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Author Topic:   Hilborn Injection Help
posted March 23, 2003 12:06 PM
Posted the same Q under "Sprint Tech" but I know a lot more people read here .... am hoping somebody can help :

All new Hilborn system, 360 Sprint, set up straight from Hilborn, is DUMPING massive amounts of fuel on the right side only, at idle only.
I know nothing about Fuel Injection. I bought it brand new, set it up just like I was told to (as far as pills and injectors and all that). Car starts cold and idles at 1300 rpm smooth as silk, except fuel is DRIPPING out the right header, and the left one isn't. Off idle the system appears perfect, as far as mixture / engine temp. Oil also looks good, not washed down.
What gives, I can't figure out how ONE SIDE is richer then the other ??? I mean, I have a basic grasp of how the thing works, how can more fuel be going to one side ???? It's bugging me, please help. Both sides have the butterflies closed, on the stops, and appear to be perfectly in sync.
Only other thing I can think of is that after running on the track, it won't idle, you have to give it throttle or it idles too slow and shuts off. This is when the motor is up to Temp.
I know this is way basic stuff, somebody feel some pity for my ignorance and toss me a bone please

posted March 23, 2003 05:42 PM
Your right side butterflies are closed at idle.Shorten the link between banks and reset the idle stops.All exhaust pipes should be the same temp. at idle. the old wet fingertip will work as a check if you dont have a pyrometer.Adjust the connecting link until both sides are the same.If one or two cylinder are much different from the others on the same bank ,you have bent butterflies.Sorry for such along reply but i wanted to be sure you understand me.

posted March 23, 2003 07:07 PM
The left headers are all similar in temp, and the right headers (at idle) are ice cold. As I said, there is literally fuel dripping out the header.
It APPEARS that both the left AND right butterflies are closed at idle ? I can remove the stacks and they sure look the same. But your reply makes perfect sense, that there just isnt enough air compared to fuel on that side - I was hung up on the idea that it was getting more fuel, not less air.
Next stupid Q is that when I let more air in the right side to lean it out, won't that raise the idle up a bunch? Should I "close" the left side as I open the right side butterflies to keep the idle ? Is 1300rpm cold too low, is that the reason when hot I am stalling out without using the throttle? I'd like to idle about 1300 when HOT. Right now it won't idle hot.

I'm REALLY sorry for asking so many basic Q's. I live in FL which isn't really SprintCar Land, and the few guys here with good knowledge aren't really interested in helping me. Thanks again for your reply !

posted March 23, 2003 08:30 PM
As you open the right butterflies close the left ones.When you have them the same set the idle to about 1000 rpms.Ahandy tool to check the butterflies with is an old "unisyn" carb synchronizing tool.Idont know if they still make them,but they can be found.Adjust both banks to the same vacuum reading.When you get it right the throttle response off idle will scare you,it will be so quick.

posted March 27, 2003 11:05 AM
Mod 4 When you open the one side up the idle will go up, but on the non adjusting side there will be a curb idle scr@w at the base of the front linkage that will get you back to your idle that you want. The key is to get both side insink with each other then adjust the curb idle.

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