HELP! lean out pop

[LITLV6]

Not that it's a big deal either way, but that's BS (for a simple base fuel pressure change)... the computer will immediately begin compensating to the new numbers without a reset, and will probably get there faster without a reset, because it's already learned in, and closer than the default/initial tables in the chip.... just sayin'..

And litlv6, not sure it was clearly stated, but with our turbo cars, the fuel pressure MUST RISE EXACTLY 1:1 with boost.... that's, a 1 lb increase in fp for every 1 lb boost.... it must rise and must be verified to rise.... your previously described 'dipping' fuel pressure is an absolute signal of a failing/inadequate fuel pump.... do not get on the car until this issue is fixed, or you will be changing head gaskets along with the pump....

thanks for the input bmackinnon. is there any type of sound, like a warning as is destroys the head gaskets? or does it just happen. or.......... is that lean out pop i'm describing cause it? thanks for the input and does a bunch of people agree that i should get a denso vs the walbro?

 

[bmackinnon]

thanks for the input bmackinnon. is there any type of sound, like a warning as is destroys the head gaskets? or does it just happen. or.......... is that lean out pop i'm describing cause it? thanks for the input and does a bunch of people agree that i should get a denso vs the walbro?

Detonation occurs before you can hear it, but if you can hear it 'pinging', you are likely seconds away from catastrophe... yes, lean pop is BAD, BAD, BAD... don't make it do it anymore.

I would go w/ the walbro, as it's a drop in replacement and used by 95% of us or more... the denso is a good pump, but it's not a straight drop in, baaaarely fits, with a bit of work/luck, and in some cases, has been reported to flow TOO much, resulting in the in-ablility to lower fuel press. to an acceptable number due to factory return line's limited flow capacity.... (the return flow can overwhelm the return line, causing increased pressure at the rail). Walbro seems to have overcome the bad lot of pumps, I haven't heard of any unusual recent rash of failures.... my opinion....

 

[bmackinnon]

Well, that's the first time i've heard of this.

If anyone else wants to chime in, I'd sure like a 2nd or 3rd opinion... as everything i've read in the past indicates otherwise. I think even Eric Marshal suggests an ECM reset.

It would be nice to know for sure one way or the other... since I have a battery cutoff switch in the back of my car and I'd like to know how it affects the ECM/tune every time the switch is flipped off/on.

A reset is in order whenever you change components that communicate with the ecm (chip, maf, iac, etc.), or other big changes (new throttle body, headers, turbo, I/C, injectors, etc), but definitely is not necessary (or even desired) for an adjustment to fp. I'm sure Eric will agree.

If you have a powerlogger or direct scan, (heck, a SM will work too, just slow to read), have someone twist around on the fuel pressure while the car is running and you are watching the int/blms..... you'll see them compensating INSTANTLY.... the int's will jump to the proper correction and the blms will start drifting towards the 'average' of the int's... that should convince you with your own eyes!

With the battery cutoff, everytime you flip it off, you are resetting the ecm, and on restart, the ecm will begin to re-learn from the initial/default fuel table in the chip... which takes a couple minutes over a wide range of operating loads... not very desireable for race car consistancy, OR for a daily driver, as it won't run right for a while after every startup when you've had the cutoff switch off....