Engine blubbering on acceleration
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Senior User
Joined: Mar 2005
Posts: 115
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From: Powhatan, Virginia
Engine blubbering on acceleration
My sons '87 f150 4WD SB 5.0L is blubbering on acceleration as if it is starving for gas. I checked the fuel pressure and it is about 35 PSI. If not under load it revs relatively well but under a load it hucks/bucks/spits/sputters/backfires....just about everyhting but run right!
Even when revved up without a laod the fuel pressure will remain constant.
New plugs...new distributor cap/rotor....relatively new wires.
Does anybody have a clue/suggestion as to what could be causing this? I am stumped as hell.
Even when revved up without a laod the fuel pressure will remain constant.
New plugs...new distributor cap/rotor....relatively new wires.
Does anybody have a clue/suggestion as to what could be causing this? I am stumped as hell.
Mountain Pass
Joined: Aug 2005
Posts: 211
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From: Newark, Ohio
You might check the idle air control. Might just be screwing up the air mixture and causing it to cough. I had that issue once. Try pulling it and hosing it out with carb cleaner and see if it helps or hurts. Just my input, good luck
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Senior User
Joined: Mar 2005
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From: Powhatan, Virginia
Well., I found out what it was! The fuel pressure regulator was bad. It was showing 35 psi at idle AND at higher speeds....After thinking for a while and doing some research, I figured maybe the pressure wasn't enough for the higher rpms/loads. Even with the vacuum hose off, the pressure did not increase. I replaced the regulator and the pressure remained the same at idle as before...but when you throttled up, it increased to 40/43 psi and ran great! If anybody has this problem in the future, remember the pressure should increase when the intake vacuum decreases or you pull the vacuum hose off.
Ray Whitlock
Powhatan, Virginia
Ray Whitlock
Powhatan, Virginia
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Senior User
Joined: Mar 2005
Posts: 115
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From: Powhatan, Virginia
I am measuring FUEL pressure. You measure on the fuel rail with a special gauge. The one I bought is made by actron and can be purchased at Advance auto parts. You screw onto the fuel rail at the port that looks very similar to a schrader valve or a metal valve stem.
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