Loss of power

[derek18105]

I am new to diesels, a few months ago I bought a 1997 F250 4x4 with the 7.3 turbo diesel and the automatic tranny for 4300 with a plow. It has 260,000 miles on it but has a few newer parts and when it was warmer out ran great.

I live in Northern Indiana and it has been getting down to 20F at night.
When the oil warmer is plugged in overnight, it seems to run just fine the next day. But if it is not, it will start up without a problem (i just replaced batteries and glow plugs) but when driving, it seems like it isnt getting enough gas.
I will be cruising at 40mph, and then out of nowhere, the truck slows down and the engine gets quieter and i can hear the turbo alot more than i normally would. It will slow down for like 5 to 10 seconds, so i let off the gas and then give it more gas and it will run fine. Then 30 seconds down the road it will do the same thing.

Ive read that diesel gels in the cold, but i have also heard that up here in the north they allready add stuff to the diesel to keep it from doing that, and i try to keep it above a half tank to keep it from freezing.

Im thinking its the oil, i just put in Rotella 15w40 a few weeks ago with a new Mobile 1 oil filter.



Has anyone had any experience with this or know any additives to the oil I can use?

Thanks, Derek

[kanuck15]

Sounds like your Exhaust Back Pressure Valve is acting up. When this happens a big hissing noise is present and you have barely any throttle response at all right?

Also Welcome Aboard the .org!!!!

[derek18105]

Yeah that almost sounds like it could be it.

Where exactly is that located? I own a twin turbo car (3000gt vr4) so i know a decent amount about turbos, but my car doesnt have one of those.. haha

[kanuck15]

haha no a car wouldnt. its on the backside of the turbine housing. its what the exhaust actually clamps to. its connected by 3 8mm 12 point bolts. there are a few options here. you can just unplug the thing. its a little red wire that runs along the drivers side bank and into the turbo pedestal. Single red wire. You can Gut the exhaust back pressure valve but that means taking it off and doing a lot of work. Or you can just unhook the arm going to the valve from the pedestal and wire the valve open. Id recommend unplugging it, its simple and reversible if its not the problem

[derek18105]

Okay, thanks for your help. I disconnected the downpipe and the valve was all the way open when it was off. I unplugged the correct wire i hope, it was under the intake side of the turbo. It was a 2 wire plug though, one was red. What exactly is the purpose of that valve?

I will see if it makes a difference when i drive it tomorrow

[kanuck15]

yes single wire under the intake side of the turbo. The purpose is it puts a load on the motor and helps it warm up faster. they are prone to going bad and the actuator in the pedestal leaks oil. Either way anymore trucks that have a chip dont need that due to a high idle setting. it can also be turned into an exhaust brake

[derek18105]

Yep, that fixed the problem!
I have a 6637 filter on the way and I ordered a TS 6 position chip but its on back order for 2 to 3 weeks.. I cant wait to get those installed

Anyways, Thanks for your help!

[plumber2311]

I just picked up a 97 E-350 and this sounds like what my van is doing. It will take off fine then it won't. When it happens it won't go anywhere, I get little puffs of black smoke, and the turbo is real loud. If I pump the pedal and floor it, it clears up but I usually go from not going anywhere to going faster than I want to. Will this valve sticking cause bad MPG? What is the purpose of the valve, and what are the repercussions of disabling it?
Thanks.

[POWERSTROKEN1/25]

I have noticed this same thing on my 95. Does this back pressure valve serve any other purpose other than warming the motor during the winter months?

[storkerlovr]

wow be easy on modding truck with 260 miles on an e4od and been plowed with

the first and best mod is gauges! pyro trans and boost. then tune it, do you have ts canned tunes or custom tunes?