Injector Flow Rate? (MK3 16v) Megasquirt

I don't wanna cause anyone to blow up an engine, still I am pretty positive that 15:1 cannot, by any stretch of safety margines, be considered lean for cruising. For low load cruising you _should_ easily get 16:1, possibly 17:1, and anyway, for the low loads it is more of a matter if it runs well, and less of a matter if it will damage something... Still, this is all theoretic, if there are any objections I welcome corrections (I wouldn't wanna blow MY engine up...)

 

I`ve aimed for stioch at cruise and idle, works great for me (same AFR as the G60 ecu runs), maps good so I set O2 authority to 15%, 8 events per step.

For the G60 temp sensors I used,

degCResistance
20&nbs p;2500

50&nbs p;900

100&nb sp;200


(Turn O2 correction on and most other things off at 50c)

I`m running 4 squirts alternating, injectors on 2 banks and Req Fuel is 4.8 I think? (305cc injectors upped to 4bar fuel pressure)

Left the warm up/ cranking tables stock (MSnSE 024s9).

Just need to sort accel enrichment and overrun fuel cutoff, either through the VE table or the settings in MSnSE.

 

Is that stock as in the settings in the default.msq supplied with 024s9? How well is it starting with that? I seem to have taken a step backwards upgrading to 024s9, all the added functionality with cranking/ASE means more things I can get wrong I suppose I did have it so it would fire straight up with no throttle, even from stone cold, but now it's taking a couple of goes to catch. If the default settings work i'll bung those back in and see how it goes.

 

Yeh it`s just as it came out of the tin! Only been trying this for a coulple of days but it sparks up and runs first turn of the key (I`ve still got the Digi1 and isv which opens more on cold cranking).

Had a problem before with a coolant temp sensor fault, so I move over to the 2 pin G60 sensor and all is well.

See what happens nearer winter...

 

Spoke too soon, went on the 3rd turn of the key this morning... set cranking rpm to 600 if that doesn`t work I`ll start modding the cranking/ ASE settings.

 

i had another fiddle with mine yesterday.... the o2 correction for one... mine was at 0% which explains why it was running so rich... Been playing about with different settings and its currently on 30%... Its active above 1200rpm.

I do notice that sometimes while cruising at a constant speed with the throttle in one position, the AFR guage dips all the way to lean and the car holds back a little... a slight blip of the throttle and it goes back to rich and pulls well... Fuel economy seems better for the 30 miles or so I've driven since yesterday.

I still can't get a decent reading out of my MAT sensor... its a cossie one and regardless of my efforts to calibrate it using easytherm, the bugger still reads -20degC... Could I use a blue vag coolant sensor for the air temp? that would make things easier if i could....

 

You could do, better off with the G60 AirTemp/Co-pot unit.

The leaning off is a product of the O2 correction, you may feel it pulsing as the afr swings back and forth around stoich, the greater the O2 authority the more noticable it will be.

With a good map you should be able to turn off O2 correction all together and have it pinned to 14.7:1 (or whatever your cruise afr is).

If you need more crossover points for MST, turn the events per step down (I have mine at 8 or 4), but you need a roughed in map first.

 

Using the coolant temp sensor will be fine. It won't be that quick to respond but that's not really an issue unless you're running boost, it's only really measuring ambient temp.

Have you checked the wiring to the MAT sensor? If there's a loose connection and the ECU is seeing the MAT spiking every now and then that would also cause a lean spike, and could also explain it sitting at -20 most of the time. Try and get a log of it doing it and check the MAT readings.

Keith, i've gone back to 024s9's default cranking/ASE settings and it's all peachy. My cranking settings were virtually identical, but my old ASE settings were way higher, dropping them right down seems to have made it a lot happier

 

Re: stefanvw

If your air temp sensor is reading -20 degrees then megasquirt will be adding a considerable amount of fuel to compensate hence your rich running.

I am using a blue coolant sensor for my air temp. It works fine when driving but is susceptable to heat soak. When my car is sitting for a few minutes the sensor heats up to bay temp and leans out the idle mixture giving me a bouncing idle. I will either be going for an insulated temp sensor or trying to insulate the head of the sensor I have in the near future.

Are you sure that you have downloaded the correct tables/code for your sensors to megasquirt? The first time I downloaded the extra code to megasquirt using easytherm I forgot to select the modified extra code. The result was that the coolant and air sensor readings were all wrong.

Gavin

P.S. Economy update. Managed 270 miles before i refilled the tank, only took around 35 quids worth leaving around 8 quids worth of fuel in the tank. 33mpg ish! A lot better than my best with k-jet of 26mpg. Tracking and camber are now fixed so hoping for more to come....

 

makes sense that MS will be making it run rich due to the duff air temp.... shall sort that tomorrow...

In regards to heat soak, could i not mount the sensor somewhere in the engine bay where it is away from other metals (ie. my intake pipe) cos after all it needs the outside temperature... If i was running boost then yeah it would need to be inside the air pipe because of the way the turbo/charger and intercooler affect the air temp...

I'm thinking of mounting it in the inner wing from where most of the air comes in anyhow... worth a try i guess...

Keith do you have any pics of your engine bay? Would love to see how that setup looks...

 

I`ll take a couple at the weekend, it looks a mess at the moment though as I`m not finally routing the wiring in until I`ve got it all 100% and the water injection in, bought an oil catch tank off ebay tonight, nice and shiney



Pic when it was first installed, looks a little tidier now but not by much..

 

StefanVW:

I guess it could be ok if it is away from the engine heat. Only one way to find out for sure!

Keithmac:

Nice pipe holder you have on your strut tower!

I look forward to seeing/hearing how it goes once you get the water injection on.

 

Yeh it does look a little over-engineered doesn`t it, there`s a matching on on the other side for cable tying the loom to

 

serious bit of engineering there!!!.... from what i can see there's no intercooler... doesn't it run hot? what sort of temps do you get from the MAT sensor?

very impressive though and I bet that inlet wasn't easy to get hold of...

very nice

 

Cerberii: On your Injectors, which wires do you have grouped together?

I can't remember what colour wires go to what injector and mine are all wired together to one batch...

Wanted to wire 1&4 toghether and 2&3 together but can't remember the colours of the wires. All I remember is the thick silicone covered one is the +tive which goes to each of the injectors.

 

green and brown together.
white and black together.
clear is the positive.

Gavin

 

fantastic....thank you sir

 

I`m not running an IC, using water injection (when I get round to fitting it) pump will be controlled by the MS and possibly mapped later on with a HSV.

I haven`t given it much on boost running due to the lack of charge cooling, maybe get the Aquamist fitted next weekend and have a good run in it

I`ve seen 200kpa on the logs froma quick stab of the trottle at around 3500 rpm, so I know the G`s making good boost!

 

when would the aquamist be turned on? Would MS turn it on according to the temp or MAP/TPS?... (haven't got a clue about water injection )

 

You can set it to go off over certain map/rev/mat value, normaly the Aquamist just uses a map sensor so it`s a good upgrade to power it of the MS directly.

Ordered the rest of the bits today so I may get it fitted on Sunday..