Re: Help!!
 

Just a big cuddly ray of sunshine.

Hope you get the problem fixed

Re: Help!!
 

What I think I found is a failed spring inside my micro switch. I measured the travel on my new switches and found .043" travel for the roller on the lever would close the switch. My old one was so weak I had to hold the roller up to zero my dial indicator. It then only required .025" travel to close the switch. I think the new switch with more travel and a stronger spring will help prevent bumping the 2 step. The new switches (bought a spare) costs about three dollars at Affiliated Electronics. Cheapest thing on the whole car.
What you look for is called a short roller micro switch. Affiliated's part number for the switch is PH30-2080B. They are online.
Hope this helps somebody.

Re: Help!!
 

Ed, what kind of button are you running?

Re: Help!!
 

Joe, it's a Biondo Terminator. I've gotten over a half dozen private messages from guys having the same issue I had. Some just changed to a different style different button. Guess I'm either stupid or stuborn. Probably the latter. <G> I feel like this new switch will take care of it. Too cold to test here this weekend. Hope I found it.

Re: Help!!
 

Well, it wasn't the micro switch on the Terminator button. Tested this afternoon at Tulsa. Still cuts off & back on. TPS graphs have been ugly, so changed it at the track. Also changed the FAST XFI ECU. Cleaned up the TPS graph. Still cuts off. Unplugged the rotory dial MSD 2-step selector, plugged on a rev limiter chip. No help. When it doesn't cut off the car is the fastest it has been. Can't race it like this.
If I find it I will post it with the hopes it might help somebody else.
Ed

Re: Help!!
 

What are your wide band readings when it is cutting out?
Another trhing I've heard about are tachometer problems effecting the motor.

Re: Help!!
 

Art, wide band doesn't change, voltage to the ECU doesn't show a change. Had the tach disconnected, still did it.

Thanks, Ed

Re: Help!!
 

I couldn't get a good O2 reading below 5500 (the O2 sensor is in the collector). I had to put an extension and a muffler to get the O2 to read in the lower rpm ranges. I found I was lean leaving the line (it never showed on the dyno). The car would stutter, pop and bang, leaving the line. With the motor cold. Richening it up between 4500 and 6000 cleaned it up.

Re: Help!!
 

I had this same problem and it turned out the Battery mount had broke at the bottom where I couldn't see it. Everything looked fine upon inspection but once the car launched it would rock out of the mount and short out on the chassis. I assume that since you changed your batteries that this isn't you problem but it sounds like some where down the line there is a short. May have to start tracing wires to see if any are chaffing and shorting out.

Re: Help!!
 

Batteries aren't moving. Yesterday afternoon it cut off 5 out of 8 passes. Getting more frequent. It runs ten to twelve hundredths slower when it does it. Sounds like a loose connection, but according to the XFI internal data logger the voltage doesn't vary. May be too slow to catch it.