Backfire through intake EFI & Carburetor

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svocapri
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Re: Backfire through intake EFI & Carburetor

Post by svocapri »

slow_hemi6 wrote:VEAL will also add fuel to compensate for an ineffective Acceleration enrichment. This obviously makes some unusual bumps in the VE table.
I have seen this happen, and I'm trying to find a way to filter out the data that causes it. I started this thread http://www.msextra.com/forums/viewtopic ... 34&t=65987 about filtering the VE analyze data but haven't gotten any response yet.

Julian
billr
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Re: Backfire through intake EFI & Carburetor

Post by billr »

Data from injector manufacturers is generally useless, they aren't using your drivers (regardless of settings) and your fuel pressure. They probably aren't even using the same fuel. You want to get the P&H settings about right, but those won't matter so much if you flow the injectors with whatever P&H settings or driver you settle on. Flow and dead-time will "be what they is" until you change the injector drive characteristics. Formulas for adjusting injector flow for different fuel pressures are good approximations, but I don't believe they are fully accurate and can be relied on.
svocapri
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Re: Backfire through intake EFI & Carburetor

Post by svocapri »

billr wrote:Data from injector manufacturers is generally useless, they aren't using your drivers (regardless of settings) and your fuel pressure. They probably aren't even using the same fuel. You want to get the P&H settings about right, but those won't matter so much if you flow the injectors with whatever P&H settings or driver you settle on. Flow and dead-time will "be what they is" until you change the injector drive characteristics. Formulas for adjusting injector flow for different fuel pressures are good approximations, but I don't believe they are fully accurate and can be relied on.
OK you may have tipped me off to the issue. I decided to play with the PWM Current Limit, and PWM Time Threshold. As I increased the Current Limit from 30%, it kept getting richer. I stopped at 75% but I might take it back down to 60%. I couldn't tell if it was still going richer or just fluctuating over 55%.

I also changed the time threshold. I started at 1ms and went smaller which made it lean out. So I went larger and settled on 1.2ms.

I did not change the PWM period from 66us. Should I try a faster or slower cycle on this?

Thanks,
Julian
billr
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Re: Backfire through intake EFI & Carburetor

Post by billr »

Sorry, I can't help with the PWM settings. I use Jean B's P&H boards. I wanted more than two injector drivers and Jean's boards are too reasonably-priced to bother with anything else.

I have used the mainboard drivers on occasion, when experimenting, but still can provide little help...
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Re: Backfire through intake EFI & Carburetor

Post by kjones6039 »

FWIW, I run 30, 1.0 and 66 with a .500 DT on the same injector.

Ken
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svocapri
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Re: Backfire through intake EFI & Carburetor

Post by svocapri »

billr wrote:Sorry, I can't help with the PWM settings. I use Jean B's P&H boards. I wanted more than two injector drivers and Jean's boards are too reasonably-priced to bother with anything else.
How do I go about acquiring one of those? His web site shows them as unavailable.
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