7427 with G1 memcal mismatch

[ralmo94]

This might help with the cylinder select knowledge.
http://www.gearhead-efi.com/Fuel-Inj...ull=1#post3374

Also, when you use the g1 adapter as far as I know it is only really used for limp home mode, and possibly knock, I have used mine with a chip only and no memcal, and I got no complaints from the ECU, but iirc, I had disabled the kr sensor, or at least the timing pull from it.

[dave w]

This might help with the cylinder select knowledge.
http://www.gearhead-efi.com/Fuel-Inj...ull=1#post3374

Wow, posting that link moved mega bytes of memory from the Hard Drive to RAM Memory

[1project2many]

So cylinder select... that could be my problem. If it thinks I have a 6 cyl then my injection pulses will be off. So fewer pulses would solve the riddle on why I'm needing to tweak my flow rate and engine size parameters so much. So I at least need a V8 memcal. Seems like a logical enough reason to swap memcals.

Well, it's not quite that way. The ecm will still deliver injector pulses and spark pulses. The challenge is in how the ecm uses the information. If a V8 engine is spinning at 2000 RPM it's generating 4000 pulses per minute. A v6 engine at the same speed is generating 3000 pulses in a minute. So if the ecm is programmed for a v6 and it sees 4000 pulses in a minute, that's going to look like almost 3000 rpm to the ecm. Now you want to go in and add fuel or change spark advanced, what rpm is appropriate to make changes? If you're using the scantool data you'll see the same rpm as the ecm. But if you're using a tachometer then you're in the wrong place.

One good question, is the ecm actually using the code? Is the check engine light telling you that the chip is good?

[Dieselsj]

So, interesting update. I had written down that the memcal which came with my 7427 was for a 4.3 so I really thought I was onto something with switching to the 7.4 memcal. When I pulled the old memcal, I looked up the code and it was actually a 5.7/4l60. I don't know why I had noted that it was a V6. Not thinking anything would really be different between the 5.7 and 7.4 with the parts of the memcal that are still in use with the Moates adapter, I really didn't think anything would change. I went for a quick drive and it felt horrible, stumbling and just not running as good as it had been. So I hooked up the laptop and went for a drive and to do some datalogging and my VE values changed. Biggest changes were right in the area where I was having that spike in values, where now it brought those down slightly and several cells into more load and into higher RPM from where the spike was have now increased. So it smoothed out the big hump. I took about a 30 mile drive and got some good logs. I'm getting ready to burn a new chip right now. I'll get this chip in and go for another drive in the morning to see what happens. On the surface it would seem that there are differences between the 5.7 and 7.4 memcals that do affect the tune.

More later...