I have a lot to update lol.
For now, here are some beans. Unfortunately its been a very long weekend and I've done this same test about 6 or 7 times now with all the same results.
Holley is still losing crank signal - this time at 6800 rpm religiously. It eventually after maybe 5-10 seconds finds RPM signal again and keeps running.
https://www.youtube.com/shorts/SbCbVB-8Z10
I have Holley exhaustion.
It sounds very cool.
It feels quite fast imo for what it is.
This is without any tune refinements outside of my start-up tune. It has only hit ~19* of timing so far too - I have a very soft timing curve going from 17 to 20* at WOT.
It feels SOTP like it is ready to start soaring above 7000 rpm.
I'll reserve judgement on low end torque until I've actually tuned the engine, but I've been WOT in 2nd gear at very low speeds and it is extremely stable and planted feeling. Its not even working the tire. I'm quite optimistic.
Ok, so - I said there was more to the story. I got real busy and haven't had time to write this up. I've been traveling for work this week.
I had a pretty f'ed weekend working on this thing. I regret going so deep into Holley ecosystem.
I go up last Friday like usual to wrench and had plans to return on Sunday and maybe be putting finishing touches on the car and a bunch more break-in miles. I arrived in the morning - decided to take the car out for 2nd of 3 drives to put some miles and heat into the diff so I can swap the fluid. I was going to drive it in the morning, and in the evening, and then change the fluid on Sunday.
So, I drive for 15 minutes or so and I'm loving it. Taking it easy, but still getting a feel for the car again and bombing around a bit. I'm staying close to the house in case anything happens.
I'm driving down a hill and I feel it cut out a couple times as if I'm running out of gas. No sweat - I used to run out of gas with about 3-4 gallons still in the tank because Mazda didn't know how to build cars properly in the 90's lol. I stop at the stop light and the car is idling fine...figure on flat ground I'd be ok. I turn right into the main road, and I go about 20 feet before the car sputters a bunch of times and then just dies entirely. I park and call my mom to come rescue me with some of our 91 octane "race gas" from Chevron that we use in our pump gas drag race cars lol. Ironically, this is the same stretch of road I've run out of gas on before because my wife (then GF) didn't want to stop for fuel at the end of date night one night, but I had a bit more momentum and was able to crest the hill, and then push it into my neighborhood. This time it looked like I just stopped for an impromptu photoshoot and roasted myself on instagram for everyone to laugh at lol. I was also kind of surprised but I was there about 20 minutes on the side of the road and only one person eventually stopped to see if I needed help. He has a 1972 rx2 I guess and said the car looked great - I told him don't look up front it has a 427 in it lol.
Put a splash of gas in it and decide to head to the gas station a couple miles down the road. My old man was just getting home too as I was stranded on the side of the road so he followed me to the gas station to make sure I don't get stuck again. I get 3/4 of the way there and it starts to act up again, but this time I notice my tach is jumping around. I killed the ignition at a stop light not knowing if it was fuel level or what was going on...refired it luckily, and made it the short stretch into the gas station parking lot coasting and keeping up speed as the car is sputtering and trying to die. JUST MADE it on fuel - so I thought lol.
Fill up the tank, and it clicks off around 18 gallons. First time a light bulb went off, and I really thought back to the tach jumping around. I definitely should have been able to keep driving if it only took 18 gallons. I've put over 19 in it back in the day when I didn't have a surge tank in it so I know I can get it down to fumes.
Also, as I'm filling up the car I've got 3 people stopping to talk to me about it. One told me about his friend's 1100whp rotary rx7 - totally believable. A couple wanted to know more about the car. Meanwhile I'm just trying to get home again lmao! It is going to take some getting used to again I forgot how much (male) attention this car gets lol.
Well, I fire the car up and try to leave the gas station and I go about 2 feet before it dies. Crank again drive a few feet and dies. Fired up again, made it to the other side of the parking lot and it dies in the way of everyone. Try again and it won't even start. Got out and pushed it into a parking spot lol. Now I'm getting glares from people haha. More attention, wrong kind.
Luckily I had my laptop with me to do some datalogging and I saw that when the car was sputtering the RPM was reading either Error! or Sync. Both are bad news obviously. I go in and disable the cam sensor and enable batch fire and cross my fingers...luckily that was enough to get me moving again, although it had cleared my fuel learn table and I was back on the struggle bus, but at least able to move more than a couple feet at a time lol.
Now mind you, this quick drive has now soaked up a solid hour and a half lol. I was heading back to the house and I am taking off from the stoplight, and I thought break-in miles be damned, I'm not going back to the garage to start diagnosing cam/crank sensor issues again without feeling this thing at WOT. I figure if I don't slam the throttle, and don't bang gears or slip the clutch crazy, simply rolling into it in 2nd isn't going to hurt anything. I roll into it from ~30 mph at around 3000 rpm and it definitely gets my attention while I'm also staring at my AFR to make sure the closed loop fueling is doing its job. I see it hit 12.5:1 afr and its really coming into the powerband above 5000 rpm. I really was excited to see how the power carries above 7000 - and right as its about to start screaming past 7 it pops and backfires and loses ignition and the tach drops to zero lol (actual engine revs are still way up there) - so even with the cam sensor disabled, the crank sensor shit the bed at high rpm.
Long story longer, I bought my dad a Gen4 holley harness and a digital dash for our stroked LS3 powered malibu station wagon. We've wanted a datalogger in that car for ages, and the autometer tach shit the bed, so using my old termi-X and a digital dash to get a datalogger and a new tach suddenly seemed like a great proposition.
Well, my dad told me I need to swap harnesses, and he made me steal back his birthday present and we wrenched from ~3pm to midnight and ripped out the old engine harness and completely rewired the car undoing a couple months of work and redoing it in record time. We were almost back together, but ran out of energy at midnight and just set the intake and I decided I'd come back Sunday to finish it up. Lemme tell ya...there is an appropriate order to assembling a car, and installing the harness last is not the correct way to do it. Huge pain in the ass.
Out with the old:
In with the new:
Proper sentiment for midnight:
I went back Sunday with the wifey as my parents are on vacation now, and that is where the video is from on the post above. I made probably 6 or 7 pulls in total now testing all different combinations of tune changes and physical changes I can think of to no avail. Like clockwork at just over 6800 rpm the thing will lose ignition and die. I take a system log and I see where the crank pulses start to smear together and eventually the engine loses its place and kills the ignition. After swapping the harness, I will say this is the best the cam sensor pulses have ever looked.
My last hail Mary, I have a genuine GM sensor coming from a dealership to replace it this coming Friday and pray that it resolves the issue. If not I'm really at the end of the road. I've had two of everything and have always had cam and crank sensor issues - two different engines w/ different sensors, two harnesses, and two computers. I've completely isolated the Holley stuff from the Mazda wiring, and everything power and ground has been connected directly to the battery. Grounds are huge and multiple. It really just doesn't make any sense why there'd be a problem. On the LS2 I just accepted that it was an aftermarket crank, aftermarket cam gear etc. This LS7 is the factory sensor, and factory rotating assembly that was assembled by GM.
End of the day I'm really thankful I did the irresponsible thing and got on it on the way home because first of all, I wouldn't have known there was a high rpm issue, and I wouldn't have known it was isolated to the crank sensor when the cam sensor has been most suspect up until this point. Second of all, I got a huge hit of adrenaline, and also dopamine hearing this thing at full song. The adrenaline was more from the thing backfiring and shutting off on me suddenly than pure speed, but I've been riding that high through all the rewiring and diagnostic bullshit I've been going through.
I'm quite optimistic about this engine combination I put together, and the rest of the drivetrain is feeling more refined than ever. I just really have to get this sensor issue resolved or I'm going to be hurting in a big way.
Pulses are supposed to look like this for a 58x, 60-2 type wheel:
This is how they look, or even more smeared together before the thing cuts out:
