smokeshow

iTrader: (16)

I just swapped out my stock pump for a walbro 255 and I'm getting some issues now. Now once I go to start it it takes forever to start up, just keeps cranking for a few seconds longer than usual. Once its running though, everything seems ok. My code reader reads 58-60psi. Once I shut it off though, it shows pressure drop to zero in 10-15 seconds. And again trying to start it takes much longer than usual.
One thing I thought was odd...I pulled the fuse prior to doing the pump so I could run the system down since its still supposed to have pressure. Funny thing was, the pump still ran with the fuse pulled... So I pulled the relay too, pump still ran. ???

Amy ideas what might cause the truck to take forever to start? Somehow my system doesn't hold pressure in between starts.

gao8302

iTrader: (13)

Is there a check valve on the pump?

smokeshow

iTrader: (16)

No the new pump doesn't have one. Is there any way I can put one in-line somewhere?

gao8302

iTrader: (13)

well the correct spot for it is on the fuel pump. You can try to put on inline...it may help some but i have never done it like that. But im 100% sure thats why you are having problems starting the truck. you may just want to pull it out and install a check valve.That way you know your good to go.

CODE4LS1

iTrader: (4)

My Walbro 255lph has done this for 90,000 miles now. What I do is turn the key to "on" and let the fuel pump prime for about 2 seconds. After I count to 2 I start it and it does not take any excessive cranking to fire. I have also thought about installing an inline one-way check valve.

La Tu Papi

walboros do this just like other aftermarket pumps, cycle key once then turn it on to fire truck and it shouldnt have any issues. if you hold starter in longer then needed youll run risk of shortnging the life of starter. cycle key then fire it and never have an issue

Mangled03gmc

iTrader: (95)

You just need to turn the key on 1 or 2 times to get prime.. You need to or should have put a check intfront of the pump, to hold FP after shutting it off.. Other then that no problem...

smokeshow

iTrader: (16)

Okay I've got the check valve...where should I put it? The line coming out of the top of the sending unit is rigid plastic

Mrgoodwrench3

The fuel pump module assembly is designed to hold pressure after it is turned off. There should be no need to add a additional check valve. You may have a bad pump. What was the reason for replacing the pump? Why not use a Delco?

budhayes3

iTrader: (19)

He didn't install a factory module, he installed a high volume aftermarket Walbro 255, which doesn't have a check valve. I've read many threads about guys having this same concern after their Walbro swap...