Tune/walbro fuel pump - cold start problem

[benvw]

Since I had my car reflashed I am having a little more trouble starting the car on cold starts. It starts and kicks over for about 3 seconds and then stops. It always starts on the second turn of the key. before the reflash it always started first turn. I'm not sure if this is due to the fuel pump (walbro 500hp) or the reflash which were done at the same time. Has anyone else experienced this issue?

[50BIE]

Ben, never heard of the Walbro's giving cold start issues before, most of the RSLC boys use this a a quick and easy upgrade with no issues. My old wagon had a Bosch pump and apart from a louder pump noise no other problems. Maybe ask Paul/Adam via email they may have some answers or you may just have to wait until they visit again next month.

BTW, how did yours end up after the re-flash, I know you had quite a substantial gain but never heard the end results?

cheers....Steve

[B.C]

i was having the same problem and was told it could be either my Walbro pump not holding pressure over night or leaky injectors. changed the pump and it seems to be o.k
dunno could be a coincidence or maybe it was the pump after all. take it to your mechanic and get some pressure gauges put on to be sure.
next time you go to give it a cold start prime the pump a few times using the accessories and then give it a crank. just make sure you let it prime till it stops whining .
if that fixes it like it did mine i put my stock pump on to see the diff.

[adhar]

Answer is Walbro pump not holding pressure over night.

When changing the pump you are supposed to change the o-ring on the intake nozzle as the walbro is a fraction smaller in diameter. To get around the problem until you change the o-ring just turn the key on and off a couple of times to prime it before starting, it will start straight away.

The o-ring size is 5/16 x 9/16 x 1/8, sorry i don't have metric sizes, this is from LGT.com

If you find where they sell these o-rings in Oz let me know

[benvw]

Ben, never heard of the Walbro's giving cold start issues before, most of the RSLC boys use this a a quick and easy upgrade with no issues. My old wagon had a Bosch pump and apart from a louder pump noise no other problems. Maybe ask Paul/Adam via email they may have some answers or you may just have to wait until they visit again next month.

BTW, how did yours end up after the re-flash, I know you had quite a substantial gain but never heard the end results?

cheers....Steve

I ended up with 175kw at the wheels which is a nice increase. Hopefully it is safe.

[benvw]

Answer is Walbro pump not holding pressure over night.

When changing the pump you are supposed to change the o-ring on the intake nozzle as the walbro is a fraction smaller in diameter. To get around the problem until you change the o-ring just turn the key on and off a couple of times to prime it before starting, it will start straight away.

The o-ring size is 5/16 x 9/16 x 1/8, sorry i don't have metric sizes, this is from LGT.com

If you find where they sell these o-rings in Oz let me know

Great info thanks heaps. I got a mechanic to do the job, should have done that at the same time. bummer.

[B.C]

just wondering how your going with this problem. i've actually reverted back to the stock fuel pump but the problem
persists. starting to think my injectors are leaking because when i do get it started it coughs and spits like it's flooded.