97 F250 cylinder contribution

RyanG · June 9, 2016

Customer had this truck at independent, engine was removed for an oil pan. Its an old farm truck, manual transmission. Says has no power, found map sensor hose hanging off, replaced that and drove. Truck does feel sluggish, its hard to tell being as old as it is and a manual trans. Has ebp codes and plugged up sensor

and tube. Checked fuel pressure at regulator, have 60 psi at idle, it dropped to 25 at wot. Pulled apart regulator and found screens plugged up. Replaced regulator and now have 45 psi wot. Checked inlet restricton, less than 6 in. Truck starts ok but has blue/ white smoke when revving, ran cylinder contribution and flags 6 or even 7 cylinders, starts rolling blue/white smoke during contribution test. During test I also got a p003c solenoid 1-2 shift open/short and p0068 tp sensor a inconsistent with maf/map. If I run the test multiple times I will get a p00fa no description found and sometimes sets a p1000. Never seen this before, not really sure where to go. Swapped cam sensor, icp sensor was replaced, did a compression test and all cylinders are between 400 and 425 psi. At idle mfdes. is .17-.18 and ipr at 12.89%. Customer requested to have glow plugs replaced and ebp sensor replaced. Koer self -test will pass, sometimes truck dies and throws a p0603 power interrupt code. Never come across the codes during a contribution test, codes are not even listed in pc/ed. Anybody have any insight? Possible pcm issue?

lmorris · June 9, 2016

P0603 : Check power and grounds at PCM, if they are good you need a PCM. P003c is invalid, auto transmission codes for this are P07** and P17**. Given it's a manual transmission truck means you have an issue right there. PCM tuning is dependent on transmission type, there are differences. P0068 is a 6.7L code...the 7.3L never got anywhere even close to even caring about emissions. Something just ain't right with that whole scenario. Find a PCM for it. If you don't have PTS access, throw us the VIN and we can get you the tear tag for the correct PCM. Also the EBP issue will may cause a VREF issue, which usually causes a PCM reset with a stall/restarts condition or will cause a no start. Leave it unplugged till you get the funky codes issue fixed.

RyanG · June 9, 2016

Tear tag on pcm is MLE1, build data says MLE0. When viewing the pids it displays automatic transmission pids commanded gear, tss,

tcc etc. Wouldn't think those pids would be displayed in a manual trans. truck. Wondering if has junk yard pcm, truck has junk yard steering column from an automatic.

lmorris · June 9, 2016

I would have to say you have the wrong PCM in this thing.

Buddy_M · June 10, 2016

MLE code is a PCM for a manual transmission. I'm thinking maybe someone either reflashed it to the wrong code, or has a programmer or chip with wrong coding which could explain the 0603 also. I'd say try and do a blank path programming back to a MLE1 and see if it helps with the codes/datastream. Cant hurt to try for as little time it would take to rule out that possibility.

8WA Sman · June 10, 2016

When ever I think white smoke and low power on a 7.3L the word "gasoline" comes to mind. Farm truck also screams check fuel quality. Make sure PCM does not have a chip hanging on the circuit board. Usually if the V Ref is being pulled low the CEL will not come on during bulb check.

lmorris · June 10, 2016

Come to think of it, other than the indy shop doing the oil pan, can you find out more history on this truck. Someone had to mess with the PCM at some point, question is when and why is he now complaining about it. It could be a possibility that the funky programming has absolutely nothing to do with the complaint and more so fuel quality, like 8WA Sman suggests.

RyanG · June 12, 2016

Haven't had time to look at(just had a baby, taking some time off). The vref issue does sound like possibility. I forgot to mention when the truck occasionally dies after contribution test, it will not restart unless i cycle the key.

Bruce Amacker · June 12, 2016

A BS way to check PCM grounds on that truck is to look at the case ground pid, it compares PCM and FP ground levels, should read 0.00v.

In addition to the other issues it's starving for fuel, MFDES is considerably elevated, showing it's starving for fuel, has bad injectors or low compression. Fuel command is way too high, it should be 12-13 tops at hot idle. Probably needs injectors, a wise tech would do a compression test at the same time to CYA. Pull the FF lid, suck the fuel from the housing, and fill it with Stanadyne Performance Formula or another lubricity additive (Motorcraft). Put the lid back on and immediately run/drive it, if it runs better it shows the barrels and plungers are sticking. I have screen caps showing 1.27ms FPW at idle on a '97 with VFDES at 15.1mm3 on a known good truck.

Where are you in Ohio? I have a good '99 PCM, not sure if I have a '97 or not. I think they're wired differently.

Matt Saunoras · June 12, 2016

Are you using a VCM II to scan it? Maybe the truck is too old and some of the code is getting messed up causing bizarre DTCs?

8WA Sman · June 13, 2016

Are you using a VCM II to scan it? Maybe the truck is too old and some of the code is getting messed up causing bizarre DTCs?

I was also wondering about this. Then I got to thinking we had to reflash some of the early PSD to get the dash connector to work so I went and looked and it appears it was the 94/95 PSD that I was thinking about. Swap the PCM power relay with another relay & see if it still dies, next time it dies see if the CEL is on.

8WA Sman · June 13, 2016

Haven't had time to look at(just had a baby, taking some time off). The vref issue does sound like possibility. I forgot to mention when the truck occasionally dies after contribution test, it will not restart unless i cycle the key.

Congrats on the baby :rockon:

RyanG · June 20, 2016

Well, pulled the pcm and found a banks ottomind chip in the back. Removed it and drove the truck, truck has decent power but still sets, odd contribution test faults. Going to see if pcm can be tested and repaired.

RyanG · June 20, 2016

Can the chip actually damage the pcm?

lmorris · June 21, 2016

Those are piggy back chips, I am pretty sure all they do is override the stock programming. The only issue I have ever seen is when they come loose and cause the issues, never had one actually damage a PCM. Try to reprogram the PCM, maybe the software is corrupt.

RyanG · June 21, 2016

Did rotunda ever make a 7.3 injector kill box?

8WA Sman · June 22, 2016

They can crack the circuit board from the weight of the chip/bouncing around.

Can the chip actually damage the pcm?

Keith Browning · July 3, 2016

I have also seen the circuit board damaged by over aggressive cleaning of the coating where the chip plugs in. Also have seen corrosion failures because the opening in the rear of the PCM is now open with the ship installed... add a water leak to the scenario and... you know.