I notice that if I leave it in 4th and drop below 50MPH or so, if I get on it there is no turbo spool and low power. If I drop down to 3rd gear that will get a boost in power and I can hear some turbo spool.

The weird thing (I think possibly a problem) is that there's also no black smoke in 4th when I floor it with no boost. I'd think flooring it would be dumping fuel without a turbo boost, no? I don't know these things too well... maybe there's something (perhaps a sensor input) limiting fuel boost until turbo boost is happening???

I have a boost gauge and the highest I get is about 10 psi. But I have ZERO in 4th even if I floor it and I can't hear any spool at all. I have to drop to 3rd before anything happens. Something doesn't seem right.

 

if you are only getting 10 psi wot you should check the uppipes for leaks usually you will see soot around the base of the collector thats to start as turbos need drive pressure to make em work and a leak bleeds off the pressure to drive the turbine

 

don't see any soot on the up-pipes. I also sprayed them with soapy water and watched. Didn't see much in terms of bubbles.

 

What RPM's are you at in 4th with no boost? RPM's when you see 10psi?

 

It's around 3000 I'd say (vans have no tach) that I see boost. 2k and flooring it doesn't get me much in 4th until the rpms hit about 2500 or a little higher.

I have a 3.55 and E4OD and it's about 50-55mph where I begin to hit boost in 4th gear with the pedal to the metal.

 

Maybe vans are different, but my trucks won't stay in 4th at wot 50-55 mph. 3.55 gears at that speed is about 1500 rpms.

If you have no exhaust leaks, check for boost leaks and compressor wheel damage.

 

Mine's different because I have my E4OD's harness plugged into my own shift computer. I can keep it in 4th with WOT.

 

Your not going to have any power 4th gear converter locked with 3.55's at 50 mph, let it rev!

 

X2, but he still has a low boost problem. 10 psi max is way low.