Creating a Switch to Shut Off Cylinders on the Fly

[SVOboy]

How long until you get gas so we can see if there's any difference, should be pretty apparent I'd think.

[rh77]

Originally Posted by SVOboy

How long until you get gas so we can see if there's any difference, should be pretty apparent I'd think.

What a trip to the airport. 60-70% of the time on the highway was WOT to maintain 70 mph and averaged 4500 rpm and high engine load. It can't be good it. Anyways, the gas guage is fairly inaccurate, so I'll be back home Thursday night so then I'll fill up to get a result. I'm at 26 mpg right now before the mods. Another question...

If the firing order is 1-3-2-4, then you get Fire, Fire, Delay, Delay which would probably explain the shimmy. Someone over at the Yahoo MPG group suggested cutting 1-4, but that would mess up the TDC, BDC arrangement, right? It's worth a try at least.

RH77

[SVOboy]

I agree that about trying the 1-4, it may work, it's worth a shot just to go out there and try it and see about the vibrations. If your datalogging you prolly know all about chipping, so you could tune down the WOT a bit also, though I dunno about it, just wait and see I suspect, I have a sneaking suspicion it's our damn autos.

[dfoxengr]

1-3-2-4 is the same as 4-1-3-2 so it isnt off. i definitely wouldnt do 1-4 only. that would be unbalanced.

and i wouldnt even cut the cylinders until your up to around 45mph, and are going to stay on the highway.

also, check to see what your rpms are for these two cases:
60mph, 4 cylinders firing, cruising on the highway in 5th gear.
then
60mph, 2 cylinders, cruising in 5th gear. that 3rd gear is why your rpms are so high. thats what a transmission purpose is.

[rh77]

I've done a lot of thinking and research, and it's a great idea, but but not applicable in this situation. With the 2 cylinders running so rich, I'm probably trashing the cat, and creating an uneven temperature within the engine block. Furthermore, I'd need to trick the ECU and make sure the torque converter is locked to allow power to be used at its utmost. I can run it below 3500 rpms, or the whole car shakes. I think the fact it's not only a 4-cyl., but an automatic makes it too difficult to finalize. Thanks to everyone who has helped with this experiment. It's been a pipe dream of mine for many months, but it didn't pan out. Oh well, it looks like there's lots of other things to do on this site to improve economy.

Thanks again...

RH77

[Matt Timion]

The more I've thought about this, the more it doesn't make sense on a 4 cylinder engine.

I can see it working without a hitch on a 6 or 8 cylinder, but not a four cylinder engine. From the sounds of it your ride was a bumpy one while you were experimenting. That would be enough to scare me away.

[dfoxengr]

i might try it on my v6 truck soon, but i may be too lazy.

rh77 send me your wiring and whatnot and ill try it.

and yes it would work best in a manual car.
which mine is. also if i try it, ill be using an AFC to lean it out.

[rh77]

Step One: Am I ready for this??? Just joking...I was really excited with this project, and now I'm disappointed that it won't work, but that doesn't mean it won't work in your application (although I hear Inline-6s, V-8s, and makes with manual transmisions are more friendly for this).

First thing is to determine the firing order and cylinder placement. For example on my car, for 4 cylinders, the 2 middle (2 and 3) are in the same position at top dead center, when the outer 2 (1 and 4) are at their bottom-most point. To balance out the load on the crankshaft and minimize uneven firing, determine the firing order. My problem is that the 2 similar cylinders fire next to each other, then there's a long delay while the dead cylinders are moving up into what would be the compression stroke, and it becomes seriously unbalanced.

I hope your engine config. allows easy access to the fuel injectors. Mine, as you can see in the photos in previous posts, are the black plugs. After you've researched which cylinders to deactivate, try to disconnect those injectors, start it up, and see what kind of idle you get (the electrical connection might be a squeeze-clip style). Mine ended up rocking forward and backward. I'm not sure what kind of idle is expected -- but my guess is that it shouldn't stall.

Wiring: After you find the injectors to deactivate, trim-away the tape/piping to expose the 2 wires to each injector. Find the same colored wire to each injector -- this should be the ground, and is the safest to work with (mine was black and yellow). Each positive lead should be a different color -- brown, white, etc. Cut the ground lead to each cylinder, leaving plenty of room to strip wires on the injector side. Tape off the "hot" leads (except one -- I'll explain this in a moment) to prevent shorts. Now on the wires coming out of the injector plugs, strip the wires and wire them together assuming 1, 2, and 3 are to be deactivated. Pardon the rudimentary diagram below: (I shorted out the PGM/FI circuit so, keep fuses handy).

|--|-|---> Run this to a switch in the cabin
1 2 3

4 5 6

You may have to drill through the firewall.

To complete the electrical connection for normal operation, take a negative lead from the "hot" source (usually the same colored wire). In my case, I just used the negative lead on the other side of the number 1 injector, because the harness stopped at the 4th cylinder, so I new it was the first lead "upstream".

..... --------------> back through the cabin to the switch.
..... x
1 2 3
4 5 6

It's usually close to a "Y" bundle -- basically complete the circuit. Flipping the switch essentially kills the power to the injectors and voila, cylinder deactivation. Flip the switch the other direction, and now each cylinder has a complete circuit and will run normally.

Now on how to use it, I have no clue. Perhaps get up to speed and flip the switch and cruise...but I never got it to work that way -- I had to floor it to keep at speed and stay down a gear (3rd instead of 4th), or a wicked shimmy would result.

Let me know what kind of truck you have and if you have any other questions. I honestly hope it's a manual. Feel free to take pictures if you need to. Good luck!

RH77

[dfoxengr]

yes its manual, i said that in my previous post.

yeah ive been building honda B series motors for 5 years now, and have been working on hondas/acuras for just as long. i know exactly how to do all this and what it requires.

[rh77]

What kind of truck is it? Also, any advice on getting the Integra efficient? I used to have a '99 Civic Si with the B16A2 -- what a great setup. B-series engines are great -- it's too bad the K-series is taking over.

RH77