Pedxing

Having problems with my initial run after building the MS any help would be very appreciated!

I just completed a from-scratch build based off of the awesome guide at trubokitty. MS3X with the harness and connector. Car is a 94, mostly stock, just a RB type header, not boosted, 14point7 Spartan II wideband, GM IAT kit from diyautotune, that's it. I loaded the firmware from the site as recommended and had no problems. Used the 94 base map. MAP line is plumbed, IAT is installed, original airbox still there but MAF is unplugged. IAT is sitting in the airbox for now.

I calibrated the TPS, IAT, and CLT per the guide. Seemed ok. Started it and did the initial timing setup.

Wideband is wired directly to the MS. First start (and all starts) worked but car ran like crap and it will die if any throttle is given. The sensors have readings but the AFR is pegged at 19.2. This wideband goes through a sweep when given power and that shows on the dashboard in tuner studio ... it will sweep from about 12 to 16 to 19 and then stay there until the car is started (normally). The WB has been in the car for a few months now using the simulated narrow band output connected to the car's harness. On the stock ECU, the car runs fine with the simulated NB output. The gauge i have is a speedhut calibrated for the Spartan and it works fine as well. The gauge and TunerStudio dashboard always match exactly.

Basically the car starts and the RPMs are really low then it climbs to 950 then drops to an even 850. However the car is shaking a lot like it's running on too few cylinders or the firing is off or something. Any throttle causes it to stall. Tune is set for wasted spark, sequential injection. I haven't changed these from the original basemap Brain provided. No sync problems. Main thing is that the AFT is pegged at the top and doesn't change. I set the req fuel to 7.5 and although I could smell gas from the tail pipe, the AFR didn't budge. Same on the gauge which is wired directly to the WBO2 as well.

I put the stock ECU back in and plugged in the MAF and it ran normally.

What did I do wrong? Any ideas to go from here?

CurrentTune.msq
2018-06-08_14.25.29startup.msl
2018-06-08_14.21.39highspeed.csv

Pedxing

Oh also i have a DW200 fuel pump. It runs fine on the stock ecu. On MS I can hear it prime no problem.

curly

iTrader: (25)

Pedxing

Thanks for taking a look. Sorry MS noob here. Do you mean the crank pulse % or the crank settings? I have this:



Ambient is hot -- 95 or so and CLT was at operating temp I think. I checked for leaks and upstream the only option is the manifold gasket which still seems ok. I couldn't feel or smell anything. Downstream is a flange with a bit of soot, could that do it? It ran super smooth on the stock ecu. Only weirdness was the AFRs jumped around a bit at idle - avg was 14.7 but it bounced between about 14 and 15.5. I was assuming that was because of only using the narrow band on stock but maybe was a leak?

Timing is dead on and idle rpm is 850 and no hunting but it sounds like a lawn mower. The vibration is excessive.

curly

iTrader: (25)

WigglingWaffles

I had this exact problem with my brain-built ms3x
make sure your settings reflect sequential injection, then double your req_fuel value. It sounds stupid but thats what fixed it for me. Not sure why.

Pedxing

I'm set for wasted spark ignition and sequential injection. Right now req fuel is 11.4, so try 22?

I was verifying my harness so once I get it back together I'll try it out.

curly

iTrader: (25)

That can't be right.

I might suggest trying the 1.1 multiplication. That adds 10% additional fuel, and if it gets better you know it was a fuel issue. If you're unsure, return to the previous fuel table and multiply by 1.2. If that doesn't fix it, you most likely don't have a fuel issue. But if your fuel table was off by 50%, I don't think it would start.

This is all just guessing because I think you've got a secondary problem of your wideband not working properly.

Braineack

iTrader: (62)

double check all coils are firing and all injectors are squirting

Pedxing

The wideband definitely works. There's no change between the sensor and the gauge from before the megasquirt and after. On stock ecu it provides very valid looking values. On MS it's pegged at lean...almost like when you go into full decel vacuum and it will go to 20 for a few seconds. I've seen the same behavior on other widebands on deceleration (though I'm def not an expert). The wiring seems ok, it will match the gauge number in tuner studio exactly. I think the tune is really off for my car and it can't read anything in this state.

I checked the harness again because it really sounds like a cylinder is wrong like no fuel or spark. But every thing looks correct.

I'm about to try both suggestions and will report back. Current tune is the braineack base.

Pedxing

Ah, ninja'd. I was looking at the test mode screen and found a video on it. If I do a quick injection test will it flood? Maybe start it between each test?

Pedxing

Ok I multiplied the fuel table by 1.1 and got the same result. Rough and no afr movement from 19. Put it back to original and changed req fuel to 22. Still very rough but now got some readings on the afr. Still reading very lean although I can smell the richness.

Pedxing

Spark is good. I tested all 4 via the test mode screen. They are brand new (less than 150 miles) and 1 and 4 look normal, 2 and 3 are sooty.

Now I need to figure out the injector test.

curly

iTrader: (25)

Something wrong with 1&4 or 2&3 usually means ignition issue.

Something wrong with 1&3 or 2&4 usually means injection issue.

Edit: this is obviously for batch fire.

curly

iTrader: (25)

Injector testing is a little less intuitive than ignition testing. Go to general fittings and find out what injector channels you use, usually A, B, C, and D. Set your interval for ~100ms (1200rpm), set test mode to "one", select your first injector channel (again usually A), set pulsewidth to ~2.0, and total # of injections to ~1000. Click start, and you'll see the counter counting down. Once it reaches 0, it'll stop. But you should hear clicking at 1200 clicks per minute. If not, you've found your problem. Repeat for B, C, and D channels.

Braineack

iTrader: (62)

fuel pump isn't running...

Pedxing

Thank you for the details. Yep inj A and C, cyl 1 and 4 is nothing. B and D check out. so yeah, explains the lawn mower.

curly

iTrader: (25)

Start by checking for voltage with the key on at those two injectors. They should have constant battery voltage with the key on. Second, check the signal pin for resistance/continuity from the injector plug to the MS. I'd check the wiring first, because at first glance I see nothing wrong with the sequential settings.

Pedxing

Unfortunately it's checking out. Battery voltage to each injector is ok +12V and I get continuity to each signal wire with very low ohms. I measured from the plug end on the injector to the back of the pin on the MS harness. All are going to the expander board, inj A is to pin 19 (white wire) on the expander db37 and inj C is pin 13 (light green/white) on the same db37. Damn, wish it was just the harness.

OK now it's the MS itself doing something wrong? I'm not sure how to probe that.

Pedxing

I swapped injector plugs around and tested the physical injectors. They all fired when connecting to a working plug (B or D). Anything connected to A or C would not fire.

Also I measured the voltage for the signal wire when running the test mode and strangely it was the same as a working one. They are like 0.010 V when off and 0.035 when active. I don't have an oscope. Maybe if I slow the pulse i can see it change on the multimeter, not sure.

From what I can tell, the injector drivers are on the 3X board itself and not something I assembled. I took it apart again and inspected everything for burns or evidence of over heating or anything but didn't see anything.