haynes test would have ID'ed it.

The Haynes numbers are correct, but that's the wrong procedure for your truck. They didn't revise the manual after 1992, so your CCD system isn't covered. Read this caption and don't overlook the plug wire spec:



If the plug wires fail, read these:



Don't worry about the injectors - there's nothing wrong with them.

 

-I removed each vac line/hose and vacuum tested it.
-The MAP is a RPM frequency type so Haynes said I should have 310 rpms at closed throttle and 200 at WOT. I was pretty close to those numbers (yes my multimeter does rpms).
-I guess I could remove the EGR restriction. I don't think it did much any ways.
-I did get a 522 code because I did not hold in the clutch during the test but then I got the 111 system pass code. (KOEO & KOER). I could not get it to go into the cylinder balance test? I did a quick WOT within two minutes of the last code during a KOER and waited ten minutes. Nothing ever happened?
-What is a CCD system?
-What do you think about the Ignition coil primary circuit continuity check numbers?

Two other systems are intermittent long start. It usually starts within three turn overs. Every so often it can take 5-10. BUT it always starts the first time I turn the, just the amount of time that it turns over while I am holding it will vary.
Also A slight diesel on shut down. Very slight, basically if I shut the truck off in gear I will have the clutch in, turn the key to off/pull it out, if I don't pause before I let out the clutch the clutch will grab because the engine is still moving. If I pause for 1.5sec before I let out the clutch, its fine. I don't know, maybe these older engine take a little longer to come to a stop?

I am reading your plug wire caption now. Thanks

 

OK I read the entire article and I now know what CCD is and I have two failures (that I have previously tested) per the articles procedure. AA28: Is my Ignition coil primary circuit continuity check and it says that it should be greater than 10k ohms, I have 7,100 ohms. AA30: TFI (ICM) Ground check: (NOW more confusion!!!) The Haynes manual says that if the resistance is less than 5 ohms, the circuit is OK. This procedure (which I guess is accurate for my year truck) says if the resistance is less than 5 ohms, replace ICM (TFI).

Now a bad ICM might be causing the low resistance in my coil primary check!! Wow I might have actually found a legitimate problem. Again unless one or both of the procedures are wrong. It is very subtle how they could easily be incorrect, with a swapped greater than for a less than or a yes for a no!!!

How confident are you in these checks?

I am going to do AA29 to back up the possibility of a problem in the coil to ICM circuit. It is the same as AA28 but with voltage instead of ohms.

 

Ignore Haynes ignition procedure - it doesn't apply to your truck. The coil should have been tested while DISconnected, so the ICM couldn't affect that test.

Any time you read that a circuit test should show >10KOhm, that means open circuit - the same reading as if you don't connect the probes to the meter. If you get any other reading, it means there's some connection between the 2 circuits (either a short or resistance). If you didn't disconnect things when the instructions said to, that would give a false fault.

Your description of long crank is actually normal. Long crank is more like 5sec of cranking before the engine even coughs or sputters.

EFI engines can't diesel (actually run-on, in this case) because the injectors don't open with the key OFF. Your engine might spin extra-long if it has poor compression, but I suspect it's normal spin-down time, and nothing to worry about.

 

The Haynes manual does say to disconnect the ICM connector and coil connector when checking the coil connector negative to ground for >10k ohms. I will make sure I did disconnect the ICM and I will recheck it. But you agree if the ICM is disconnected and I get 7,100k ohms, then I have a problem?

With 10k meaning open, then if I set my multimeter to an audible ohms setting, should I get a noise or not?

What about the major differences in the ICM ground check? The Haynes manual says that if the resistance is less than 5 ohms, the circuit is OK. This procedure (which I guess is accurate for my year truck) says if the resistance is less than 5 ohms, replace ICM (TFI). This test is disconnecting the ICM connector and checking resistance between the connector ground pin (6) and a ground on the distributor.

I have 1 ohm during this check.

Thank for all of the info

 

I just did every check in your article AA1 - AA31 and everything passed. As long as open in the audible setting means NO noise? Next are the fuel pressure checks and a compression check. Thanks for the help