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390 is pulling over fuel
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Author:  Bren67Cuda904 [ Tue Mar 31, 2009 6:10 pm ]
Post subject:  390 is pulling over fuel
Just got the engine back in today and broke in the cam. I noticed that during break in that any time the engine RPM reached 3000 the front shooters would start to drizzle and as rpm increase they would pretty much be spraying. (only the primaries though) What could cause this?

PS the wide band would go from 13.5 to 10 or even 9.5 when it starts to pull over.
Author:  Joshie225 [ Tue Mar 31, 2009 6:21 pm ]
Post subject: 
Sounds like the float level is high or possibly the fuel pressure, maybe some of both. There is an anti-pullover booster if you find the float level and fuel pressure are both correct.
Author:  ceej [ Tue Mar 31, 2009 7:10 pm ]
Post subject: 
Check the bowl bolt torque. I had that problem when the bowl wasn't tightened up correctly. Vibration caused the accelerator pump to dribble fuel through the shooters. Double check your pump cam clearance too.

CJ
Author:  Bren67Cuda904 [ Wed Apr 01, 2009 11:28 am ]
Post subject: 
Quote:
Sounds like the float level is high or possibly the fuel pressure, maybe some of both. There is an anti-pullover booster if you find the float level and fuel pressure are both correct.
It coming from the accel pump nozzle.
Author:  Joshie225 [ Wed Apr 01, 2009 11:46 am ]
Post subject: 
Sorry, meant nozzle not booster. Anti-pullover boosters would be a bad thing.
Author:  ceej [ Wed Apr 01, 2009 11:59 am ]
Post subject: 
Grab the bowl and push and wiggle on it without touching the pump lever.

Does it squirt fuel?

CJ
Author:  Bren67Cuda904 [ Wed Apr 01, 2009 12:27 pm ]
Post subject: 
Bolts are tight and bowl doesn't move. I thought maybe vibration was moving pump arm so I reved it up to the point it started feeding fuel through the nozzle, then held pump arm and it had no effect. Looked under the nozzle (by removing it) and the weighted needle is in there. I also found that if I rev it up even more the secondary nozzle starts fueling also.
Author:  68barracuda [ Wed Apr 01, 2009 12:52 pm ]
Post subject: 
It sucks..... :twisted: very hard

using mechanical pump ?- what is your fuel pressure like, and your float levels?
Author:  Bren67Cuda904 [ Wed Apr 01, 2009 1:21 pm ]
Post subject: 
Mech pump at 5.5 psi and floats set to just dribble out of side hole if car is bumped slitly.
Author:  68barracuda [ Wed Apr 01, 2009 1:31 pm ]
Post subject: 
you had your engine out - did you recheck your levels? btw scored a 390 with center hung bowls
Author:  ceej [ Wed Apr 01, 2009 1:46 pm ]
Post subject: 
Did you check the fuel pressure hot or cold? Liquid filled gauge?

Pressure should be checked with engine full cold if you run a gauge under hood. As the fill heats up it gives an artificial low reading as the fluid compresses the bourdon tube.

I'm with Fanie, double check the float level too!

Do you have the weight over check ball, or the weight type needle check? Got some grit in the orifice?

CJ
Author:  Bren67Cuda904 [ Wed Apr 01, 2009 9:25 pm ]
Post subject: 
Check both hot and cold. Gauge is air filled. There is a needle under the nozzle and it looks like steel, however with a strong earth magnet held over it and the accel arm jolted it doesn't seem to come out.
Author:  Charrlie_S [ Thu Apr 02, 2009 3:59 am ]
Post subject: 
I have had this fuel "pull over" problem, with both the 500 holley 2bbl, and the 390. Never did cure it. Holley teck was no help either. They told me to drill a small hole from the float bowl into the pump passage, above the fuel level, so the fuel would return to the float bowl, instead of flowing out the shooters. Didn't help.
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