PDA

View Full Version : Loss of power and miss!



clm15
05-06-2012, 09:45 AM
We raced last night,and in the feature about lap 6. The car picked up a miss and on the restarts it bogged. Then about lap 10 lost power to where it would idle but miss when i gave it some gas.
We think the battery is junk,we had to push start it for the feature? Was told the MSD takes alot of volts to run. I hope its just the battery?
Anyone have this problem! what else could it be?
Thanks fellow racers!

Egoracing
05-06-2012, 10:21 AM
We raced last night,and in the feature about lap 6. The car picked up a miss and on the restarts it bogged. Then about lap 10 lost power to where it would idle but miss when i gave it some gas.
We think the battery is junk,we had to push start it for the feature? Was told the MSD takes alot of volts to run. I hope its just the battery?
Anyone have this problem! what else could it be?
Thanks fellow racers!

I would say it is a battery or wiring problem. When the engine heats up AND the wiring of the car heats up they can loose conductivity and cause problems. The MSD can use from about 11-14 volts it does require amps to run though, Amps are what makes electrical devices work, not volts. You can run a phone wire to the front of the car and have 14 volts at the starter but the wire size can not flow enough amps to the starter to make it turn.

Putting a voltage meter on a battery is NOT a test of the battery or an eletric circuit for that matter as you can have full voltage and no amerage. You need to test the battery under load. Put your meter on it on voltage, then hit the starter button and see what the voltage does, this will give you an indication of the condition of the battery. I have seen MANY in my line of work that have 12-14 volts but when put under load fold up and the voltage drops to 0.

js11
05-06-2012, 11:13 AM
If the miss on the throttle occurs while the car is stationary (not going around the track), check electrical parts. I had a similar issue in the past where the wire from the main ignition toggle was loose because a screw backed out and eventually fell out altogether. It was close enough to idle, but would fall on RPM gain (wire moved around). Also, check the coil. It will fall off when heat increases.

If this happens only on the track (especially when there is alot of chassis movement), check the fuel system. Is the pickup in the correct corner, is the fuel cell sufficiently vented, is the pump failing to maintain pressure, powervalve bad, needle valves stuck, etc.

Good luck

sj valley dave
05-06-2012, 11:55 AM
If the battery is junk and you had to push start the car...before I started doing anything, just put a good quality battery in it....Try the obvious things first as they usually are the problem...

GUARDRAIL
05-07-2012, 04:35 AM
Maybe the MSD cap and rotor. Sometimes the rotor will get a little pinhole burn or the cap has a little button inside that will wear down flat and these type of things will also make the motor run as you described. Something to check real close at least.

clm15
05-07-2012, 08:42 PM
well the battery checked out a ok. (took it to auto zone) The master disconect was the problem. With the engine running,we wiggled the switch and cables and the engine would shut off. Thanks to all,If your switch is more then a year old you mite want to replace it. Good luck to all. And thanks for the info.