vanillagorilla

iTrader: (1)

So other than checking the fuel pressure, and seeing an overly lean AFR, what other symptoms are there for a fuel pump going out?

I haven't checked my fuel pressure yet (I'm going to), but despite my recent re-tune, my truck is still running incredibly lean. It was just under load, and now while cruising at 2000rpm and sometimes as low as 1500rpm it starts to cut out.

I think its probably the fuel pump, but in my past experiences with OBS trucks they just go out, with no signs of a warning.

Also what pumps are ya'll using, because the autoparts stores around here want around 3 bills for one and I can get a walbro for like half that.

BTW there's no way in hell my injectors are maxed either, because I'm still sporting the mighty 4.8!

1slow01Z71

iTrader: (36)

When mine went out it just went out try changing the filter first it may be clogged.

desTRUCKtive

This is after the logging that you have done. You have got a new tune since the last time that we talked.

You are saying that it is cutting out at 2000RPM, will it do it when it is in park and you rev it to 2000, or it will just do it when you are crusing along and slam the pedal.

whitt1

I've lost 3 stock fuel pumps,none of which gave much warning.I towed it 2 times and limped home on the third one.I was using a Boost a pump at the time.Now I use an inline pump with the stock pump.

vanillagorilla

iTrader: (1)

Yes, this tune is a ton better from a drivability stand point, don't get me wrong. But as for performance its making me question everything.

It'll rev to like 4500 in park and then it starts to cut out. I'll ease out into traffic under part throttle, light load and once it gets above 2500-3000 it starts to do it. Then when I get up to speed, and cruise (~1500), it cuts out sporadically. I would think if it were the tune, it would adjust at least adjust in closed loop mode during cruise. It's as if its not, so that's why I'm thinking its the pump and/or filter.

It completly shut off at the stoplight today. It's never done that!
I'm putting a gauge to it tonight and changing the filter I'll keep ya'll posted.

whitt1

Check the fuel regulator,that sound like the problem you are having.

vanillagorilla

iTrader: (1)

Check it how? It's just the factory one, and it's never been messed with.

quicksilverado

iTrader: (8)

If you need an intake fuel pump I have a new Walbro 255lph pump I'll let you have for 85.00 plus shipping.

vanillagorilla

iTrader: (1)

Okay, I just put a pressure gauge on it, and at idle I'm seeing 53psi.
Then, while in Park:
-When I quickily blip the throttle it jumps up to 58psi and then back down.
-Slowly reving it up, it drops to about 47-48psi then it breaks up and shuts off, or I have to let off.

Shouldn't I be seeing 58-60psi? Hmmm....

vanillagorilla

iTrader: (1)

Ok, changed the filter and I gained a few psi.

I sit at 55psi at idle, and as I rev it up it finally drops to 50-51psi at about 4500rpm. This isn't normal is it?!?