Anybody have a MSD 6A or similar in their spare parts I could borrow for a test? Really having a hard time chasing down a stumbling issue that seems to only happen when it's really hot out. Hoping not to replace another part without confirming it's the cause first.
A hot stumble, if ignition related, tends to point to a bad coil, however, for the sake of testing if the box is bad you can bypass it and run directly on the coil. Forgive me for not remembering how to do the bypass but Im sure it's on the inter web somewhere.
Are you fairly convinced the issue is spark and not fuel?
Fairly convinced it's spark. I am monitoring fuel pressure and there is no drop. I get no vapor lock symptoms at startup. Plus, its so intermittent, I'm just convinced since the AFRs aren't staying high (ms, not s). I run a fairly high volume pump and return system via a new aeromotive external FPR, so I don't see how the fuel could be staying in the rail long enough to be affected by heat. The AN -6 supply hose is nice and cool right where it enters the rail.
The MSD box, seems to be getting really hot. I never had a reason before to monitor it, but I just don't think it can be normal. With my setup, I can't easily bypass the box. I would have to modify my ECU (at the board level) to enable it to fire the coil directly. That's something I won't do because I would have to replace transistors and the whole shebang. I may look to go EDIS if this gets ugly and get rid of the whole existing ignition setup.
Thanks for the input!
ETA - the coil has been replaced already, as well as the fuel pump
@lt1fire - You can stand down. I much appreciate the offer. I went to relocate the MSD box today for a test and it has completely died. My guess is there was a cracked solder joint somewhere on the board from nearly 20 years of vibration. Long story short, I am about to order a replacement right now. Knowing my luck, the problem will be unrelated.
Ramon
