Fuel pumps

DeathBus · Post by **DeathBus** » Sat Feb 19, 2005 4:57 pm

raygreenwood wrote:STOP!...Please do not get rid of your injection. This is really easy. I have a 5 gallon bucket full of pumps. I will be happy to send pne to you...but it will be the end of the month before I can get to them.

But bear this in mind. There is nothing forcing you to use the D-jet pump. In fact...other than for originality sake...I reccommend getting away from them. They are just too expensive to replace. The nly reason they have 3 connections, is that one has a spring loaded check alve to keep pressures even and help keep flow from being broken by loading up too fast. That goes right back to the tank return line with the "Y" fitting. If you used a two connection pump...like early L-jet, with only an inlet and outlet...it would run just fine. Simply remove the "y" in the retuen line and all will be well. Since pressure is pressure and volume is volume...any FI pump that provides the right pressure and volume will work. For instance...the digifant systems run with just slightly higher pressure...and the same volume. Yes, they generally run feeder pumps...but there is no law that says that cheesey feeder pump has to run inside the tank. It can be right outside, beore either a digifant or L-jet pump.

Now 1 of 3 of my spare pumps have problems...like low volume, or weak relief valve. They were removed because they cause fuel pressure flucuations due to poor volume. But...left in position in the front end....with their suction ability, they would be awesome feeder pumps for a digifant pump mounted in the rear about where the fuel lone exits the body. They can be had by the pile from any Golf, Jetta etc...from the Junkyards. They are good pumps. This set-up will also make a weak D-jet pump last forever. In fact...it eases the load on both pumps. My personnal reccommentaion is a didgifant pump on each rail at the rear on the forward side of the sheet metal outside theengine compartment. The coldstart valve can feed from one or the other...and be dead ended on one side...or you can swipe a single line cold start valve from a CIS or other car to use in its place....or with a pair of Y's...you can feed thecold start valve from both sides of the fuel ring for simple visual symmetry and balance sake. Use equal length fuel hoses from each pump to its injetor pair. Then use equal length fuel hoses anda "y" to connect the downstream side of each injector rail together...right before the fuel regulator. This way they have identical fuel pressure regardless of volume. This is an outstanding set-up for reliability, fuel pressure stability, throttle response...and pump life. Ray

Could I use a pump from a FI bus?

vwbill · Post by **vwbill** » Sat Feb 19, 2005 4:57 pm

Hey is that a 1700 or 1800? So you are running the D-jet system, so is it possible to change over to the L-jet on her? I have L-jet stuff too. Have to look to see what I have in pumps if any! If you have the carbs already why not use them till maybe parts come up to go back to FI.
Is the big issue the pump cost? So if you use carbs you can use a low pressure off shelf pump? Also, can you combine the lower motor part of the pump with the sump top of another to work or put new brushes in to rebuild it? So guys another in line pump really helps out? So where in the lines does it go, before the fuel rails or after and why doesnt the second pump get limited by the first flow rate? I have used the pump Ray spoke about since I had a 78 Monza V8 that would cloud you out at the light,lol! Then I would fanish in the cloud.... Reliable pump. Man the FI pumps are bucks!!! The Vanagon ones are gold,lol! I just feel you have to figure out which part of the pump is causing the clog or lack of power. bill

ubercrap · Post by **ubercrap** » Sat Feb 19, 2005 5:04 pm

Can you use this?

DeathBus · Post by **DeathBus** » Sat Feb 19, 2005 5:07 pm

ubercrap wrote:Can you use this?

ABSOLUTLY!

Does it pump fuel?

ubercrap · Post by **ubercrap** » Sat Feb 19, 2005 5:11 pm

I haven't tried it yet, it came as a spare with one of my cars. How can I test it? Can I hook up 12V to it with a hose to "S" inlet and some gasoline? Makes me a little nervous, electricity and gasoline together?

ubercrap · Post by **ubercrap** » Sat Feb 19, 2005 5:14 pm

So, what the heck, is this a D-Jet pump? I guess I don't understand which is which...

DeathBus · Post by **DeathBus** » Sat Feb 19, 2005 5:15 pm

ubercrap wrote:I haven't tried it yet, it came as a spare with one of my cars. How can I test it? Can I hook up 12V to it with a hose to "S" inlet and some gasoline? Makes me a little nervous, electricity and gasoline together?

It will only hurt a little while.

You would have to ask which nozzles are which, my Haynes manual is outside in the car

If you have a 12 volt power supply It should work, But if a FI pump from a Bus will work then I have 2 of those, problem solved.

ubercrap · Post by **ubercrap** » Sat Feb 19, 2005 5:19 pm

With my very limited knowledge, I believe they are labelled "S", "R", and "P" and I was thinking that the "S" stood for "Suction", "R" stood for return, and "P" stood for pressure. I hope that's how it is.

So does L-Jet have only have two hose connections on it? Like I said, I'm confused now. I thought that '74's had L-Jet? Argggghh... oh well, at least I have the forum to set me straight.

DeathBus · Post by **DeathBus** » Sat Feb 19, 2005 5:23 pm

ubercrap wrote:With my very limited knowledge, I believe they are labelled "S", "R", and "P" and I was thinking that the "S" stood for "Suction", "R" stood for return, and "P" stood for pressure. I hope that's how it is. So does L-Jet have only have two hose connections on it? Like I said, I'm confused now. I thought that '74's had L-Jet?

S= Suction

D= Pressure

R= Return

ubercrap · Post by **ubercrap** » Sat Feb 19, 2005 5:29 pm

Oh yeah, it is "D".

raygreenwood · Post by **raygreenwood** » Sat Feb 19, 2005 5:37 pm

Yes...that is a D-jet pump. Yes, you can test it by running fuel through it. You should do this by having two containers. One that the suction line and return line drops into, one for pressure, going into a graduated container. Its best to have an old fuel pump plug pigtail....but it can be done using standard crimp on fully insulated pigtails. use about 10' of wire and a 12 volt battery. Keep them upwind. Ground the pump to the ground...ground the containers by setting them on the ground. Get a cheap switch to put in line on the ground by the battery. Plug up the terminals to the pump first before connectong to any fuel lines. The terminals are specific and marke + and -. Then turn of the switch on the negative wire...now connect the fuel lines. Put a good fuel pressure reg onto the presure end right before it drops into the bucket...and get a decent fuel pressure gauge slaved in. Connect up the battery. I the switch id off there will be no sparks. Turn the switch on...run the pump for one minute into the graduate.....while checking the pressure. See how much it pumped. It should be close to one liter per minute at 30 psi.

Yes...you can use a bus L-jet pump no problem. Just delete the return line from the pumphead that the D-jet pump used. Ray

vwbill · Post by **vwbill** » Sat Feb 19, 2005 5:57 pm

So Ray, what goes on the pump? The actual motor, ie windings/brushes or does the top parts go? bill

Longbeach412 · Post by **Longbeach412** » Sat Feb 19, 2005 7:33 pm

If all you want is a 3 port early pump, well....I got it, tested and runs good. Give me the address and I'l send it. Simple as that. Now what else do you need?

Longbeach412 · Post by **Longbeach412** » Sat Feb 19, 2005 7:37 pm

Oh, now I see ubercrap got one too.

ubercrap · Post by **ubercrap** » Sat Feb 19, 2005 8:24 pm

I haven't tested it yet, condition completely unknown! It was in the trunk of one of my cars that has been sitting since '87.

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Fuel pumps

Is the early one a Djet system only?

rebuild?