Slow starting after new petrol pump

[JulesCharles]

Hi, my 1996 VSII wagon always started quickly. Last November (8 months ago) it died at the local servo after filling up. I could not get it going, RACV bashed the tank with a rubber mallet & it started. I replaced the fuel pump, paid ~$109.00 for Bosch vs ~$20 for cheapies, as I didn't want to do it twice! Ever since, slow starting. Normal cranking, 6-8 seconds from cold. This can be cut to 4 - 5 seconds by turning Ign on (not starting), doing it again twice, then starting. When hot, it takes 4 - 5 seconds crank to start, but if I turn on Ign, wait 2 seconds, it starts immediately. The manual says the fuel is continually circulated to remove vapour. Have I missed something? Is there a bleed I need to do? The only other change was a new fuel filter.
I can't understand why a new fuel pump slows the starting. Thanks, Jules.

 

[jeepster]

Hi, my 1996 VSII wagon always started quickly. Last November (8 months ago) it died at the local servo after filling up. I could not get it going, RACV bashed the tank with a rubber mallet & it started. I replaced the fuel pump, paid ~$109.00 for Bosch vs ~$20 for cheapies, as I didn't want to do it twice! Ever since, slow starting. Normal cranking, 6-8 seconds from cold. This can be cut to 4 - 5 seconds by turning Ign on (not starting), doing it again twice, then starting. When hot, it takes 4 - 5 seconds crank to start, but if I turn on Ign, wait 2 seconds, it starts immediately. The manual says the fuel is continually circulated to remove vapour. Have I missed something? Is there a bleed I need to do? The only other change was a new fuel filter.
I can't understand why a new fuel pump slows the starting. Thanks, Jules.

Sound like the fuel rail is draining. One cause can be the check valve in the fuel pump. But since you got a new Bosch pump, I will rate that unlikely.
Another possibility is the fuel pulsation damper. It is 23 years old, and the rubber may not like a new pump being rammed in, so that no longer seals.

 

[JulesCharles]

Sound like the fuel rail is draining. One cause can be the check valve in the fuel pump. But since you got a new Bosch pump, I will rate that unlikely.
Another possibility is the fuel pulsation damper. It is 23 years old, and the rubber may not like a new pump being rammed in, so that no longer seals.

Thanks Jeepster, can you tell me where the pulsation damper is, and is it an easily replaceable item?

 

[jeepster]

Thanks Jeepster, can you tell me where the pulsation damper is, and is it an easily replaceable item?

It's the thing that joins the fuel pump to the pipe inside the tank. So a lot of work to replace. I doubt you can get them anymore.
I installed a check valve next to the fuel filter - that was easier than pulling the tank out again. I have seen a thread where somebody just replaced the pulsation damper with some fuel hose and two clamps. But then there is no pulsation dampening. Which may become a problem if you want wide open throttle.
HSV used an external pulsation damper to sooth their souped-up V8s.
There is one listed on eBay, but ridiculously expensive $250!

 

[JulesCharles]

It's the thing that joins the fuel pump to the pipe inside the tank. So a lot of work to replace. I doubt you can get them anymore.
I installed a check valve next to the fuel filter - that was easier than pulling the tank out again. I have seen a thread where somebody just replaced the pulsation damper with some fuel hose and two clamps. But then there is no pulsation dampening. Which may become a problem if you want wide open throttle.
HSV used an external pulsation damper to sooth their souped-up V8s.
There is one listed on eBay, but ridiculously expensive $250![

 

[JulesCharles]

Thanks again Jeepster, I'll wait for any other replies, but I presume the check valve is just a one way petrol proof valve that fits into the fuel line? I had to install a similar (smaller) valve in the windscreen washers some years ago, it worked a treat!
Many thanks, I'll keep you posted. Jules.