1988 f150 5.0 no start
08-01-2015, 09:10 AM
#1
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1988 f150 5.0 no start
hello I have a 1988 f150 5.0. when I bought it I had to install upper intake. the truck will run if I prime it. I have spark, injection pulse, not sure on fuel pressure. I replaced the fuel pump in front tank. I know I am getting fuel to the engine not sure right pressure. could the high pressure fuel pump on frame rail be bad and not letting the right pressure get to the engine.
Last edited by vdiddy; 08-01-2015 at 09:13 AM.
08-01-2015, 04:29 PM
#3
Senior Member
If you prime it a few times and it'll start but then die after a few seconds or a minute or two then it's definitely a fuel deliver problem. Replace the fuel filter with a new Motorcraft unit if you haven't already. And like said above, get a fuel pressure gauge.
Hook the gauge to the schrader valve on the fuel rail. Prime it but don't start it. See what the pressure pumps up to. Then start it and watch what happens with the fuel pressure while it runs then dies. There could be something restricting flow or one of the pumps. Once it's running if the pressure drops until it dies, but you know you have a good filter and there are no kinks or restrictions in the fuel line then you can sometimes listen to the pumps.
For instance. In a truck that I was diagnosing the same issue you have I knew that there were no restrictions, had a good new filter, and had a new pump in the tank. I primed it and pressure came up. Then I had someone start it while I was underneath the truck listening to the high pressure pump. When the truck started it was pretty quiet. Then it started to get pretty loud and several seconds later the truck died. What it was was that the new pump had an issue and wasn't putting enough pressure to the high pressure pump to keep the rail pressure up. Replaced the new pump with an actual Ford pump assembly and all was good after that.
Hook the gauge to the schrader valve on the fuel rail. Prime it but don't start it. See what the pressure pumps up to. Then start it and watch what happens with the fuel pressure while it runs then dies. There could be something restricting flow or one of the pumps. Once it's running if the pressure drops until it dies, but you know you have a good filter and there are no kinks or restrictions in the fuel line then you can sometimes listen to the pumps.
For instance. In a truck that I was diagnosing the same issue you have I knew that there were no restrictions, had a good new filter, and had a new pump in the tank. I primed it and pressure came up. Then I had someone start it while I was underneath the truck listening to the high pressure pump. When the truck started it was pretty quiet. Then it started to get pretty loud and several seconds later the truck died. What it was was that the new pump had an issue and wasn't putting enough pressure to the high pressure pump to keep the rail pressure up. Replaced the new pump with an actual Ford pump assembly and all was good after that.