Problems...

I have a NHRA Pro Mod car with brad 6, M5 blower, MSD Pro Mag 44, Two step, EM box and a six shooter.
When I warm up the motor in the pit, everything workes fine, but when I try to make a run or a burnout it doesnt rev up like it should. I missfires around 8000rpm at the same time the EM box starts working. Ive changed: point box, crank trigger, coil, vires, cap, rotor, plugs etc.
Any ideas

 

I bought the motor complete from TRE. Ive used the motor the last four events,and its been great. Im running the fuel flow and EGT:s the same way as the last weekend, when it worked perfect. I believe its a ignition problem, I just cant figure it out...
The EM box takes som timing avay after 0.3 s.
Thanks for the reply...

 

checked battery voltage and connections to it?

 

Yes I have a weather station, I never make more than 2-3 runs with the plugs. The battery voltage is ok.
The only thing I changed before this started happening were valve springs.
I have not tried to change anything in the EM box.

Thanks
Adam Flamholc

 

what does Taylor say about it?

 

Does it sound like it is hitting the rev limmiter? if nothing else has changed, try changing the chips or the 2 step out, I have seen them cause this kind of stuff before, if you think it is the EM timer or 6 shooter, you can by pass it for a burn out or run by putting a switch on the black and clear wires or the 6 shooter, and if you close the switch that will bypass all of the retards.
just my 2 cents . good luck

Butch

 

You probably have checked them for proper pressure but just have to ask. Maybe you had a mis-boxed set. Stranger things have been known to happen.

Tom

 

Hi all...

Ive have changed all the chips, Ive changed just about everything in the ign. system...

Next weekend I have a very important race in Norway(Europe) At this point Im nmbr two in the point with only two events left.

Thanks for all the replies, please keep them coming...

Thanks
Adam Flamholc

 

I know this may sound too simple but one thing I have found is that when the car does something weird and I have only changed one thing it usually turns out that whatever I changed caused the problems. If this started after changing valve springs I would look a little closer at those springs. Can you actually measure coil bind and spring pressures? Misboxed springs happen-thankfully not very often. Dave Germain

 

did you or can you try it on the mag alone, taking the em box/6shooter ect out of the loop would tell you for sure if your problem realy was electrical

this will sound wierd but i had an M5 with the DMPE set back plate we chased a problem and found the set back plate was cracked and distorted, due to something we did whilst servicing the engine, we changed out the coil/points box/6 shooter befour we found the real problem