7.4 MPI no start
05-23-2015 | 08:43 AM
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From: Fredericksburg
7.4 MPI no start
I've got a 2000 7.4 MPI that won't start. I'm leaning toward a fuel issue. Here's what's going on:
Uncovered it from the shrink wrap earlier this spring. Put it on the hose and could barely keep it running and when it did the rpm would rise and fall like it had a big cam. I heard the IAC opening and closing like crazy so I thought that may not be operating properly. Frantically threw a new IAC in it trying to get on the water. Ran a bit rough, but ran. Got to to the lake and nothing.
If I cycle the fuel pump by turning the ignition on and off several times without bumping the starter it will fire for a brief moment. The pump is definitely spinning but at what pressure I dunno. I've checked simple things like my Racer fuel filter, drained and topped with fresh fuel. Replaced the worn vacuum line on the fuel regulator. Previously when I'd open the fuel filter id need to purge any air from the lines using the port just behind the thermostat housing. There's no air in the lines, I'm pretty sure.
Where do I go next? I'm thinking regulator or pump. How can I check fuel pressure on this motor and how can I differentiate between a regulator problem and a pump problem?
Uncovered it from the shrink wrap earlier this spring. Put it on the hose and could barely keep it running and when it did the rpm would rise and fall like it had a big cam. I heard the IAC opening and closing like crazy so I thought that may not be operating properly. Frantically threw a new IAC in it trying to get on the water. Ran a bit rough, but ran. Got to to the lake and nothing.
If I cycle the fuel pump by turning the ignition on and off several times without bumping the starter it will fire for a brief moment. The pump is definitely spinning but at what pressure I dunno. I've checked simple things like my Racer fuel filter, drained and topped with fresh fuel. Replaced the worn vacuum line on the fuel regulator. Previously when I'd open the fuel filter id need to purge any air from the lines using the port just behind the thermostat housing. There's no air in the lines, I'm pretty sure.
Where do I go next? I'm thinking regulator or pump. How can I check fuel pressure on this motor and how can I differentiate between a regulator problem and a pump problem?
