99 7.3 cold surging

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Nov 18, 2010 | 08:25 AM

meporsche

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99 7.3 cold surging

I'm cross posting this from the 7.3L forum hoping to get help.

I've only had the truck for a few weeks, 193K on it. 99 F250SD. WHen I drove it yesterday (temps in mid 30s) it was surging for about the first 15 miles, then it flattened out and ran fine. This happened twice. A little better if I goosed the throttle but still there. This is the first time I have sriven the vehicle in lower temps.

I'm thinking the fuel filter is partly plugged and the thicker vis fuel is not flowing well enough to injectors/pump? Or is there a fuel heater on this that has failed? Combination?

Any help appreciated. I'm going to change the fuel filter today anyhow but have a nagging suspicion it isn't going to correct the problem.

Thanks,
Darwin

Nov 18, 2010 | 08:32 AM

pbr man

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From: North Idaho

There is an exhaust back pressure valve that closes when the temps drop down around 30*. It is supposed to help the engine warm up faster. When you drive it will open and close until the engine temperature comes up. It is perfectly normal.

Nov 18, 2010 | 08:47 AM

Fishin76

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From: Canton, IL

I know what the OP is talking about. He needs to let it warm up more before driving. mine does the surge thing too in colder weather. after it gets some heat into it, it's all good. If the EBPV valve is operating, your truck exhaust will sound more like a jet than a truck. In the cab, you can hear something like a rush of air coming from in front of the passengers seat. If that correlates to the surge (or loss of power) that you feel, thats what your experiencing, the Exhaust Back Pressure Valve (EBPV). You can also have cold surge just from not being warmed up. Wait till your next sub-32 degree day. startup and immediatly go into reverse and goose it just a little. You'll see what I'm talking about.

Nov 18, 2010 | 08:59 AM

meporsche

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Wow, pretty undriveable, doesn't like to shift up without a heavy throttle. I wouldn't want to have to pull into traffic like that. What's the cure, let it warm up for 15 minutes? Seems like a waste of fuel. And I'm sensitive to the price of diesel right now

Nov 18, 2010 | 09:24 AM

Supercab

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From: Palm Bay, Florida

Are you guys using synthetic oil?? this condition sounds like what the guys over on the '99-'03 PSD forum call "the romps" and changing to synthetic motor oil usually clears this up-alot of guys over there use the popular Shell Rotella 5W40 full synthetic....might also want to run a strong concentration of Diesel Kleen through a couple of tanks of fuel then change your fuel filter too.......

Nov 18, 2010 | 09:50 AM

pbr man

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From: North Idaho

Quote:

Originally Posted by meporsche

You can unplug it. Look at the base of the turbo and you will see the plug. I unplugged mine about 5 years ago with and haven't had any problems since.