My '96 f350 started stalling when i would come to a stop. i ran the scanner for the DTCs. I got multiple codes: codes related to TPS, CMP, and po236.

i took out the TPS and cleaned it. no new codes related to this. i put in a new CMP, but i still continue to get code po344, and the truck continues to stall when coming to a stop. i replaced the MAP. what is interesting, there is the port for a vacuum hose but there is no vacuum hose. where does the other end plug into? also, i have had previous bouts where the computer is throwing po603 and another one related to the PCM. since i put in the new MAP, im not getting the PCM codes.

if somebody could assist me with the vacuum line, i would be greatful. moreover, if anyone has any suggestions regarding the stalling, i would appreciate some input. i really hate the idea of having to take this truck to either the incompetent dealer or some jacked up mechanic who only wants a bunch of money.

thanks.
paul
1996 ford f350 7.3L psd.

 

Welcome to fte Paul.

As for the map line, it goes to the passengers side of the motor by the intake plenum. You need that.

On the stalling, where did you get cam sensor? Parts store ones have been known to be bad right out of the box. Ford or IH should be the only ones used, and then a spare should be carried with you at all times also. You could check over the wiring harness real good leading to the cam sensor too. Over time, chafing of the wires happens. I just changed all my wires to the sensor a couple weeks ago as I kept setting that code after a new IH sensor. Found one of them had some pretty good chafing on it.

Do a wiggle test of the wiring harness while its running and see if it stalls. Does it only stall when coming up to a stop sign and does it do it all the time? Does it always start back up right away?

 

first, thank you for the welcome!

i bought the CMP from autozone. as for the stalling, when driving down the road, it will bog down. when that happens, i just press the accelerator forcing it to downshift and then it goes away. before i replaced the MAP, it would take about 5 minutes before i could restart the truck. now, it will restart in less time up to that 5 minutes or so.

 

Get that map line on, check over the wiring good, and if you can get a ford or ih cps first. See how that is, also you can check the fuel pressure at the schrader valve on the drivers side of the fuel bowl on the regulator. You can just use a cheap stick style tire gauge.

How recent of fuel filter change?
Have you cleaned the little screen in the fuel bowl on the drivers side down about an inch?
How recent of an oil change and what oil is used?

Some of these are pretty basic questions I know, but when answered can help diagnose your problem.

 

i got the map line on. the turbo related codes are resolved.

i havent checked the fuel pressure, but i certainly can. what is the normal fuel pressure supposed to be? i think it is supposed to be around 35 or 40 psi. what i have done with the fuel filter, i have spun off the top cover and pulled out that basket filter gizno because from time to time i get the water in fuel light coming on. i was told by a guy who has a 94 roll along package that he cleans and drains out the water every time he changes the oil. my question regarding this: is there a separator or something that allows one to drain out the water? as a result of the water issue, i have been using diesel kleen, i think it is because it says it helps remove or displace water. i forget the actual verbage from the bottle.

as for the oil, i have maybe 3000 miles on the oil change. i bought the truck last september from as a repo from a place up in ut. i brought it back to ca and later changed the oil, as the oil was freshly changed when i got the truck. i use 15w40 motorcraft oil in it.

after resolving the map issue, i went out for a test drive to see if it was good. well, the po344 code showed again and now the truck doesn't start. i had to ask my wife to get my chevy to tow me home! i was looking on the net in different forums, as you were suggesting cmp's outside the dealer or IH are generally not good. so i found a part number from IH on another site so i will contact IH assuming i can get their contact info and order a new cmp. so, the only code now is hte po344.

i will look at the harness to see if the wires are a bit challenged or not! im done with it today. i sat an hour before i was rescued!

 

latest: i still keeping dying when i drive. but what is different now is that it doesnt take nearly as long to start; however, it takes more cranking time to get started. i checked the fuel pressure. the pressure is about 50 psi. the book said the pressure is supposed to be 40, as i suspected. so i think its safe to rule out the mechanical pump is dying. so, i looked closer at the fuel pump/engine valley because there is evidence of fluid there. couldnt tell if it was fuel, water, or what. i took out the fuel filter, which was super nasty. because of the fuel lines from the pump to the filter assembly was cracked, i pulled out hte whole fuel filter assembly. the crap inside was beyond my comprehension!!! there was also some water too. i need fuel lines and orings.

the saga continues!!!

 

Sounds like you're finding your problems. Bob @ dieselorings.com has an oring kit and new blue fuel lines for the fuel bowl/regulator. Clay at riffraff has them also. Keep us posted how it goes and turns out.

 

Also dont forget to clean the screen in the bowl as mentioned above.

 

well, i found the heating element was bad inside the filter assembly. so i am now waiting for the new one to come. i bought it from extreme diesel power for 375. ford wanted about 500 for it without the new regulator and water sensor - strictly just the case. i had a question in the beginning of jionging FTE: how do you get the water out of the filter / separator. i figured that out; the valve on the side was seized tehreby thwarting my ability to operate it and get the water out. i do think that ford could have come up with something better to get rid of the water; that is, the hose is just a couple of inches long and it drains on top of the engine. i think that is so ridiculous!

the fuel lines were toast! so i went to ford and bought the fuel lines because they are certainly more heavy duty than buying the fuel line stock from the local auto parts store.

i do have a question: somebody has suggested that there are filters or screens inside the tanks. is that true or is my truck new enough (march of 1996) that they stopped putting them inside the tank?

 

If your bowl is not in bad shape, as in it doesn't leak, you don't need the heating element so I'd cancel that order if you can. Most of us unplug that element from the fuel bowl anyway as it runs on the same fuse as the pcm and can cause issues. Besides that, you can buy a new heating element if that is all you want/need. If your bowl is leaking/rotted, it can be patched with some jb weld if not real bad.

Yes, you do have screens on the pickups in the tanks.

 

what happens with the pcm if the heater inside the filter assembly runs on that same circuit? where i live, we need that element because we get subzero weather; this truck is so hard to start when its cold. at times, it takes up to two hours to start it.

as for the fuel tank, i will drop my forward tank and check the screen. at this juncture, im confident that the issue(s) with my truck is related to fuel delivery.

as for the fuel filter assembly, i will keep your suggestion under advisement.

 

Subscribed....just watching/lurking here. LOL

 

Dont use worm type clamps on the fuel lines.i use clamps for fuel injection.most good parts stores have them.

 

Is it possibly to use braided lines in there? Just thinking.

On edit: using AN fittings instead of clamps.

 

If your truck is that hard to start when cold, you have other problems too. Have you tested the glow plugs and relay to make sure everything is working there?

Nothing will happen to the pcm besides the fuse blowing if the fuel bowl heater shorts out. Fuse 22 under the hood.