Dan, happy to supply a photo. I have mine set up identical to the schematic Dick included in one of his posts. It fit in without issues despite the additional lines. I believe I ground down the edges of the one way valve so the board that goes over the tank would fit properly. I have had zero issues.
Electric fuel pump to prime carbs
- Thread starter Dick Steinkamp
- Start date
Last edited:
In my NK I have the anti-back flow valve in the engine bay and not parallel to the priming pump in the trunk.
Chris,
For some reason, your mechanical pump is able to draw fuel thru the electric pump and BavBob's isn't.
I have no idea why it works for you when the instructions for the pump say it shouldn't.
I guess it's better to be lucky.
Dan, that this happened only once is odd. But, now that you know how to resolve it I guess there's little reason to put in the bypass line and check-valve.
John
Last edited:
This was the first time I had fuel starvation from the Pierburg without the check valve in maybe 40 starts.
Here is my setup. Recall my car was impossible to start after sitting for a few days and the primer pump run off the defrost switch made a big difference. The first real drive I had, the car dies after about 1/2 mile from the house. That was with the Pierberg in series like Chris has. I then switched to match the diagram above and have had no issues.
Dan,
I don't get it. When the car starts, the fuel bowls are filled almost immediately by the mechanical pump if not already filled by the electric (if using it for prestart). I don't see how a fuel starvation event can occur after driving 1/8 mile. What am I missing?
EDIT. Is there a chance the Pierburg pump stops at a point that will not allow draw through by the mechanical pump, but 99% of the time does not stop in that position?
I suspect that is what happened as @JFENG mentions.
I ordered on of the Amazon pump that you are using in the E3. It appears I have enough room. If it doesn't work, I will use it in the 77 Wagoneer that also evaporates fuel from the carb bowl.
That was my theory, which is possible with a cane type pump.
//My5UV
Member
I'm getting ready to do this and had a dumb question about the defroster wiring: does it run through the same harness as the trunk light plunger switch, or did you just tap into or remove the spade connector at the defroster and then fish a wire into the trunk? The thin plastic trim in the trunk seems pretty fragile so I'm hoping to limit how much I disturb it instead of just poking around at random.
Also: my '74 has two fuel lines connected to the tank. I assume the one attached to the sender is the output, and the other that's plumbed into the middle of the tank is the vent? Weird to see for a carb car but I guess it's part of the later model emissions?
Also: my '74 has two fuel lines connected to the tank. I assume the one attached to the sender is the output, and the other that's plumbed into the middle of the tank is the vent? Weird to see for a carb car but I guess it's part of the later model emissions?
In 1974 a fuel return was added from the carbs
Wiring for the defrost is behind the rear left seat. I just crimped on connectors to 18G wire and joined the defrost wiring and ran it through one of the holes behind the right rear seat, perhaps the hole that is the mirror image to the one on the left for the trunk light wiring. 100% sure I did not touch the elephant skin covering of the wheel well other than to run the wiring behind it. Note red wiring in the two images above.
Last edited:
I always find this to be an overly complex solution to a simple problem. I fitted a manual pump years ago and it couldn't be any simpler. Use a good quality one ( I have a Yamaha outboard motor pump) as the cheap ones tend to crack and perish quite quickly. If it has been sitting for long enough for the bowls to empty you will likely have the bonnet open anyway to reconnect the battery so it's no hassle to give half a dozen pumps before you start it up.
//My5UV
Member
If it was just from non-use I wouldn't bother, but I got vapor lock the second day I had the car on a not very hot Texas afternoon 
Not something I'm bothered with on the north east coast of ScotlandIf it was just from non-use I wouldn't bother, but I got vapor lock the second day I had the car on a not very hot Texas afternoon
//My5UV
Member
Skipped cars and coffee this morning to get it done. I found the defroster wire by removing the left rear seat and was able to tap into that and add the pump I got from Amazon. Doesn’t fit as nicely in my e9 as the Pierburg does in e3’s but seems to work well and doesn’t block flow through the mechanical pump when not powered
This solution makes good sense to me. So you just cut the fuel line running to the carb and slotted the pump inline?
//My5UV
Member
Yep, I'm not happy with the two loops. If the pump were a tiny bit smaller I could have done it with just one loop, or maybe I could reroute the hard line to put the pump in the dead space near the spare tire, but it seems to run fine and it's protected from any accidental bumps if somebody is getting the spare in our out, so I declare it good enough. Now I just have to finish fixing the radio and find somebody to get the AC running.
Get an angle grinder and cut those wings off, use a bit of velcro to secure the pump.