Somebody knowledgeable in megasquirt and small bloc chevy?

Dread Specter

Dread Specter

New member
*small block

So the last thread asking for a megasquirt pro dates from 2007, and I tried to get in touch with the Walter chap but haven't been in luck.

I have a small block chevy with vortec heads, vortec injectors and ls2 coils which I'm hoping to get running on full sequential. In theory, everything is dialed in, but I can't get the damned car to idle. I went through 2 starters already and I'm really running out of ideas as to why it runs so piss poor (aka, barely cranks over and doesn't idle). I just noticed thansk to some cool chap on msextra that there might be an issue with the main map sensor, which I'm going to try and fix tomorrow morning, but otherwise, I will need someone better than I am to figure out what's wrong with the damn thing.

Anybody knows anyone that knows the MS3X and SBCs, to give me a hand in troubleshooting this? That's the tune and log in case anyone is curious..
http://www.msextra.com/forums/viewtopic.php?f=131&t=56304&p=419619#p419619

Thanks!
 
I just checked the log and it seems like nothing is calibrated properly.
The map sensor shows 227-258 kpa while the engine isnt even turning. Tps is at 10.7 when not cranking (why is that).
Total fuel correction jumps from 100 to 161% meanwhile, the pulsewitdh stays roughly the same (what's up with 45ms of pulsewitdh, it is INSANE).

I'd check my entire wiring and the sensors calibration if I were you.


edit: looking at the tune, the injectors deadtime are at the default 1.00ms, wouldn't explain the nostart condition but I'd fix that.
The required fuel is 6.03ms, why are we seeing 45ms of PW when cranking?! I'd check the fuel pump and pressure control, it is sometime really dodgy when troubleshooting a start condition.
 
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ThermalAce said:
I just checked the log and it seems like nothing is calibrated properly.
The map sensor shows 227-258 kpa while the engine isnt even turning. Tps is at 10.7 when not cranking (why is that).
Total fuel correction jumps from 100 to 161% meanwhile, the pulsewitdh stays roughly the same (what's up with 45ms of pulsewitdh, it is INSANE).

I'd check my entire wiring and the sensors calibration if I were you.


edit: looking at the tune, the injectors deadtime are at the default 1.00ms, wouldn't explain the nostart condition but I'd fix that.
The required fuel is 6.03ms, why are we seeing 45ms of PW when cranking?! I'd check the fuel pump and pressure control, it is sometime really dodgy when troubleshooting a start condition.
Click to expand...

Definitely there was an issue with the calibration, it didn't save it for some reason.
I have new logs ans tune as of today, maybe it could shed some more light.

The 45 pw is normal a/p the fuel calculator I reckon... the 6.03ms would be x8 injectors, but it doesn't come into play since squirts/cycle don't apply on full sequential. Went better today but still won't fire up....


Thanks a tonne for checking it out though!
 
Have you been through the firing order and the wiring to be sure they are paired properly? it wouldn't show in the logs since MS can't alter the injectors numbers without re-wire
 
ThermalAce said:
Have you been through the firing order and the wiring to be sure they are paired properly? it wouldn't show in the logs since MS can't alter the injectors numbers without re-wire
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Yeah, did just that today.. it's all good, I was hoping there could have been an issue with the wiring..
 
I'd start to check with the ignition logger for sync error or noise that mess with the sparks. Everything else seems good enough for the engine to be able to run/idle
 
why not get an HP tuner ?

there are so many inexpensive tuning software nowadays. It might be a lot less complicated to use GM sensors than to try to run a MS
 
Gregster said:
why wouldn't you run HP tuner in the first place.....
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SRT-What? said:
why not get an HP tuner ?

there are so many inexpensive tuning software nowadays. It might be a lot less complicated to use GM sensors than to try to run a MS
Click to expand...

Because they don't make HP tuners for 1953 Buicks...? Did you read the thread at all guys lol? And further to that, information you didn't have, the whole car is a mix and match of different parts. 1969 Camaro SS350 engine lower-end, 1996 vortec heads, 1998 vortec manifold, 201* ls2 coils, some hyundai radiator fans, and it goes on and on.. So MS was the only option, it's what I have now, and it's what has got to work.
 
seriously ...it called Megasquirt?...hard to find any info on google ..you need to go through 1000 sites of porn before...
 
Dread Specter said:
Because they don't make HP tuners for 1953 Buicks...? Did you read the thread at all guys lol? And further to that, information you didn't have, the whole car is a mix and match of different parts. 1969 Camaro SS350 engine lower-end, 1996 vortec heads, 1998 vortec manifold, 201* ls2 coils, some hyundai radiator fans, and it goes on and on.. So MS was the only option, it's what I have now, and it's what has got to work.
Click to expand...

I dont get your point.

Plenty of high HP cars will big cams, stroker kit, and high flowheads runs HP tuners. You dont need the full car, just the ECU and the sensors (i'm pretty sure that with the "pro" version you can fit any sensor you want.

Ask me how im running a Ford TPS on my neon with a 3 bar map instead of a 2.5 (could actually whatever I want as long as it is 0-5v).
 
SRT-What? said:
I dont get your point.

Plenty of high HP cars will big cams, stroker kit, and high flowheads runs HP tuners. You dont need the full car, just the ECU and the sensors (i'm pretty sure that with the "pro" version you can fit any sensor you want.

Ask me how im running a Ford TPS on my neon with a 3 bar map instead of a 2.5 (could actually whatever I want as long as it is 0-5v).
Click to expand...


My point is I'm coming from an engine with no sensors because it's it's half a century old. By the time I buy a GM ecu, buy a GM harness, modify the GM harness, buy the HP tuner, buy the license, then figure out every single modification I have to make to the GM ecu for it to work because none of the stuff is factory original, I'm in it for more than the megasquirt and unlikely to have any less headaches.

The point is moot anyway because as I said, this is what I have now and this is what will stay. Now it needs to work.
 
a Megasquirt is fine, they are good ecu with tons of feature for a relatively low price.
it's not PnP and that's why there are often a lot of troubles with MS setups.
 
does it loose sync signal? many ms have isues with crank signal wires running along injector wires, keep em as far away as possible and you MUST use shielded wires . what signal are you using,what crank sensor? check for inverted signal and return wire (you can change atack or decay mode on ecu).
 
pep fab said:
does it loose sync signal? many ms have isues with crank signal wires running along injector wires, keep em as far away as possible and you MUST use shielded wires . what signal are you using,what crank sensor? check for inverted signal and return wire (you can change atack or decay mode on ecu).
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Hi mate. Thanks for you assistance.
Turns out the earth for the even bank coils was bad. Fixed it and she fired right up.

Thanks to everyone. MS is really a fantastic piece of hardware I tell you...
 
good for you! ms is a great system to work with, wouldn't change it for much more expensive system
 
rebel said:
seriously ...it called Megasquirt?...hard to find any info on google ..you need to go through 1000 sites of porn before...
Click to expand...

Seriously you've never heard of megasquirt ? The fuck rock did you crawl out of under?
 
So far, the 2 MS I used broke/stopped working after 3-4 years... I guess it all depends on the person who assembled it...
 
AntonN said:
So far, the 2 MS I used broke/stopped working after 3-4 years... I guess it all depends on the person who assembled it...
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Absolutely yess

It's really easy to get sync error or missfire issues if you don't have any electronics skills.

IT's also easy to scrap the firmware if flyback/surge happend...
 
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