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DIY Fuel injection thread.


yoeddynz

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Doing the test again at 10% throttle was pretty painful haha. 

But some graphs from each rpm range. The horizontal scale is cam advance degrees and the vertical scale is map pressure drop from atmospheric (divided by 2)

2500rpm.PNG.bec454efdfb780361c184ec0d1d1508e.PNG

 

3000rpm.PNG.7e65489f6b67caf37e64c7b61e481138.PNG

 

3500rpm.PNG.79501dac1e8af7db677112e3ca833f5d.PNG

 

3750rpm.PNG.91fd455d55cc4f2d6842d2715fa2667f.PNG


Conclusion: No idea to be honest. The MAF reading seems to be much more resilient to cam timing changes than expected. 
MAP is swinging around all over the show but it seems to cause very little resistance to fresh air coming in. Which maybe makes sense.

I can say this though, once I got to around 40 degrees advance the car felt like it lost heaps of power.... Took a long time to get to 60kph in third haha.
So perhaps that is the EGR effect at work. Probably needs heaps more ignition timing.

Ultimately though this hasnt shown me anything as insightful as I was hoping and I'm not sure what the conclusion is here. 

Thanks for reading / sorry for pointless post / etc

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Okay I think looking at the data in megalog viewer gives some more sane results / actual labelled axes etc 

52989893_651250925329889_5102338997808529408_n.jpg.ee0fa74e5f15a9e6b9626dc835bf06f2.jpg

If we look at the cam timing angles which give the maximum vacuum then the results sanity check quite well against my full throttle cam timing. 

If you aim for minimum vacuum then it basically just says bang in 50 deg advance everywhere haha. 

So this is ramping up my cam advance much more aggressively than before but it's settling on around 20-30 degrees at 30% throttle which seems reasonable. 

It also sanity checks against the toyota documentation where it says "advance cam about half way" for medium load conditions.

Will have to take it for some nangs though and see what its like now / maybe do same thing again at a few more throttle iterations. 

If this works well then I'll have a MAFless method for doing the same with quad throttles which is excellent news! 

 

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So I got a new wideband and setup the fuel nicely for the new cam angles, and went for a bit of a drive out of town. 
I also had my new dash setup with a realtime economy gauge so you could see what's happening and adjust your behaviour to suit. 
Results from a ~2 hour drive from Auckland to Morrinsville:

Capture.PNG.1f5661e100c10609de0ace4f7c793b97.PNG

Pretty stoked with that! One of my goals has been to get it into the 6l/100 range but I thought I'd need the dual VVTI engine and the revised 6th gear ratio to acheive that.
The mean cam angle value for the trip was just a shade under 20 degrees, when it was previously around 10.
It's hard to say whether improvements came down to having the economy gauge of the cam angle changes but good results.
So either way thats a win. Felt nice to drive in any case.
Having that realtime gauge was great though, in some situations where you think you're better off going straight to 6th to keep the revs low you cut the fuel consumption in half by staying in 4th or whatever. 
Other situations the opposite. Seemed really counter intuitive but I think that'll stay on my dash screen for sure! 

One suprise is that the car is actually quite economical just trundling around the 50kph mark.

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Starlet is finally running ECU controlled ignition timing.

Runs well, will throw it on the dyno on wednesday probably and give it a good ignition map.

Just need to resolve the sync loss issues during cranking. It looks like there is interference from the new starter motor. I might try making it just skip a few more pulses before attempting to sync.

Running 35 mm diameter 20-1 wheel with VR pickup at cam speed. I guess 35 mm diameter is a bit small, but OEM does it like this quite often so it shouldn't be too bad.

 

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1 hour ago, h4nd said:

@ajg193 Got a 'scope trace of it? (can loan you one, or you could use an old android phone).

It was fine on the scope, just too low voltage at cranking speeds to be of any good.

 

Instead I've made this to pick up a signal from outside (goes up and over) the vr sensor (59 mm vs 35 mm diameter). Should give significantly higher cranking voltage and the teeth are more evenly spaced compared to the worn out gear. This one is 30-1 teeth. I've also modified the pickup so it can read from the outside.

15532255312413379310582465864189.thumb.jpg.700432b18e62c483bc09e0946ad9f107.jpg

 

Hopefully the steel going over the vr sensor won't interfere with the signal. I'll throw it on the oscilloscope as soon as I weld it to the distributor shaft

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According to oscilloscope it gets slightly over 0.5v peak to peak at approx cranking rpm (400 rpm).

I managed to break my rotor so will need to buy one in the morning before testing it. 

20190322_182436.thumb.jpg.7f2fe4494e82ed53080ca6730c6f62f7.jpg

with all this effort I could have just gone crank trigger with coil on plug wasted spark, but I'm known for going to insane lengths to make something that looks factory.

 

I still need to make a cover for the igniter so it isn't blatant

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Had same issue using stock  toyota triggers with ms back in the day.   my half assed solution was to run super tight clearance between  trigger wheel and vr sensor. to get voltage up when cranking

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2 hours ago, ajg193 said:

Turns out I wasted all my time and too much $ on the ignition setup. A 30-1 wheel at cam speed on a 4 cylinder doesn't work with the math used by a microsquirt.

 

Straight back to fuel only.

:'(

Can you not just weld two more teeth in... 

images (1).jpeg

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If the new starter motor wasn't interfering with the ignition during cranking and causing the car to flood (rpm spikes, telling ecu to put more fuel in) I wouldn't have any issues with running the fuel only setup. But as it stands my only real option is to either fuck around making another one of those wheels and try again or spend even more money and just install a big ugly wheel and sensor on the front of the crankshaft.

I don't feel good taking the car for a wof when it is just as likely to flood as it is to start when hot.

 

Does anyone know of a place where I can get a crank angle sensor/wheel for cheap? I guess pick a part could be a start. But even then they charge too much for second hand crap.

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