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TOPIC: Fuel tank

Fuel tank 6 years, 11 months ago #5654

  • JRichard
  • Senior Racer
  • Posts: 107
I've been suffering from hard-right-hander-fuel-starvation-syndrom, and after changing out just about everything and checking all the electricals, talking to jim fox at nationals he chased his issue down to changing out the tank and it solved his problem. Since it's not exactly a simple deal and who knows if another tank won't have the same problem, I was thinking about just filling the tank with fuel cell foam, and seeing if it solves the pickup/sloshing issue (since that's what its for in a cell). It's cheap and would be a whole lot easier than dropping everything just to get the tank out. I'm assuming that it wouldn't be against any rules to do so, thoughts?

The other option involves a rag and a cigarette lighter...

Re:Fuel tank 6 years, 11 months ago #5656

I don't think that is the problem that will solve it. I believe it could be a pinched vent line and foam in the tank won't do any thing. The fuel levels you are runing will not uncover the pickup.

If you want to retrofit a steel tank I have 3 spares in my parts cars complete with all the hardware and one is very easy to remove (it is the only big thing left in the car). Sadly no plastic tanks however.
Joe Paluch
944 Spec #94 Gina Marie Paper Designs
Arizona Regional 944 Spec Director, National Rules Coordinator
2006 Az Champion - 944 Spec Racer Since 2002

Re:Fuel tank 6 years, 11 months ago #5657

  • Oliver
  • Drivers Ed
  • Posts: 2
I was battling the same issue all season long. I have changed about everything short of the tank before Nationals. After all was done the issue still extisted. With one day to spare before Nationals I found my issue. It was the short fuel line between the tank and the fuel pump. This line has a spring inside (or at least should) that should prevent the line from kinking. In my case that spring was just a little too short and did not have any tention. Right in between where the spring inside the line ended and where the line attaches to the fuel pump the line kinked on the inside. I have overlooked this several times because the line looked normal from the outside. Only once I was under the car and looked at the fuel line on the inside radius, I saw that it was kinked. I have replaced the spring with a longer one and the problem in right hand turns went away.
Might be worth checking before you change the tank.

Re:Fuel tank 6 years, 11 months ago #5658

  • Big Dog
  • Banned
  • Posts: 700
My short fuel line does not have a spring inside. I have a new one on both cars and not spring. The old ones did not have a spring either.

I don't think that I had any pinched lines but who would really know. It just seems to me that the vent lines come from different places on the tank and should not affect fuel pressure in only a right hand turn. I can't believe that the tank can move enough to pinch one in a right turn.

When I put 15 gals of gas in, NO PROBLEM. With 8 gals, PROBLEM. When I found out the 15 gals would solve the problem, I decided to change the tank so I did not try to find out just how much gas was the tipping point for the problem.

Fuel cell foam would seem to be worth the effort to try. The only issue is that it will have to be stuffed into the tank in pieces and will, therefore, move around. I am unaware of a way to put liquid foam in and have it expand in place in the bottom of the tank. The other issue would be having the foam move around and damage the strainer sock that is in the bottom. It might even knock the sock out of the pickup. There should be a solution to this issue though.

If you try the foam idea, please let us know if it works or not so we will all have more options.

Jim Foxx

Re:Fuel tank 6 years, 11 months ago #5661

  • JRichard
  • Senior Racer
  • Posts: 107
Joe, thanks for the offer on the tank, I have a line on a plastic one, but with a crazy week or two before the next race I don't have the time to pull everything, so I was looking for other options...

I drained the tank again and dropped the fuel pump,like Jim I didn't have a spring, the fuel pump line is a moulded peice and it wasn't kinked or pinched. I pulled the cover off the fuel filler neck, all the vents were open, expansion tank and the hoses looked intact, I don't know what the proper operation of the one way valves are and the carbon canister was removed so I still need to chase down the venting, It would be nice to get rid of all this crap, and just go to a vented cap, I'm going to pull the filler neck out just to check on the flapper.

I pumped the tank dry with the car sitting on level ground, pulled the sender and looked around inside couldn't see anything out of order, then I jacked up the left side of the car, three gallons of gas were in the left side shelf in the tank! WTF? had to be more but you can't see above the fold in tank. Im begining to think they weren't exactly consistent with the moulding of these things.

The foam is pretty easy to work with I've redone a cell with the small sticks and it wasn't too hard to fit it all in snug, with a little patience so I'm tempted.

Just like Jim; 15 gallons no problem, but run down 5-6 gallons in a 40Min race and I'm shutting down if I start the race with a full tank...not to mention the extra 110lbs made the guys in tech check for passengers...

more to come...


Re:Fuel tank 6 years, 10 months ago #5809

  • JRichard
  • Senior Racer
  • Posts: 107
Well problem solved!

Earlier the fuel strainer in the tank was removed when the tank was drained and cleaned out xand I didn't think much of it... Bottom line I put a new one in and it ran strong left right whatever all the way down to one gallon of gas... Go figure.. so if you have this right hand starvation make sure the filter screen is in place and in good shape before you go too far...

Also I did check the short fuel line as mentioned but there was no way it could be pinched by g forces, I checked the airflow meter fuel pump cutoff it was ok, dme relay, and I rigged up a pushbutton power supply direct to the pump, put it in a hard right unroll it stumbled and pushed the button no diff...the strainer did the deal...wish I figured that out at the begining of the season
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