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Old 05-28-2009, 11:03 PM
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Xavier Xavier is offline
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Join Date: Nov 2006
Location: Fontana, CA
Cobra Make, Engine: Lonestar LS427, 408w, 48IDA Webers, TKO 600, 9" Currie 4-link 4.11 rear
Posts: 390
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Default Need help trouble shooting fuel issue....

Here it goes....I have had this problem since I built the car, it usually is quickly remedied, and was going to put off the repair until winter, but I can solve it this time...

After a couple of weeks of having my car down and out to replace the exhaust manifold gaskets and to eliminate some annoying back-firing, I once again, am having problems getting fuel to my engine. Its importnat to note that prior to this downtime, the car was running very well. No issues at all - other than the annoying backfiring which for a fact was due to a blown exhaust manifold gasket, I replaced both gaskets as normal, torqued down etc. Since th cork valve cover gaskets were leaking in the process, so I took care of this too. I also replaced the carb manifold gasket at this time with a new one. Pulled off the carb and replaced the gasket. I really did not need to do this, but when I put the new carb on I used the old gasket, it did not look so hot, so when I got a new one I vowed to replace it, so I did.

I go to start the car, and what has happend before after having the car down for a couple of weeks is the fuel pump gets no fuel to the engine without a huge process of different unorthadox techniques. It has done this many times, and to get it up and going this is what I have had to do.
I turn on the fuel pump, I know there is no fuel to the engine becuase my PSI gauge at the carb is at zero, and I am just used to this...I loosen one of my -AN fittings until the fuel bleeds out near the carb, catching any fuel with a rag and having a wrench ready to tighten the fitting. This may take a few minutes...the longer the car has been down, the longer it takes. Fuel starts flying out, I tighten the fitting, go start the engine, and I am good to go...its annoying as hell, and I vowed to fix it, I just did not want to do it now.

My fuel configuration is as follows;
3/8" fuel line / -6 fittings
regulator / no return line
Holley Black fuel pump mounted behind driver side rear tire
course filter before pump, fine high capacity canister filter after - both clean
The pump is higher than the lowest part of the fuel tank by about 6"

So I go through the process I have done previsouly, except this time - the gauge stays at zero - very little fuel if any is coming out. I take apart my fuel pump and it looks totally burned up - black. Smelled bad. I replace it whith a new one this evening. I bolt it back up and go through the same "bleeding process" as before. The noise or pitch of the fuel pump changes when it is under load, so by listening, I can tell when the fuel is getting to the pump. This time, the fuel is in higher pressure, pissing everywhere. PSI is at an unstable 5 to 7PSI (I have the regulator set at 7 just to get this thing going temporarily). Still, the carb is leaning out - acts like there is no fuel - although there is. Fuel sites in the carb show 50 to 60%, as usual. When starting the engine, if I keep pumping the pedal, the engine will run, but quickly dies when off. I don't want to cause any engine damage, so I kill it. Way lean.

Carb is a Summit Racing 600cfm carb (4010 clone) - again this carb has worked perfectly up to this point. No issues. No performance problems at all.

So, whats the issue?

- Did fixing the exhaust headers, valve covers, carb gasket cause another issue and changed the performance of something else that drastic so the carb is now out of whack? Hard for me to imagine it when from perfect to no gas.
- Did I screw up something when changing the manifold gasket on the carb? Something get into the carb?
- I know something is screwed up with the fuel process, that's a given - but again, it worked before - why not now? Warmer temperature causing vapor lock? Its not that warm...

I have my old Edlebrock street carb that I can switch out, I plan on doing it just to see what happens becuase I am running out of ideas.

What do you do when your car gets gas, but it acts like it has none?

I am out of money, out fo ideas and out of time before the weekend. Anyone have any suggestions, please?
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