D-jet fuel pump acting up

[GGR]

Since a few days I have to hammer the fuel pump before I start the car for it to work. What could that be? What is the fix?

Thanks!

[arkie]

Either the pump is gunked up from gasoline residue or the brushes are wearing out in the pump. We took the pump off of a 280SE 4.5 and set up a gallon bottle with two hoses, Purple Power solution, and a power supply and run the pump both forward and reverse and flushed a WHOLE BUNCH of gunk out of it. If that doesn't fix it, then the brushes are worn and you'll have to get a new one or a better used one.

[GGR]

Thanks! can't the brushes be replaced on these pumps?

[Gurunutkins]

Hi Gael
when my djet pump packed in I just replaced it with a cheaper CIS pump and turned the regulator down a bit. I run at 32 psi not 28 but other than that it has worked just fine with the djet regulator for over 3 years now. Just in case you cant get yours going again
cheers
Barri

[GGR]

Thanks Barri. In fact I have two spare Djet pumps but I was wondering if there is any kind of servicing I could do to one of the spares before fitting it. I also have a spare CIS pump. Which one should I fit in view of my future Megasquirt set-up (with Djet rails and hose top injectors)?

[Graham]

Originally Posted by GGR

Thanks Barri. In fact I have two spare Djet pumps but I was wondering if there is any kind of servicing I could do to one of the spares before fitting it. I also have a spare CIS pump. Which one should I fit in view of my future Megasquirt set-up (with Djet rails and hose top injectors)?

You can remove the end and clean up the rollers and rotor. You can also flush the internal passages around the motor. See THIS LINK.

The CIS pumps can put out a lot more pressure than the D-Jet pump. The D-jet pump also has an internal relief valve, while the CIS pumps do not. This is presumably because the rubber hoses on the D-Jet injectors and elsewhere could blow off if they see higher pressures. This could happen, I guess, if the fuel pressure regulator malfunctioned or the fuel return somehow became blocked.

There is a check valve that prevents pump from pumping backwards - not sure how those who suggest reversing the pump overcome that.

[meltedpanda]

wow Graham , I did not know these could be serviced , thanks for the link

[GGR]

Thanks! I'd rather keep the Djet pump rather then fitting the CIS one to keep the relief valve security given my hose top injectors.

[mercmad6.3]

They are available new again now too. They were off the market for years but because so many different types of cars had Djet,Bosch recognized the need to supply the classic car movement a bit better than they were.