Megasquirt - The Advanced Thread -For ADVANCED Discussions

[white90]

Road bias For sure better full Road tyres.

BullBarCowboy did a rolling road seesion and complained about tyre issues on the Rolling Road

[FridgeFreezer]

Use the most road-biased tyres you can find and pump them up well, it makes a surprising difference to the numbers.

[aaron_h]

If the answer is to go to an MS aware rolling road, anyone know of one in/around Yorkshire that I can go to ?

Were abouts in Yorkshire? Theres ZCARS in east Yorkshire. zcars.org.uk Not sure if they have Megasquirt experience. They have someone there capable of advanced tuning.

Im fairly sure its the same technique with other engine management systems. Well the technique never changes its just the software you use.... We use megatune.

Most Dynos have a lambda sensor fitted anyway they just poke it into your exhaust.

Think you will need a couple of people too. Driver / Dyno operator / megasquirt person

[aaron_h]

Were abouts in Yorkshire? Theres ZCARS in east Yorkshire. zcars.org.uk Not sure if they have Megasquirt experience. They have someone there capable of advanced tuning.

Im fairly sure its the same technique with other engine management systems. Well the technique never changes its just the software you use.... We use megatune.

Most Dynos have a lambda sensor fitted anyway they just poke it into your exhaust.

Think you will need a couple of people too. Driver / Dyno operator / megasquirt person

I Droped in and had a word with them.... Mike and Dave two of the lads there have Megasquirt experience. They mainly do race cars etc and use the Hydra EMS. Mike has used Megasquirt on something he did a while ago.

[FridgeFreezer]

I'm not sure I'd bother with a Dyno, a bit of time spent datalogging on a real road seems to get you so close it's hardly worth it. Fun if you've got the cash, but by no means required for a good tune.

[FridgeFreezer]

Just worked this lot out in a reasonably neat fashion so thought I'd post it up, these are all the inputs & outputs on the MegaSquirt board (pin designations are for the V3 board but they're available on all versions):

• Fan Control / Water Injection (X2 / JS0)
  
• Water Injection Pump / NOS Output (X3 / JS1)
  
• Output 1 / Boost Control [Experimental] (X4 / JS2)
  
• Output 2 (X5 / JS3)
  
• EGT Logging Input (JS4)
  
• 2nd MAP / MAF / O2 Sensor (X7 / JS5)
  
• Output 3 (CPU Pin 15)
  
• Output 4 (LED18 / D15)
  
• Shift Light Lower (CPU Pin 10 / JS7)
  
• Shift Light Upper (CPU Pin 11 / JS8)
  
• Table Switching / NOS Enable Input (JS9)
  
• Knock Input (JS10)
  
• Launch In (JS11)
  
• Tacho Output
  

Outputs 1, 2, 3, 4 can be configured in MegaTune to switch with any condition the ECU can measure - coolant temperature, RPM, all sorts. There is on/off hysteresis and everything. You can even combine them to do clever stuff.

To enable any of these you usually need a buffer circuit (one transistor, a resistor, and a flyback diode is the norm to switch a relay, for example) although some stuff like the knock sensor input needs a proper signal conditioning circuit.

[evo828]

What voltages do you see from the standard hotwire 3.9 narrow band sensors? I've got MSII Extra 2.0.1 with EDIS up and running (idling) but I do not trust what I see from the narrow band sensor. Megatune logs it - min 0.175V and max by 0.409V. The NB voltage target is set to 0.3213V in the Megatune EGO control menu (setup originally by the manufacturer of my MS). I was expecting a 0-1V values - with the stochio around 0.5V - but it seems that this is not the case here. Are the values I am getting correct???

[FridgeFreezer]

I believe the stock sensors on the Hotwire setup are Titania rather than the almost-completely-universal standard Zirconia and therefore resistive. Just LR being difficult for the sake of, in theory, a slightly more waterproof sensor (in reality, my Zirconia sensor has been two feet under and never suffered).

You'll want to lay your hands on a normal 3 or 4-wire Zirconia sensor (often called a Universal lambda sensor at the auto factors, just to confuse things) and get that fitted. You can find one on just about any car in the scrapyard, or the aforementioned universal sensors available for about £25 from the motor factors. The thread might be different (again, Rover use a smaller thread than the universal standard ) so you may need to weld a bigger boss into the exhaust.

[evo828]

Thanks Fridge. So there is no chance of somehow scaling the values from the titania sensor to get it logged and shown properly?

[Dave W]

What voltages do you see from the standard hotwire 3.9 narrow band sensors? I've got MSII Extra 2.0.1 with EDIS up and running (idling) but I do not trust what I see from the narrow band sensor. Megatune logs it - min 0.175V and max by 0.409V. The NB voltage target is set to 0.3213V in the Megatune EGO control menu (setup originally by the manufacturer of my MS). I was expecting a 0-1V values - with the stochio around 0.5V - but it seems that this is not the case here. Are the values I am getting correct???

The standard Land Rover lambda sensors are titania, not zirconia. You would normally supply these with a reference voltage and measure their effective resistance. A zirconia lambda generates a voltage based on lambda rather than altering a supplied voltage.

I have tried using titania in the past but, in the end, gave up and went to zirconia as, as well as the difference in operation, titania have different lambda characteristics that make it more difficult to set the engine up. Titania lambdas switch even quicker than zirconia so are, effectively very narrow band. It's a pain as the titania bosses are smaller than standard zirconia or wideband bosses but welding on an extra boss isn't that big a deal and, in the long run, it'll save you tuning time.

EDIT: Sorry for the duplication, Fridge types faster than I do

[evo828]

Yeah, I was following one of the suggestions here on this forum that wideband is not necessary and the tuning will be fine with MLV and Narrow band. That is why I was not onsatlling LC-1 WB which sits in a box in my garage from my previous car.

Can I drive with these maps until I get someone for welding the wb? The car is very rich on idle as of now - but at least it is on the safe side

[Hybrid_From_Hell]

Er

I would say the spark table is hugely out and dependant on what your required fuel is set to the VE looks HUGELY rich

All in all the that spark and VE = a proper mess

Have a lookie in this thread many have posted up spark tables which suit a V8, mine from a rolling road, then tweak

for max advance at WOT dependant on the cubic capacity (the bigger the V8 the less total adavnce they can take at wide open throttle)

The VE is related to other input screens in the MSQ, so its not easy to say if it is ok, but I'd doubt it.

There is also little pouint spending tiome VE Tunning a MSQ with either NB or WB if the spark table is as widly werid as the one above, as there is a correlation between the igntion advance and the VE, so, if you do tune the VE with that spark table, if you then change the Spark table the VE will be out again

More importnant to have a close spark table before tunning VE, and ensure that the TDC setting for EDIS are at 10 degrees spot on too

Nige

[bobtail84]

As HFH say's above and this is a good spark map from my 3.9 which is standard and I know it work's cos Nige sent it to me.. and it's the one that I use, with a few tweaks for my engine.

Also I know your MS2 so you will need to stretch it a little.

HTH Jeff.

[evo828]

thanks for the ign map - i flashed it and went for a ride - seems ok so far.

Another one: My MAP sensor readings are fluctuating at steady throttle - causing mapDOT to fluctuate between -50 and 50 sometimes - causing the ecu think that I am accelerating and then decelerating (switching quickly). Can this MAP sensor input be "damped" electronically via setup in Megatune or do I need to put some restrictor into the vacuum tube. Or I am completely wrong again ?

[Hybrid_From_Hell]

-50

How do you get minus ??

0-100 is the range of a normally aspirated lump ?

Nige

[TomG]

Mapdot is rate of change / delta of MAP isn't it? (so can be negative). But those are huge values either way!

Evo828: What MAP values do you get: 1. before the engine is started (ignition on), 2. at idle, 3. Wide open throttle ?

[evo828]

1. ignition on - MAP reading 101.2 kpa

2. idle - cca 42 kPa

3. WOT - haven't done wot - but on 71% throttle it goes to 99Kpa

[TomG]

1. This is fine (actual value will vary with the weather and altitude)

2. Perhaps a bit on the high side but this will depend on what what cam you're running (higher performance cams pull less vacuum at idle) and your idle rpm. With any idle control disconnected / disabled, try adjusting your VE bin values around idle to get the lowest MAP reading.

3. This sound fine.

Not sure how Mapdot is giving such large swings, the MAP sensor is on board so can't see how there could be any interference between this and MS. Does MS have a clean power supply and good earth (all sensors should share a common earthing point with MS)? e.g. the voltage reading in Megatune should show a steady 13.8 (or thereabouts) with the engine running.

[evo828]

tried to make a screenshot of one of the places where the moves in MAP presure are minimal 81.5-82.4, TP steady, however mapDOT is jumping up and down +59 to -50. I hope it will be visible. Any idea?

Battery seem s to be stable 13.4-13.5 - no other sensor fluctuate, earth is common (I was pluging into the LUCAS ECU wiring.

[TomG]

Blimey, i see what you mean. Mapdot has hit a max of 484 and min of -230

Where do you have the vacuum line for the MAP sensor connected to?

MAP itself looks stable but what's it like when you zoom right in (magnifying glass with the plus icon in lower right) to 8x? is the reading all over the place?

It's possible that it could be picking up individual cylinder pulses resonating from the plenum - the solution for that is to put one of those inline transparent plastic fuel filters in the MAP line or a smaller restriction like a welder tip which will help smooth out the MAP reading.

Mine runs from the middle of the three outlets on the plenum via 3mm (i think) silicone hose to MS - if hard plastic pipe was used this may help transmit noise.

Edit: Were you planning to use MAPdot for acceleration enrichment? you could use TPSdot instead in which case Mapdot is ignored.

[evo828]

MAP sensor tube is teed into fuel pressure regulator tube. I've put some small restrictor in it now - will see. May be I am going to use TPSdot anyway. thanks

[Hybrid_From_Hell]

pic may help re map pipe

Re MAPdot why use this vs the more univesally used TPS for acel enrichments ?

Bit like trying to tune via AlphaN vs the 99.99% thats others use - Normal version

Prob is you have gone to MS2.0.1 not MS1 V3 so few here have done anywhere near the playing as per MS1, and I have played with a couple of MS2s, they have far more settings and this far more to get right vs wrong. I wiouls suggest you start with the basiscs ensure you have the fundemental settings somenear right and them do basic tuinning with MLV and a NB sensor. also there was a known error with MS2.0.1 on Datalogging vs VE table correction see if thats been fixed / you have the latest download

I will also move most of this to the 'advanced MS thread' as this will blow the minds of any newbie thinking of going MS

Nige

[FridgeFreezer]

It could just be the higher resolution of the MS-II, the processor is running so fast it can see every little pulse and fluctuation in the MAP signal where the slower MS-I would just read a smoother average value. MAPDot isn't a bad idea for accel enrichment if it's working OK, it does away with the need for a throttle position sensor. I don't know if there's a setting in the MS-II to filter, limit, or change the sensitivity of the MAPDot settings - I know you can change some aspects of it with MS-I.

I run TPSdot and had similar trouble due to bumps in the road jolting the pedal enough to trigger ACCEL enrichment - solved that with a stiffer throttle spring.

[evo828]

Nige - I know - I took the more difficult MS route - but anyway - it works with my IAC and except the neccessary WB which is due now- it was not such a big pain to rebuild. I am going to write my next question in the more advanced thred

[evo828]

I am running MS2 extra 2.0.1 + EDIS - so far everything is fine - I need to add WB to be able to log my AFR as the standard titanium NB sensor are somehow hard to understand....

My current issue is - I am getting very random spikes in RPM accompanied by main and fuel pump relay click - nothing major happens - it just happens but everything runs fine and MEGATUNE is not showing any reset. It is annoying and I would like to get rid of it. See the picture of one example.

I do not have the 25mF capacitors added to the coils as noise suppressors as I have not get these here - but is it really this reason for the random relays click and rpm spikes?