I just installed the double pumper and was wondering if being tuned on a walbro 255 single pump... Is the car ok to drive like i was on the single?....I have to hook the other pump up a little later have to get tuned again but money is a little tight right now

 

I am not an expert , so please verifiy that this can be done and be ok. But I would think that , just dont wire in the HOBB switch . that way the second pump never gets power and you only run the one. Then when your ready wire the switch and your ready for tuning.

 

Yup, that's what I was thinking.

 

Wire it all in and hook up the vacuum line. Then just pull the fuse.

 

ok thanks

 

What he said!

 

Ok..... got the pump in, car starts and drives. Problem is when I step on it the A/F is running around 15 on the WB... when with my stock fuel pump assembly and my 255 walbro I was running around 10 to 11's. I just talk to Jarrod at Buschur, and he said that the pump comes with walbro 255's. The fuel filter is installed with the arrow facing towards the front of the car....

Does anyone know what the problem could be?????

 

Are you sure you don't have a kink in the "y" line that goes from the two fuel pumps to the filter?

Also, did you touch the vacuum line going to the FPR?

 

I don't see no kinks... and I left the FPR alone and tapped into the line that goes to the BOV right of the manifold


I hooked it up just like Dr.SS

 

What does the car do at idle and cruising....AFR's stable?

Are you on stock ECU or AEM? Can you look at fuel trims?

If you're tuned for a Walbro already, installing this setup should have done nothing to your tune until the 2nd pump kicks on.

 

The car idles fine and is good at cruising AFR's are pretty stable. It's just seems to be under WOT.

I am on the stock ECU

That's what I thought.........

What should the FP be on the walbro pumps? I will just check the fuel pressure.

 

On Ted B's car with the Full Blown unit running only one pump he noticed a similar phenomenon. It was like fuel was back flowing through the unused pump and killing fuel pressure. When we wired up the second pump, the problem went away. I know logic would say "Dumba$$, he must have needed both pumps and that one wasn't enough", but he was only running 19-20psi at the time. Previously on one Walbro, it wasn't an issue @ 25psi. Either way you may want to look into that and hurry up and get the tune sorted with both pumps working.

 

Can you change the pumps yourself on the double pumper, Or do you need something special to do that? I am going to put my 255 pump and see what that does. We did a FPT to check for leaks of any kind. At idle we got 40 psi and no pressure drop what so ever. Then we turned on the 2nd pump (blowing into the HOBB switch) and got 65 psi, again pressure stayed.
If it was leaking in the tank wouldn't the pressure drop?

 

^Need to check pressure drop at WOT not at idle

 

Even for just checkin for leaks?

I got the fuel pump pulled out and noticed that the PN# on the pumps are GSS340
which are the normal 255, I had the Walbro GSS342 HO pump. Would that be the problem????

Everything on the pump looks good and tight