Fuel pump update

Evildky

Anyone know the difference between the 09-2015 and the 2015-2020 pump design?

They are different part numbers, what little I can see from images online they appear to be identical. As far as I can tell the aftermarket pump solutions work on all years so I'm assuming that the wiring connection and the hose connection are the same and perhaps it has an improved internal design. Anyone done an A/B comparison?

Why am I asking? I've been fighting the fuel starvation so many others have. I experienced starvation on track at 3/4 tank. I opened up the venturi orifice and added a couple of lower holes in the fuel cup and was able to run to maybe 5/8 tank. This weekend my fuel gauge went bonkers, decided to go ahead and order the anti starvation kit. Opened the gas tank last night to find my pump had broken off the hat and the sender arm had come off. So now I need at the very least a hat.

What am I really after? A plug and play solution wiht the least dollars spent. Considering the cost of the hat plus the anti starvation kit might as well get the CJ twin pump but I don't want to rework the whole damned system. Is there a configuration that improves the siphon without having the convert to a return style system? Did the 2015 updated pump fix any of the starvation problems? To be clear, I REALLY REALLY DO NOT want to have to convert to a return system.

Jhill

Ok so I just went through some of this and ended up with the radium kit in the end. What anti starvation kit did you order? If it’s the z1 kit I have that in a box I used for about a week you can have it much cheaper if you wanna try it.

So I too replaced the pump and the one I got now has two springs on the top hat vs the original one that had only one side spring loaded cause the hat to break. I ordered for my year but I believe this is an update to all. As for the starving you say you opened the Venturi orifice? Unless I’m mistaken which one your referring too this is actually the wrong thing to do as it lowers the Venturi effect and will lead to even more starvation that’s why the instructions the cjm when installing a larger pump have you try to stay as small as possible.

In the end the walbro 255’s I used one in pump one in anti starvation kit were too loud and I also didn’t like the pressure spike at idle so I wasted money trying to go the cheaper route and in the end did the radium kit with two aem pumps and couldn’t be happier. The pumps are quiet and the adjustable fuel pressure regulator already saved me some hassle for those in Ca new smog check now checks for aftermarket tune so if you have larger injectors for e85 you’ll now be screwed and either have to pull the injectors to run the stock tune or get creative as I did and lower fuel psi until you keep fuel trims in spec on stock tune.

As from the install of the radium kit just make sure you have a friend and a fishing tool to run the hoses, everything else is very clean and well done product.

Rusty

To fix the top hat of the fuel pump housing. CJM is the way to go.

Only 2 ways to fix fuel stave. Either the CJM RRP kit or the Radium kit. I have one of the first CJM RRP kits. I have run it down to no dots. Took 18 gallons to refill it.

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Evildky

Emissions are not a concern. I'm on stock injectors, the classes I compete in do not allow for larger injectors or E85.
Z1 anti starvation kit is expected to deliver today, I guess I just need to get the hat and call it good for now.

Jhill

Bummer I woulda sent you the z1 for 100.00

Evildky

That would have been a great deal, my loss for not posting before I ordered it.

Even more fun the CJ hats are on a 4 week backorder, and my next event in just over a week away, guess I'll be doing the threaded rod fix for now.

Reconsidering the radium kit. It just kind of irks me that they want you to replace the OE pump. It should function fine as a lift pump for those of us running moderate N/A power, other than powering the venturi it could be replaced with a low pressure high flow unit.

phunk

I have a 117 CJ hats in stock. DM me or email sales @ cj-motorsports.com

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phunk

The only difference in the later hats, that makes any difference at all to the user, is a different harness connector. Earlier than that, there was a revision to put a spring on each of the 2 rods, but that doesn't solve anything.

Any anti-starvation kit installed to the left side of the tank, will all require repairing/replacing the top hat on the right side of the tank.

CJM has a surge tank add-on kit nearly available for the twin pump, which is a full right side replacement... but as you have observed, to run that twin pump requires a return fuel system since it does not have a regulator or filter integrated to it like the stock unit does. Mostly just because there is no space for those when a second pump is added. A fabricator could put those components in place of the second pump, but it would not be too simple thus not inexpensive unless you were familiar enough to make those modifications yourself.

You asked about ways to improve the siphon... that is a yes. You can improve the siphon and accelerate fuel recovery to the right side of the tank. If you installed a larger output fuel pump, and put in perhaps a pair of venturi pumps on the pressure side of the system, you could easily add 150-160lph of left to right transfer on top of the stock venturi system. It should help reduce slosh starvation a lot, but there are no guides / how-to for doing this, so you would be a little on your own other than some advice I could lend. Without having tested such a setup, I have no comment to what extent it would reduce or prevent slosh starvation.

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