Hey i picked up a 1990 b2600i a while back the truck wont rev past 2k rpm it will sputter out and die. Ive replaced the ecu,distributor, maf, removed the cat, fuel filter, checked pump pressure with a guage, compression test.... There are times where i can get it past 2k but i would say it is a sweet spot on the throttle any kind of pressure past that sweet spot it will sputter and die out or backfire through the intake, ive messed with the tps adjustments ant that seems to change the rpms just fine so i dont think its faulty but could be wrong, i cant really get to the 02 sensor because im not wanting to bloody up my knuckles just to go and grab the acetylene torch just yet. Any thoughts/ feedback/ overall help would be appreciated, thanks.

 

There’s a fuel pressure regulator on the fuel rail near the front of the engine. It has a vacuum line connected to it. Make sure it’s pulling good vacuum at this line when idling.

Hook up a fuel pressure gauge and check pressure with engine running at idle. Check it with the vacuum line connected to the regulator. Then check it again with the vacuum line disconnected from the regulator.

What’s the pressure reading difference between vacuum line connected and vacuum line disconnected? If there’s no difference, the regulator is bad.

w

 

It ended up being the fuel pump, the philips heads to the access port were rusted damn near through to the tank so lets hope some self tapping screws hold up