Good afternoon, let me start off by saying this is a great site and that I have followed some of the threads for awhile but until recently I have never had a need to join because I didn’t own a ford and technically I still don’t, nothing against ford I grew up with them and love them. My wife however recently became the proud owner of a 1997 F250 Heavy Duty BRIGHT RED 4X4 EXT cab, XLT Long bed with a 460 (167,000) and an E4OD (Rebuilt@165,000) to back it up. The truck has Federal emissions so it is equipped with an OBD1 ECM system instead of the OBD2.<O:p</O:p
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For 2 months the truck ran like a dream and then one day out of the blue after about 30 to 45min of running she started to sputter like she was running out of fuel. Now when we bought her the FWD tank fuel gauge did not work and my wife happened to be on that tank when she started to sputter I am in the NAVY and was underway at the time so without being able to physically look at the truck I just assumed that the fuel pump was going bad in that tank, told my wife (she's pretty decent with a wrench) to change out the fuel filter and just run it on the rear tank till I got home. Problem solved right? WRONG!!

After I returned home I was able to actually look at her truck and this is what I have found. The truck starts to stalls out after about 30 to 45 min form when she is first started, she does this on both tanks, she is not actually running out of fuel but instead running incredibly rich (if you mash the throttle down all 245 horses and 400 Ft/pounds of torque from that 460 comes to life), if you keep her RPM's up she stays running and runs smooth too but the minute her RPM's drop she's back to sputtering. If you keep her running long enough the sputtering goes away and she again runs like a champ. She flashes no codes and her check engine light only comes on when she starts to sputter and then that is only her sensors doing their job and telling us she is running rich.<O:p></O:p>
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I have since replaced the following in this order:<O:p></O:p>
1. Cap and rotor<O:p></O:p>
2. ECT (engine coolant temp sensor)<O:p></O:p>
3. Checked the FRV and rail pressure is around 40psi<O:p></O:p>
4. Checked the tank selector switch on the dash <O:p></O:p>
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Next on my list to look at/replace is:<O:p></O:p>
1. ACT sensor (bought it the same tie as the ECT)<O:p></O:p>
2. IAC idle air control valve<O:p></O:p>
3. MAP Manifold absolute pressure<O:p></O:p>
4. EGR valve and line<O:p></O:p>
And I plan to do it in this order unless I get some recommendations. <O:p></O:p>
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The truck does not have a diverter valve for the tank selector nor does it have a 3rd high pressure fuel pump under the driver side floor board, instead of these things it has what Ford calls a fuel module in the tank and these modules are just high pressure pumps with the tank level sending units built in to them, and as I stated before she sputters on both tanks so I don’t believe these to be the issue plus I don’t believe both pumps could go bad at the same time?.<O:p></O:p>
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I apologize for writing so much I just want to let anyone willing to help me know what is happening, what I've done so far and what I was planning to do. I really do not want to spend a ton of cash on these sensors if I don’t have to. My wife and I have talked about swapping the 460 out for a diesel if the it looks as if these sensors will be to expensive, I grew up with these trucks and turned a lot of wrenches on them but all of my trucks had 6.9 or 7.3 liter IDI diesels in them and I know the IDI’s and 5.9 Cummins like the back of my hand but this (computer controlled) 460 is completely foreign to me. However this is my wife’s truck she turns wrenches alongside of me on it and she pays for everything on it so she has the final say and right now she wants to give the 460 a chance so if anyone has any other suggestions please let them rip I am willing to try almost anything I figure if I can fix a multi million dollar gas turbine I can fix this. My wife REALLY loves this truck she too grew up with trucks like this and it is her dream truck and passed up the offer of a brand new truck to get it so any suggestions to help us out and get this fixed would be greatly appreciated. Thank you and have a good day.<O:p></O:p>
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before you throw any more parts in it, open up the pcm and visually inspect for any burn marks. my 94 lightning had the same symtoms and it was a burnt pcm. i had my dad follow behind me and when it would break up he said that it blew out black smoke sooooooo its just something to check.

 

ill take a stab at this and suggest this. When there is no spark or even intermitent spark the ECM will cut off the fuel injectors when the PIP signal goes wacko or quits. Its a safety thing the good ol ford boys developed. Being that your running rich it tells me your not burning all your fuel. I would take a hard look at the Distributor stator or TFI module. I could be wrong but its my .02 cents

BigLar

 

with mine i also replaced the tfi and the stator and nothing changed. check the pcm!!!! dont put any parts into it until you look at it!!!!! im telling you ill bet your going to find a burn mark.

 

Thay could be a possibility. If you do find out its the stator or TFI module make sure you put motorcraft parts in it!!

BigLar

 

Thanks a bunch guys for your suggestions, First this is for larrylass, I have heard about the PIP/TFI distributor problems but I put this diagnoses/parts on the back burner because from what I have researched this was supposed to only be an issue with the pre 1986 460's and that ford fixed it in 87, however I have read other threads involving newer trucks with this problem. I have not ruled it as the culpret though I just put other possible causes in front of it. Also what makes me still consider this as a possible cause is that I am Having a major issues with finding diagrams of sensor locations, wiring and so forth for this truck, it seems that this truck being a OBD1 truck and a 1997 stumps everyone up. Whenever I google or go to a parts house this thing always comes up as OBD2 or calif. emissions which none of these digrams work for me, so I have been using older stuff from the 1988-1992ish trucks and my thinking is well if Ford were using older/parts and tecnology for this truck then it is going to have the issues of the older truck heck I dont know. By the way does anyone know if this truck having OBD1 a rare case for 1997? it doesnt matter to me either way its just that it is becoming a real pain in the neck being kind of a throwback like it is.

Second this is for 92f-150 you might be on to something. When we purchased the truck the gentleman we bought it from was the 3rd owner, the first loved the truck and took care of it and babied it you can tell, the second owner was an idiot the guy put a set of aluminum lift blocks in the front to install bigger tires and then tried to reprogram the computer by himself and burned it up???? The third guy bought the truck for next to nothing and started putting cash back into it he got it running put a K&N air filter gave it a tune up and started it on a synthetic oil. He did say that to get the truck running he had to replace the computer with a remanufactured on from ford. The guy at the time was a mechanic at a local ford dealership and I really didnt think to question his integrity about this fact because like I said she ran great for 2 months no problem what so ever and I dont know my own tail from shinola when it comes to Ford F.I. gas engines so why question. Is it possible he put a faulty or cheap computer in it, or even the wrong computer all together and also I was wondering if it was the computer wouldnt it act up right away instead of after 45mins? all my years of dealing with other engines points this to be a sensor problem and that the computer is doing it's job and reacting the way it is due to bad info from a faulty sensor. Like I said Mechanical IDI ford/navistar diesels, Chevy's, Dodge's, Rolls Royce and General electric gas turbines are all I know Ford gas engines I have not a clue about. Thank you both for your suggestions I will definitely look at both of these ASAP.

 

Pre 1988 460 motors were carbed and didnt have a tfi-pip type distributor if im not mistaken. do a search on my name and check out some of the threads i asked help for. You may be able to pick something up from them. I know SUBFORD sent me about every wiring diagram known to man on my truck. Im sure youll find the solution to your problem by reading my threads. Be forewarned though they are a BOOK )

BigLar

 

Ford didn't use OBD II on the '96 or '97 heavy duty trucks. Heavy duty being a GVWR of 5800 pound or more. So to answer your question, no your truck is not rare in that aspect. I agree with both the gentelmen above. Take a look at the PCM for burn marks because it will only cost you time, so it can't hurt to look. It does sound like the PIP though. I had a '96 F250 heavy duty with a 5.8 that did the same thing only it would continue to get worse untill it wouldn't run at all and I replaced both the PIP and the TFI and she was cured. My two cents.

 

It does not sound like a bad PIP sensor.
It does not sound like you have read the codes either.
First before replacing anything run the EEC self-test.
If you do not know how to run the self-test go to this link:
Ford Fuel Injection How To Run a Self-Test
Make sure it has a Black in color ICM in the truck as most will replace it with the wrong color and they do not run well with a Gray ICM.

It does sound like your problem is with the MAP sensor or HO2S.

ICM:


MAP:


HO2S:


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I had the codes read by one of the mechanics at my Naval base hobby shop where I work on the truck at. The only code that showed up was due to the fact that we didnt shift it into gear when the code reader wanted us to and that was because we had the idle up to 2000 and there was no way I going to drop it into gear that high. I will definitely try this self test before I go any further and see what comes up. Also to my knowledge the truck passed Calif. emissions the same month we bought and I'm not 100% sure but I think it has a new 02 sensor if that is what H02S stands for and again excuse my ignorance ICM if that is the engines computer it does have a black colored one I have not had a chance to get the numbers off of it yet though. If after I run the self test and for some reason it doesnt give me any code I am going to take a peek at the computer for burn marks but hopefully it will just give me a code if not I will start from there again replacing parts starting with the MAP and H02S if needed. Thank you for the diagram and suggestions subford, larrylass and 92 f150 I at least have a direction to start in now. My ship gets underway this week but I will be in on friday and I plan on going over right away and trying some stuff I will let everone know how it turns out.

 

I do not know of anything in the OBD-I self-test that talks about dropping it into gear during the test.
No the ICM is not the computer. The ICM is screwed to the drivers fender and the computer is in the drivers kick panel area inside the cab but you get at it from under the hood. The Computer will be silver in color, non painted.
Yes the HO2S = the O2 sensor heated.
ICM = Ignition Control Module
computer = Powertrain Control Module (PCM): The module that controls the EEC system.


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subford thank you again for the diagrams, I saved them to my computer earlier but did not fully look at them, after I reviewed them I realized that if I had looked them first I would have answered my own questions about what ICM and H02S ment. I just got back on to let you know that I had figured it out saw that you had already replied and given me another diagram to help thank you. now I do not recall what color the ICM is because I have never thought to look at it didnt think it would be the issue but as I said when I get back friday I am going to check all this stuff before I move on to anything else.

 

The injectors will not fire without the PIP pulse train. He says that it will pick back up if he floors the throttle so the PIP could not be the problem.

 

Hey guys I'm back and I have some news but first I have to say thank you subford you could not have been more spot on with your diagnosis. I ran the self test and came up with the right numbers just the wrong sequence, so I finally just took it to a professinal to have it read and here is what I had.
126 = MAP/BP sensor out of self test range 1.4 to 1.6 volts.
212 = Loss of IDM input to EEC or SPOUT circuit grounded.
I checked the ICM and it is black so I am just going to replace it and check all the connections and ensure that I dont have a frayed or grounded wire anywhere and I am just going to replace the MAP sensor as well at the same time. I havnt had a chance to do much the last few days its been kind of wet here and with that thing called work added to it it just does'nt leave a whole lot of time. I will let get back on to let everyone know how it turns out but if for some reason these codes dont look right someone please let me know.

Thank you again
K8's ford