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Author Topic:   Fuel Problem
bm4183
Dirt Full Roller

Total posts: 39
posted April 27, 2005 07:29 PM  
I was in a wreck and had to replace the motor. We got the new/old motor running, but the carb (quadrajet) was leaking gas and it wouldn't idle. After we got it running the original fuel pump was leaking, so we replaced it. I had a so called expert go through the carb a few times and he still can't get it right. When we start it up after sitting a while, we can see the fuel filter start to fill up completely. Normally it would stay about half full. He suggested that it was the (new) stock fuel pump providing too much pressure, so we replaced it again and the same thing happened. We then replaced the carb and the same thing happened. I can't see anything wrong with the fuel lines, but I'll recheck them again. I'm just trying to find if anyone would have any suggestions.

bm4183
Dirt Full Roller

Total posts: 39
posted April 28, 2005 06:51 AM  
What's making it pump so much fuel that the filter in-line between the pump and the carb stays full? We took a good carb and pump off of another race car that worked fine, but it does the same thing. That leads me to believe that it's something in the fuel line, but it looks fine...

Festy46
Dirt Full Roller

Total posts: 59
posted April 28, 2005 07:46 AM  
The first thing I would do is put a pressure gauge on the fuel line to find out exactly how much pressure you have. I assume you are talking about a mechanical fuel pump. Does the pump have an extra return line fitting on it that you aren't using? Try taking the gas cap off your fuel cell and run the engine.

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Gas right. Brake left. No bumping.

bm4183
Dirt Full Roller

Total posts: 39
posted April 28, 2005 07:58 AM  
Well, the guy that rebuilt the carb said he put a gauge on and it read almost 30 lbs, but I'm starting to wonder about him now. The fuel cell has a vent, but I'll try it with the cap off.

leapinlizard
Dirt Freak

Total posts: 402
posted April 28, 2005 08:05 AM  
Your carb guy is on crack.

Q jet's need about 3-5 pounds of pressure. A regulator is never a bad idea. You full filter isn't your problem. Where is your leak coming from?

racerman707
Dirt Freak

Total posts: 374
posted April 28, 2005 08:05 AM  
Check the pressure and put a regulator on it.

bm4183
Dirt Full Roller

Total posts: 39
posted April 28, 2005 08:56 AM  
This is the same carb and set up we ran on this motor for two years. All we did last season was swap everything over to the new motor. We never ran a regulator on either motor. I blew the new motor a few weeks ago and we swapped everything back to the original motor. It is the same carb that I've been running for 4 years with a stock pump and no regulator on either motor. The only difference we see is that when it starts to run bad the fuel filter fills up completely and it dies.

TEAMPCR
Dirt Freak

Total posts: 238
posted April 28, 2005 03:34 PM  
Is it possible there is an obstruction between the filter and the carb?? Like a collapsed hose or kinked metal line?

[This message has been edited by TEAMPCR (edited April 28, 2005).]

bm4183
Dirt Full Roller

Total posts: 39
posted April 28, 2005 05:59 PM  
It doesn't look like it, but we are going to swap the lines over from the other car just to rule them out.

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