Okay, let's try again. 2.8 MPFI won't start when warm, starts fine when cool. Started a few days ago. Fuel pressure in specs, plugs fire whether engine starts or not, code readings are clear. I know carbed cars have the problem of vapor lock but never heard of FI cars doing it. If not vapor lock whiat could it be?
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Re: Acts like vapor lock
When they went to fuel injection the fuel that was not used returned to the tank thus cooling the fuel and ending vapor lock, my question is did you do a fuel pressure test? and di you do a fuel leak down test? and the first thing I would do is change the fuel filter. with ethanol in the gas it kills the filter. I have to replace mine every three months they just plug up from that junk. Other than that the only other thing would be a coil breaking down when it gets hot the coil shorts out when cool it starts so check those things first. be sure fuel pressure is 50 to 60 PSI and does not drop below 30 PSI for at least a minute, if it does the fuel pump check valve is bad, also the fuel sock could be bad as well.
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Well it could be numerous if things but you want suggestions...So here's mine..Your gas tank might be vapor locked...This is caused from over filling your gas tank with gas over the years..Its when the pressure in your gas tank becomes greater than your fuel pump. It wont start until the pressure in your gas tank becomes lower then you fuel pump...Sounds crazy...This got me once...I didn't understand it...A lot of people (including me) Go to the gas station and get that extra 50 cent after the gas nozzle clicks off...over time that extra gas will run down the vapor lines intended to burn fumes....Like when you fill a gas can to cut your grass...If you sake the gas can it builds pressure and bows up. But with time that pressure will go away...Well saying that...Your gas tank needs to vent to....So your car burns not only gas but fumes...If you keep over filling your car with the extra gas it cloggs up your vapor canister intended for fumes or vapors...The gas will will go into that canister and clogg up the charcoal that's inside it. (Breaks it down) then the vapors can't get to your carburetor where it supposed to burns it. So what happens is the pressure in the gas tank becomes greater than your fuel pump and then car won't start..Are you with me? Lol Its crazy..Putting a different gas cap can cause the same thing...Simple test...When you open your gas cap to get gas.. Do you heat air sucking in.. Yes you can hear it....A lot of times loosening the cap let's the pressure out and the car will start right up.....Thus might not be your problem but worth telling at the gas pumps to other people..... Just trying to help
Try blowing out your Airlines with a air compressor just disconnected the linesshit from the fuel pump and from the injection port and just blow it out start with low pressure and slowly work your way up. If that doesn't help you most likely have a leaky injector
fuel pick-up in tank is blocked it has a sock over the end as a gross filter to keep out any big junk from getting sucked into the pump and causing damage to it. the sock can get so plugged up that no fuel will flow, causing the pump to run for a short time then with no fuel flow to cool it it trips the safety and shuts off
It could be a vapor lock but not likely. Since the introduction of fuel injection vapor lock has been eliminated. You need to figure out if you are loosing fuel pressure or spark when it will not start back up. Could be a fuel pump relay or ignition module among other things. Even a problem with the vent for the gas tank.
I'd have fuel pressure tested. I had a 95' did same thing. Cold winter day, worked fine, as soon as it got warmer, or hot out, it would quit, and re-start 20 minutes later and go for a distance then die again. If I parked in the shade on a hot day, I'd get further before it quit for the first time. I started carrying a fuel pressure gauge with me. Cool in the morning my fuel pressure was up to spec @ 49-50psi. Once it got warm/hot out and it died, Hooked up gauge and it was at 2-5psi. Let it sit and cool off 20-30 minutes, pressure would jump back up and run good until fuel pump got hot again and then pressure dropped off and car quit. It sure sounds like the fuel pump, but the hard part will be getting the car to the shop at the right time, or they will need to let it run on the lot until it quits to confirm the pressure drop. One thing you can try is when car quits, have a can of WD-40 or quick start with you and a screwdriver. Loosen the clamp on the air intake hose where it connects to the front of the throttle body and pull it off. With vehicle off, turn throttle linkage so the plate opens up enough to spray WD-40 a second or 2 in the throttle body. Then try to start it. If it starts and runs momentarily, then you can be pretty sure it's fuel related and my guess is the pump needs replacement.
i know on the 99 mountaineers with the 5.0 the way the fuel lines were routed from the factory, heat from the motor would vaporize the fuel in the lines when engine was cut off warm. It would turn quite a few times before starting after that happened. try turning your key on and off a couple of times before you actually try starting it and it should start quicker. I know this from experience.
U may have a defective fuel pressure check valve in the electric fuel pump, u have the classic symptoms, to check this buy a fuel pressure test guage for your truck, about $40, the test port for fuel pressure is on the top of th engine in the fuel rail that supplies fuel to the injectors, hook up the guage to the test port and run the engine, make sure u have no fuel leaks at the hook up, then shut down the engine, the fuel pressure should not drop more than 5 PSI, if it does the check valve is defectiveand you need a new fuel pump