Powerstroke question

[redthies]

My 97 has started to act up in the past couple of weeks. I thought it was cold weather/glow plug related, but having changed those and the gasket/harnesses, I am now at a loss. The truck starts great, but it bogs when I am not on the throttle. It runs fine if I stomp on it, but sounds like it is going to starve if I let off. It runs like normal after 10-15 minutes, but the truck will intermittently shut off. Any thoughts?

My Ford mechanic friend is thinking injectors, but it seems electrical to me. Would cam position sensor cause these symptoms?

Thanks for the help!

 

[Betarocker]

Might get more help at powerstrokearmy dot com

I barely know enough to be dangerous about the 6.0L.

 

[redthies]

I spent some time on powerstroke nation, and signs of intelligence there lead to cam position sensor or maybe fuel pump dieing. I will change the cps, test fuel pressure and go from there.

 

[bftank]

did you check fuel lines in the intake valley for cracking? air in the fuel can do funky stuff too. check your high pressure lines too. i had one blow out on me do to rot.

 

[redthies]

I was just in there doing the glow plugs, and things were dry and clean. It had started acting up before that. I'll do the cps, and if it is not that, then I'll have a spare, and I'll get into fuel system stuff.

Maybe if it's big trouble, uncle Jesse and the Keebler elves will drop by and put a 12v in it for me:elkgrin:

 

[Rot Box]

IDI's will do that when the fuel filter needs replacing. Has the filter been changed recently? Have you verified fuel pressure from the lift pump? Not sure about the PSD but a lot of diesels will run with a failed fuel/lift pump but they give symptoms similar to what you mentioned.

 

[IdaSHO]

intermittent shut-off = Crank sensor (CPS)
This is a very common problem for the 7.3 Powerstroke. So much so, that Ford has introduced an updated version of the sensor.

It could also cause your bogging. But the tell-tale sign is random shut-offs. Like somebody turns the ignition key mid stroke. The engine will just shut off, and sometimes turn right back on!


Another possible is injector control pressure sensor (ICP)

It controls injector functions based upon oil pressure int he heads. These motors use hydraulic injectors.
This cold contribute to your bogging, but generally also shows up as a rough or surging idle.



Finally, is the exhaust making any strange noises when this happens?
You have an exhaust backpressure valve on the turbo that can stick.
It is designed to close when the motor is stone cold, to aide warm-ups. Will definitely cause a BOG, but never a stall.

 

[redthies]

The engine noise is definitely different when bogging, but it actually idles fine. It won't restart on its own when it shuts off. It just dies, which is kinda scary when steering and brakes go away in crazy snowstorms like we have been having. It does restart right away though. I replaced the fuel filter in mid sept. I initially thought about fuel gelling the first time it was bogging, but we have only seen a few degrees below freezing so far this year, so I'm doubtful of gelling.

I am going into the big city tomorrow, so I'll stop by a stealership and grab an updated cam pos sensor and start there. All this could be avoided by a simple lotto win, and the corresponding ability to have a second truck and live in a warmer climate...

 

[surlydiesel]

It sounds like your exhaust back pressure valve functioning normally in the cold and a faulty CPS. Once the truck is warmed, the EBPV will stop fluttering open and closed and the bogging will go away. There is also a sensor tube you can clean leading up to the valve, I forget exactly where that is. I wired up my EBPV to function as a cheap exhaust brake. You can also unplug it so it stops fluttering closed, small 2wire plug under/near the turbo. Also some people "gut" it if they ever have to rebuild their turbo or replace the turbo pedestal O-Rings. Otherwise, yea, ICP, IPR and you did the under valve harnesses...

Go to www.thedieselstop.com for very in depth knowledge of all things ford diesel.

Cheers, jorge

 

[redthies]

I wired up my EBPV to function as a cheap exhaust brake. Cheers, jorge

I would love to know how to do this! Any link to a "how to"?

 

[scoutkid]

I have had a CPS go out - the truck just dies.
I have had a computer go out - the truck just dies.
I have had bad glow plugs/relay - no/difficult start.
I have had your exact problem and found out my oil level was low - 7.3's need a certain oil pressure before they will start.
I have had the ICP go out - it acted EXACTLY like yours, both times to me, on different vehicles.

Just my $.02

 

[redthies]

Just remembered that the IAT (intake air temp) sensor is not in the factory air box. When I bought the truck the po had used ether instead of fixing glow plugs, which blew a big hole in the factory box. I'm sure this isn't helping, but according to the fsm, it should only cause a limp mode situation at worst. I will check oil levels in sump and hpop res.

 

[redthies]

After reading what the nerds on powerstroke nation have to say, I am thinking that the bogging is likely the EBPV which is like an exhaust brake valve that closes in the turbo to help with warm up. Whoever thought that closing off the exhaust to a point where the truck barely gets out of its own way just to help it warm up, should look for other work.

I also phoned the Ford dealer closest to me, and on a whim asked for service instead of parts. By happy chance, there are two open recalls on my truck, one of which is the cam position sensor. It is booked in for friday. I'll let Ford pay for parts and labour on this one. Cool they will still honor an old recall on a truck with almost 300,000 miles on it!

 

[Buliwyf]

After reading what the nerds on powerstroke nation have to say, I am thinking that the bogging is likely the EBPV which is like an exhaust brake valve that closes in the turbo to help with warm up. Whoever thought that closing off the exhaust to a point where the truck barely gets out of its own way just to help it warm up, should look for other work.

!

That eng would likely just point a finger at the consumers that insist that the engine needs to warm up quickly and never need a block heater.

I'd imagine they allready tried an air intake heater on thier prototypes and they didn't work well enough. Allthough Volvo has had excellent luck with thier new intake heaters.

 

[redthies]

The funny thing is, the bogging quits FASTER on a COLDER day! Humidity related?