Wondering if anyone has found a way to change over to an EFI tank and still have the low fuel light work on the dash of a 69 XR7? I’m going to use the Holley sniper X flow on my 69 and would like for my low fuel light to still work. As of now, I’m thinking of using a new 20 gallon tank with the original sender/fuel pickup and the Holley universal in tank pump. I’ll have to block off the original fuel pickup on the original part. I’m hoping someone else has already found a good option. I don’t want to have to reinvent the wheel if someone has a good option.
This is not an issue if you want to use an external pump. There are several consideration though. First the 20 gallon tank requires a '70 sender to work properly, it is also possible to modify your existing sender. You can have that sender modified with the addition of a return line. You can use another 5/16 or 3/8 inch fuel line run parallel with the stock one for the return. ACP is offering a reproduction sender with low fuel and a return line. That can also be modified. I think they are working on a '70 with return line as well. You can also block off the fuel line as you described and use a 70 reproduction low fuel sender. Or you can add a return line plumbed directly into the tank.
Bill,
I’m really not interested in using an external pump. In your response, you mention ACP. I’ve never heard of them, so do you have a link for them? Also, WCCC part #18899, the description is:
“Exclusive to WCCC, here’s our reproduction in-tank, fuel sending unit with the low fuel option. Good for all 1969 Mercury Cougar XR7’s and all Ford Mustangs with 16 gallon fuel tanks. This is a reproduction of a 1969 fuel sending unit with 3 prongs (2 electrical and 1 alignment prong). The original Ford casting number was C9WF-9275-C. This unit comes with a new 3/8 inch filter, brass float, and sending unit gasket. These are completely interchangeable on all 1969 20 gallon fuel tanks.”
So can this part be used with the 20 gallon, or would I need a 70’ sender as you suggest?
Really appreciate the assistance.
Bill,
Did a little digging and found the ACP site. I’m doing some research now on external fuel pumps as far as how loud they are. It sure would be a lot more cost effective to use a replacement tank, the ACP sender w/return and an external pump if I could find one that is quiet enough. Any recommendations would be appreciated.
Thanks again!
I upgraded to the Holley EFI system and used the external fuel pump, it’s loud when you first turn the key to run (waiting 5 seconds for full pressure before cranking). Once the engine is running it’s had to hear over the engine (I have a convertible so maybe louder than a coupe).
With that said I did upgrade to an “In-Tank” fuel pump to make it a bit quieter and lost the low fuel indicator.
To get around that I bought an after-market fuel gauge calibrating unit that included a low fuel discrete output to drive a relay (Classic Instruments SN34 Fuel Link).
I believe it sets the output when it gets to 1/4 of a tank. It works but the accuracy of the output is only slightly better then the original sending unit.
But I believe that is my fault as I could have spent more time working on the calibration.
Oh, and the Holley in-tank fuel pump had 3 different float rods, one for 18 gallons, one for 20 gallons, and one for 22 Gallons.
Good Luck.
Jay
Thanks Jay,
The noise from external pump was my worry as I also have a 69 convertible. I’ve been looking at the exact same setup today, but my problem is that I’m installing a 521 big block in mine with the Sniper X flow. From the instructions, that unit mandates a return stye fuel system, and the pump that I believe you used is the same one that I’ve been researching, and it has a built in regulator, which makes it returnless. I don’t know a lot about the ins and outs of the EFIs to go against what they are requiring.
I may try to see if I can adapt an in-tank pump to the stock pick tube on one of the 69 units with the low fuel level sensors and add a return fitting. It seems to me that if they made the pump work in the tank on the model you have, then there might just be enough room to install a pump without the regulator. Otherwise, I’m gonna have to use one of the retrofit Holley EFI modules and just cap off the pickup tube on the stock unit, which will allow me to use the low fuel level light.
I do see you have the Hyperspark system on yours too. How is all that working out?
Appreciate your input. I knew someone else out there has dealt with this same thing…
Mike J.
Mike,
I plumbed a return line on my car back to the tank when I had the external Fuel pump. Used flexible EFI (High Pressure) line and modified the tank with an AN fitting to accept the return. I ran it on the passenger side, mirroring the supply fuel line on the drivers side. The return is low pressure so you don’t need to go to crazy with fittings, but since I had left over EFI hose I used it.
The Holley distributor I used works great, the Sniper EFI controls the timing and the car runs great. The only issue I found out was the distributor was designed for later model truck 351W and was a few inches taller than the stock distributor causing me to change to a different air cleaner, since the stock air cleaner was interfering with it.
You might want to contact EFI System Pro, they are very helpful with Holley EFI systems and were a great resource for me.
https://www.efisystempro.com/
Jay
I found this on NPD website this am. It uses an operating fuel gauge to illuminate the low fuel light instead of the thermistor on the sending unit. And its solid state.
https://www.npdlink.com/product/conversion-kit-low-fuel-level/203014?backurl=search%2Fproducts%3Fpage%3D3%26search_terms%3Dfuel%252Btank%26top_parent%3D210001%26year%3D1970&year=1970
My options seem to be opening up…
So to close this topic, I ended up ordering a Tanks Inc. EFI kit from Summit that included an EFI ready tank, 400lph in-tank pump, and the fuel sender. I’ll eventually order the same part that Jayco59 used to illuminate the low fuel light on the dash. Thanks for the responses.
For anyone following this thread and interested in issues with fuel level sensors in the '69 and '70, 20 and 22 gallon OEM fuel tanks, there is lot of dimensional information on the tanks and the relationship to the float arm length on the level sensor in the following thread starting at #24 on page 3.
https://cccforum.discoursehosting.net/t/c4-rebuild-servo-kit/77/1
Tom
Related to the low fuel level sensor: If you can acquire and mount the correct sensor, mounting it low in the tank and wiring it per the original, to the relay, it will work. That said, at one time, the low level sensors on the market were not the correct thermistor resistance range and did work correctly. This included the original WCCC SS replacement level sensor and fuel pick-up assembly that they pulled from the site when issue was identified and the replacement thermistor that ACP sold. Bill Basore identified this issue some time ago and he is using the correct thermistors. I don’t know who else has caught up and corrected their products. I was going to detail how I mounted and wired the thermistor on the Holley OEM Style in tank fuel pump 12-305 (it mounts in the OEM fuel tank and doesn’t require a return ling) but it doesn’t have the capacity for the Sniper Xflow.
Tom