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Old 06-26-2014, 05:57 PM   #1
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Default Loses power when in boost. Little help please.

So for the last few weeks when in boost I lose a lot of power. I've been running my setup successfully for the past year with no issues. The problem doesn't happen all the time. Sometimes the car accelerates in boost just fine.

When I'm down on power I also notice my afr stays closer to 13.5 to 15. I've looked at my data logs but nothing seems off. According to logs the injector duty cycle gets to 50%.

The lose of power usually happens between 2-6psi. When driving out of boost everything drives normally. I am curious whether the ecu switches over to closed loop when this happens.

My set up:
Sr20 turbo no intercooler 6psi
Begi log manifold and sgdp
AEM F/IC (MAF still connected)
AEM uego afr gauge and boost gauge.
RX-8 440cc injectors.


Thanks for any help.
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Old 06-27-2014, 01:15 PM   #2
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bump for help.

After some more time reading, I leaning toward fuel pump issues. Fuel pump not able to supply enough pressure when getting into boost.
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Old 06-27-2014, 01:16 PM   #3
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you have 440cc...you better have at a minium a walbro 255...please tell me your fuel pump is not stock.
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Old 06-27-2014, 01:34 PM   #4
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Quote:
Originally Posted by Alejo_NIN View Post
you have 440cc...you better have at a minium a walbro 255...please tell me your fuel pump is not stock.

Please explain why 440cc injectors require a big fuel pump for the ~160whp OP is making.
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Old 06-27-2014, 01:36 PM   #5
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Please explain why 440cc injectors require a big fuel pump for the ~160whp OP is making.
It isn't stock inj. Even at 6psi..and then again. Why even bother with 440s if he is just doing 6psi
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Old 06-27-2014, 01:37 PM   #6
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well if the fuel pump is working properly it should be sufficient at my power levels. It worked well for over a year.
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Old 06-27-2014, 01:37 PM   #7
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Better yet..explain why not. Seriously. I'm curious. I could be wrong
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Old 06-27-2014, 01:39 PM   #8
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Quote:
Originally Posted by Alejo_NIN View Post
It isn't stock inj. Even at 6psi..and then again. Why even bother with 440s if he is just doing 6psi
I got the 440s for free so why not?
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Old 06-27-2014, 01:40 PM   #9
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Quote:
Originally Posted by Alejo_NIN View Post
It isn't stock inj. Even at 6psi..and then again. Why even bother with 440s if he is just doing 6psi
So? None of that has anything to do with fuel pump.

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Originally Posted by ericsbestshot View Post
well if the fuel pump is working properly it should be sufficient at my power levels. It worked well for over a year.
True story. I'm not sure what else could be failing.... TPS possibly?

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Originally Posted by Alejo_NIN View Post
Better yet..explain why not. Seriously. I'm curious. I could be wrong
No, not "could." "Am." Read up on how fuel pumps work and how to determine which pump is right for you.
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Old 06-27-2014, 01:45 PM   #10
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Originally Posted by concealer404 View Post
So? None of that has anything to do with fuel pump.



True story. I'm not sure what else could be failing.... TPS possibly?



No, not "could." "Am." Read up on how fuel pumps work and how to determine which pump is right for you.
I guess I am. I stand corrected.http://www.deatschwerks.com/resources/fuel-calculators/fuel-pump-calculator
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Old 06-27-2014, 01:55 PM   #11
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Not sure about TPS. How does the stock ecu use tps as it pertains to fuel? I just know that i'm not using Throttle position to dictate fuel in my piggyback.
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Old 06-27-2014, 01:56 PM   #12
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Change the fuel pump.
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Old 06-27-2014, 02:00 PM   #13
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Quote:
Originally Posted by ericsbestshot View Post
Not sure about TPS. How does the stock ecu use tps as it pertains to fuel? I just know that i'm not using Throttle position to dictate fuel in my piggyback.

Just thinking out loud. Unlikely to be the issue, but bad TPS can cause shitty tip-in enrichment, go lean, etc.

I'm liking the pump solution so long as nothing else has truly changed since the year it ran great.
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Old 06-27-2014, 02:07 PM   #14
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nope no changes. Also I think I would see weird readings on throttle position in my datalog but everthing looked spot on.

Well I'll go ahead and get a new pump. I'm thinking deatschwerks DW200. Quite and gives me something to grow into and 3 year warranty.
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Old 06-27-2014, 02:08 PM   #15
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Yep you'd see some weirdness. I'd say throw a pump at it. Worst case scenario you can add another modification to your signature.
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Old 06-27-2014, 02:10 PM   #16
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yeah my signature does need to grow huh.
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Old 06-27-2014, 10:37 PM   #17
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Spark blowout?
Check the plugs, look for fouling, adjust gap.
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Old 06-27-2014, 11:01 PM   #18
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If i had spark blow out I think I should expect lower afr.
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Old 06-28-2014, 12:18 AM   #19
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Quote:
Originally Posted by ericsbestshot View Post
If i had spark blow out I think I should expect lower afr.
If I recall this properly, spark blowout means that there is un-burned oxygen in the exhaust and the oxygen sensor reads lean (high AFR).
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Old 06-28-2014, 07:33 PM   #20
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If you are running higher than .30 gap you deserve blowout.
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