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. |
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. |
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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Originally Posted by Alejo_NIN
(Post 1143978)
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. |
Originally Posted by concealer404
(Post 1143985)
Please explain why 440cc injectors require a big fuel pump for the ~160whp OP is making.
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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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Better yet..explain why not. Seriously. I'm curious. I could be wrong
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Originally Posted by Alejo_NIN
(Post 1143987)
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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Originally Posted by Alejo_NIN
(Post 1143987)
It isn't stock inj. Even at 6psi..and then again. Why even bother with 440s if he is just doing 6psi
Originally Posted by ericsbestshot
(Post 1143989)
well if the fuel pump is working properly it should be sufficient at my power levels. It worked well for over a year.
Originally Posted by Alejo_NIN
(Post 1143990)
Better yet..explain why not. Seriously. I'm curious. I could be wrong
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Originally Posted by concealer404
(Post 1143992)
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. |
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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Change the fuel pump.
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Originally Posted by ericsbestshot
(Post 1144005)
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. |
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. |
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. :rofl: :)
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yeah my signature does need to grow huh.
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Spark blowout?
Check the plugs, look for fouling, adjust gap. |
If i had spark blow out I think I should expect lower afr.
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Originally Posted by ericsbestshot
(Post 1144168)
If i had spark blow out I think I should expect lower afr.
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If you are running higher than .30 gap you deserve blowout.
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Not sure if serious, are people with stock coils really gapping down that far?
Ive been going down to 0.6 and then upgrading ignitions around 16psi where it seems to get blowout with those gaps. Thanks, Dann |
0.6mm should do it. Maybe sixshooter meant 30/1000 inch? That would be .076mm
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Its a typo he means .030in obviously
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Spark blowout usually happens around 14psi on stock ignition system. Degrades slightly as plug wires age, but not much.
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Originally Posted by Gt2560rMiata
(Post 1144368)
Its a typo he means .030in obviously
I'm running .028 with mine. |
Well i changed out the fuel pump for a DeatschWerks DW200. Took it for a drive and all seems well.
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Interesting. My stock '99 fuel pump delivered sufficient fuel to blow up an engine (~250hp) at 14psi. Something must have been wrong with your stock pump....
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Originally Posted by stefanst
(Post 1144782)
Interesting. My stock '99 fuel pump delivered sufficient fuel to blow up an engine (~250hp) at 14psi. Something must have been wrong with your stock pump....
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My stock pump wouldn't flow enough for 12psi on the 2870 turbo.
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Originally Posted by sixshooter
(Post 1144832)
My stock pump wouldn't flow enough for 12psi on the 2870 turbo.
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Originally Posted by stefanst
(Post 1144839)
What year is that? I _believe_ the NB pumps have higher flow.
NBs have no pressure compensation in the fuel system for forced induction referencing. Not a big deal unless your boost is set high. |
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