VT 355 supercharged AFM issue

Holden/Delco Tuning. ALDL, OBD 1.5. Circa 1989 to 2004.
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The1
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Re: VT 355 supercharged AFM issue

Post by The1 »

ive done heaps of L67's and regularly gone past 256 limit and higher on the maf.

The VT V8 enhanced only has the MAF mod done and extended MAF tables, everything else is stock. The ADX is stock apart from the MAF scalar value X*2

If the ADX has issues then we need to fix them. Idea at the end of the day is a drop in and go system with enhanced and the files to match. Obviously testing without access to vehicles alot of the time especially on the ADX end because of BCM's etc is a pain.
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delcowizzid
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Re: VT 355 supercharged AFM issue

Post by delcowizzid »

theres a voltage spike right at the same time
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shane1
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Re: VT 355 supercharged AFM issue

Post by shane1 »

While we are at it anyone know why the rev limit will only go to 6300 odd ( not in front of my laptop now ) rpm ? I know the tune is set to 6000 but if I ever get it to run up there it will pull to 7000.
I went back and started again today using the original enhanced bin etc just to make sure . If you guys open the bin is the enhanced tables there and correct ??
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delcowizzid
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Re: VT 355 supercharged AFM issue

Post by delcowizzid »

and no volt spike on the loose belt log look at injector volts in both logs
If Its Got Gas Or Ass Count Me In.if it cant be fixed with a hammer you have an electrical problem
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delcowizzid
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Re: VT 355 supercharged AFM issue

Post by delcowizzid »

and the carbon canister purge duty cycle is different in both but you probably dont want it purging on boost at all if its still attached LOL
If Its Got Gas Or Ass Count Me In.if it cant be fixed with a hammer you have an electrical problem
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The1
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Re: VT 355 supercharged AFM issue

Post by The1 »

setting it to 6375 should disable the fuel cut, it can't go any higher because the code for that can only goto FF or 255 in decimal. There is another variable we can use to take it further, it's on the drawing board with the rest of it.
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antus
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Re: VT 355 supercharged AFM issue

Post by antus »

I took a closer look. It def. looks like your hitting the limiter in the logs. I see 6114 rpm when it turns to shit, and the bin shows fuel cut at 6000. 6375 is the upper limit because in hex thats FF and theres nowhere to go from there. You'll get a little head room using that. To change that The1 will need to change the scaling on that variable, or offset it to give it some more headroom. edit: I see hes on the case already :)

Some feedback on the adx would be good, Some of the data def. looks wrong with the vt adx and its hard to figure out whats going on from your log. Your MAF also seems pegged at just over 10khz, which might also be a factor - It might be a clone that isnt capable of going higher. Not saying it is, but that is also a common problem.
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The1
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Re: VT 355 supercharged AFM issue

Post by The1 »

pretty sure the Card MAF was one i sent down, which scaled right upto 15khz on the test bed.
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antus
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Re: VT 355 supercharged AFM issue

Post by antus »

ahh ok if its one of yours its a known good source :)
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Jayme
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Re: VT 355 supercharged AFM issue

Post by Jayme »

delcowizzid is onto something...there is definitely an injector voltage spike at the exact moment the maf HZ and g/sec drops off. it goes up to 13.7v. id bet if someone (the1?) puts a card maf on their test bench and sets it at a constant airflow, then alters the input voltage between 13v and 13.8v, I bet it drops the MAF hz like we are seeing. perhaps the loose belt only solves the problem coz its slipping on the alternator and not spinning it as hard.