So today I was trying to change settings to run some low imp 720cc injectors(I had high imp 550cc) and had troubles changing everything to get my car running again. But while I was working I noticed that I could not connect with the megasquirt after a while. So I swapped in a fresh battery I have for back up and rechecked connections and power was good to the ecu but no communucation. I put on the stim to check and still nothing. At this point i rebooted my computer and got comunucation. So I tried starting it again and noticed it would not comunucate when I was cranking? Also I got 2 real bad backfires!! Sounded like a shootgun. I did not have that problem before. Then I looked at the ignition table and it was full of BS numbers like 2064 1000 -900 etc.And the ve table under tuning was all scrible on the screen. So I opened the last known good file and everything seems ok??? Any Ideas what happened? And I have not got to see about it sinced I opened the old file and got the car started but had to shut it off cause the wife and kid got home.

 

Excessive electrical noise can cause flash corruption. It sounds like that may be what happened to you.

It has to be a pretty bad noise problem to cause that though.

Ken

 

Could it have been a weak battery? Of my laptop that shut off on me? Could fouling spark plugs do it?For that to just happen from no where was wierd.

 

it could have been all or any of that. megatune can be kinda temperamental sometimes. luckily a flash usually will cure the weirdest of problems.

 

IF it was a low battery, sometimes if you're burning a setting while there's a low battery, the voltage to the chip is too low for reliable flash burning, and that can definitely corrupt settings, or even the main firmware.

Ken

 

cool I was wondering if that could have been it. But now I am pretty sure my plugs are fouled from flooding trying to get the 720's running. It sounds like its running on one rotor. So getting new plugs and going to try again.

 

make sure your reqfuel is low enough...

Ken

 

reqfuel was 9.4 with 550cc's what should it be with 720cc on a half-bridgeport? 7.0?

 

You can use megatune or tunerstudio to calculate it. With 550cc injectors, it should not be 9.4, it should be 7.9.

With 720cc injectors, it should be 6.0.

Ken

 

Ok got the 720cc injectors running 6.0 reqfuel. Time to retune.