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-   -   sudden lost power and lean out at 5psi, fuel pump? (https://www.miataturbo.net/megasquirt-18/sudden-lost-power-lean-out-5psi-fuel-pump-49712/)

skyline397 07-18-2010 12:45 AM

sudden lost power and lean out at 5psi, fuel pump?
 
1 Attachment(s)
I just installed my 460cc injectors today and couple pulls. The car suddenly lean out to 17:1 when i have 5psi of boost. Here's a log of what happened during the pull. fuel press seems to shot up to like 55. Can anyone confirm this? Thanks

lordrigamus 07-18-2010 01:32 AM

Well, your tach signal drops about 300 rpm when it happens along with your injector pulse width but goes back up right away and AFRs return to where they were. It's almost like it thinks your decellerating and the overrun is kicking in. Did it misfire at the same time or do you have any questionable grounds that may be creating a noisy signal?

By the way, how do you know your fuel pressure went up? Hood mounted gauge?

skyline397 07-18-2010 02:06 PM


Originally Posted by lordrigamus (Post 603074)
Well, your tach signal drops about 300 rpm when it happens along with your injector pulse width but goes back up right away and AFRs return to where they were. It's almost like it thinks your decellerating and the overrun is kicking in. Did it misfire at the same time or do you have any questionable grounds that may be creating a noisy signal?

By the way, how do you know your fuel pressure went up? Hood mounted gauge?

i don't think it mis-fires, it just felt like the car jerks back when i reach that psi. As for fuel pressure , i thought it shows on the log, but i guess i am wrong after all. I didn't have this problem when i have the stock injector and the vortech along with ms earlier. These 460 injectors are clean and flowed. I thought putting bigger injectors put less stress on the fuel pump no? Also, what is a sign of fuel pump failure? I notice you had a tre pump, how's that working out for you?

Ben 07-18-2010 02:25 PM

Looks like overboost shut down

lordrigamus 07-18-2010 04:27 PM

Or this /\.

The pump was holding up good until recently, now it's somewhat questionable. I have had it for a while though. I have a gauge on the fuel line but it's only good when not under load.

I'm not sure it's a fuel issue, it seems like something is deliberately stopping it. Double check your settings.

skyline397 07-18-2010 07:01 PM

it seems like the overboost setting, sorry for being such a newb, thank you guys for your help.

lordrigamus 07-18-2010 07:24 PM

Ben is the winner!!!


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