95 7.3 with gremlin problem

[kevinwoo11]

Got a 95 one ton that died going down the road in july. Running down the road it just quit wouldnt restart after getting some time to work on it truck has no codes. Now the truck will fire up and then die. Then trying to restart it it would not start until you cycled the key then would start and died. Checked all the fuses and relays all are good. Checked batteries they are good. Then truck fired up adn drove about 4 miles then died no check engine light. Pulled back home and checked codes none. Played with it some more had same results then truck fired up again stayed running drove anout 10 miles and then had no power could only go about 15 mph in 3rd gear. Thought it might be an ecm problem. Fired it up again tonight and truck ran good for about 10 miles then lost some power and then had check engine light. Had an icp code. Checked the duty cycle and at idle the duty cycle was at 55% unplugged icp and duty cycle dropped to 14% would a bad icp cause the truck not to start and kinda load up the heui system?

[tvmechanic21]

Have you checked your fuel pressure???? I had an electric fuel pump drive me slap crazy one time. It would run fine at start up but the further you drove it, the less the fuel pressure was. It would get down to an idle and go dead when you tried to rev it up.

[kevinwoo11]

I got a 95 with a mechanical fuel pump and the pressure is good when the engine is pegged and when it is at idle. Any other ideas? Cause I am drawing a big blank. The only thing that i can think of is that icp. What is the duty cycle supposed to be at idle do you know cause mine is at 55% and if i unplug the icp it drops to 14%.

[kanuck15]

sounds like a crappy PCM

[kevinwoo11]

Can i swap out a pcm with another one or are there certain ones that will only work, What I mean is can i swap out mine with any other 95 pcm or are there certain codes on mine that i have to match up?

[kanuck15]

just find a 1994.5 to 1997 pcm that has the same trans as yours and it will work. provided you dont have a 1997 California emissions truck cause those need special ones

[kevinwoo11]

ok before swappin out pcm's i changed icp's with a good one still had same result. The code that comes up is P1211 icp out of range. Swapped out pcm's and had the same result with the same code. It always happens when I acclelerate kinda hard gettin up to 70. Code P1211. On my scanner it gives me some trouble shooting steps and says to run the engine at WOT for 30 seconds and the icp reading should be lower than 1600 psi. So i did that and the icp reading was around 1300 - 1400 psi. And then it dont tell me any other steps to do since my pressures are ok. The only other thing that it tells me to that can cause that is low fuel pressure, wrong or bad oil, oil level incorrect, or bad or damaged hpop. I know that the oil level and oil is fine. The fuel pressure i am not sure about but can i drop a bb in between the spring and the spring retainer to up the fuel pressure to make sure that i am getting enough pressure. I just put a new lift pump on 3 months before the truck died the first time. What else could be causing this I am at a total loss.

[kevinwoo11]

Oh and it also says that there could be an internal high pressure oil leak in the system how do you test for that?

[kanuck15]

I'm stumped, maybe a wiring harness issue

[kevinwoo11]

You dont think it could be a hpop issue cause when i putt around town it doesnt throw a code but it throws a code when i get on it kinda hard to accelerate?????????