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DIY Fuel injection thread.


yoeddynz

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If it's a bosch based efi system it will probably run 3 bar fuel pressure and drop at pretty much 1:1 with the manifold pressure, so like 2.3 bar at idle.

Since you are running an aftermarket ECU you should be able to get away with just disconnecting the vacuum source from the regulator and running at fixed pressure and tune for that. A simple inline fuel gauge should do the job.

Are you using a wideband oxy sensor?

You were posting about it pulsing or something at idle? That is often an indication of your AFR being wrong so it swings between too rich and too lean

 

You also mentioned your temperature sensor was all over the place. Fueling changes significantly with temperature readings, so this could be the cause of your issues.

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reg isnt going to move with vacuum on it alone.       standard  43psi fuel pressure reg will need round abouts 43psi before it allows fuel to bypass.       so if  had 43psi fuel pressure, then added vacuum to the top side it would start to move more, to allow more fuel to bypass and drop the fuel pressure  by how ever much vac added to the top

if you could put negative 43psi on the reg with zero fuel pressure it would move.  but yeh that much vac isn't possible

Also,  always use the vac line. unless its a NA itb setup

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2 hours ago, ajg193 said:

If it's a bosch based efi system it will probably run 3 bar fuel pressure and drop at pretty much 1:1 with the manifold pressure, so like 2.3 bar at idle.

Since you are running an aftermarket ECU you should be able to get away with just disconnecting the vacuum source from the regulator and running at fixed pressure and tune for that. A simple inline fuel gauge should do the job.

Are you using a wideband oxy sensor?

You were posting about it pulsing or something at idle? That is often an indication of your AFR being wrong so it swings between too rich and too lean

 

You also mentioned your temperature sensor was all over the place. Fueling changes significantly with temperature readings, so this could be the cause of your issues.

 

 

Yeah there are other issues I need to sort, but this is the main problem. The surging at idle is caused by the fuel pump cavitating as is completely in sync with the noise's the pump makes as it gets hot and vaporises fuel.. When I plumb the feed straight to the return there's no restriction for the pump and it doesn't get remotely warm. As soon as I go back through the fuel rail it gets hot and surges at idle.. Surely that's the regulator as its the only restriction.. Might need to bail back out to pick apart and get another reg.. 

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2 hours ago, ajg193 said:

If it's a bosch based efi system it will probably run 3 bar fuel pressure and drop at pretty much 1:1 with the manifold pressure, so like 2.3 bar at idle.

Since you are running an aftermarket ECU you should be able to get away with just disconnecting the vacuum source from the regulator and running at fixed pressure and tune for that. A simple inline fuel gauge should do the job.

Are you using a wideband oxy sensor?

You were posting about it pulsing or something at idle? That is often an indication of your AFR being wrong so it swings between too rich and too lean

 

You also mentioned your temperature sensor was all over the place. Fueling changes significantly with temperature readings, so this could be the cause of your issues.

 

 

Yeah there are other issues I need to sort, but this is the main problem. The surging at idle is caused by the fuel pump cavitating as is completely in sync with the noise's the pump makes as it gets hot and vaporises fuel.. When I plumb the feed straight to the return there's no restriction for the pump and it doesn't get remotely warm. As soon as I go back through the fuel rail it gets hot and surges at idle.. Surely that's the regulator as its the only restriction.. Might need to bail back out to pick apart and get another reg.. 

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  • 3 weeks later...

There's a full efi conversion kit for single cyl engines 100cc to 400cc bout 1k

Also saw an old thread of a guy using a megasquirt for a bit cheaper.

There's a throttle body unit from a Suzuki 125 on TradeMe now for a hundy. Could mash a speeduino on that and be done pretty cheap

 

I worked out how many Kms it would take to pay itself off. Only 10 times around the clock...

 

 

 

Same kit but $430

https://www.ebay.com/itm/motorcycle-ATV-scooter-buggy-moped-UAV-EFI-engine-Electronic-Fuel-Injection-kit/273127447029?hash=item3f97aa19f5:g:PHwAAOSwaudbUUTp

Only 5 times round the clock for that

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The Link G4X has landed!

 

Only Atom and Monsoon versions for now. But some cool new features.

1000hz logging with more onboard memory.

Math channels so you can create new variables which can be used as a load axis or switch trigger or whatever.

Proper MAF support.

And a few other cool bits.

Might get a Storm when they come out / fixed first few rounds of firmware haha

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I've been working on a new loom. 

Bought a bunch of thin wall TXL wire from the states. Really nice to work with! 

Using all 20 gauge except for where heavier is needed. But now kinda wish I went to 22 for the sensor wires. As it's all still quite a big bundle.

Also it's considerably easier and quicker to actually make a loom from scratch, because you can just pin and lay out bundles of wires as you go, then look what outputs you have left and then see where's a nice place to put the next one. Rather than dealing with the spaghetti of a full prewired loom.

Gotta say its quite satisfying having decent crimp tools and all of the right connectors plugs etc.

This time around the plan is:
4x coils
4x injectors
4x temp sensors (rad, engine, oil, air)
4x wheel speed sensors
2x vvti solenoids/cam sensors
Bosch Ethrottle
Cruise control
Map sensor (for fuel pressure differential calcs)
Maf sensor (For main load source)
Knock sensor
Fuel pressure sensor
Rad fan
Fuel pump
Oil pressure sensor
Purge valve
Starter moror control
Brake & clutch switches

Then some more stuff coming over canbus such as wideband oxy sensor.

Adds up to a big loom pretty quick.
I've scavenged a bunch of the dead end plugs / distribution block type plugs from some factory looms to use for 5v supply / sensor ground / 12v supply. 
Works really nicely because I've got more than 1 plug full of sensor grounds so seems unrealistic to do an open barrel splice for that many wires.
As well as being easy to add/remove things this way.

loom.jpg.d838a27e6b24f91de0006542b5d9eec0.jpg

I've run out of DIs but still plenty of outputs and analog inputs left.

I'm building a new body loom for the car too, so will have just one central fuse box and go outwards from the center console area to everything.

Just trying to decide where to have the breaks in the loom so its removable. 

Currently thinking fuse box and all fused items will be part of the body loom.
Then wheel speed sensor wiring on seperate plugs close to the ECU,
Then all the engine stuff on a single branch or maybe 2 branches into the engine bay.

I've learned a bit from my previous looms but still feels a bit intimidating redoing all of the body wiring.
But then in some ways its actually easier, feels like integrating into an existing loom and figuring it out is always the hardest part.

Half tempted to go DR25 in the engine bay because it looks cool buuuutttttttt makes things really difficult to alter 
(I'm guaranteed to chop and change things later..)

 

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Its the same for injectors and coils, but I usually twist the 4x drives and the power feed together through to engine, then split with an open barrel crimp into the 4 individual power feeds and split to each injector/coil from there.  I can't find a photo of the last set of COP's I've done but with smart coils for example I usually slam a plug in there to avoid having to take the whole shooting box out if the engine/loom has to come out, but from there seperate the earths off to the head while the loom shoots back into the cabin.  Many ways to skin the cat I guess.

20597414_526343791030625_502029401337327

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Yeah definitely keen to look at idea of some sub-looms to make life easier. 

I'm splitting my headlight wiring down each side of the car so nothing runs across the front anymore.
So dont have to unplug and move wiring in order to get the engine out. 
Just little things that slowly annoy you over years and years of pulling out same motor over and over 

God bless that 3S reliability 

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  • 2 weeks later...

It's amazing how much my wiring has downsized on new loom. 

Toyota e-throttle unit for example. 

Previously 12 wires, 3 plugs, and a throttle cable arrangement. 

Bosch unit - 6 wires, 1 plug, no cable. 

Huge difference to how messy that area is.

Then just putting some effort into placing things so they're less of an eyesore (InB4 "Throw a blanket over the 3S")

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  • 2 months later...

Technically everyone does! 
Then widebands assume Lambda 1 is 14.7:1 and then scales it from there.

But then the funny thing is that if your stoich value was actually say... 13:1 for a different fuel, it will still read as 14.7:1 and you'll still effectively be tuning it to Lambda 0.9 or Lambda 1.1 or whatever and it will still be fine haha. Which is why everyone insists that using Lambda as the scale makes a lot more sense. Good habit to get into.

Yeah that's not hugely lean, but keep in mind that as you go leaner you can end up needing a fair bit more ignition timing as the burn rate slows down by heaps. 
Like at cruising conditions you could probably quite happily add another 5 or more degrees over what's good at Lambda 1.

Supposedly with petrol 15.2:1 ( Lambda 1.034) is the best point to aim for lean burn power/efficiency. But obviously engine to engine that's gonna change.

 

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