Engine/Transmission (1994 - 1998) Unusual Problem!! Please help!!!

[Blacksdieselhp]

Buddy of mine has a 97 2500 4wd auto. it has a Suncoast full transmission and converter, #10 plate, and 370's. he came in this morning and said it wouldn't boost over 20 psi and it usually hit 36-38 psi. I drove it and it would go to about 25 psi and pull normal then it would loose power and drop down to 20 psi and thats all it would do. It seems like I remember this problem on the 12 valves but haven't seen this in a long time. Not sure I've ever seen one act like this one. Checked all hoses and clamps to innercooler, thought it might be the wastegate, but its plugged. Shutoff solenoid is good. Everything checks out. I know I'm forgetting something simple. Hope you guys can help.

 

[REFLOYD]

boost could be leaking out of the boots still or the afc could have a bad diaphram causeing it to not get full fuel there for not spooling the turbo as hard.

 

[JO'Leary]

Sounds like a fuel problem, fuel filter, prefilter screen. May have to check fuel pressure under load.

 

[Vaughn MacKenzie]

Make sure the shutdown soleoid is coming up fully to the Run position.

 

[KYOUNG]

What Vaughn said plus check fuel bypass banjo fitting for correct function... .

 

[MCummings]

I just talked to a guy extensivly on the phone with the exact same problem.



he had allready done all teh "normal" stuff, Shut down solenoid, OverFlow Valve, AFC housing, IC Boots, Wastegate.



Turned out, he hadn't changed the fuel filter in "awhile", and I suggested he did, and the truck went from a Dog, to tearin' the tires off again.



His Fuel Pressure with a Modded OF valve was 35psi at idle and 20 at 2,000.



He hasn't re-checked fuel pressure after FF change, but, it's obvious it's closer to where it should be...



Merrick

 

[JO'Leary]

I was burnt by a plugged fuel filter last year, only had 2k miles on it. I didn't find it until i checked fuel pressure. It was good at idle but dropped to below 5 psi @ WOT. It felt like i picked up 75 H. P. after installing a new filter.

Joe