Nothing new on the surge tank. I'm going to go for it with my in tank Walbro 255l feeding a single Bosch 044 + the 225psi dual nozzle Alky kit. It will support whatever I can wring out of this kit so I'm going the shelve it until I get this kit running to it's potential. I really need to swap my 60 lb'ers for 80's or 90's to take advantage of the second 044 so I probably do both at the same time. I thought it might be problem with one of the check valves but hey tested fine so it looks like both of the used 044's may have been bad. I'll pickup another new one when I put it all back out to trouble shoot it. I designed everything to be modular so I only takes about a half hour to convert it back to a dual pump surge tank setup.

My project has been stalled by a rear main seal leak that is keeping me from putting it under any boost. My weekends have been sucked up from helping my Brother-in-Law pour concrete the last four Saturdays and getting prepped for a weeklong business trip to London. The rear seal is a whole weekend job in my driveway for me so I'm waiting for one of the local LS1 side-job Mechanics to have an opening to knock it out. Looks like I may get in this weekend so I'll keep my fingers crossed.

Rick

 

Cooo man hope you get it resolved

 

Damn jus read the whole thread all I have to say is NICEE! You have some real talent whitch no doubt in my mind will pay off soon

 

Just spotted this thread. Nice build!

Thinking about your fueling issues......Was the surge tank able to vent adequately to keep up with the dual pumps? I had issues with mine after I rearranged the plumbing.

Are you still utilizing the factory venturi system of the intank fuel module? My stock intank module requires backpressure on the pump to operate properly. With the pump free-flowing it does not function. Your module may be different.

 

At the moment, I can't tell if it was the surge tank design or if the used pumps were the culprit. The truck would idle and cruise fine but the fuel pressure would drop under any kind of load. I picked up a new pump from JayZ Racing and bypassed the surge so the new single is fed directly from the intank 255l. I'm still waiting for the time to fix the rear main seal so I haven't put it under any kind of load yet. I'll take it out this afternoon to see if it fixed the fuel pressure issue. I'm going to look around the Bay Area and see if I can find someone to test the pumps. The odds that both are bad are pretty low. I had Rick switch the power leads to swap the primary and boost switched pump and it didn't help. As you can see in one of the photo of the pumps, both have an OBX check valve. If the check valves didn't work properly, the 2nd pump could be bleeding off all the fuel pressure when it's not on (no internal check valve on a 044).

I'm still using the OEM intank regulator and venturi with the intank Walbro 255. I've only driven the truck with a full tank of gas so I can't tell if the venturi is working or not. The pump should be under some pressure since it is constantly keeping the 3l surge tank full with the overflow going back to the tank. The -6AN retrun line dumps into the filler neck of the tank so it should always have an abundant air source to vent the surge tank but I'll have to see when I pick up another pump. When I pulled the surge tank, it was 100% full but I've yet to see how it works with both pumps at max. I have an unused outlet on the tank so I can hook up a fuel pressure gauge to see if the intank is keeping it presurized under load.

Rick

 

How are the pumps oriented in the tank? The feeding socks arent on top of each other are they?

 

I think he is just has the stock module in the tank except that he has replaced the pump with a 255. From what I recall, the truck fuel modules use the waste from the in-tank FPR to drive the venturi system. There will be no spill from the FPR unless the surge is getting pressurized to 60 psi. Shouldn't be an issue though if the tank is filled higher than the top of the module.

I had the same thoughts re the likelyhood of both Bosch pumps being bad.

 

Correct. The intank just pumps to the surge tank with the overflow going back to the stock tank. It will never see anywhere near 60psi so I guess the venturi won't be refilling the bucket. I usually keep the tank pretty full but even if it does get low, the two flapper valves on the bottom of the bucket let fuel in to raise the bucket fuel level to the tank's fuel level. With 3l of fuel in the surge tank, I don't think I can run it wide open long enough to drain it.

Slim to none is about the right odds. I bought them on eBay but they are suppose to be from a track car with low hours. They appear to be in pretty good shape and sound fine when running.

I played around this afternoon with the check valves. I can blow pretty much un-restricted in either direction so I think they are the culprit. I took them apart and the spring loaded rubber check ball doesn't seal well enough in the reverse direction to stop backflow. I'll have to look for another check valve to try out.

Rick

 

Lol sorry rick !!

 

Nice!

Rick