As many regular readers know, I’d had my Megasquirt MS1/Extra Rover V8 starting within a couple turns of they crank. So why the picture above? – Once you spot it, it’s obvious!
The next evening, with 2 wires on the idle valve reversed, I tried again.
Absolutely nothing. It didn’t even try to start. I swapped the idle valve wires back and still nothing.
It was like there was no fuel or spark.
The previous night I’d fitted the headers and p-clipped down the loom so maybe I’d trapped or broken some wires?
I checked the wiring, fuel pressure and finally the spark. It appeared I had a weak spark on 2 cylinders (same coil pack). I had spare leads and coils so I swapped them in, but now the spark was almost non-existent on the same two cylinders. Huh!!??
I disconnected the Megasquirt from the engine and connected it to the JimStim. It appeared I had identical coil/spark driver signals on all 4 outputs. So nothing odd there.
My suspicion was still something inside the Megasquirt wasn’t quite working right, so I pulled off the lid. There was no obvious signs of burnt components so I contacted some experts for help and credit to them, lots of advice was given. However, still no faults were found.
I was totally stumped.. After all, it had started easily the previous night.
Bosch Ignition Drivers (BIP373)
Three evenings later, whilst playing with Tuner Studio I spotted a potential problem. In the picture above there are small copper coloured stripes across the legs of the Bosch Ignition drivers – they are stress fractures due to flexing. The broken halves were touching so a signal was getting through, but under load hardly any current could flow. Hence a very weak spark.
The heat-sink is flapping in the breeze. So I’m making some mods to the case with a fixed heatsink so hopefully the problem doesn’t happen again.
I’ve ordered new BIP373 drivers from the US, but in the meantime I soldered over the cracks.
WOOOOO HOOOOOO!!!!!! 🙂
I swapped the idle valve wires back around and the idle dropped from 2400rpm to 1600rpm. Still not good, but a step in the right direction.
Whilst learning Tuner Studio, I noticed just about everything in the various maps was wrong. The required fuel pressure seemed to be set for a 355ci V8. The sensors also appeared to match a Chevy and the VE table had KPa values up to 150Kpa. It appears my map was for a turbo’d or supercharged Chevy V8. This megasquirt had come from a Triumph Stag – so an odd choice of engine! A super-charged, fuel injected 355ci Stag? HHHmmm the classic car boys probably wouldn’t approve.
With the high VE values and the required fuel wrong, it explained why the exhaust smoke was a bit black and possibly the high idle.
Megasquirt MS1/Extra Rover V8 – Required fuel
Here’s my GEMS P38 Rover 4552cc / 477.8ci required fuel settings. If you copy someone else’s VE map without these set, you’re onto a looser.
Megasquirt MS1/Extra VR Sensor Set-up
During de-bugging, I’d re-checked the crank signal from the standard Rover P38 VR sensor and it appeared fine. I’d used the MsExcel spreadsheet to set up my Megasquirt MS1/Extra to the 32nd tooth. E.g. 3 before the missing tooth on the 36-1 flywheel. My custom manual flywheel has the missing tooth in exactly the same position as a standard P38 automatic flex-plate. I’ve spaced out the sensor with two plastic spacers instead of one, but essentially everything is standard GEMS Range Rover P38 automatic. No toothed front pulley for this engine 🙂
Megasquirt MS1 – Calibrating Sensor Values
I’d used non-standard CTS and IAT sensors from FAE. After reading the documentation, I thought I could simply use easyTherm to re-calibrate my MS1/Extra to them.
I was very wrong!
Panic set in as everything seemed Dead! – Again!
Except this time the Megasquirt had no lights on and no outputs!
It turns out on a Megasquirt MS1/Extra rev029y4, hitting ‘Download to Megasquirt’ wipes your firmware and .msq and you need to re-program from scratch.
BEWARE!!!! I hope you have project and msq back-ups!
I had data-sheets so I didn’t need to measure resistances, so I entered my values into easyTherm.
- Click ‘Write .inc files and .s19 Files’.
- Find the 3 new .inc files in the Easytherm Directory (e.g. C:\Program Files (x86)\EasyTherm)
airdenfactor.inc – Thats for the inlet Air Temp sensor
matfactor.inc – Thats also for the Air temp
thermfactor.inc – this is for the coolant temp sensor
- Download and create a copy of the latest firmware directory (e.g. 029y4-copy)
- Open up your firmware folder and go into the ‘src’ directory (e.g. 029y4-copy/src)
- Overwrite the 3 .inc files with your new ones
- Double click ‘compile.bat’
- This batch file will generate a new ‘msns-extra.s19’
- Copy ‘msns-extra.s19’ to 029y4-copy (One directory up) – overwriting the existing
- Pop the lid of your Megasquirt and short the 2 ‘boot’ pins or holes (I used a paper-clip)
- Power Up Megasquirt (I had mine on the JimStim)
- Double click ‘download-firmware.bat’
- Select your comms Port
- It counts up to 1480+
- Once complete, power down the Megasquirt and remove the boot short.
- Open up Tuner Studio and re-install your current project / .msq
- Hopefully you’re ready to go.
Tuner Studio – Auto Tune
I have the Ultra Version of Tuner Studio, so I’m going to type in some more realistic values into the VE and Spark tables ( Read All This! ). Then I’ll try the auto-tune facility. Sure, with the car immobile the results won’t be great but they have to be better than what I have. After reading endless blogs and forums I know Auto Tune isn’t going to give the results of a rolling road session but I should be ‘in the ball park’.
I need to get my custom water pump fixed first. – Watch this space!!