VWDiesel.net The IDI, TDI, and mTDI source.

Engine Specific Info and Questions => IDI Engine => Topic started by: Big Daddy Roth on February 10, 2011, 09:21:09 am

Title: In-tank lift pump
Post by: Big Daddy Roth on February 10, 2011, 09:21:09 am: I'm swapping the AAZ from my TD B3 into a syncro B3.

I'm thinking of keeping the lift pump in the tank. Good or bad idea? Under what fuel demand conditions should it operate?
Title: Re: In-tank lift pump
Post by: R.O.R-2.0 on February 10, 2011, 12:27:40 pm: is it a supply pump for the high pressure fuel pump? or is it the high pressure pump?

if its just a supply pump, then its fine to rig it up so it comes on with the key.

if it puts out more than about 5 psi, i would take it out and forget about it.
Title: Re: In-tank lift pump
Post by: Big Daddy Roth on February 11, 2011, 10:36:30 am: It's the OEM in-tank pump from the G60. However, it's the only supply pump for the Digi1. So I guess it must be high pressure.
Title: Re: In-tank lift pump
Post by: rodpaslow on February 11, 2011, 01:03:21 pm: I have a gasser golf that still has the high pressure pump in it. I just bought a cheap regular holley fuel pressure regulator 1-4 psi ( HLY-12-804) about $25. I had to open the tank in my car to take off the return line that usually goes from the plastic joint (top inlet & outlet) into fuel in the tank to reduce the effort the return fuel had as it was just enough pressure to have one of the return lines in the engine bay leak. So now the return fuel just spills back into the tank from that top plastic cap. (there was a hose going from this cap into fuel for the return, I guess maybe to reduce noise or something? Not sure why.)

I have about 15,000 km on it since my swap and not any problems with the high pressure pump. All it's pumping is diesel fuel so I think it will last forever.

It's kind of nice, when you bleed the system you don't somehow have to pressurize the tank or use some sort o vacuum to do it. You just turn the key on.

If you have any other questions, be glad to help.
Title: Re: In-tank lift pump
Post by: arb on February 11, 2011, 09:19:21 pm: I tried to use an electronic fuel pump on my diesel caravan conversion, I was not even high pressure. It cause problems on hot days in the summer. After I removed it, no issues, winter or summer.

Keep the simplicity of our injection pump's lift pump.
Title: Re: In-tank lift pump
Post by: R.O.R-2.0 on February 12, 2011, 07:55:10 am: i had a small sheet metal shaker style pump in my rabbit as a lift pump/primer..

it worked great, and made my fuel filters last like twice as long..
Title: Re: In-tank lift pump
Post by: theman53 on February 12, 2011, 09:05:22 am: Quote from: arb on February 11, 2011, 09:19:21 pm
I tried to use an electronic fuel pump on my diesel caravan conversion, I was not even high pressure. It cause problems on hot days in the summer. After I removed it, no issues, winter or summer.

Keep the simplicity of our injection pump's lift pump.
Weird, I had one on my 81 and it did the same thing.
Title: Re: In-tank lift pump
Post by: Big Daddy Roth on February 13, 2011, 12:54:48 am: nm, The in-tank g60 pump is high pressure
Title: Re: In-tank lift pump
Post by: R.O.R-2.0 on February 13, 2011, 05:27:21 am: yes, digi equipped vehicles had 1 fuel pump, and it was the main pump.. if it would have been an AUX pump, it woulda been great.
Title: Re: In-tank lift pump
Post by: JGWarner on February 20, 2011, 08:00:18 am: I'm doing a TD swap into a VW Fox, so I've already got the CIS-E dual pump setup in the rear. I've been thinking about keeping the in tank pump as well (low pressure) and it's already wired to come on with the ignition.

But what happens if/when it dies? Will the IP have trouble lifting fuel through the dead pump?

I really prefer simplicity, but the idea of easy fuel bleeding is hard to pass up.