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Starving for fuel (or spark?) at speed

Posted: Fri Jul 03, 2009 6:45 pm
by Moph
Similar problem to what B4T had back in this thread. Idles beaut, drives fine around town all day at 60kph, revs out happily to redline in first ... but can't be coaxed above about 70kph whatever I do.

Cuts out really suddenly which made me firstly think it was ignition related. Gives heavy engine braking when it drops out, then surges a bit, then drops, and slowly gets worse until the car is stopped and idled for a bit.

I've just replaced plugs, leads, dizzy cap and rotor button and it's still doing it. Nowhere near cold enough to ice up either. Fuel pump seems to be working fine - filled a 250mL glass in about 15 secs at idle.

I had been having idling issues over the last couple of days which I 'fixed' by swapping leads 2 and 4 over to get it to backfire, and then blowing compressed air through the fuel inlet on the carby to try to clear the jet. Idling issue is now fixed but I'm not sure if my 'fixing' hasn't stuffed something else... :? Maybe stuffed something in the float chamber that is now causing vapour lock?

Posted: Fri Jul 03, 2009 8:12 pm
by Moph
Have also blown out fuel lines with compressor, checked fuel filters (original + one on suction side of fuel pump) and disconnected the carbon cannister. No joy :cry:

I actually floored it until it completely died (about 70kph), cut the ignition and coasted to a stop in neutral. Checked the clear fuel filter near the fuel pump and it still had a normal amount of juice in it, so it really seems like the delivery system is doing its job to the point of the carb, but the bowl is emptying out under load :?

Posted: Fri Jul 03, 2009 9:05 pm
by built4thrashing
Undoo the nut that connects the hard fuel line to the carby as there is sometimes a screen filter in there.


Mine was a PITA to find as it ended up being a gum nut blocking the pick up in the tank. Next time it dies clucth in and stop engine asap and check filter at pump. Dont let it fill up again with idle or coasting pump pressure.

B4T

Posted: Fri Jul 03, 2009 9:38 pm
by Moph
Thanks B4T - you may have fixed my problem :D

Still gotta road test (heading out now) but when I undid the hard fuel line to the carby, the end of the hard line was absolutely jammed full of crap.

I'm not 100% sure what the crap is exactly, but it has a legs and headsy sort of look. I may have had ants die in my compressor line that didn't get blown out when I cleaned it before use, and ended up jammed in my fuel line :oops: :oops: :lol:

Will take it out and try it now :)

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UPDATE: Yep, I'm an idiot. Bugs in the compressor line were the cause. Runs beaut on the highway now! :armsup: