1992 f150 5.0 302 won't start
08-12-2016, 02:23 PM
#1
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1992 f150 5.0 302 won't start
Hello. I'm new to the forum. This is my first post and I hope someone can help me out.
I have a 1992 F150 4x4 with the 5.0 liter 302. It has been running well except for periodic (every few days) times when I would get some hesitation in the throttle. Felt like vapor lock symptoms. I tested and confirmed that the cat is working and couldn't find any vacuum leaks either.
A couple of days ago it gave me that hesitation again and then the next day it wouldn't start. It cranks over and spraying starter fluid in the intake will get it to start and run briefly but then die. I put a pressure gauge on the fuel rail and it registers 0 psi. It doesn't even move the dial at all with KOEO, but when I remove the gauge, fuel trickles out from the test port so I know some fuel is getting there. It doesn't seem to be at enough pressure though. I replaced the fuel pressure regulator and the inline filter. I replaced the fuel pumps in both tanks as well. I checked the inertia switch and it is not tripped.
Any suggestions?
I have a 1992 F150 4x4 with the 5.0 liter 302. It has been running well except for periodic (every few days) times when I would get some hesitation in the throttle. Felt like vapor lock symptoms. I tested and confirmed that the cat is working and couldn't find any vacuum leaks either.
A couple of days ago it gave me that hesitation again and then the next day it wouldn't start. It cranks over and spraying starter fluid in the intake will get it to start and run briefly but then die. I put a pressure gauge on the fuel rail and it registers 0 psi. It doesn't even move the dial at all with KOEO, but when I remove the gauge, fuel trickles out from the test port so I know some fuel is getting there. It doesn't seem to be at enough pressure though. I replaced the fuel pressure regulator and the inline filter. I replaced the fuel pumps in both tanks as well. I checked the inertia switch and it is not tripped.
Any suggestions?
08-12-2016, 07:29 PM
#2
Senior Member
Welcome to the site!
When you roll the key to On, you should hear the fuel pump engage for 2 seconds. If it doesn't, then have a look at the fuel pump relay to ensure it's pulling in - on mine it was in a cluster beside the brake booster, the fuel pump, or the wiring in between.
You're looking for fuel rail pressure somewhere in the 35-40psi range. If the fuel pump is running during the key ON thing, and you've already changed the filter and regulator, perhaps something wrong with the tank switching valve, gas line somehow got kinked, or fuel pump inlet screen is blocked. Perhaps a divide-and-conquer approach - such as pulling the fuel line off the inlet to the valve and seeing if the pump will push fuel at least that far, then move on down or up the line.
Hope this helps, good luck, and keep us posted.
When you roll the key to On, you should hear the fuel pump engage for 2 seconds. If it doesn't, then have a look at the fuel pump relay to ensure it's pulling in - on mine it was in a cluster beside the brake booster, the fuel pump, or the wiring in between.
You're looking for fuel rail pressure somewhere in the 35-40psi range. If the fuel pump is running during the key ON thing, and you've already changed the filter and regulator, perhaps something wrong with the tank switching valve, gas line somehow got kinked, or fuel pump inlet screen is blocked. Perhaps a divide-and-conquer approach - such as pulling the fuel line off the inlet to the valve and seeing if the pump will push fuel at least that far, then move on down or up the line.
Hope this helps, good luck, and keep us posted.
08-13-2016, 05:54 PM
#3
No switching valve on that truck so don't go looking for that. Other than that what wde3477 was saying about listening for the pump to run for 2 seconds every time you cycle the key is where to start - if it doesn't you have to chase down the electrical circuit - relay-dash switch- inertia - pump.
If the pump is running and you're not getting pressure, considering what you've changed, the line is kinked or plugged or the pumps are NFG.
Unfortunately, new parts do not mean working parts anymore for certain, so you can't assume.
Sorta the same thing wde said.
If the pump is running and you're not getting pressure, considering what you've changed, the line is kinked or plugged or the pumps are NFG.
Unfortunately, new parts do not mean working parts anymore for certain, so you can't assume.
Sorta the same thing wde said.
