733,000 miles. fuel prob???

SCOOBYDOOS' HUMAN · January 14, 2020

At 733k mi. i installed another transmission in my 97 silverado 2500. 7.4 vortech. it ran like RED DOGS did before swap. now won't keep running. gas on a rag on air filter allows it to run on vapors. i'm an old school mech. if it had a carb, i'd be driving it instead of the mitsibushi. got fuel pressure through fuel filter. nothing at pressure test port in front of intake manifold. i don't have a good tech manual yet, looking for suggestions. Can't trust a vehicle like this to chilton or haynes. gonna see about getting a "GRANATELLI MAF SENSOR" this payday. i put all fresh fuel in tank with can of B-12 chemtool. any ideas???

davester · January 14, 2020

First, see if a site like alldatadiy.com has the full-service manual for your vehicle, subscription is relatively cheap, or ebay/amazon for the paper books if you prefer that.

Second, it seems pretty obvious to me, you have fuel pressure after the filter, but not at the test port, so follow the line from the filter, and disconnect it at the next connection and see how fuel flows there. Repeat as necessary.

CamGTP · January 14, 2020

The " GRANATELLI MAF SENSOR " is a waste on money, please don't buy it.

You gain nothing from spending the money on one. If you need a new MAF, get a OEM MAF sensor from the dealership or an online retailer that sells new OEM AC Delco parts.

carkhz316 · January 15, 2020

You said it won't keep running? Does it start okay, or not at all? How are you ascertaining fuel pressure? You noted fuel at the filter, but nothing at the test port. This would imply a line is physically pinched shut.