Hi ford guys
I have a 2000 f350 7.3 it starts great but when i put it in drive i can't go more than 30 mph after i get about a 1/2 mile it's fine.
I've changed the gas filter and air filter no change.
Now i'm going to change the exhaust backpressure sensor if that don't work does anyone have any ideas.

thanks
pipeman

 

I am assuming this is an automatic transmission? 1/2 a mile isn't much to let the engine warm up, but maybe you should check your ATF level to make sure you're not low on fluid. If fine, when was the last time you've changed your tranny fluid? If it's old or highly contaminated, it can also be the cause of the transmission slipping when cold. Once the fluid warms up, it will perform a little better due to the fluid expanding a bit. It is a bit odd that it's fine after only a half mile.

Those are just a few ideas.

 

Welcome to FTE !

 

thanks for the feadback tailgate trans is good i heard it might have to do with the turbo sticking

 

I take it that it is cold in Michigan? Your Exhaust Back Pressure Valve (EBPV) is closing to warm up the truck a little quicker. This is what closes and makes the hissing sound (from the exhaust velocity increasing due to the restriction).

It will automatically open after around 2,000 RPM's. Once the engine oil temp comes up, it will open again.Nothing is sticking, it is working as designed.

 

I have the same symptoms starting in 50F COLD mornings. I read that exhaust pressure sensor mounted on the front of the engine gets clogged and might cost the delay, but mine has frozen threads and I didn't want to break the tube.
So I just live with it driving slowly first mile. When I pull the trailer I let it idle for few minutes.

 

Unplug it off the turbo pedestal. May throw a soft code,but you can put a resistor on it and solve that.

 

Interesting thread. I have experienced this in the past and, of course, thought it must be indicative of a bad sensor or something failing. If I stepped on the pedal too much in the effort to force the engine to power up, the engine would resist and would stutter, spit and kick back at me. So I'd back off the gas pedal while gently continuing to seek engine power. Then after a relatively short distance down the road, my engine would suddenly transition back to it's normal healthy self and run like a spinning top.

I researched this and unplugged the EBPV solenoid wiring harness from the turbo pedestal after reading that this wouldn't harm the engine or degrade engine performance. I also purchased and placed the recommended resistor into the end of this wiring harness, jumpering the two wires together across the resistor.

Did it solve my delay of engine power upon cold start problem? Well, I only use my truck for hunting once or twice a year. A 1000 mile round trip. So I haven't driven it enough to confirm my no power upon cold start issue was resolved. I found it pretty strange that I couldn't start the engine and gently come up to 50 mph until getting 1/2 to 3/4 mile down the road. To the point that I thought the engine couldn't be functioning as designed, and concluding that there must be something amiss. What surprises me is that there aren't a lot more Threads similar to this one appearing on the Forum. Does every 99-03 7.3L display this symptom? Or is it that this symptom is more pronounced on some 7.3 PS engines than on others? My truck did this on cold starts when outside ambient temperatures were in the 40-60F range.

Since the engine was running great after this cold start - sluggish lack of power - delay, I decided it probably wasn't a serious problem. I won't know if my cold start lack of power nuisance was cured by unplugging the EBPV wiring harness from the turbo pedestal until this summer/fall hunting season. I've cancelled the insurance on the vehicle for the winter.

Edit: Change EBPS to EBPV. I disconnected the wiring harness at the location of the EBPV connector which is located on the turbo pedestal. As is illustrated within PaysonPSD's Post #16 in this Thread.

 

I run a van turbo, so had to get rid of my stock EBPV. Funny thing is, I then went and made one to fit my turbo so I could use it as an exhaust brake, works great. OP- yep, that's just normal. I gotta remote start and hit it about 5-10 minutes before I leave in the morning and by the time I leave the EBPV would open as soon as I tapped the pedal.

 

One important point that's been missed here...

The 7.3 cannot have a "sticking turbo" that's a 6 liter problem.

The 6 liters use a Variable Geometry Turbo (VGT) that utilizes vanes on the exhaust side to direct exhaust gases. This means that you have the same components as a normal turbo but have added the vanes, a unison ring, etc. that can stick and cause problems as you've described.

The turbo on a 7.3 is just 2 housings, bearings, a shaft, and 2 wheels. There is nothing there to stick.

 

I experienced the stuck butterfly on the exhaust side of the EBPV once or twice in the past and my experience was the same as the OP, my truck was a slug starting out. It eventually unstuck but it did happen. At least thats what I thought it was all these years.

 

thanks to all who reply
woodnthings--kajtek1--dieselfitterbum01--pauldh--mongo75--7.3rocket and bigpoppa

I found that the waste gate valve was sticking I put what they call sea foam in the fuel after 5 miles it was great.

As far as sensors go engine light never came on so its not a sensor engine analyst never found anything

 

WTH?? Hey pipeman, I'm glad it's working, but don't see how burning Seafoam is gonna unstick a wastegate valve? It wouldn't even unstick the Exhaust Back Pressure Valve.... headscratching...... if it happens again just take off the downpipe and look in the turbo outlet with a mirror and flashlight, see what's going on in there....

 

What Danny said. It's a cylinder in the turbo base ran electrically.

 

Maybe the butterfly was 'soot stuck' and something in the Seafoam exhaust cleared it? I know I'm reeeeeeeeeeally reaching here and I agree it sounds odd that Seafoam would cure it, maybe it's just coincidence. My old F250 stuck once and could barely get out of the driveway, never did it again after that though.