My own MPFI swap

Heh, well, I just started my MPFI swap on the car I bought from KoDKingVegeta... but I didn't want this one to turn out like the last one that I did, with someone over my shoulder hounding me and telling me how to do it.. even though he'd never even heard of it being done...

So, I wish this time, I'd have taken pics so I could write up the tutorial for it, b/c I basically went against everything in the walkthrough, other than the basic wiring and such... but even that I didn't follow 100%.

It's all small things, like looping the yellow w/ blk stripe from the DX injectors back to the harness end-plug they come from, then running the wiring from the other side of that plug to the resistor box... just to clean up a small mess.

I trimmed out a bunch of wire that was just way too long...

Things like extending the TPS wires, one can always negate that by just peeling the tape and cover off the wires, and pulling the TPS end plug back to where you need it, then re-taping the whole thing.

For the CPS wiring, and the extra two injector wires, instead of adding new plugs under the hood, I just used the existing ones.. the d-side shock tower has 3 open pins on it... if you use one for the blk/ylw wire, you have 2 left... guess what you can put in there? Injector wiring!

If you do that, you have two choices... you can either run them with the factory chassis side of the harness over to the p-side, and in like your CPS wiring, or you can run them in the D-side, and under the dash across to the ECU... choice is yours.

The CPS wiring, hell, just use the male and female plugs from the Si or HF or 90-91 EX (mine) dizzy you're using.

Repinning is quite easy, and you can't even really get those two solid white wires mixed up, b/c if you peel the covers back far enough, you'll find that 4 of the wires are in sheathing, and the one left over is the bastard white wire... You just have to cut enough of the wiring harness on the donor car with the plugs to get some of that sheathing, so you can tell which one is which... if you can't figure it out, the lonely white wire is the "bastard".. on the 6 pin plug, it's the one that is all alone, with no other wire above it.

You can see every section of wire that I've manipulated in some way right now, since it's all been redone with blue electrical tape.. I'll take some pics tomorrow while I'm finishing it up... this is the first time I've done it w/o hacking it together, and decided to make it seem/look like it was actually supposed to be that way, even tho some of the wires will still be exposed, since I ran out of blue tape... until I get more.

This has taken much longer than it should so far though, since I'm actually stopping to think about each section as I'm working on it, rather than just doing it the same as I always have.

All that's left, is the wiring at the ECU, and the actual installation of the manifold and dizzy... they're both just sitting in there right now, so they could be removed easily if necessary.

I also have to find my vacuum diagrams, since I can't remember which hoses go where... lol.

Oh, and I'll have to calibrate my TPS... the old one on this manifold was borked even when I was running it on the last car, so I decided that I'd change it since I had another one... and even if I can't get it right, I'll just get another TB gasket and use the TB off my ZC engine.

So, that said, I"ll get pics of the install up as soon as it's finished, they'll be in my build thread, for those who want to see them.

Ok, so apparently all that extra stuff I did was wasted time, since I had to take it all back apart anyway, to figure out why it's running on 2 cylinders and I'm getting the code 16.

So much for this one looking nice... it's turned out exactly like the last one, only I can't think of what I did to the last one to fix it.

Help. Please.

The first MPFI I did, I ended up going to the salvage yard and getting a new DX harness to fix it all because I was having issues with it too. Now my first MPFI harness is my donor harness for plugs and such.

Can't remember if I extended the TPS wires on the second one, or undone the tape and moved them like I did on the first.

All I have left on my black hatch is doing the engine harness for MPFI, I just can't motivate myself to go out and do it. I need to do it so I will finally drop the z6 in there, because I don't want to drop the engine in until after I get the harness swapped to it, much easier swapping it while the engine is out.

I figured out how I can fix this once and for all...

Instead of following things to make it seem like it's a stock install, like it was done from the factory, I'm going to instead,

Flip the injector harness around
Run A1,A3,A5,A7 all through the firewall.
Mount the resistor box (maybe) under the IM... or somewhere in that area.
Wire the resistor's ECU (yellow/blk) lead to the ECU manually, by tracing it back through the harness and cutting off the 3 or so feet of excess...So, basically, what I"ll end up with is the injector harness facing the other direction, with the wires sticking out the pass side... I'll run all four injector wires, blue, brown, red, yellow, into the pass foot well to the ECU.

The resistor will be attached to the red/blk wires, as per norm, and the yel/blk from the resistor box back to the ECU will be cut back and wired directly via a new wire/pin from the ECU.

Any unneeded wire at the d-side strut tower will be removed from the terminal clip, and stripped from the harness.

Still clean, and funkshunal.:D

I really get tired of playing with things after awhile... then I figure out how to just do it.

And, by the way, I have months and months of work still to do on this car... I'm just getting started.

Eventually, the whole wiring harness is coming out anyway, and being replaced with one from an EX, so it's pre-wired for MPFI... and most of that harness is coming out... whatever I don't need for my build. (I'll keep the extra wires tho... I won't cut them... I'll leave the terminals on them, so I can use them later to wire up other stuff if I need to... I find those stupid little pin terminals invaluable when adding things to cars' wiring harnesses.)

I so wish I had a camera handy... I'd love to take pics of this so you could all see it...

Frankly, I got tired of trying to diagnose wiring, so I just flipped the injector harness around, soldered some ~16 inch extension wires (all yellow 16g) to each injector, and soldered pin terminated wires on the other ends of those... So, my injector wire colors are all wrong now, like... yellow is #1 instead of #4.

But... I have 5 new wires running into the ECU area... 4 injectors, one Resistor box ground.

As soon as I put the wires in, got everything pinned up, made sure nothing was touching where it might short out, started the car... it started before I could get my fingers off the key.

Checked the TPS, it was perfect, never had to adjust it, checked the timing, by ear of course, I don't think I could have gotten it any better with a light, never had to adjust it either.

Finally, it runs again... the MPFI swap basically went to shit from what it was supposed to look like... but this works for me, since it's only gonna be like this until I get another car to take this one off the road for an extensive rebuild, at which time I will change the wiring harnesses (chassis and engine) for ones from an EX most likely, since it will pretty much match my car, and it's already MPFI wired.. no hacking necessary.

BTW, in doing what I did, I found a way to do the MPFI swap without affecting the stock wiring harness in a way that can't be easily reversed...

If you're wiring all 4 injectors directly to the ECU, there is no need to touch the DPFI injector clips or ECU connections, so they can be hidden.

There is NEVER a need to cut wires at the ECU, since you can just as easily move C1 and C2 to B10 and B12, then insert NEW terminals into C1 and C2 to run into the engine compartment. This leaves the original C1 and C2 wires intact, to be moved back in the future, if necessary (like for sale... or emissions, in the case that you can't pass with MPFI)

Attaching the resistor box to the pass-side strut tower behind the stock battery location will allow it to be used, and you'll only have to run 4 wires from the harness to it across the open area above the tranny... they can be tied off to the existing harness if you make them long enough.

Flip the injector harness around, so all your wires come out the pass-side of the black plastic box they're in.

This leaves 5 wires for the fuel system, and 2 for the CPS that need to be run into the ECU area. Depin the A1,A3,A5,A7,and A11 or A13 wires, and go to the junkyard to get spare wires from an A-clip and a B or C clip.

Add 2 B/C clip wires to the holes that you de-pinned wires from at C1 and C2, and run these to the corresponding CPS wires.

Add A-clip wires to A1,A3,A5,A7, A1 is injector #1, which, if you flipped the injector harness the right way, should now be Yellow.

The process is the same for each injector, check the color at the injector, follow it into the engine bay, connect it at the ECU.

Now, the reason you took out A11 or A13 is simple... these two wires are the DPFI/main relay power... Whichever wire you removed, tape or heatshrink the end of it off, so that nothing can come in contact with it, since it will be powered via the other wire, then add your wire back into it's place, and connect it to the ylw/blk on the resistor box.

Make sure, as usual, that all your connections are sealed and soldered, taped off, whatever you do.

This will keep all your stock wiring intact, to the extent that it can be re-used if necessary, or if you're not comfortable cutting your wiring harness... there is no need to "hack" the DPFI harness to have MPFI... I'm not sure what genius came up w/ the idea that all the wires had to be run back through the harness, using the stock wiring, but I hope this information proves useful to someone... it worked perfectly for me.

Obviously, this isn't the complete walkthrough... the parts about the TPS are missing, and a few other things that you need to pay attention to are also missing, but I'm sure you can figure them out by reading other walkthroughs... If anyone actually wants this information put together so they can use it, PM me, I'll write up an actual instructive so you can print it and use it for yourself.