I am having a problem with my tune. There seems to be a mishap in the upper RPM's of the engine. The tuner, Ed Senf, who Grassroots MotorSports uses exclusively, can't figure it out. We did several pulls, and even at the low psi pulls it was present. Only the higher the psi, the lower in the range did it begin to show. Here it shows at ~6000 rpm. Here's the setup up:

Recent rebuild. < 1 mile before the dyno (had to make sure it fired up )
B16A
SRP 9.9:1 Pistons
Crower Rods
ACL Bearings
ARP Studs
OEM head and gasket
OEM intake manifold
OEM fuel pump
RC 550
TD05-18G Greddy setup @ 11 psi w/ FMIC
Greddy timer and MBC
AEM EMS
MSD 6A w/ Blaster SS coil
NGK Blue wires
NGK BCPR7ES-11 plugs

I have tested the CKP/TDC/CYP sensors in the distributor for the Ohm specs and continuity tests according to the helms. What else might effect the rpm readings and the weird shape of the power band? Need some insight on this because I know I should be at a higher HP # than 232. I should be around 250 with this setup, not to mention a better looking curve. Any suggestions?

 

From the looks of the dyno graphs it seems the like you aren't running enough ignition timing. Make sure you "sync" timing in the aem software. Is the motor misfiring @ 11psi? What are your plugs gapped at? Another thing you can try is bypassing the igniter and triggering the MSD with the AEM.

 

hey man something similar with just happened with my seyup, i ran 9psi on a missing distributor (dying ignitor?) sounded like it was hitting a revlimit, but it was the dizzy missing cause the dyno signal was going out too.

check out my powerband:


think you have the same problem i was having..?

i got a new dizzy and it fixed all my issues, havent got it redynoed yet

 

My dizzy is a few months old. I got the MSD 6A and blaster coil installed back in March/April and it was fine then. I need to test the MSD stuff to make sure it hasn't crapped on me. The tuner doesn't think that it is misfiring. He said it doesn't sound or feel like a misfire. I could check the wires too for wear and tear. I'll see if I can hook the MSD through the AEM. The timing is syched becasue we checked that first before the first pull. He did advance it to 18* but it did nothing to the curves. The plugs are gapped at .028. The first set were gapped at .032 and popped in the second fresh set. No difference. We even retarded my exhaust cam gear a few degrees and no difference whatsoever!?! He has said the AEM showed the RPM fluctuating in that range in the datalog. He's still going through the information. Any other ideas?

 

Gap the plugs to .024 and bypass the igniter and trigger the MSD with the aem...thank me later.

 

I'll look that up and when it works...

I'll thank you.