stalls
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Junior Member
Joined: Nov 2004
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engine stalls when hot 4.9
i have a 87 f-150 pick up 4.9 duel tanks when truck cold will idle for about 1/2 hour then start missing and stall, let sit for about 2 min push acc1/4 down then will start and idle and take gas for about 10 minutes etc etc etc changed all three fuel pumps coil control mod cap plugs wires rotor fuel filter fuel pump relay when shuts down still has some spark. i pulled fuel line lose from both ends of filter and gas burst out almost like its plugged in the fuel rail. any help appreciated [tem] fuel pump 49lbs then drops too 25 and stalls resart right back too 49 again5 more minutes shuts off
Last edited by tem; Nov 4, 2004 at 04:49 PM.
Senior Member
Joined: Jul 2004
Posts: 6,200
Likes: 39
From: Easton, Pa.
There should be pressure in the lines right after shut down dependent on how fast the pumps bleed down.
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Next, are you sure the fuel pressure is 49 psi? If so it is to high. Should be less than 40 psi with the engine running and the regulator vacuum hose on it.
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Sounds like the problem with the stall is the engine is being flooded with too much fuel from the high fuel pressure, if it restarts with a little opening of the throttle.
You normally won't get a check engine light if the regulator is faulty because the computer has no way of monitoring it's operation except possibably on a secondary basis, the oxygen sensor trys to correct for the fault by taking the computer tables out of range and generating a fault code.
.
Next, are you sure the fuel pressure is 49 psi? If so it is to high. Should be less than 40 psi with the engine running and the regulator vacuum hose on it.
.
Sounds like the problem with the stall is the engine is being flooded with too much fuel from the high fuel pressure, if it restarts with a little opening of the throttle.
You normally won't get a check engine light if the regulator is faulty because the computer has no way of monitoring it's operation except possibably on a secondary basis, the oxygen sensor trys to correct for the fault by taking the computer tables out of range and generating a fault code.
Last edited by Bluegrass; Nov 5, 2004 at 01:09 AM.
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Junior Member
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bought new frame fuel pump {high pressure pump} get 60lbs pressure when key on only. get 50 lbs when running when temp goes up too 200 degrees pressure drops too 40,30,35,10lbs then stalls let sit 2 minutes then tun key off an on a couple off times then sarts right up will run 5 too 10 minutes then drop again 40,30 25 10 lbs etc ect ect when cold will start right up at 50 lbs please help
