Reprogramming the MEFI 1 ??
#2
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Joined: Apr 2018
Posts: 134
Likes: 1
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.
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.
#3
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Joined: Jun 2011
Posts: 1,208
Likes: 141
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.
#4
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?
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?
#5
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?
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?
#6
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.
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.
#10





