As we kick off what will likely be a farewell tour for our C5 Corvette Z06 project, we’re opening the season with back-to-back, top-level SCCA autocross events.
The plan was to kick off the season at the Florida International Rally and Motorsports Park–a facility we’re no stranger to as that’s where we do all our official testing–with the SCCA’s …
I have heard of this sort of thing happening to enough smart people to be really afraid to trust aftermarket ECUs. Would you amend your previous article on switching to aftermarket based on this, or do you consider it part of the risk already?
tuna55 said:I have heard of this sort of thing happening to enough smart people to be really afraid to trust aftermarket ECUs. Would you amend your previous article on switching to aftermarket based on this, or do you consider it part of the risk already?
Nope, still team standalone all the way for an applicaion like this and here's why: Weird, inexplicable stuff can happen with any system, whether it be OEM or aftermarket. with an aftermarket system like our Holley, we have way more ability (assuming we bring the laptop) to directly troubleshoot issues than we may with an OEM setup. Yes, setups like HP Tuners alow you to go deep into the digital components of an OEM ECU, but running our stock ECU would have taken a LOT of mechanical adaptes to adapt the LS3 style sensors and controls to the LS6 computer. With the Holley Dominator, we're Holley from ECU to engine, with no middleman to translate.
Now, for other situations, preferences may vary, but for this particular situation I still say this was the best call.
EDIT: Oh yeah, aftermarket ECUs also tend to have warranties and technical service departments. That's also a big plus.
Weird, sounds like it could be a bug in the Holley software and/or ECU. When I read the title I expected that you went out with an untested tune and ran into an issue you couldn't fix without the laptop. Did you try disconnecting the battery as a fix in case it was something the ECU was perhaps holding in some kind of RAM using always-on power?
Weirdest problem I ever had with my MS3X was the data logging channels not working out of the box until I did a disable logging channels --> flash --> re-enable logging channels --> flash cycle. But I've never heard of an aftermarket EMS apparently losing settings on its own like this before.
In reply to JG Pasterjak :
Are the higher-end systems prone to the same weirdness as the Holley's seem to be? I don't have data handy, but I don't know of any long-term Holley usage that didn't have some weirdness.
In reply to tuna55 :
I don't really have expertise to answer that. But I can tell you my project x1/9 has an aftermarket ECU made by Electromotive. In about 1994.
And even with the car sitting with a dead battery in a storage unit for nearly 20 years, the ECU still runs the engine nicely.
Now, I may not be able to tune the ECU without a DOS laptop, but I've got to say I am really quite impressed with the Electromotive stuff.
I can't really relate because I daily an unmodified economy car, but I feel like this situation is a lot like going camping only to realize you don't have batteries in your flashlight after you hear a large animal outside your tent.
Definitely not something that's happened to me, though.
My laptop is pretty essential at the track. I use it to track car setups, tire temps and pressures and session notes, to review video and data traces and for tuning. I'm unlikely to forget to bring it. Now, the cables to actually connect to various things. Those I forget despite having dedicated ones that aren't supposed to leave the trailer.
I also have forgotten to put fuel in the car more times than I care to admit and I frequently don't get times for the first session because the transponder is still in the trailer.
I have never had a weird issue like that with Megasquirt, although ever since the incident where I fried the injector flyback transistor (1.01 board weakness, especially at 100% duty cycle) and needed to borrow a laptop and cell phone internet to download Megatune so I could run my injectors at 100% current (for a very gentle, nervous drive home) I do bring the laptop with me. Always. (and switched to a resistor block, and later, high-Z injectors)
However. I fried the MSPNP computer in EvanB's Miata while trying to make the tach work before Nationals. DIYAutotune did a fast repair turnaround but not in time, sadly. When I plugged it in, the car WOULD NOT run right. Pig rich, only running on two cylinders, the works. I brought my laptop to the party to see what was up and noted that the data was... weird. The little dancing green ball on the 3D map was way off in left field, not at the proper manifold pressure or RPM. And, similar to your plight, merely looking at every table with the engine running would "fix" it. I am thinking that random electrical noise in shipping or repair caused something to get corrupted. Sounds a lot like the issue you had.
OEM computers do seem to be a lot more robust in this regard compared to aftermarket. That is not to say all is perfect: I had a Caravan come in one time for an ABS light. Problem: Van did not have ABS. Some weird glitch happened and flipped a bit somewhere and the cluster thought the vehicle had ABS, so sensing no ABS controller on the network, turned on the light...
And this is why OEM ECU's are better.
I've been running a Microsquirt and Megasquirt for years without any issues.
FWIW, the reaction seems much like an electronic throttle fault.
UPDATE: It started doing it again today as I was putting it on the trailer. Reflashing the tune would fix it, but it would do it again eventually. Got in touch with Holley and they said the most likely culprit was the throttle body, as the type we had on there was actually quite old, not 100% compatible with the Dominator ECU, and sometimes gave them issues with recent builds of the software, and also had a high physical failure rate in their experience. So while that wasn't a definitive answer, it was as close as we could get without just throwing parts at it, so we heaed to the Chevy dealer with the list of Holley's favorite throttle bodies. We found one they had in stock that matched the physical dimensions (from the LSA-powered Camaro ZL1), took it home, slapped it on, told the Holley software what it was and she fired right up.
Fingers crossed that was the actual problem. According to Holley, the only things that would likely produce that failure mode would be the throttle pedal or the throttle body, and they said they've almost never seen a pedal go bad. Here's hoping.
Really.
I can't count how many GM pedals I have had to replace due to electrical failure.
Hmmm if you ran a proper car with a carburetor these things wouldn't happen............(someone had to say it).
Pete. (l33t FS) said:Really.
I can't count how many GM pedals I have had to replace due to electrical failure.
When they failed did they 100% fail or were there intermittent issues?
In reply to JG Pasterjak :
Both.
Granted, GMs are also very common, so there is a bit of numbers bias there, but I think every APP that I've replaced was in a GM.
Dorman bothered to make a version, so you know they were having some issues 
Love the grandsport-esque advan fender decals
stylngle2003 said:Love the grandsport-esque advan fender decals
Yeah now let's see if their tires work at 28-degrees.
Having a Dominator sitting at home waiting to be installed (need to fabricate complete wiring harnesses for my application) I was debating on converting to DBW since that is within the capabilities of the stand alone. I'll be watching for updates to see if this fixes the problem!
JG Pasterjak said:Pete. (l33t FS) said:Really.
I can't count how many GM pedals I have had to replace due to electrical failure.
When they failed did they 100% fail or were there intermittent issues?
Having no idea how the developers for this system deal with electronic throttle- the kind of fault that would trigger what you are seeing is pretty minor. If one comparison of the multiple sensors fail, it will do whatever fault action is decided. That would apply to the pedal or throttle. And that's not a full failure of the sensor, either- just that the comparison fails.
Which is to say an intermittent fault on either end would be a problem.
(I did ETC development back in the early 90's when I was just starting)
DjGreggieP said:Having a Dominator sitting at home waiting to be installed (need to fabricate complete wiring harnesses for my application) I was debating on converting to DBW since that is within the capabilities of the stand alone. I'll be watching for updates to see if this fixes the problem!
If indeed this turns out to be either the TB or the pedal, it sounds like the weak link in the chain is the GM stuff, not the Holley stuff. Actuall one of the only good parts about this whole experience has been the fact that Holley Tech Support has been helpful and responsive. Probably can't say the same thing for GM tech support.
Although, I gotta give a big shoutout to the parts counter lady at Jon Hall Chevy in Daytona. When she hit me with "Yeah, make, model..." and I was like "Yeah I'm gonna stop you right there..." I showed her the list of compatible TBs that Holley sent, and my old TB and said "I need whatever is on this list that's as close as possible in physical layout and size to this." And, shockingly, she was totally game. Pulled like three off the shelf and we looked them over and found the closest match. Really over and above, particularly for a dealer parts counter, which is not usualy a place you expect awesome customer service.
In reply to JG Pasterjak :
The weak link in the chain, IMO, is still the Holley stuff. GM might throw codes but will still have the fault-tolerance to keep on truckin'. There is a mind to safety but also a bias to keeping the vehicle mobile. It sounds like the Holley system's response is to curl up into a ball at the first sign of a glitch. This is still sensible, mind you, but not very robust.
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