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Reprogramming the MEFI 1 ??

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Reprogramming the MEFI 1 ??

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Old 07-13-2018, 09:43 PM
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Default Reprogramming the MEFI 1 ??

What parameters if any can be altered on a MEFI 1?
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Old 07-14-2018, 07:27 AM
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MEFI Burn you can change almost anything in the MEFI EUU's, Whe I did a custom plenum and cam swap I used a Split Second PSC1-003 to alter the MAP signal voltage. It worked a lot better than I was expecting, I was able to get it to idle pretty good and still use the IAC to control the idle in gear.
Before altering the voltage signal the MAP was showing 2.80 volts at idle with the new cam so was super rich, I ended up at 1.7 volts which it really liked. Using a wide band lambda I was lean from 3500 up but show 4.5 volts on the scan tool, so was at the limit of the injectors. I installed larger injectors and pulled a % out of the VE table on the PSC1 and started to alter the 3500rpm up, I ended up with a WOT lambda of 12.3 to 12.50 A/R and showing 4.3 volts with the scan tool so still have a little more if needed.

So for around $300 US you can alter the fueling for any MAP controlled fuel system with surprising results.
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Old 07-14-2018, 09:56 PM
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Originally Posted by fastlane40 View Post
What parameters if any can be altered on a MEFI 1?
MEFI Burn will let you alter anything you need to on a MEFI 1. There are very few tables you actually need to play with. MAP/BPW/RPM and Spark/MAP/RPM are the two of most importance. Install a wideband for AFR readings. The vast majority of the other options you don't need to touch when tuning.
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Old 07-15-2018, 02:14 AM
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Okay ,I just sent my MEFI 1 over to be altered and this is a quote of the reply i received.
"Steve, bad news on the ECU reprogram. They are unable to reprogram your ECU. They are saying they won't be able to get the MEFI 1 computer you have to support the huge cam and intake/injector change. He also said the ECU has no provision to operate the IAC.He said you could get a MEFI 3 computer to support the changes, but says that reprogram would require the engine to be on a DYNO at the time of the reprogram."


I asked for lift rev limiter to 5600 and idle to 750.
Advised i was using 525efi intake , 741 cam and cmi exhaust.
Does the above sound correct?
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Old 07-15-2018, 05:05 AM
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Originally Posted by fastlane40 View Post
Okay ,I just sent my MEFI 1 over to be altered and this is a quote of the reply i received.
"Steve, bad news on the ECU reprogram. They are unable to reprogram your ECU. They are saying they won't be able to get the MEFI 1 computer you have to support the huge cam and intake/injector change. He also said the ECU has no provision to operate the IAC.He said you could get a MEFI 3 computer to support the changes, but says that reprogram would require the engine to be on a DYNO at the time of the reprogram."


I asked for lift rev limiter to 5600 and idle to 750.
Advised i was using 525efi intake , 741 cam and cmi exhaust.
Does the above sound correct?
Sounds like BS, a 454/502 WITH mefi1 stock has a iac in throttle body, why anyone would say it has no provision makes no sense. For injector changes, tuner would revert to the bpw tables vs rpm map. Now, mefi 1 DOES suck and makes giant rpm and map jumps in tables (poor resolution) and what that means is between certain areas and above certain rpms, there is no as adjustment so you have to richen fuel somewhere else to be safe and it ends up being rich somewhere you dont want it to be
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Old 07-15-2018, 06:46 AM
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Okay,
I sent this to who i thought was one of the leaders in doing these reprograms if i can call it that.
Where do i go from here?
Do i argue it can be done?
Have it returned to me in Australia then send it to someone else?
Who should i send it to?

I started with a 502 mpi fitted 525 intake with injectors,crane 168741 cam and CMI's.
I asked for the idle to be lifted to 750.Rev limit to 5600 and whatever else they thought necessary
given the changes i had made.
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Old 07-15-2018, 03:10 PM
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Who did you send the MEFI to?
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Old 07-15-2018, 03:27 PM
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CP.
Who should i send it to?
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Old Yesterday, 04:20 AM
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Where do i go from here?
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Old Yesterday, 06:55 AM
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Originally Posted by fastlane40 View Post
Where do i go from here?
needs to go to mark boos at precision marine or eddie young, id do it but i havent set up a mefi1 for a 525 intake so id only be guessing at your fuel tune, mark boos has prob done this setup
Padraig and Gimme Fuel like this.
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