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DIY Fuel injection thread.


yoeddynz

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Most motors will respond better with more fuel whilst warming up. at around 13.5:1 -> 14.0:1 at idle this can be pulled at around 40->50 deg coolent temp to get you to 14.7 or where ever you idle at. 

 

The reason you have noticed the injector pw increse as you increse as your throttle position is that you are introducing more air into the motor. You will notice cranking vaccum drop away and more fuel injected because of this. So you have identified that you require more fuel to get it to start with no throttle opening.  If injector pw were to remain constant whilst opening the throttle and this got it to start you would be too rich as you need more air to get the required mix to ignite. 

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It's good info this. Thanks guys. Shame there seems to be no way to up the pw when cranking on speeduino. 

Im reluctant to change too much as the cold start is good, as is almost everything else, just not the damn warm start lol. 

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  • 1 month later...

Where  do you gezzers that run  aftermarket trigger wheels, get your vr sensors from ?    something barrel style would be best

melted the vr sensors in the stock 4age cas the other weekend.  Plus the stock cas's kinda suck,  old leaky and in a dumb location.  
So,  done  some rangi mods and made a 36-1 prototype using a stock vr sensor and a rx7 abs sensor.  running on the exhaust cam gear.

works way better than the factory stuff. just need to make it pretty and reliable

img_20170709_131748s.jpg

 

 

 

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53 minutes ago, kpr said:

Where  do you gezzers that run  aftermarket trigger wheels, get your vr sensors from ?    something barrel style would be best

melted the vr sensors in the stock 4age cas the other weekend.  Plus the stock cas's kinda suck,  old leaky and in a dumb location.  
So,  done  some rangi mods and made a 36-1 prototype using a stock vr sensor and a rx7 abs sensor.  running on the exhaust cam gear.

works way better than the factory stuff. just need to make it pretty and reliable

 

 

 

 

That is a very sweet home job there bloke. Once it's all tidy that will be the tits. 

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  • 3 weeks later...

TO the peeps that know what they are doing, why would my engine backfire through the intake every time i am cranking to start it? Usually pops at least once when cranking. If i open the throttle WOT (into flood mode, cutting fuel), it makes an almighty bang when it backfires in the intake (nothing stopping it).

Its a Rover V8, running Speeduino EFI, crank 36-1 trigger wheel, wasted spark coils (two four post coil packs), and batch injection. Base timing has been set by disabling the injectors, setting cranking timing to 0 degrees, and then checking the TDC mark lines up with a timing light when cranking. I have also verified No1 is at the top of its stroke with a bore scope when the TDC mark is at 0. Cranking timing is normally something like 10 degrees BTDC.

When it backfires in the intake the engine struggles, the lights dim. The engine will start fine, although takes some churning over when warm, and runs and drives great. Lots of grunt, so hesitation, uses a bit of fuel but what RV8 doesnt?

This is an example of it cranking

and you can hear it when its cranking in this one

 

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On ‎9‎/‎07‎/‎2017 at 14:16, kpr said:

Where  do you gezzers that run  aftermarket trigger wheels, get your vr sensors from ?    something barrel style would be best

melted the vr sensors in the stock 4age cas the other weekend.  Plus the stock cas's kinda suck,  old leaky and in a dumb location.  
So,  done  some rangi mods and made a 36-1 prototype using a stock vr sensor and a rx7 abs sensor.  running on the exhaust cam gear.

works way better than the factory stuff. just need to make it pretty and reliable

img_20170709_131748s.jpg

 

 

 

 

http://nz.rs-online.com/web/c/automation-control-gear/sensors-transducers/hall-effect-sensors/?sort-by=P_breakPrice1&sort-order=asc&rpp=100&pn=1

 

not VR sensors, but there are 101 mounting styles of hall effects you could probably make work. We have used the threaded body cherry brand ones on a few things and they work sweet.

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2 hours ago, 00quattro00 said:

Might need some more fuel while cranking

Don't have proper control over cranking pulsewidth yet, apparently that will be fixed next update. I can only really control priming pulse and cranking enrichment as a percentage.  

This issue never happened with standard ecu. 

Would a small leak around the throttle body shaft cause an issue like this? The tps isn't sealed against the intake, so I suspect there may be a small it leak there. Will spray some carb cleaner with the engine running and see if it's leaking. 

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19 hours ago, kws said:

TO the peeps that know what they are doing, why would my engine backfire through the intake every time i am cranking to start it? Usually pops at least once when cranking. If i open the throttle WOT (into flood mode, cutting fuel), it makes an almighty bang when it backfires in the intake (nothing stopping it).

Its a Rover V8, running Speeduino EFI, crank 36-1 trigger wheel, wasted spark coils (two four post coil packs), and batch injection. Base timing has been set by disabling the injectors, setting cranking timing to 0 degrees, and then checking the TDC mark lines up with a timing light when cranking. I have also verified No1 is at the top of its stroke with a bore scope when the TDC mark is at 0. Cranking timing is normally something like 10 degrees BTDC.

When it backfires in the intake the engine struggles, the lights dim. The engine will start fine, although takes some churning over when warm, and runs and drives great. Lots of grunt, so hesitation, uses a bit of fuel but what RV8 doesnt?

This is an example of it cranking

and you can hear it when its cranking in this one

 

 

 

sounds like its too advanced.  try less timing when cranking.   otherwise it maybe  getting some trigger errors when cranking,  possibly sensor too far from trigger wheel.  vr or hall?

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VR. Sensor is pretty close. I could maybe move it a little closer. The trigger logs look all good from what i have seen, but i havent logged when cranking for a while. I was going to do this tonight but its pissing down.

How close should the sensor be? I dont want to risk contact.

Heres my setup.
DSC09182.jpg

In the photo there is a pin on the crank pulley, you can see it just below the sensor. This misses the side of the sensor, but only by a couple of mm. Could this be an issue?

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if its fine once engine is started, the pin shouldn't be an issue.  since its more likely to pick it up when spinning fast.  probably isnt ideal though

as you probably already know,  vr sensor will put out more voltage the faster the trigger wheel is spinning.  and moving it closer will raise the voltage at lower speed.    ive ran them near touching to get  a megasquirt to work.    other option is to swap to hall. which will read better at lower speeds

but yeh i would try  adjust the timing first.    start at 0 degrees at crank speed and adjust it 5deg at a time see what it does.    most stuff will  start good on 10 deg.

 

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Logged starts this evening, this was the first start and a cold one. It did backfire in the intake once, and the battery was getting a tad low.

THis is the mess that i logged.
wn2LqHC.jpg

That was the only one that backfired in the intake, out of probably 20 starts this evening.

All the rest look similar to this
4UFlitH.jpg

I increased the trigger filtering, and the waves between the missing tooth are almost gone now. The car cranks fine, but it could be a fluke. Ill find out in the morning when i start it cold if it still backfires in the intake.

I also added a LOT more fuel to the cranking. I had it about 10 or 20% extra, but it seems happier when its at 60% or so. I also dropped the cranking angle down to 10 degrees from 15.

If the weather is a bit nicer tomorrow ill try get the Rover in the garage and move the sensor closer to the trigger wheel and see if it helps.

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On 27/07/2017 at 09:35, 00quattro00 said:

Might need some more fuel while cranking

So it turns out, you were right. Have an internet cookie. :-)

Upped the cranking fuel to 70% (of what? on top of what? who knows) from about 10%, and it was starting good last night (lots of cranking when warm, but no intake backfires). Cold start this morning, it started almost on the turn of the key, no intake backfire and ran good. It still cranks heaps when warm starting, but no intake backfire. Thats an issue i just cant get to the bottom of, but hey, it does start. It cranks heaps and wont start unless i give it a couple of jabs of throttle.

I think the crank sensor is a little too far from the trigger wheel, so ill move it a little closer if i need to, but might leave it whilst everything is going good.

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Does the speedduino software have a setting called tooth skip or something like that under cranking settings. It makes sure it counts the missing tooth a certin number of times before engaging the ignition. Pretty much helps it stabilise and figure out where it is while cranking before applying fuel and spark.

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It does, yes, and i have it set to 2 revolutions. Cold its mint, but when starting after anything longer than a couple of minutes running and its a good 8-10 revolutions sort of thing. Can also be accompanied by a plume of fuel smoke (but only when warm)

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