Hey all, my 97 is completely stock shy of a full exhaust 3 inch down pipe and 5 inch out the back no cat no muffler and a clean new filter and A BRAND NEW TURBO. I bought the truck as she sits with 100550 miles on and clean as a whistle. I'm a technician and I have a snap on Solus Ultra so I can monitor everything the truck sees. My complaint is the truck accelerates normal as long I stay no more than about 1/4 throttle if I go WOT the truck drops gears as it should and the turbo screams but I go no where. Now I know everyone will just go to trans shifting but this isn't the problem as the rpms don't rise, they rise initially when I downshift but even in direct drive my rpms rise slowly as the truck slowly accelerates. Now I have no faults at all, except for P1111 for system pass.
I have verified correct operation of the EBPV and it moves free
I measured boost at the map sensor and had a max reading of 8psi WOT
I then under WOT manually applied vacuum to the map sensor and then the truck made no additional power, shook a bit and made no smoke.
The truck has never smoked any color.
As I said before this is a brand new turbo so there is no play in the wheels

I have no soot build up anywhere its clean as a whistle under there.
Ran a cylinder contribution test: PASS
Buzz test: All 8 injectors sound the same... PASS
Solus offers a expected range that everything should be in and every monitor is 100% in
line with what is expected.
Fuel pressure at idle is 50-60 psi bouncing between the 2
Fuel pressure at WOT seizes between 30-60 psi but at higher RPM`s it levels out to 50-60
Next i smoked the intake with an actual smoke machine and found 0 leaks in the intake, through the map sensor hose, the up-pipes everything is solid...

alldata says at 2500-3000 RPM while t-ed in on map sensor line. " If boost pressure us 15.5 (90kPa) or more, boost level is ok. So theres definantly something peculiar happening im almost half of that.

Any other ideas? Of what to check, im running low on ideas.

Thank you all.

 

Simply unplug your map sensor and take it for a drive. If yall are boosting more then before then you know that your sensor needs replaced, or there is an obstruction inside the pass plenum to map sensor hose.

 

Yea, tried that. No change

 

PCM is also New for the record.

 

Auto or standard transmission?
Do you have split shot injectors, California truck?
Why a new PCM and is it the correct one for injectors, federal or cali?
Why a new turbo and what brand, original oem?

Applying vacuum does nothing as MAP uses boost (pressure).

 

Yea that was my fault I meant to say applied pressure to it.

Replace the PCM for no communication.

Turbo is OEM

Truck is federal with single shot injectors

And an automatic transmission.

 

Check the exhaust back-pressure with scanner. It usually won't go over 19 PSI hard accelerating and around 16 PSI at idle.

 

Yea it maintained 16 at idle and went to about 21 at WOT I was able to get to to boost to 11.1 today too. I think it may be normal for the truck. The only thing I noticed is one of the PID on my scanner is for turbo speed but it's flat lines at 0, do we not have this sensor on the truck OBS?

 

No sensor for turbo speed on OBS.
With an automatic it's hard to get the upper boost numbers. Need to get it working hard such as pulling something up a hill.

 

Yea, I'm beginning to fear more of a slipping trans more than anything. It's like I have more power on the first half of throttle soon as I go wide open I basically stop accelerating

 

How is the icp pressure and ipr duty cycle?
Curious if hpop is loosing maybe.
it takes oil to get fuel.

 

ICP pressure at idle is 584.8
IPR Duty cycle at idle is 13%

ICP Pressure at WOT is 1621.8
IPR Duty cycle at WOT is 35%

 

Idle look good, very good.

I would expect much higher ICP pressure at WOT though ~ 2200 or more. Heck, I cruse @65 MPH on the freeway, flat road, and am running ~ 1600 ICP pressure.

 

Yes but I would think your mods would effect that reading over mine stock or do you disagree? Ill be performing the FPR Mod in the morning with a screen cleaning as well and see where I'm at then. Otherwise what would you suspect? HPOP?

 

I really have no major mods or any chip. HPOP seldom fails so I doubt that's it. What type oil are you using, I'm wondering if it is old or wrong type and/or foaming causing pressure issues.

Just thinking out loud here but check the TPS with the scanner and make sure the go peddle has full travel with no dead spots.