Hey guys, I have a problem and I haven't figured out how to work towards a solution yet...

The car runs extremely rich in all portions of the map. For some reason changes to the VE tables have very little effect on the air fuel ratio. you can change the VE from say 15 to 2 in the idle bin and surroundings and it wont influence AFR's at all, still idles with the gauge pegged at a ratio of 10:1. under light loads the AFRs do drop to 12's but cruising is also pegged at 10's. the required fuel was calculated using the calculator. it is 4.3 with 4 - 1000cc precision injectors. If you reduce the required fuel to 2 or 3 you gain a little "finer" adjustment in the ve tables (a smaller change affects AFRs), but its no where near what it should be.

I think the problem is a megasquirt hardware issue. The reason is i have a second megasquirted rx7 that i used to test the megasquirt in question. I loaded my maps and the megasquirt is built exactly the same (except for using gm sensors instead of mazda) as the one on the good running car. when i swapped to the ecu in question it ran terribly rich, i had to pull out 30 clicks from the ve tables to make it driveable.... at the time i assumed it was because the sensors were different. now i think otherwise.

anyway i need to figure out a way to systematically check every ecu circuit that could cause this problem.. can anyone help.

 

What's your opening time?

 

running 1ms injector opening time

 

I had something similar; a component in the flyback circuitry for the low-imp injectors had burnt up. The injector was therefore staying open for much longer than actually called for/demanded, making it run rich regardless of VE table setting

 

thanks that will be the first circuit i check.