I'm beating my head against the wall with my megasquirt install. I need a fresh set of eyes and an experienced hand. At this point in time, I'm so confused and frustrated that I'm not sure what to do or where to go next.
I'm near Charlotte NC.
Anyone know who I can call, or would one of you be willing to help?
Had it starting and sort of idling, now won't even do that. Seems like the more I try, the worse I make things, and I think that I completely boned myself at this point.
Wish you were closer. Hope you get it sorted. Sometimes you just need to step back and go back a couple steps and re group.
Did you save any of the previous settings in a previous tune file?
If so, try going back to a previous version that worked and try to work slowly forward.
If you can post some video to YouTube, going through the various settings/sounds, then perhaps we can help remotely.
I saw your other post a few days ago, but didn't have time to answer....
Anyway. I think your trouble is the way the GM HEI-7 module is set up.
To get the engine going, the bypass terminal on the module should be grounded. Then physically rotate the distributor assembly until the engine starts. With the engine running, use a timing light and move the distributor until your at 8 degrees BTDC.
At this point you can fiddle with the mixture and whatnot to stabilize the idle.
Once the idle is stabilized, you'll need to put 12V on the bypass terminal... The engine will likely stall.... that ok. With tuner studio, Adjust the offset in the ignition window ... something like 25 degrees.
The main point is to get the engine running with bypass grounded. The rest of the ignition setup should be relatively easy.
Uploading a video now. Hopefully it will help. By monkey berkeleying with the distributor it's starting again, but....
Ok, while this uploads...
Car won't start easily. Bucks and knows against the starter. While cranking, rpm all over the map on tunerstudio. When it does get running, tach is completely inaccurate, and I'm not sure megasquirt is reading rpm correctly either. It finally revs when given throttle (which it wouldn't do earlier today). Idles at an unknown rpm, somewhere in the 2-3k range with my finger blocking the iac hole and the throttle blades closed as much as they can. If I retard the timing, idle lowers then car cuts off. Timing still unknown, but when tunerstudio said I should be seeing 35 degrees, I was there according to the timing light. That is assuming that the marks on the harmonic balancer are correct, which I have all reason to believe.
So, what the berkeley?
Still waiting for the video to upload.
Also found throttle linkage binding, so we got to a more reasonable idle rpm, around 1000 ish.
Think I have a ground issue, due to rapid relay clicking and dash indicator lights glowing but not lighting.
So, I have some direction to start in, but still want to pay/bribe someone who has done this successfully to help. I feel like I'm chasing my tail in the dark while tripping on acid over here.
Quick easy ground fix is to redo your battery to body and engine to body. Those two are really easy and often overlooked.
Too far to help directly, but check your grounds again. I bet you're on to something there. You also may want to log the crank signal (there's a tool in Tunerstudio to do this) to make sure you're not dropping signal or picking up other electrical noise. This tool can be used in conjunction with the noise filtering tool to smooth out the signal. If MS is getting inconsistent or incorrect RPM information from grounding or noise, it will never run correctly and more or less do what you're describing because timing and fueling end up going all over the place.
still trying to get my video to upload.
chasing grounds is tonights plan. every single one, throught the entire car. even if completely unrelated to megasquirt, just to be sure.
I had grounds going all over the place in the last iteration of my MS install. I haven't actually started the car since re-doing everything (so that may or may not be worth anything...) but when I upgraded to MS2/Extra and re-wired everything, I put every. single. ground. wire. for every. single. sensor. to the exact same bolt on the head and I used two Big Ol' braided ground straps from the body of the car to different places - one on the intake manifold and one on the head. MegaSquirt is also grounded to the same spot on the head as the sensors, as is the AEM UEGO wideband.
Like I said, I haven't actually fired the motor yet (I may get to that point today if I can find time), but I did some testing on the wideband readings in MS versus the gauge display and with the grounding changed to the same place as everything else the reading is much more rational now than it was before. I didn't really buy in to the whole obsessive grounding thing initially, but I'm coming around.
Another grounding thing I found: I have a digital water temp gauge that I added on purely for my own eyeballs - not fed in to the ECU or MegaSquirt. I grounded it to the same spot that a headlight was grounded on the core support. Vastly different temperature readings depending on if the headlights were off, low-beam, or high-beam.
That stuff may all be common knowledge and I might be the only one that's ground-tarded here, but just in case it might help you, that's what I've learned.
For Megasquirt, you generally want sensor ground FLOATING not connected to the block/head/intake, for the exact reason that you saw when hooked up to the headlight ground.
I had some trouble with this on my Volvo, that I could see injector noise on the sensor inputs if I hooked up a scope. The problem was that they were sharing a ground path with the fuel injectors, so when the injectors drew current, sensor ground would move around relative to the MS's internal ground. You want the ground reference for your sensors to not share a current path with anything that pulls significant current, like injectors or the ignition system.
You'll need to log in to post.
