Holley 750 not maintaining Idle after installing fuel pressure gauage

[AM.MSCL]

I guess maybe I should mention that the car had been running just fine for 2 years with the exception of issue number 1.
I current have 10 degrees of timing which is the max I could do without introducing lifter clatter at high rpms.
If I remember correctly I had 15 units of vacuum when I tuned it.

[Sieg]

Sounds like the issue started with installation of the pressure gauge.

Did you use teflon tape or some type of thread sealant that could have clogged a passage in the carb?

Has E10 fuel sat in the carb for an extended period?

Could the gauge be restrictive/defective?

Fuel pump possibly giving up? I just had a mechanical pump start to fail in the middle of resolving idle issues.

10*-12* initial timing should be fine and 32*-36* total timing.

The idle transfer slots in the venturi's should be set to expose .020" for a baseline.

Idle mixture screws are usually in the .75 to 1.50 turns out range.

The way it's seeking a high idle then falling off means it "could" be lean. Vacuum leak or idle mixture setting and/or butterfly transfer slot relationship.

Accelerator pump linkage should have a .010"-.015" play also. Too tight and the pump can weep fuel into the idle mixture.

All these settings should get you close......but if a circuit is experiencing blockage or there's a vacuum leak or fuel supply issue you'll have issues.

[GregWeld]

Call Eric - he's there in Austin.



He's on this forum… and also Carbuff is there as well as Gerno… They can point you how to get hold of Eric.


Go to this thread - find the guys and PM 'em if you don't know them.


https://lateral-g.net/forums/showthread.php4?t=29609