95 F150 302 5.0 4x4 stalling issues
 

Hello everyone, my name is John and I am having issues with my F150. It all started like 4 or 5 months ago when I was pulling into my parking spot and my truck died, it started right back up and I thought nothing of it. Soon after that it seemed to stall a few more times while parking it, so I decided to start some maintenance on it and I removed the throttle body to clean it. It was pretty nasty in there and the egr and iac ports were completely caked over. After the cleaning I decided to pull the codes since there was already a cel light when I bought it, the codes pointed to the egr and the iac(surprise, surprise) so I cleaned them up and put them back on with no change in performance so now begins my part swap experiment. What I have done so far is: new battery, sparkplugs and wires, dist cap and rotor, fuel filter, tps, egr valve, iac valve, canister purge solenoid valve, ect sensor, ignition coil, and o2 sensor. At the present time I am going through a random stall at anytime meaning cold starts, warm starts, at idle or while driving. At idle what happens is the idle will start to drop and the engine will fight it and the engine will die and come back with a surge of power and repeat until it fully stalls out. While driving when the episode starts the truck acts like it is running out of gas and bucks if I give it gas at all so I have to pull over and turn it off, it starts right back up without a prob and then it's good to go. In either case, after the episode it starts right back up and runs perfect until it sits for a few hours and then it does it again. I checked the fuel pressure and it is all within the specs, pressure running: 31psi running with vacuum off fpr: 38psi returned back to 31psi when reconnected after engine shut down pressure slowly raised to 40psi. Tested it twice with the same results. The codes that I pulled just before the new o2 and ect sensors were:KOEO 565 172 334 KOER 411 225 but I plan on pulling the codes once again to see if any change since the last repairs. Any thoughts or advice on where to go next, I have checked for vacuum leaks because of the 411 but did not find any.

My truck still randomly acts up and I re-pulled the codes after the last repairs and what I am getting now is KOEO- 565, 172 and KOER- 411, 225. All 4 codes are current codes and any help at all would be greatly appreciated at this point.

KOEO Code 172= HEGO sensor circuit indicates system lean
KOEO Code 565= Canister purge circuit failure. verify the Canister Purge (CANP) solenoid is electrically connected. Since you already replaced it there may be an open wire between it and the PCM.

KOER Code 225 = Knock Sensor (KS) signal not sensed during dynamic response test. Typically operator induced, you did not floor the throttle enough to trigger the knock sensor to activate. Also could be a faulty or missing knock sensor.

KOER Code 411 = Cannot control rpm during KOER low RPM check. This is a key clue, along with code 172 that you may have a vacuum leak (what is the warm idle RPM?). You stated you already replaced the IAC, which is another common cause of this error and stalling.

It might be worth it to spend a few minutes to remove the PCM and look for problems.

Here's a little something for you to read:A9x ECM's (and same years ECM's) Failures Due to Age

And note in the article, "It started giving some problems starting up, engine flooding, random hesitation, missing and stalls."


Bob

Unfortunately the dash does not display the rpms, but from personal experience I would estimate that the warm idle is above 1000 rpms. Cold idle sounds like mid open throttle, and there is a delayed idle kick down even while driving. While idling, if I rev the engine the rpms will decrease steadily to a higher than usual idle and stay there for a few seconds and then kick down real quick, which happens every time I rev it. While driving, if I am coming to a full stop, as soon as the truck is fully stopped it also momentarily rests at a higher than usual idle and then kicks down suddenly to a lower idle, every stop sign/ light it does this. The other day it did something new which is while driving to work, my check engine light came on and immediately I noticed the power drop off and it would not accelerate over 50 even with the pedal to the floor. I could slow down and re-accelerate to 50 but no faster until I pulled over and restarted the truck and then it ran perfectly fine, I was able to accelerate to 70 with no problem.

Thank you for the article, that would be awesome if I just needed to solder a few new capacitors onto the pcm circuit board, I'm currently working on a electronic engineering degree so this is more in the realm of my expertise. As soon as it stops snowing/raining around here, I will examine the pcm for faulty components.

Ahhhhhhhh.........

So I guess you're rather familiar with electrolitic capacitors leaking due to age !!!!!!

Keep us posted !!!

Bob

So it turns out the intermittent stalling/bucking it was doing was the ignition control module. I took it to autozone and tested it and it passed the first 3 tests and failed the 4th test, passed the 5th and failed the 6th time. Then I tested the new one and it passed all 6 tests. Now I just have to find the source of the 411 high idle and where the break in the canister purge solenoid circuit everything will be working properly. I still am going to pull the pcm and have a look inside and possibly swap out the caps.

Looks like you are knocking these out one at a time! Thanks for replying back.

Well I hope the ignition control module they sold you was Black in color.
If it was Gray in color it was the wrong one.
Your truck and computer is not wired to operate a Gray ignition control module.
Also the program in the computer is not the right one for a Gray ignition control module.

False alarm everyone, my truck ran awesome after the new icm was put in for like 2 days and then it started acting up just like before so I guess it's back to the drawing board. And yeah I made sure to get the black icm and not the grey. By the end of this I'm going to have a brand new truck, which was the the original plan, but not at this rate. It was supposed to be a gradual project. It could be worse I suppose, I started working at autozone right before the bulk of the repairs I've done and man I'm loving the 20% employee discount.

:eek: An autozone employee, that knows how to pull codes on one of these trucks!?

But, really it sounds like you got a bad computer. The longer you run it with it acting up the worse things are going to get, and more likely damage could come to the board...

Case in-point That there is limp mode, of the worst kind. I don't recall reading if you stated if you have a auto, or manual trans; if you have a auto, I bet it felt like it was ether in 2nd gear, or 4th didn't it?

Have you ever, prior to starting the truck, heard the fuel pumps just run none stop?

The trans is an auto e4od, and no so far I have never heard the fuel pump run continuously. I am going to pull the pcm and have a look inside to see if anything looks visually damaged. Plus to add to everything, today I noticed that the water pump has a slow leak so I'm going to have to take a look at that as well. The funny thing is that my buddy said the idler pulley is making a noise and he suggested that I replace that, the belt tensioner, and the belt so I am already going to be down there so I guess I'll take a look at that while I'm at it. I'm just surprised that it is not throwing any other codes, the cel light comes on when it starts to happen but nothing gets stored.

Another sign something is amiss with the PCM or KAM circuit.

Well, I'm am not having any luck yet on my search for the problem. I pulled the pcm and there was no visual damage to any component on the board, no leaking capacitors, or a single lead out of place. Didn't have the usual smell that comes from burnt components. I did how ever notice no change at all in the idle when the iac valve wire harness was disconnected, I unplugged it multiple times and no change at all. The book says that the voltage that should be present at the iac is approximately 10.5 volts, and I am getting 12.4 volts. The resistance between the 2 terminals while unplugged on the valve is supposed to be between 7 and 13 ohms, which it is at 9.3 ohms. I'm not sure if the 12.4 volts is too high because they don't give the high and low end range of the voltage. One thing that I will note is that when I replaced the tps a while back, it would only fit a certain way and then it had to be slightly rotated so that the screw holes on the sensor would line up with the ones on the throttle body. I'm Going to finish testing the voltage on the tps once it stops raining, there is 5 volts present in the green wire, but then it started raining. Does any of this sound off or does this sound correct.