I always had a problem towing up steep grades with only a hardtop camper behind; black smoke and reduced power. Vacuum pump was working, waste gate closed at idle and vacuum on-line to actuator. I didn't measure vacuum but it seemed ok.

I recently changed out the wastegate solenoid because I was sure it had to be a problem with low boost. Sure enough, 40 bucks later truck is a changed beast. Tows like a diesel should and no black smoke to poison those unfortunates behind me. Best 40 bucks I ever spent, wish I had done it 2 years ago. Moral... if in doubt - change it out. I'm thinking new injectors now that my confidence is restored.

Any codes set, such as P0236?

Does that wastegate solenoid close the wastegate and allow more boost? I thought it was the other way around- that at high pressures it commanded the valve to open the wastegate and dump pressure?


I always had a problem towing up steep grades with only a hardtop camper behind; black smoke and reduced power. Vacuum pump was working, waste gate closed at idle and vacuum on-line to actuator. I didn't measure vacuum but it seemed ok.

I recently changed out the wastegate solenoid because I was sure it had to be a problem with low boost. Sure enough, 40 bucks later truck is a changed beast. Tows like a diesel should and no black smoke to poison those unfortunates behind me. Best 40 bucks I ever spent, wish I had done it 2 years ago. Moral... if in doubt - change it out. I'm thinking new injectors now that my confidence is restored.

Turbine is spun by exhaust gas. Wastegate controls amount of exhaust used to spin turbine thereby controlling speed of turbine. More speed=more boost. Boost pressure is used up by motor, wastegate/exhaust merely decides how must pressure will be available.

Wastegate = waste gasses
Open = out exhaust
Closed = spin turbo

Add to that - wastegate solenoid is controlled by PCM to regulate vacuum to wastegate actuator. PCM is actually controlling boost based on RPM's, engine load, fuel, ECT's, etc etc.

Pressure is not dumped.

epooh member since June 2004;

all of which is covered in great detail in your handy 6.5 how does it work guide; otherwise known as FAQ stickies at the top of the forum and also linked every 6.5 moderators signature,

You get an F on assigned reading

Hey T.D.---sounds a bit harsh.

Wise guys...
I know how a turbo works. There is more than one way to control boost and control a wastegate -or pop off valve.
I was just asking if this one is spring loaded closed or open. Just that simple.

so which is it?

I'll did through the FAQ's when I get home and have time instead of sitting in a roadside motel burning road time.

I have not checked codes yet. The solenoid stuck on me a few times in the past and turbo wouldn't spool at all. I squirted some wd40 into the solenoid to free it up as per another post and then promptly ignored what turned out to be an incomplete fix. If I had the F engine I would probably try a mechanical setup for boost. But I'm quite happy with the end result even if it was a long time coming.

The reason I ask is I seem to get a lot of smoke on accel, but smoke clears once at cruising speed and occasionally the PCM posts a P0236.
So is it the Boost sensor (MAP type thing) or the boost solenoid, for me?

The reason I ask is I seem to get a lot of smoke on accel, but smoke clears once at cruising speed and occasionally the PCM posts a P0236.
So is it the Boost sensor (MAP type thing) or the boost solenoid, for me?

If in doubt - check it out.

A pretty decent vacuum gauge will cost 30 bucks at Can tire, or any auto parts store.

Check vac at the pump, solenoid and wastegate actuator, then you know what you are up against.

Same thing happened to me... added Banks wastegate and no more black smoke. I tried real hard to make it smoke too. I haven't seen any smoke in almost a year.

I read that the wastegate solenoid uses a metal ball as sort of a check valve and it rusts and sticks over time hence the wd40 fix. I was thinking that the corrosion was probably not ensuring a tight seal and leaking boost vacuum under load. not sure if that was a correct train of thought but the truck sure pulls now with the new solenoid.

Not sure if a vacuum check at idle or even revved up would point to loss of vacuum, probably only impacts under load.