Symptoms were:
Bad idle - had to sit in the car and feather gas to warm it up the last 2 track days.
first track day out of some turns and under load it would sputter on me.
last track day out of every turn and every time i hit gas it was sputtering...
Found some of my throttle body to intake boots 2 of 4 were split.
So I thought maybe bad air fuel ratio, so ordered new ones. Before the new ones came in I made some connections with a silicon tube to see if I could fix it. Put them on ran for about 10-20 sec then shut off. Looked like I was leaking fuel out of the tubes so I assumed my mickey mouse job didn’t work. I figured it just wasn't able to seal too well because it didn't have the mechanical lock that the correct boots have.
After I installed the correct boots last night it did the same, started for 10-20 seconds and then stalled…saw the same fuel leak, so i pulled off the air box to take a better look. It appears that the return/overflow/vent hose that goes from the top rail on the carb back into the air box had a steady flow and was just dumping fuel back into the box and running down into the top of the carbs and flooding the engine. I first thought my floats were stuck open in the carbs, but having all 4 of them fail at the same time is highly unlikely. Right???
I figured it was my fuel pressure regulator so I measured pressure before and after the regulator. both were measured about 5.5 PSI, no drop after the regulator???…does anyone know the correct pressure(s)?
nothing is "sticking" when applying throttle
everything seems to be opening and closing fine
Black bottom tube is the feed line, the top black line with the orange hose is the overflow/vent that dumps right back into the air box.
Should i move this topic to the DIY?
I’m not an expert on carburetors, but it sounds like you could nave a stuck float valve or similar issue going on. When was the last time the car ran properly? Is this the first time that you have run the car since your accident? If it is perhaps something in the carbs got jammed ? It might be a good time to rebuild your carbs. Hopefully @RLM-dan with give his input.
As Charlie said, my first thought would be that you have a stuck float bowl so the carbs are constantly filing with fuel. It could be a bit of dirt/debris stuck on the float seal.
I think (but don't hold me to this) that the fuel pressure should be around 3 psi. This could be the other problem, as if the pressure is too high it will overcome the float seals and again constantly cause the carbs to fill.
Trying another pressure regulator and dropping the pressure back a little would be the easiest thing for you to try first?
Thanks guys....
Car has run 4 track days since it went off roading. last 2 have been the issue days.
Jonathan from Group A (awesome shop by the way) wrote over to the factory and asked on the pressure...5 psi was correct.
we did more testing on it, and now we do think it is an issue with a float level or one of the seals. seems cylinder #2 is not sealing properly and calling for fuel non stop. so the fuel makes its way up the vents in the carb to the top vent tube, overflows into the other cylinders, then out the vent tube once the other cylinders are all full.
checking if the factory has a rebuild kit. might rebuild all of them, but definitely at least #2. im kind of sketched out buying a kit on amazon. they are only $28 for each and they come with everything though.
