throttle hesitation

Cashburn · #1 (**permalink**) 04-13-2008, 02:43 PM

Yes, that is the responsibility of the dealer to verify in that engine install since the motor is not shipped from Ford Racing with an intake manifold, let alone a carb.

If the engine is built and dynoed by a shop then it should arrive off the dyno with the proper jets (another reason we are in favor of true crate engines as opposed to crate long blocks). But ultimately the dealer should verify before delivery.

We had a spell of issues with the Holley Avengers as delivered on the Roush motors for a period last year... this has since be resolved (for those in the know we went from red dot to blue dot to green dot etc.) But happy to report things are as they should be now.

Bottom line is your dealer should have sorted that.

ekrupa2 · #2 (**permalink**) 04-13-2008, 03:30 PM

Hi Jay - I just contacted Roush about mine (402SR TW with a Holley Street Avenger 770). I have about 140 test miles on mine after my self install. Severe stumble/hesitation during mild to moderate acceleration (no issues when really gassing it). What are they doing to remedy the issue? I tried everything to get rid of it - I have verified the timing, tried tweaking the mixture, verified the float levels, changed the Accelerator Pump Arm Play, changed the Accelerator Pump Cams, and changed the secondary springs (parts at my own expense). Just curious what your resolutions were.

Thanks!

Cashburn · #3 (**permalink**) 04-13-2008, 04:41 PM

Quote:

Originally Posted by ekrupa2

Hi Jay - I just contacted Roush about mine (402SR TW with a Holley Street Avenger 770). I have about 140 test miles on mine after my self install. Severe stumble/hesitation during mild to moderate acceleration (no issues when really gassing it). What are they doing to remedy the issue? I tried everything to get rid of it - I have verified the timing, tried tweaking the mixture, verified the float levels, changed the Accelerator Pump Arm Play, changed the Accelerator Pump Cams, and changed the secondary springs (parts at my own expense). Just curious what your resolutions were.

Thanks!

What color dot is on your carb?

Jim Powers · #4 (**permalink**) 04-13-2008, 05:34 PM

Jay, since I did not specify the 67o Avenger, and ordered the 302 expecting the builder would be professional enough to know what carb worked properly, then it's their fault. So this would be Fanatix at Backdraft. This is only one of several issues on that engine. They installed originally an 870 carb, valve covers for a fuel injected engine ( no breather valve on one side). Both of these issues were corrected in due course, but all of this just footnotes some very careless engine knowledge.

jdean · #5 (**permalink**) 04-13-2008, 05:41 PM

I installed a new 670 Avenger on a 302 in an FIA Cobra replica a month ago. It continues to have a very slight hesitation at light and mid-throttle acceleration. Once the half-second of hesitation is over, it catches and runs very well.

Tried adjusting the pump, idle air, vacuum springs, timing etc. and none of these have made any difference.

The Avengers are supposed to be "plug and play" for Holley to compete better with the Edelbrock carbs (which if sized correctly for the application are plug and play). False advertising.