as some of you may or may not know, I just megasquirted my FC. we've been working on it for a while, struggling with a vac leak, and a bunch of other stuff.

anyway, the point we're at now, the car fires up every time you turn the key, just like normal, but as soon as it starts, it dies in about 1.5 seconds. if you don't touch the gas pedal at all, if runs for about 2 seconds, and the more throttle you give it, the faster it dies....its kind of like if the AFM is unplugged on a S4 car and you try and start it. but the AFMis plugged in, and I don't think it should really matter anyway.

I tried unplugging the TPS's for the stock computer(controlling ignition), AND for megasquirt, but niether made any difference. also, if we increase the fuel being injected, it starts to get much worse, and eventually floods, and if we decrease the fuel, it doesn't run as well either. I think the fuel part is right on, especially because it sounds great when it starts for those 1.5 seconds.

but is there something with the stock computer that could be doing this? another reason I ask, is because it used to do thissometimes before I went megasquirt . it would start and die like 5 or so times, and then after that it would continue to run, and run well. but now it doesn't ever continue to run.....

any ideas are welcome.

 

You're still using the stock ECU right? Well to keep it running you still need the other devices plugged into it such as the AFM. Are you sure you have everything wired correctly?

 

try jumping the fuel pump test connector and see if it makes a difference.

 

fuel pump is wired through megasquirt. it is running, and has 12.7 volts to it.

yeah, stock ECU is controlling spark. and I'm pretty dang sure the everything is wired correctly. but the air temp and coolant temp sensors aren't connected, and the knock sensor isn't hooked up to the knock control box(just remembered that one). could those make any difference? I was under the impression, it should run fine with basically just the CAS, and that all the other sensors were just for adjusting the timing....

 

i would throw a fuel pressure guage on it just to be sure the fuel isn't getting cut off somehow.

 

Any sensor that would make he ECU stop or go into limp mode could be a problem, i'd connect everything just to be safe.

 

thank you big retard head I had the same problem you did and so I was searching around to see what causes this and you put the nail on the head when you said "its kind of like if the AFM is unplugged on a S4 car and you try and start it" As soon as you said that it dawned on my that I didn't plug the afm back in. I love this site !!!!!!

 

bump. checked the fuel pressure, its good.

any more ideas?

 

bump. anyone?

 

did you try using another afm yet it sounds like afm problems

 

I haven't, but megasquirt is controlling fuel(and the fuel pump). maybe a bad AFM could be causing another wierd problem with spark? I guess I'll check that out tomorrow anyway....