Help, I have a 02 7.3 psd which has no power at all when dead cold.
when the truck warms up it is ok . Truck idles and runs ok, doesnot blow any smoke and has no DTC's . Engine produces no boost under load cold, ok when hot (17 to19 psi).Also tested a brand new truck which does make boost from dead cold .My truck wont even break traction.
Turbo appears ok, no damage. No exhaust system or engine pipe leaks or restrictions. Fuel pressure ok at 50psi in both cyl heads ,ICP sensor reading within specs. Turbo wastegate not stuck open and no signs of any intercooler hose or pipe leaks.Engine compressions all the same on all cylinders, and within specs. Exhaust back pressure valve is functioning ok and is not sticking. Have replaced Injector O rings and nozzle seats. No slip in Torque converter or transsmision forward and low/Reverse clutches.Boost pressure sensor and CKP sensors have been replaced. Boost pressure line to sensor is also ok and is not split.
I am starting to run out of Ideas, tomorrow I am going to run the engine on some fresh diesel as alast resort and see how the engine performs.
Has anyone had a 7.3 PSD doing the same, if so I would be very interested to know what the problem was.

Cheers 460 Style

 

due to the nature of a diesel, you can't get in them, start it up, and hold it to the floor. you should be forcefully dragged out of the driver's seat and into a gasser. you need to properly let them warm up, and don't get into the throttle until it's completely warm. i baby mine on the stock postition until i see the needle halfway between cold and the normal position. Diesels use heat to make combustion, and with no heat (stone cold engine), you arent going to make power. it seems 6.0's are different, as both of our 6.0's can run great when cold. i know it's not good for them, and i have accidentally made over 15psi with just light throttle accelerating. you will ALWAYS see higher boost at any time with a 6.0, as they run a variable geometry turbo that is (should) always be able to spool extremely quick.

 

Strokin_it is right, you need to gently warm up a diesel for the first few miles.
That said, my truck will make as much power stone cold as when fully warmed up, so you definatly have a problem there.
My first question is: That fuel pressure reading; was it measured in the service bay or out on the road with the engine under load? There is a HUGE difference in fuel demand between idling and driving along.

 

Thanks guys for your responses. The fuel rail pressure was 50 psi @ idle and under load.Today I ran the engine on some fresh diesel, but it made no difference. In an atempt to raise cylinder temp,I increased the fuel pressure to 65 psi and carried out the 5.6 and 10 k ohm mod on the ICP sensor. The 5.6 k mod made the most difference, even when cold. The Truck still idled ok too. Have yet to try it on the road, will do so tomorrow when I get back to work.

 

My truck has no guts when first started, but the more troubling symptom is it seems to jump and hop in reverse unless you gently feather the accelerator pedal. Sometimes evn does it when its warm. Fluid looks and smells fine. I am getting one code as the OD indicator flashes on startup until its put in gear. Code come up prndsl error.

Any ideas?

Thanks,
Tim

 

Unfortunately I don't know what that code is. What you describe sounds like the torque converter is trying to lock-up at low speeds. It should never lock-up in reverse. Here's something to try,

Manual shift the transmission and see if that does anything? I'm curious to see if you experience the same problem in 1st gear, shifting it manually, as you get with it in reverse.

 

most of the time (90%) only does it when cold, and only in reverse. Smooth as silk in all other gears

 

Something is telling the torque converter to lock-up. I would bet on that. Need to know what the code is you've been getting. Is there a local transmission shop that you can trust?

 

the only transmission code i get, and have ever got is 0705

 

I would be looking for a good reputable tranny shop and have them check it out. There are a lot of electronics in these transmissions that could be causing your problem.

 

Thanks for the help.

reputable and tranny shop usually dont go together around here though,

 

Find your local chapter here on FTE. What state you live in, and post up there. Somebody in your area may be able to help you.

 

guys if it is cold enuf outside, i dont think this sounds like a transmission problem. It sounds like it is the EBPV staying closed until warm up. Once it warms up, the sensor senses that and opens the EBPV. Mine did this all the time when i was in Alaska and wyoming. When i gutted the EBPV, this symptom went away. This is perfectly normal. Let your truck warm up a little more before taking off

 

Sounds exactly like when I first got my DP Tuner and got my tune numbers mixed up. I had it set on Decel (EBPV Closed) instead of 80 Economy. I was pushing the go pedal and thinking... This can't be right. Dohhh.

 

Wow, a thread from 2006!