surging
 

I have a 2002 f350 DRW auto trans. with 498,000 miles on it. At times the engine will begin to surge. It may happen going down the road at any speed and it may start surging sitting in park with the engine at idle. Now, the interesting part, when the check engine light comes on it smooths out and runs great. Anyone have any ideas about what may be the problem? It doesn't show any codes with my tester, but it isn't the best one in the world.

Thanks,
Charlie

describe surge - RPMS come up with no speed response or speed increases with no pedal input

RPM's go up and down, even with trans in park sitting at idle

How is the oil level? How many miles on the oil? Damn that is alot of miles on the engine. Post up a 500000 picture if you can!

There should be codes stored and this is just a stab in the dark without them but with it smoothing when the light is on I am suspecting the ICP sensor. When the light is on the PCM sees a fault in the ICP circuit and commands a default pressure, with the light off (no fault detected) the pcm is reacting to a fluctuating ICP pressure and commanding the IPR accordingly causing the bouncing RPM.

O.K. i am going to stab at this with my limited knowledge, "it may start surging sitting in park with the engine at idle"
that could be the EBP operating, since the turbo really provides no boost at idle.

"At times the engine will begin to surge. It may happen going down the road at any speed " could be the turbo is toast at 498K (original?)
Any tuners or power adders, any other mods to intake or engine

could be stopped up air filter, EBPV line clogged,EBPV sensor, CPS, injector, UVC harness, weak HPOP, ETC...

what codes does your reader pull when the SES light comes on?

It is the original turbo, stock engine and intake(no mods except crankcase vent), and no codes showing. When the engine light is on it runs and pulls like a new truck. The surge always seems to be only when the engine is running at a constant speed. At idle, highway speeds, or 20 or 30 miles an hour, it will do it at any speed. If you press the throttle to speed-up the surge is GONE.

does it sound like a hissing sound coming from the tail pipe?

you guys think it might be as simple as the throttle position sensor?

If there is a light there is a code, What type code reader do you have? The plain OBDII code readers that can be purchased at local auto stores do not read our diesel specific codes.
but as bigredford says it might be as simple as a TPS, your pedal has been pushed alot in 500K

Do you think the throttle position sensor could cause the problem when it is just sitting at idle?

Thanks again for all the input,
Charlie

"Do you think the throttle position sensor could cause the problem when it is just sitting at idle?"
YES, could in fact be.
Same symptoms as our '02 at almost 900,000. One of just a few issues it has ever had (NO modifications other than fuel supply/filtration). I attribute the miles to good maintenance, and it's unmolested. The same two guys hace been 'teaming' it for five years now. It gets started on Sunday and turned off on Friday, has flipped the odometer...A true testament of these T444E's.

That's gotta be a record!
It would be interesting to know what other issues might have come up in that period of time so that we could look for pattern failures, if any.
Things like u-joints, ball joints, wheel bearings, water pumps, alternators, etc.

Perhaps start a new thread about it to avoid highjacking this one. :)
I would be all ears. :-X06

And now back to this thread: A lot of driveability problems have been corrected by a simple oil change with these engines. It wouldn't surprise me to learn that you have a lot of miles since the last one.

Wow 900000 miles, that is amazing! i would love to see that odometer. What do you usually do with it? just towing?

Im going to have to agree with you on that one. Where on earth do you drive that thing?