Fuel Surge in 2WD T25's with injected engine conversions?

rjes

A couple of customers have mentioned their fuel systems are picking up air under certain conditions, mostly when the tank is reasonably empty. This seems to affect a small number of 2WD models, and I want to find out why. I have only ever had Syncro's myself. As far as I know it's pretty much unheard of in Bays and Syncro's.
If you've had this happen, perhaps you could answer the following questions, in the hole that the cause of this can be pinpointed to a particular model / tank / installation detail. Thanks:

1. What year is your 2WD T25?
2. Was it originally petrol or diesel?
3. If petrol, was it originally injected or carb'd?
4. Do you have the fuel feed to the injection pump coming from the left or right side of the tank?
5. How big a problem is this (minor annoyance, big problem, etc)?
6. What tank fuel level do you start to notice this problem at?
7. Is it most noticeable when turning left, right, accelerating or braking?
8. Do you have an original VW tank, or an aftermarket replacement?
_________________
Regards,

Richard,

R J Engineered Solutions
Quality Subaru Powered VW Components
www.rjes.com

doppelganger · Posted: Wed Aug 06, 2008 3:59 pm Post subject:

lowered 80mm
low fuel ,heavy cornering or acceleration ,
carb tank
turbo engine

but only ever happened a couple of times
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13 window deluxe · Posted: Wed Aug 06, 2008 6:19 pm Post subject:

i had the air sucking noise when cornering on my 1990 t25 started from about 1/4 tank on gauge it had a brand new euro car parts 2.1 injection tank with the 12mm outlet and swirl pot in. the engine was a 1.8 8v gti motor and in 1 year it went through 3x high pressure bosch fuel pumps dont know if running them dry during hard cornering caused them to seize?
_________________
1964 rat 13 window deluxe 1Z tdi,
1975 rhd twin slider tintop (TBA)
1991 golf 2 gti with tweaked AHU tdi,

previous tdi swaps: gone but not forgotten
1979 rhd twin slider tintop bay ahu 1.9tdi
1990 T25 1Z 1.9tdi
1993 suzuki samurai with 1Z 1.9tdi

rjes · Posted: Wed Aug 06, 2008 7:45 pm Post subject:

Thanks for the replies. 13 Window - where was your pump mounted - higher than the fuel level?, and did you have a filter before the pump?
_________________
Regards,

Richard,

R J Engineered Solutions
Quality Subaru Powered VW Components
www.rjes.com

13 window deluxe · Posted: Wed Aug 06, 2008 9:17 pm Post subject:

on the chassis rail just behind the tank outlet pipe
_________________
1964 rat 13 window deluxe 1Z tdi,
1975 rhd twin slider tintop (TBA)
1991 golf 2 gti with tweaked AHU tdi,

previous tdi swaps: gone but not forgotten
1979 rhd twin slider tintop bay ahu 1.9tdi
1990 T25 1Z 1.9tdi
1993 suzuki samurai with 1Z 1.9tdi

13 window deluxe · Posted: Wed Aug 06, 2008 9:25 pm Post subject:

filter was after pump as per factory t25 setup it was a 12mm pipe from tank to pump inlet (suction)8mm pipe from pump outlet(pressure) to filter inlet 8mm pipe from filter oulet to injectors, i would say pump inlet was below bottom 1/4-1/3rd of tank. i did think of adding a low pressure lift pump and a additional swirl pot to feed the pressure pump but i fitted the tdi engine soon after as i was fed up of putting petrol in the van after a year or so!
_________________
1964 rat 13 window deluxe 1Z tdi,
1975 rhd twin slider tintop (TBA)
1991 golf 2 gti with tweaked AHU tdi,

previous tdi swaps: gone but not forgotten
1979 rhd twin slider tintop bay ahu 1.9tdi
1990 T25 1Z 1.9tdi
1993 suzuki samurai with 1Z 1.9tdi

mike1978 · Posted: Wed Aug 13, 2008 2:37 pm Post subject:

i had problems with this -

considerable stuttering and juddering with the tank pretty empty (in the red).
If i go round a roundabout fast and pull away quickly, i get a stumble in the engine as i can`t pick the fuel up. (above the red but still low)

I just keep the tank above a quarter

oringally diesel tank

1992 LLE Multivan T25
feed comes from right side of tank as you face forwards
original vw tank.

rjes · Posted: Tue Aug 26, 2008 9:03 pm Post subject:

I had a good look inside a rusty old tank from a 1984 diesel - well as much as I could see with a torch through the sender hole. There was no sign of any part numbers on it (I think they may have originally been on a label), but it did appear to be the same inside as the photo's I have of a late '80's tank from a carb'd petrol. Useful, but it's not shed much light on why some tanks seem to have fuel surge and others don't.
_________________
Regards,

Richard,

R J Engineered Solutions
Quality Subaru Powered VW Components
www.rjes.com