losing boost under load

[whateverittakes]

I have a 2000 f-250 7.3 has edge evolution box, mbrp exhaust and s&b cold air kit. I have noticed here lately that when under a load the truck is losing boost. I know when I first got the truck it would make 18 to 20#'s of boost before it would lose it out the waste gate. Here lately It makes 8 to 10#'s then it dumps the gate. makes a shshshshshshsh sound until you let off the pedal. Does anyone have any ideas why the truck is doing this? Any and all help will be greatly appreciated!!!!

[EArmsF350]

I would try the 7.3 motor problem forum, you might get a better response. I have heard the plungers get sticky and dry and need to be lubed but I have never had trouble with mine and don't know that for a fact. Did you check the vaccum lines going to the wastegate to see if the have gotten dried and maybe cracked or accidently taken off?

[7.3eleanor]

I would unplug the wastgate. And see what happens. If nothing changes. Check the intercooler boots. If there is no holes or loose clamps I would start looking at the turbo. Let us know what you come up with.

[whateverittakes]

Originally Posted by EArmsF350

I would try the 7.3 motor problem forum, you might get a better response. I have heard the plungers get sticky and dry and need to be lubed but I have never had trouble with mine and don't know that for a fact. Did you check the vaccum lines going to the wastegate to see if the have gotten dried and maybe cracked or accidently taken off?

Are you talking about plungers in the waste gate?

[whateverittakes]

Originally Posted by 7.3eleanor

I would unplug the wastgate. And see what happens. If nothing changes. Check the intercooler boots. If there is no holes or loose clamps I would start looking at the turbo. Let us know what you come up with.

Are you talking about unplugging the vacuum line to the wastegate?

[EArmsF350]

I would see if the lines are still good and everything looks sound. But as to the plunger, yes I have been told it could get sticky and not function properly. Again I have had no issues with mine so I was hoping someone with more experience than I would have chimed in. I recall my mechanic saying something about lubing the plungers on both the EBV and the wastegate. My dad was having trobles with his EBV surging and that led to discussion about the plungers getting dry.

[CSIPSD]

Originally Posted by whateverittakes

I have a 2000 f-250 7.3 has edge evolution box, mbrp exhaust and s&b cold air kit. I have noticed here lately that when under a load the truck is losing boost. I know when I first got the truck it would make 18 to 20#'s of boost before it would lose it out the waste gate. Here lately It makes 8 to 10#'s then it dumps the gate. makes a shshshshshshsh sound until you let off the pedal. Does anyone have any ideas why the truck is doing this? Any and all help will be greatly appreciated!!!!

Almost sounds like surge, but I doubt you would have it that low.

Check the up pipes, intercooler boots and check the turbo for play.

How many miles on the truck?

FYI, you will NEVER hear the wastegate on a 7.3. Never. You could remove the canister and leave it wide open and you would not hear it.

So what ever sound you are hearing is a boost leak, or drive pressure leak.

Originally Posted by EArmsF350

I would try the 7.3 motor problem forum, you might get a better response. I have heard the plungers get sticky and dry and need to be lubed but I have never had trouble with mine and don't know that for a fact. Did you check the vaccum lines going to the wastegate to see if the have gotten dried and maybe cracked or accidently taken off?

There are no Plungers to lube. Not sure who told you that but there is nothing to lube.

Originally Posted by EArmsF350

I would see if the lines are still good and everything looks sound. But as to the plunger, yes I have been told it could get sticky and not function properly. Again I have had no issues with mine so I was hoping someone with more experience than I would have chimed in. I recall my mechanic saying something about lubing the plungers on both the EBV and the wastegate. My dad was having trobles with his EBV surging and that led to discussion about the plungers getting dry.

The EBP valve does not surge, it can open and close erratically due to back pressure sensor issues, but it does not surge.

Again, there is nothing to lube, the EBPV rod goes into the turbo pedestal and is lubed with motor oil. The rod that runs thru the exhaust housing is in bronze bushings, and experiences 1200* temps, no lube needed.