I have a '97 F350 7.3 powerstroke that cut off driving down the road back in May. Didn't sputter, just cut off and wouldn't crank back. Tach moved, WTS light functioned as normal. Hoped it was just the CPS, even though it didn't seem like it. Replaced it and didn't solve anything. Trailered the truck and took it by a guy with a shop. He ran codes and got hits on exhaust backpressure sensors, fuel pressure relief, and the IPR valve. Replaced the IPR and no change. Tried a buzz test, it failed and got codes P1298, P1293, P1294. Swapped IDMs with another 7.3 we have and it cranked right up.

Ordered a new IDM for it, installed it and ran the truck for ~60 miles with no problem. Parked the truck for 2 or 3 days and then it wouldn't crank again. Swapped IDMs again and the truck cranked. Out of curiosity tried the theoretically bad IDM in the other truck and it cranked fine as well. Swapped them back and no crank. Initially coded P1219 CID Low, P1298 IDM failure, P0472 EPS low, P0603 KAM error, P0470 EPS. Cleared codes, ran injector test, tried cranking and coded P0344 CPS intermittent, P1280 ICM out of range. Changed EPS and cleaned out tube, cleared codes and gave a system pass. Tried cranking, no go. Still no codes popping.

Shook wiring harnesses for EPS, IDM. Cranked at 180rpm, idled at 790rpm. Coded P1280 Injection cotrol pressure out of range low. CEL light on. Truck ran for 5mins and cut off. Wouldn't restart. Gave P1111 system pass. Came back little while later and it was reading code for P0344 CPS Sensor circuit intermittent and P1230 Injection control pressure out of range low. No crank. shook wires for ECU, IDM, CPS and it cranked. Ran for 15 minutes, would idle roughly on occasion after revving the engine. Moved truck to shade, ran for another 5 mins and truck just cut off. Would not recrank.
Cleaned connection at ICP, checked voltage on pin A to B, and C to ground at 5V. IPR voltage at 11.97. Cleaned and checked IPR connection, looked over wires. Plugged back in and no crank.

At this point we are figuring it's electrical, but ??? Any ideas on narrowing it down further? Or am I completely off base? Thankful for any help yall can give. Thanks, Also apologies for the giant font, can;t figure out how to change it.

 

Was wondering about that. But not a problem by me, cause it helps me old tired eyes to see better! So thanks for whatever mistake got us there.

I'm not really going to be much help (if any) but am curious to make sure we're talking about the same thing. When you say it "won't crank" do you mean the starter will not crank the engine? Or the starter cranks all day long, but you get no joy and the engine won't start? If not cranking, do you still get clicks from the starter relay, or nothing at all?
Just making sure, since being on the same page in that one regard could make all the difference.

Thanks. And good luck.

Paul

 

When you see multiple sensor or actuator failures like that, it usually points to a bad splice, bad ground or a failing PCM.

 

Sorry for the confusion. Its a no start situation. Starter turns over with plenty of kick, batteries are charged. It cranked and ran several times today, and then wouldn't start again. I have a cheap OBDII reader and it has the injector pressure reading at 7MPa (1010psi) that goes up to 11.4MPa (1600psi) at 2200rpm. Is that an inaccurate reading? I thought it wouldn't run below 1600psi? Would a bad IPR or bad connection cause a low reading?

Since I have three other 7.3s, should I just swap PCMs and see if that changes anything/rules it out? Or do the PCMs need to be calibrated for each vehicle specifically? Any other method to check the PCM?
Thank you for any help you can offer. I'm pulling out my hair

 

https://www.ford-trucks.com/forums/1...ostic-faq.html


Get the No Start Flowchart from the FAQ page over at the powerstroke forum. Work your way through it. There are links in the chart to follow but it is good to print it too so you can make notes on it and such. You need to check your fuel pressure at some point on the chart and will need a gauge for that. Tire pressure gauge will work if you don't have a fuel pressure gauge. There are lots of no start threads you can read over on the powerstroke forum.

I'll read your first post when I get time.

See if your scanner will read RPM, ICP, IPR, Volts 12v, Volts 5v and CPS sync.

 

Glad I asked about the cranking then!

Seems like if it died while running initially, then it's got to be fuel. Correct? Don't the diesels pretty much not have anything electrical that can kill a running engine? Or is that just the old days? I remember the first diesel I drove needing to have the manual fuel cutoff **** pushed to kill the engine!
Computers probably changed all that.

Also doesn't the 7.3 have fuel pressure trouble if the oil-pump fuel pressurizer thingy is leaking oil? Or is low pressure just a fuel pump or filter thing?
I remember helping a buddy work on some contraption on top of the engine and under a lot of other crap... uh, I mean stuff, that was leaking oil but involved the fuel pressure.
I don't remember his engine dying from the issue, just more of a taking care of an oil leak issue. But since it had to do with fuel pressures I thought I'd mention it in case it was relevant.

Sorry for just throwing haphazard thoughts out there with no real diesel knowledge to back it up.
I'll try to just sit quietly over here in the corner now. Attempt to listen and learn...

Paul

 

Your terminology has me confused.

You say "no crank". Does that means it turns over and will not start? Or does that mean that it will not turn over?
Because an IDM has absolutely NOTHING to do wit the engine turning over

 

Yep, cranking is what the starter does. But he did clear that up yesterday. Sounds like the starter and batteries and switch and all are working properly, as the starter is turning the engine over easily. It just won't fire up/start.

Is it correct that an electrical glitch won't kill a running diesel? Or are there circuits on a modern (or semi-modern as the case may be) truck that can shut off the fuel or do some other mischief along the way?

Thanks

Paul

 

Oh, an electrical glitch will certainly kill a powerstroke, they are run electrically.

From the IPR, to the CPS, IDM, ECM, IPC, all have their hand in electrically controlling the engine.

Then there is the High pressure oil system

The mechanical parts...
fuel system....

etc

 

Gotcha. Thanks for bringing me into a newer decade!

Paul