(GONE!)Spark dropout under load(DATALOG AND TUNE INCLUDED)

[WillExoIX]

what exactly am I checking?

The power line for the MS. I had a wacky fuse confusing hesistation when warmed up

It gets its power from one of the two injector fuses, both banks of injectors get thier power from one of the injector fuses, leaving the other unused, which is why I used that power source for the MS. I have put in a couple different fuses with no change.

[WillExoIX]

As far as we can tell, it was incorrect rotor phasing. I used my old dizzy cap and cut the entire center out, only leaving the outside posts. Put the harmonic balancer at 10* on the timing tab, the rotor lined up properly but the reluctor was off. So I loosened the dizzy and turned it till the reluctor lined up, which wound up changing the base timing to 0*. Went into the MS and changed the base timing from 10 to 0, took it out on a drive, and SUCCESS!!!!!!!!

Problem Solved!

Thank you for all the help and support, and thank you slowhemi for mentioning rotor phasing! If you hadnt I would probably have given up!

[WillExoIX]

Well it happened to be a combination of two things, incorrect rotor phasing and a leaking EGR valve causing a misfire under lean cruise conditions. The EGR was disconnected, but still on the car. All I had to do was make a couple blockoff plates and the misfire was gone.

To recap,
Incorrect rotor phasing was causing the resets,
Leaking EGR was causing the misfire.

[WillExoIX]

Well since I told everyone I was doing a turbo setup, I figured I had to post the video.

This is the second start, and you can hear the exhaust leaks that Im working on, need better manifold gaskets. What happened after the first start was this; Started nicely, so figured Id take it out for a log and do some tuning. Little did I know, after a boost leak made the boost spike up to 15psi with a 6psi spring, the collector gasket was slowly deteriorating. (Ceramic fiber gasket BTW). So halfway through the ride I gave it some gas, collector gasket blew out, melted an oil line, and caused a fire, what a ride! Had a fire extinguisher handy and the hood was off, so I had it out quick enough with no major damage.

Without further ado, here is the second start with squealing belt and all(good part starts at 1:18)
http://www.youtube.com/watch?v=IXSGWhhme-Y

Enjoy!

[WillExoIX]

Its Fuc*ing misfiring again.

Gets warm out and it completely goes away, starts getting cooler out and it starts misfiring again.

New wires, dizzy(complete), plugs, etc. Entire ignition system is pretty much brand new. 140psi in every single cylinder. No emissions equipment left to malfunction, it has all been removed.

It mostly will happen while cruising, but it will also do it under accel.

The only think left that I could think of is the timing set, its about 5 years old. BUT, the last time the timing chain went, the timing would keep jumping every time I reset it. It hasnt jumped once this time, and timing is still dead on.

Any Ideas?

[Matt Cramer]

A fresh data log with all else eliminated may shed more light on the problem.

[WillExoIX]

A fresh data log with all else eliminated may shed more light on the problem.

Matt, seems that the base tune I had gotten from Dave had the wrong dwell settings from the start. I switched dwell settings to "Minimum for HEI4" and voila!

Is it really that simple? Cause it doesn't misfire now!

[WillExoIX]

Its starting to misfire again.

What are the CORRECT dwell settings for a small block Chevy?

One article says minimum for HEI4, another says to use dwell settings, WHICH ONE IS IT?

[WillExoIX]

This whole time, I have been chasing my tail. It was the MS1 cpu. Finally bought the MS2 cpu and installed it and the misfire is COMPLETELY gone.

The car has never run better. So the issue is solved for good.

[WillExoIX]

Quick update. All is still well. Was definitely the cpu.

Sent from my SCH-I535 using Tapatalk