DIY Fuel injection thread.

[kpr]

wire it back to the same place as the ecu power grounds are, which are usually on engine somewhere.    

[gibbon]

20 minutes ago, kpr said:

wire it back to the same place as the ecu power grounds are, which are usually on engine somewhere.    

Ok thanks... There's also a main coil ground on the plug, I was guessing that would go to the block too, but do I do that but try to just keep them apart a bit?

[Hyperblade]

10 hours ago, gibbon said:

so I am just sketching up a wiring diagram to use direct fire on the rx7 using IGN1A coils and the plugin link ECU. Google tells me the 'analog ground' for the coils needs to go back to the ECU. the factory ECU doesn't appear to have a "coil ground" pin, but has several "input" and "output" grounds. Should I wire it to one of them? I was going to get an expansion harness anyway, would it be better if I had a dedicated pin for it? Even the Link doesn't appear to expect to receive an 'analog ground' from the coils as there's nothing in the pinout for it

 

10 hours ago, gibbon said:

Ok thanks... There's also a main coil ground on the plug, I was guessing that would go to the block too, but do I do that but try to just keep them apart a bit?

I don't know about your specific coils (and Analog ground means nothing to me), but with standard K20 ones, you have 3 pins

• Ground (wire to engine block)
• 12v (your main 12v source for them)
• ECU (how the ecu triggers them)

So the ecu pin should go to the ECU IGN-1 (2,3,4)

[gibbon]

1 hour ago, Hyperblade said:

 

I don't know about your specific coils (and Analog ground means nothing to me), but with standard K20 ones, you have 3 pins

• Ground (wire to engine block)
• 12v (your main 12v source for them)
• ECU (how the ecu triggers them)

So the ecu pin should go to the ECU IGN-1 (2,3,4)

nah this one already has dedicated trigger pins as you mention, it just also has these two separate grounds for some reason (as well as the 12v feed)

[Hyperblade]

42 minutes ago, gibbon said:

nah this one already has dedicated trigger pins as you mention, it just also has these two separate grounds for some reason (as well as the 12v feed)

ahh right.

https://www.hpacademy.com/forum/practical-harness-construction-club-level/show/star-point-wiring-ign1a-coils/

 

Adam from Link says this...

Quote

Since these coils have the primary, secondary and logic grounds all isolated from each other, the most appropriate way to ground them is exactly how everyone that sells them tells you to.

Pin D is the primary winding ground (coil negative in old fashion terms) so to keep the return path as short as possible it should be grounded to the same power source that supplies the primary positive (Pin E, i.e. the battery).

Pin C is the secondary winding ground. So to keep this circuit as short as possible this needs to be connected as close to the spark plug as possible (i.e cyl head).

Pin B is the logic ground for the trigger circuit so needs to reference the same ground as the ecu ignition output, usually ECU sensor ground is the most appropriate.

 

 

[kpr]

Good coils  but they are a pain with all the grounds.   

If your engine is grounded well.  as it probably should be if your starter motor works.    running both the main grounds  (high current and secondary) to the engine block  will be fine.  keep them separate on the way there, but ok to ground in same spot since nowhere is far from the plugs on a rotary.     the ecu reference  ground will be fine  with the ecu grounds on the engine. 
I would avoid grounding  the main coil grounds in the same spot/ bolt,   as ecu grounds and  coil ecu ref.   If you get any loose connections, the coils may try ground through the ecu and bbq things.  

Its when people start grounding them in random places on the chassis and things, when will start running into issues 

[yoeddynz]

Someone on a Goldwing group had asked about fuel injecting the 1500 carb'd engine. This fella Kim is not a fan of injection it seems and wondered why anyone would want to change. I'd replied and the conversation goes as such..

Kim Egil smoother idle, smoother off idle transition, potentially more power, better emissions. But a lot of fab work.

 

Kim Egil

exactly everything I don’t need, or even care about having. To each their own though. 

•  
•  
• Kim Egil but it's pretty nice once you've tried it. Hence Honda moved on to injection for the 1800. I love the injection setup I've built for the 1500 engine in my car.. but.. I'm also pretty happy with the original carbs on my Gl1500 bike even though it's not as smooth or economical.

Kim Egil

Alex Davidson if a carb is well tuned it’s just as efficient as any EFI system. Obviously it will change with temperature and elevation (known as density altitude) but every bike I have (with exception of a track bike Ducati) all have carbs and they work great. The cost of gas is very far down on my list of priorities compared to reliability. Honda and everybody else moved to EFI to pass emissions and save money in production, not to make a better product.

 

 

Wow. Have we been duped all along by BIG INJECTION and actually should have stuck with carbs? 

 

 

 

[Yowzer]

Anyone who says a well tuned carb is just as efficient as EFI needs to drag their arse out of the 90s

[Roman]

Hes happily ignorant and wont ever change his mind. 

[Yowzer]

Just gotta post some dyno graphs that he can't beat then

[kpr]

No amount of science  and poof will convince him.  The best you will get out of him is radio silence,  but dont make you think, that means hes wrong 

[Yowzer]

I actually enjoy fucking with carbs from time to time, but I find it's often a pain in the arse trying to diagnose issues with them coz my shop no longer has any of the old-school equipment and none of my resources have the technical info on them. 

Tbh 80s-90s EFI is worse. 

[yoeddynz]

53 minutes ago, Roman said:

Hes happily ignorant and wont ever change his mind. 

Yep- I too figure that he'll never back down. So I replied with this..

Alex Davidson

You're right! I guess this is why every performance car produced since EFI was invented is still running carbs. I love seeing the brace of Webers sticking out through the engine lid on Lewis Hamiltons F1 car, the polished SUs lined up gracefully on the side of a BMW S54 screaming away at 9000 rpm. Or the 12 fish Carburetors that Gordan Murray recently asked Cosworth to spec on his latest T.50 supercar engine because he knows as well as you do that they are every bit as efficient as any EFI system and bugger the emissions.

[Roman]

Ever noticed how a lot of race classes would ban EFI but no one ever banned carbs... 

Probably because they're happy for you to participate and come last.

[HumberSS]

I'm still interested in injection on the 4V in the camper, for many of the reasons listed above, as well as not having to recert later (scope creep being the only downside..). Is a link g4 for $750 a reasonable buy, and will it have the necessary injector and coil outputs for a V8? 

[cletus]

carbs are as dumb as a bag of rocks, and not as efficient as efi, sure

 

but they always work.

 

ok if you leave it sitting for 5 years you might have to hit it with a rock to unstick a float valve. unga bunga.

 

 

OEM efi is obviously very good, but

i have had a lot customers have problems with those bolt on efi 4 barrell things

and quite a few with problems on home brewed efi setups

 

i was thinking about putting efi on my plymouth but the one problem my carb was having, part throttle richness, was solved with a small $40 part, now its mint

 

 

[tortron]

Efi minis produced 10hp less for a few percent more economy compared to the SU l, which IS ALL YOU NEED TO KNOW

[HumberSS]

3 hours ago, tortron said:

Efi minis produced 10hp less for a few percent more economy compared to the SU l, which IS ALL YOU NEED TO KNOW

I always love how efficient and well mannered my super snipe was on the twin 1-3/4 strombergs

[Nominal]

I don't have any desire to convert my carbed cars (autolite 2V, Stromberg bxv, I think the woodie has an edelbrock carb, some Toyota thing on the 2Y, to efi, but I like the efi on the sr20det, except for the fuel pumps dying due to lack of use/water in the tank due to lack of use.

 

[Bearded Baldy]

I still want to put a set of jenveys on the falcon motor to replace the holley, hard to justify the expense when the car is still is still in bits/full of rust.