Das Beast: My E30 track / street build

[Digitalwave]

Awesome! Finally! Now to start the fun process of tuning it from scratch!

[dvallis]

Speaking of "Tuning From Scratch" with Megasquirt anyone have advice on that? I have a known good tune from KaMotors, so assume most of the settings are in the right ballpark.

Yes, I will RTFM. Just asking.

[zaq123]

Speaking of "Tuning From Scratch" with Megasquirt anyone have advice on that? I have a known good tune from KaMotors, so assume most of the settings are in the right ballpark.

Yes, I will RTFM. Just asking.

Congrats!!! Hard to tell from the vid...did it die before you killed it with the switch?

As far as the tune goes.... If your setup is very similar to Kamotors (same exact injectors etc) , you can probably use it to crank her up to around 2k to set your rings.
I'm in the same boat (just way behind you). Still playing with MS, jimstim, ICV, knock sensors etc etc.
My goal is to tune down (slightly) IGN map I got from the similar to mine setup, set good idle and compare VE/AFR table with actual AFR readings and adjust VE table as needed, maybe play with IGN table using my fancy knock sensor monitoring setup.
Eventually put her on the dyno to tune IGN table for HP and check on other stuff while there.
Mine is NA though. I would be extra careful with your boosted setup. BTW,
I am a total noob when it comes to tuning but I'm learning :D.

[citizen_insane]

I'm also starting this process soon, but not on a rebuilt engine (so I don't have to worry about break-in). My plan is:

• Rescale all my maps (they're not consistent)
• Fill VE table with high values while in boost
• Put in conservative spark table (based on the tables floating around)
• Confirm spark @ idle
• Street autotune for my conservative spark map
• Dyno tune for max power

[wworm]

boop boop bumpin for updates?

[dvallis]

Start me up

We're back after a Christmas and New Year hiatus. Holidays are pretty busy with family for Rob and I. Not to mention getting taken DOWN by Austin allergies and the flu this year. Ugh. I run on caffine and Zyrtec now.

Last thing we did before starting up for real was give it a value adjustment. We're starting with 0.010" clearance per Benteys. We even found a couple of adjuster lobes in backwards. Argh. :devil: Once everything was good we buttoned it up.



Here's the first real engine start. Click picture for video. Before getting to this point we had to screw around with basic load, fuel, ignition and startup settings. (More on that later) I punch the starter button below, the car fires up and goes into idle. Once we come out out After Start Enrichment (ASE) the car starts using the regular fuel VE Table, and trying to "close the loop" for Air Fuel Ratio. I figured out later that the LC-2 Wideband O2 hasn't been open air calibrated, so it's pumping out a solid 5V. This means LEAN (22.4) to Megasquirt, so it keeps dumping more fuel into the injectors. RPMs go to the moon. I shut it off at about 4K. We'll calibrate the O2 sensor before going any further.



Speaking of tuning, paging VARG!! Please comment on what we've figured out below:

Note: We're starting with a "known good" tune from KA Motors.

1. I can't find a concise Megasquirt tuning guide out there. It's either too brief or 1000 pages of rambling information with no structure. As an engineer I write guides for boards and chips. They make sense. Step 1 to step 10. With pictures. They document tested and known processes. Why can't I find this for MS?

2. We set Engine and Sequential Settings -> Required Fuel to 4.8 based on the calculator. 2700 CC (we're stroked) and 60# injectors. Seems Ok.



3. We started with this cold advance. It seemed to like idling better with a bit less. Temp was 70F.



4. This was the initial cranking pulse curve. We had to raise it about 30% to get a proper idle.



5. We also had to bump up the After Start Enrichment from this starting point to get an idle.



So, maybe after we calibrate the damn O2 sensor we'll end up changing these again since MS will be seeing real AFR. I did notice that we started it once when the O2 was still in warmup. Car idled GREAT because the O2 was putting out 0V, not telling MS "More fuel more fuel".

6. This is our VE table. We dorked with lower left idle corner, adding fuel to get out of lean, but will probably put it back like this since we're NOT lean.



To be continued. ....

[Elysian]

Nice!

[dvallis]

So, we thought the wideband O2 sensor was jacked. It's not.

We pulled the sensor and did a free air calibration. Then we tested it by applying a gas soaked rag. It reads rich, like it should.



Rag removed. The fuel is evaporating off the sensor. A/F ratio is getting leaner. Voltage and AFR makes sense.



Fully lean. Sensor is outputting slightly less than 5V for AFR of 22.2. Exactly as expected.



Now we know the wideband O2 sensor is working. So why the heck does it always read lean? Can we really be that lean when we're smelling gas in the exhaust? Very frustrating.

We still haven't solved WHY the car starts, idles briefly then RPMs run away to the rev limit. Without touching the accelerator. We checked / messed with:

Throttle Position Sensor
Cranking pulse
Afterstart enrichment
Warmup enrichment
Idle advance
VE table
Spark table
Basic fuel required

Nothing makes a difference. We're out of ideas. I'm starting a separate thread on this.

[zwill23]

I'm sorry to hear about your Megasquirt issues. I ran into my own set of problems when I converted my car and it turned out to be a faulty PNP unit that has been with Megasquirt for the past couple weeks... frustrating.

This may seem a bit rudimentary compared to what you have already been trying, but have you checked for vacuum leaks?

When I switched over to Megasquirt I had a very similar issue - rpms spiking up to near 4k rpms as soon as I started the car. Assuming it was an issue with the tune I spent the better part of a couple hours checking and tweaking Megasquirt settings.

I simply just never plugged my brake booster back into the intake when I swapped in the variable TPS. After that the car idled just fine.

Might be worth checking.

[digger]

Likely Massive vacuum leak or throttle blade problem or icv issue. The ecu can't raise rpm much without there being a big enough hole to let air inside in the first place ( no amount of fuel or timing will do it) rpm raising will probably be the mixture coming into range while after initial start the mixture are way off.

[Digitalwave]

O2 sensors look for oxygen (not fuel). It could be that it is so pig-rich that it's misfiring (at least some cylinders), thus letting out a lot of unburnt fuel and air. This reads as a lean condition, rather than rich, since it's seeing lots of un-combusted air.

Eventually it's probably going to be worth you hiring an experienced tuner. Megasquirt is not necessarily hard to learn, but there's a lot to it, and a lot can be knocked out easily by someone experienced.

[dvallis]

Thanks guys. Concensus is definitely vacuum leak, from Varg and others. Looking into it.

[zaq123]

Thanks guys. Concensus is definitely vacuum leak, from Varg and others. Looking into it.

How do you control you ICV? closed loop or warm up?

My recommendation is to get Jimstim and run your MS tune on the bench. Jimstim will drive your actual ICV nicely and simulate your Air/Fuel, rpm, engine and air temp, 60-2 wheel etc etc etc. Jimstim can be bought as DIY kit to save a few $$$
If you are using PNP MS, I recommend to make Motronic to DB37 (Jimstim comes with DP37 for a generic MS). That's what I did, old Motronic pigtail someone sold me here for a few bucks and DB37 can be found anywhere.

This way you don't have to run your car with a bunch of issues and will be able to work out most of the bugs with the tune setting right at your bench. Highly recommend

Not my vids but it will give you an idea:

https://youtu.be/zxKSVzzmN70

[dvallis]

ICV was deleted. We may un-delete it. Need to isolate the vacuum leak first.

- Stroked 2.8L turbo M20
- Wasted spark
- Return fuel system w Nuke rail, Aeromotive FPR, 60lb injectors
- ICV delete
- MAF delete
- TPS
- Spring controlled waste gate
- MSPNP2 + Tunerstudio MS Ultra 3.0.28

[dvallis]

Eventually it's probably going to be worth you hiring an experienced tuner. Megasquirt is not necessarily hard to learn, but there's a lot to it, and a lot can be knocked out easily by someone experienced.

I only WISH we could find Megasquirt tuner in Austin. Some I've heard of in Dallas and Houston. We may be dragging the car there.

Gotta fix the vacuum leak first.