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Discussion Starter #1
well i did not check anything yet since i dont have much time, but for some reason i am hitting fuel cut @ 1.1 bar, even though i have maft and gm maf blow thru mode and i dont see any reason why this might be anyone ideas?

ps. i had no problem with same setup and ct26 i run sp63 with hks external wg now (old zazzns kit)
 

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greasemonkey
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do you have the fuel cut option activated? ive run 1.2 bar on mine before. have the frequency clipped at 1400hz. 440's, 4:1rrfpr. 3in gm maf.
 

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I'm running into a similar problem - I enabled the fuel cut option on my MAFT, and yet the MAFT is still sending way over 1400 Hz to the ECU. Hell, I hit 2800 yesterday.

Do you have access to a Digital meter with a frequency function? Try plugging that into the AFM connector - positive to pin 3, negative to pin 1, and see what frequency the MAFT is sending your ECU.
 

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greasemonkey
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yes it shows hz. thats how i check mine however under hard boost in higher gears i dont look at the safc2, im looking at the road ahead of me. i have mine set to 1400hz and have run 18psi on a 57 trim upgraded ct26. id hope it flowed more then 1400hz
 

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Discussion Starter #6
williamb82 said:
yes it shows hz. thats how i check mine however under hard boost in higher gears i dont look at the safc2, im looking at the road ahead of me. i have mine set to 1400hz and have run 18psi on a 57 trim upgraded ct26. id hope it flowed more then 1400hz
well i believe it also shows peak values as well, or else i will have some one gowith me and look at it (it is in a glove box)
 

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greasemonkey
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ill have to check the manual to see how to set it to record the peak value then.
 

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Street Sleeper
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dziuggy said:
ps. i had no problem with same setup and ct26 i run sp63 with hks external wg now (old zazzns kit) [/B]

Remember fuel cut is done on volume not pressure and at 1.1bar you will have a much larger volume then with a ct 26.
 

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Discussion Starter #9 (Edited)
Re: Re: fuel cut with maft

Buttmunch said:
Remember fuel cut is done on volume not pressure and at 1.1bar you will have a much larger volume then with a ct 26.
yes i know that why i mentioned, thanks though.



also i have another idea, i use maft and then i use SAFC2 to tune it the car but maft setting are left on base. now both of these devices change HZ values to trick ECU to lean out/enrich mixture, now maft is capping HZ @ 1400 (i checked safc readings and peak value is 1398hz wich is fine).

but now that goes to safc and if at that point (then safc gets 1400hz reading) safc is set to enrich the mixture it would give ecu bigger reading then it got from maft to do that and this might result in a fuel cut............

i dont know if this make sence or not, so any elaboration welcome

ziggy
 

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Moderator, megalos ntabatzis!!
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did you solve this?

From what i know, the car doesnt just depend on hz to cut fuel. We did some testing on mc_h's car and i dunno what the hell was up with it, it would hit 1800hz and not hit fco then it would hit it randomly as we increased the boost. Something was up with the afm we think, but the ecu was still seeing the hz reading, so i dont think hz tells the whole story. Either way im thinking of running one, will i need my fcd to clamp the signal or has this been solved?

Ang
 

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greasemonkey
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i dont have a prob with it. but if he has an between the maft and ecu and has it set to inrich it will increase the signal pass the clipped value and can cause fuel cut.
 

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Fuel cut is absolutely dependant on several factors. That said, the primary one is the Hz reading from the AFM. In testing, we have discovered that keeping the Hz reading below 1400 usually means no Fuel Cut under any circumstances.

The Fuel Cut feature on the MAFT really is not an issue. Good tuning (or even halfway decent tuning, for that matter) will get rid of any fuel cut issues you might run into, without using the FCD feature in the MAFT.
 

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Formerly Nosechunks
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this might be a stupid question, but do u have bigger injectors then stock? if u do then y would u be richening the mixture? it should be flooding if u richened it with bigger injectors.
 

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I was hitting fuel cut with my maft at about 15psi on 440cc injectors. 1600hz was not uncommon. Now I have 550cc injectors I have run over 20psi on a 50trim ct26 with no fuel cut and the freq stays under 1250hz. The maft scales the output freq to match the injector size, smaller injectors means higher frequency. I figure I could run over 28psi without fuel cut but I don't want to try that without race gas. Actually I may never try that because it's plenty fast for me at 18psi. Now one time when I first ran it at 20psi the vacuum line popped off the stock fuel pressure regulator and (thank god) the fuel cut kicked in when I needed it. Check your vacuum lines for any leaks to the fpr under the intake manifold behind the alternator. Please don't try to eliminate the fuel cut, it is there for good reason and it can save your motor. If you are running it excessively rich then you can lean out the wot adjustment and the fuel cut will be at higher boost. Reguardless of how much power you COULD make on 440cc injectors, it is always on the unsafe side and 550cc injectors are just added protection in helping make sure you don't run lean. Fuel cut means something is out of the range that the ecu can handle while maintaining the proper air/fuel mixture. Like mentioned earlier, the volume of air will be higher with a big turbo so you could still hit fuel cut at fairly low pressure. To fix that you may have to run bigger then 550cc but the maft is supposed to handle up to 1000cc so your not in bad shape.
 

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greasemonkey
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wont be a prob. im about to install 830cc/min injectors with a new fmic, ffi, new i/c pipes, etc.. with my current 57trim upgrade. should run pretty good. :D
 

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Moderator, megalos ntabatzis!!
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830cc injectors are too much for even a maft setup, you will be pulling too much frequency to get it to run, this will result in too many problems. And can you say overkill for a 57trim?

Just trying to help, but if you can get it to work more power to you.
 

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680cc would even be overkill. 550cc is about as high as I would go with a 57trim ct26. Well, you are the test subject, we will see how it works. What do we know, mabye it will work great? The part I wonder about is at idle. Sometimes mine idles at 15hz, how much lower can it go and still maintain a smooth idle?
 

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greasemonkey
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well, im not doing it for this turbo. i plan on a gt40 with 88mm compressor once my built 7m is done. why buy 550's when i will need much larger injectors in the end? its also the reason i bought such a huge i/c and am about to swap to a th400. its all in the master plan. hehehe.
 
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