Sluggish when cold

[blackf3504dr]

My '96 F350 with the 7.3 has always been slugish when starting out after starting it up in the morning. No mater how hard you try to get it to go it won't do over 35-40 mph for the first 1/2 mile or so, I've put up with it for years but lately it's really bugging me. Any ideas as to the cause?

[JRNOLL]

My 99 F-350 does the same thing. It is caused by the turbo bypass valve being closed to warn the engine faster. It closes off the exhaust to the turbo( creating hot back pressure to warm the engine). Hope this helps.
Joe

[blackf3504dr]

Quote:

Originally Posted by JRNOLL My 99 F-350 does the same thing. It is caused by the turbo bypass valve being closed to warn the engine faster. It closes off the exhaust to the turbo( creating hot back pressure to warm the engine). Hope this helps. Joe

That explains why it does what it does, now I'd like to find a way to bypass it..... Thanks Joe.

[RVtomtom]

Im slugish when Im cold too. Guess I should move to Florida.Not looking forward to winter

[blackf3504dr]

Quote:

Originally Posted by RVtomtom Im slugish when Im cold too. Guess I should move to Florida.Not looking forward to winter

I live in Florida and have the same problem! And not just when it's cold....

[Bo]

Quote:

That explains why it does what it does, now I'd like to find a way to bypass it..

The butterfly can be removed from the EBPV. The hardest part of removing the butterfly is removing the turbo to get it apart. Lots of guys have done it themselves. I know you can get info on the procedure on The Deisel Stop in the 94-97 forums. There are a few other PSD forums where the info can also be found.

Sluggish performance when cold seems to be a characteristic of diesels. Even after removing the EBPV from my old PSD it would hardly move after first starting in the winter but it would take off after only a few minutes of warmup. My new Cummins isn't as bad but it still is sluggish for the first half block or so on cold winter mornings. If your problem is the EBPV, your truck will sound like a jet engine when it is sluggish. When working properly the EBPV should open if you floor the accelerator. Sometimes the EBPV will be carboned up and will stick.

[blackf3504dr]

Quote:

Originally Posted by Bo The butterfly can be removed from the EBPV. The hardest part of removing the butterfly is removing the turbo to get it apart. Lots of guys have done it themselves. I know you can get info on the procedure on The Deisel Stop in the 94-97 forums. There are a few other PSD forums where the info can also be found. Sluggish performance when cold seems to be a characteristic of diesels. Even after removing the EBPV from my old PSD it would hardly move after first starting in the winter but it would take off after only a few minutes of warmup. My new Cummins isn't as bad but it still is sluggish for the first half block or so on cold winter mornings. If your problem is the EBPV, your truck will sound like a jet engine when it is sluggish. When working properly the EBPV should open if you floor the accelerator. Sometimes the EBPV will be carboned up and will stick.

I haven't heard the "jet engine sound", and flooring the accelerator makes no difference but I don't doubt it's the problem.
I've driven tractor trailer for over thirty years and the big diesels don't react like this... Heck my old '89 6.9 never acted like this. The only 5.9 Cummins I've driven was in a KW cab forward back in the early 90s...

[TXiceman]

I always hold my speeds down for the first 1/2 to 1 mile to let the engine have time to start building up some heat. Not good to push any cold engine.

Ken

[blackf3504dr]

Quote:

Originally Posted by TXiceman I always hold my speeds down for the first 1/2 to 1 mile to let the engine have time to start building up some heat. Not good to push any cold engine. Ken

Believe me, there is no pushing this truck when it's cold! If not allowed to warm up for about five minutes it won't do over 40mph no matter what....

[blackf3504dr]

Quote:

Originally Posted by Bo The butterfly can be removed from the EBPV. The hardest part of removing the butterfly is removing the turbo to get it apart. Lots of guys have done it themselves.

Found out the EBPV can be unplugged to disable it. The connector is at the front driver's side of the turbo.

[Bo]

Quote:

Found out the EBPV can be unplugged to disable it. The connector is at the front driver's side of the turbo.

Glad you found this. I was in a rush on my last post and totally forgot about just unplugging the EBPV. I found your post when I got back to my computer to tell you about the unplug. I had the EBPV unplugged on my 95 and my 97 had it gutted. Hope this fixes your problem. Keep us posted on how things work out.

[blackf3504dr]

Quote:

Originally Posted by Bo Glad you found this. I was in a rush on my last post and totally forgot about just unplugging the EBPV. I found your post when I got back to my computer to tell you about the unplug. I had the EBPV unplugged on my 95 and my 97 had it gutted. Hope this fixes your problem. Keep us posted on how things work out.

I'm going to unplug the EBPV as soon as I get the fuel injection wire harness replaced ... It dropped a cylinder (#3) and I'm replacing both sides of the harness... I did this about four years ago too , back then it dropped one whole bank. The truck only has 227,000 miles on it, my 6.9 went 310,000 with not even half the problem before I sold it.

[luvglass]

My 2006 F350 did this a few years ago when I was in Florida for the winter and I took it into a Ford dealer. They diagnosed it as a bad #8 injector and changed it under warranty.

[blackf3504dr]

Quote:

Originally Posted by luvglass My 2006 F350 did this a few years ago when I was in Florida for the winter and I took it into a Ford dealer. They diagnosed it as a bad #8 injector and changed it under warranty.

I had taken it in to have the wire looms that fire the injectors replaced (it dropped #3 cylinder) and they tested the injectors and said they were fine.
I'm still putting up with the problem until I get over my lazyness....