Unsolved mystery

SST159 · 11-05-2011, 10:33 AM

Looking for some input.
Last race out a few weeks ago between 1000’and finish line I heard the motor pop once.
After losing the round I drove back to the trailer thinking what was that all about.
I pulled the run up on the computer from Race Pac and I see a spike in the graph.
This explained the pop because it went up on the rev limiter chip.
The mystery is that the motor spiked only once and very briefly but the driveshaft did not. The converter slippage ratio was normal after the spike and the rest of the run was fine after the pop. Anyone ever experience this and if so what did they learn from it? Your input may save me from a wild wrench chase? I have to assume its either converter or trans related. PS converter is new with only 30 passes on it and Trans is PG with only 150 passes on it.

RIP SHAW · 11-05-2011, 04:13 PM

Drew, I just had a problem with a bare spot on the crank trigger wire causing a miss at 6500 rpm. the tach started jumping around from 3000 to 8000. MSD said it was interference getting in from the fan and water pump.Sealed up the wire and its fine now. Rip

Pvt Parts · 11-05-2011, 06:11 PM

Quote:

Originally Posted by RIP SHAW

Drew, I just had a problem with a bare spot on the crank trigger wire causing a miss at 6500 rpm. the tach started jumping around from 3000 to 8000. MSD said it was interference getting in from the fan and water pump.Sealed up the wire and its fine now. Rip

I had a similar problem when I ran A/SM with a front drive distributor and the coil mounted inside the car. The crank trigger wire got too close to the coil wire and caused a high speed engine miss from interference.

SST159 · 11-06-2011, 10:28 AM

Thanks Guys.
Sounds like its more motor related than drive train.
My trigger wire, fan, water pump wire is not real close to the coil wire at all but I will check both to make sure its not a wire issue.
I would think think a miss would cause the RPM to Drop rather than spike and also the drive shaft would show a small amount of drop as well?

11-05-2011, 10:33 AM	#1
SST159 Member Join Date: Jul 2005 Posts: 301 Likes: 4 Liked 18 Times in 12 Posts	Unsolved mystery Looking for some input. Last race out a few weeks ago between 1000’and finish line I heard the motor pop once. After losing the round I drove back to the trailer thinking what was that all about. I pulled the run up on the computer from Race Pac and I see a spike in the graph. This explained the pop because it went up on the rev limiter chip. The mystery is that the motor spiked only once and very briefly but the driveshaft did not. The converter slippage ratio was normal after the spike and the rest of the run was fine after the pop. Anyone ever experience this and if so what did they learn from it? Your input may save me from a wild wrench chase? I have to assume its either converter or trans related. PS converter is new with only 30 passes on it and Trans is PG with only 150 passes on it. __________________ Drew Wonderly SST 159

11-05-2011, 04:13 PM	#2
RIP SHAW Junior Member Join Date: Oct 2009 Posts: 6 Likes: 0 Liked 0 Times in 0 Posts	Re: Unsolved mystery Drew, I just had a problem with a bare spot on the crank trigger wire causing a miss at 6500 rpm. the tach started jumping around from 3000 to 8000. MSD said it was interference getting in from the fan and water pump.Sealed up the wire and its fine now. Rip

11-06-2011, 10:28 AM	#4
SST159 Member Join Date: Jul 2005 Posts: 301 Likes: 4 Liked 18 Times in 12 Posts	Re: Unsolved mystery Thanks Guys. Sounds like its more motor related than drive train. My trigger wire, fan, water pump wire is not real close to the coil wire at all but I will check both to make sure its not a wire issue. I would think think a miss would cause the RPM to Drop rather than spike and also the drive shaft would show a small amount of drop as well? __________________ Drew Wonderly SST 159