My 1990 B350 5.9 will turn over but not start. I ma unsure whether it is a fuel pump problem or not but it seems that there is very little fuel being delivered. How much flow should I see when I crank it over?
wreckrunner
Dodgevanman
11-18-2006, 07:13 PM
This is a 4bbl. carburetor right? Most mechanical pumps put out around 7-9 psi. You can disconnect the fuel inlet line to the carb. and see if fuel is being pumped out as you turn the engine over. You should see a pretty good flow.
wreckrunner
11-19-2006, 08:21 AM
The 1990 350 5.9 has a dual injector TBI, when I turn it over without the breather on, hardly any fuel is delivered. I tried to check the fuel pump for power but was either unable to detect any or unable to find a good ground. The reason I am asking you this question is because I wish to avoid replacing the fuel pump if it is unnecessary that is, I don't want to waste time on a wild goose chase. I have Chevy mini that also has duel injector TBI and when it is cranked a good quantity of fuel is delivered (this van also has problems so I can't automatically use it to judge what is happening with the Mopar) which system is working properly?
Dodgevanman
11-19-2006, 08:38 AM
Oh yeah, duh, I should've known it was TBI. Well, that's a different story. According to the manual, the TBI system requires around 14.5psi.
Have a helper put their ear up to the fuel filler or if possible up to the tank itself while you turn the key to "ON". There should a 3 second prime. If they hear the pump, then you know that you're getting power to the pump. Oh and check fuses too.
The factory manual outlines a fuel system pressure test. Let me know if you'd like to scan the pages and post them.
wreckrunner
11-19-2006, 10:26 AM
That would be really helpful because I think that there could be a real pressure problem. I changed the fuel filter without trying to depressurize and had only a small amount of leakage--certainly no release of pressure.
