Surging idle 1989 351W after sitting for a few days
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10-25-2012, 05:25 PM
Join Date: Mar 2011
Location: Palmyra, VA
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Surging idle 1989 351W after sitting for a few days
Hello everyone:
My 89 F150 4X4 with a 351W engine has the following issues. If the truck has been sitting for a few days, when I start it the idle surges from almost dieing to around 1500 RPM. It will do this for a few minutes and then if it does not die it will settle down to a nice idle at around 700RPM. I have replaced the IAC and there are no codes in the computer. I have also replaced both fuel pumps and the pressure at the rail is per spec. New plugs and wires too. Now for the odd part: I took off the radiator cap as soon as the engine started and noticed the water level would fluctuate with the RPM. RPM goes up and water level goes down, then when RPM goes down the level almost overtops the radiator. This has me confused, maybe normal but doesn't seem normal. Hope someone can enlighten me as to what is causing the surging. Oh yes, checked compression when changed plugs, levels around 90 - 100psi but no zeros or adjacent really low values. No sign of water on the old plugs and no bubbles in the coolant. No sign of water in the oil either. Sorry for the long post, hope to hear from someone soon. Take care, Burt.
My 89 F150 4X4 with a 351W engine has the following issues. If the truck has been sitting for a few days, when I start it the idle surges from almost dieing to around 1500 RPM. It will do this for a few minutes and then if it does not die it will settle down to a nice idle at around 700RPM. I have replaced the IAC and there are no codes in the computer. I have also replaced both fuel pumps and the pressure at the rail is per spec. New plugs and wires too. Now for the odd part: I took off the radiator cap as soon as the engine started and noticed the water level would fluctuate with the RPM. RPM goes up and water level goes down, then when RPM goes down the level almost overtops the radiator. This has me confused, maybe normal but doesn't seem normal. Hope someone can enlighten me as to what is causing the surging. Oh yes, checked compression when changed plugs, levels around 90 - 100psi but no zeros or adjacent really low values. No sign of water on the old plugs and no bubbles in the coolant. No sign of water in the oil either. Sorry for the long post, hope to hear from someone soon. Take care, Burt.
