first off, I hate not being able to use the search
OK here we go, I have a 2000 psd and the thing surges at speeds up to about 65 mph if I use the cruise at any speed it goes away? It doe not do it all the time, seems like 20% of the time. the truck has 108000 on it I just got it 3 months ago and dont know if the fuel filter has ever been changed. Its like a dirt bike going in and out of the power band. Any suggestions?

 

How many miles is on the engine oil? How about the level of it? If you aren't sure, change it. Also with the fuel filter. These engines run off of highly-pressurized oil that is used to fire the injectors.

 

It is due for an oil change in another 200 miles, I will just change it now. what oil do you recommend?

 

For Michigan I'd reccomend Rotella T 5w-40 synthetic. Really helps out with those cold starts.

 

ok thanks, I hope it works

 

Before you change it, check the dipstick level (make sure the engine has sat for at least 20 minutes after being run to allow it to settle) and let us know what level it is at. Helps for diagnosing future problems.

 

it was about a 1/4" below the full mark but extremely black

 

Could also be the TPS on the throttle going out. That can cause surge issues, and would explain why it goes away with cruise on.

 

Good catch there Pocket.

compensating.. Do you ever notice dead spots in the pedal when starting off

 

What are the outside air temps when this happens? Are you getting a hissing sound when it surges? Im asking becuase when it was cold enough and my engine was at cruising speed 65 or so and i was giving it very little throttle, My ebpv would partially close.

When youre just cruising along and not putting the engine under load the oil temp drops and in conjunction with the outside air temps being low enough your ebpv flap will shut until you get back on the throttle pretty good. This is normal , but remember the more your tube is clogged the more back pressure from the engine it will take to open you to overide the ebpv flap.

Im only guessing but when the flap is closing on you you get that loss of power feeling in the go pedal and when you really give it some go pedal it's got some power again.

If this sounds like what you are experiencing ask around here or do some searching on the cleaning of ebpv tube/ sensor.

 

The opposite, it would be abnormal, and would be a malfunction. There's no way that even cruising unloaded the engine oil would cool enough to trigger the ECM to close the EBPV. On level ground at highway speeds your EGT's average close to 600 degrees when feathering the throttle. I've gone down mountain grades coasting and egt's below 200 degrees for several miles and never has the engine temps dropped enough to try and trigger the EBPV. This is in Colorado mountain winter weather as well.

So if the EBPV is in fact trying to close, you have other issues, and this is not a normal part of PSD operation.

 

[/QUOTE] This is normal [/QUOTE]

To a point, if all the variables come into play and it is super cold youre truck will do it.

 

The temps that it would take to do that, would be too cold for your truck to even start anyway. Your fuel would be gelled, and you wouldn't be able to test that theory, so it's a moot point.

 

I am only merely trying to give the guy some place to start or something to think about. EGT's have nothing to do with the flap closing. There are two or three truck owners a day coming on here trying to figure out why there truck has no power when pulling out of an intersection and at full throttle. If you have an EGT guage you know that when accelerating from a dead stop your exhuast temps are going to be higher. And when they are trying to pull out of the intersections or onto highway's there EGT's have to be screaming with a malfunctioning ebpv sensor or clogged tube that they come on here complaining about.

. My point is if what you are saying is true they shouldnt have a prob becuase there EGT's are high. I hope this makes sense. Easier to explain by mouth than type .

 

some on else chime in here