SEARCHED - Mini-Me help

[FAC3L3SS]

I bought my '96 DX w/ a Y8 head on it, but not wired up. I recently bought a knock sensor so today I got that in and ran the VTEC switch and pressure sensor wires, etc...so I ran the 3 to the ECU pinouts and popped in my P2P ECU and at idle it's jumping back and forth from 1500-1700 HARD. Just surging basically. There are NO vaccuum leaks, and when I toss the stock P2E ECU in it runs normal again, so I know it's wiring. ALL my connections are solid, but I talked to the PO and he told me it's a Y7 TB on the Y8 intake manifold. On top I can see a 3-wire IACV, but it's spliced into / onto a 2-wire one that has a resistor in it. The ECU pinouts have something in A13 and A14, so it looks like it's a 2-wire from the factory, but the new ECU is looking for a 3-wire setup (which I have). Do I need a Y8 throttle body and 3 to 2-wire IACV swap (BOTH those are in there, spliced to each other) so I can run whichever I need. It was a stupid frustrating day and now I'm convinced that I've got a wire to move on the ECU pinouts and/or something to change on the IACV itself (ableit using the FFSQUAD write-up or just tracing the wires to find which ISN'T wired into anything). Either way I know that that's the issue because it's doing exactly what people have said it'll do if you don't do the IACV fix. Final question is should it be running a 3-wire IACV for the P2P ECU? Since mine is already 3-wire, do I just find the unused one and wire to pinout A12? Do I need a Y8 throttle body to make this "simpler" and be a smooth fix? I'm potentially 1 wire away fromt VTEC.

I apologize if that is uncomprehensible. We fought and tweaked all day to get it right and at the end of the night I popped in my stock ECU and drove home VTECless.

 

[FAC3L3SS]

This may or may not have an effect on this as well, but the car was once an automoatic, so it's now a swapped 5-speed AND mini-me swapped. The stocky Y7 TB is probably messing me up then, eh?

 

[FAC3L3SS]

Well I put the old ECU that it's been running off of (P2E auto) and it ran / runs almost normal. Idles closer to 1100-1200 but it still chugs, stinks quite a bit (not like oil, but something more), and is FLOATING through gas. Any ideas? Head gasket? SOMETHING?

 

[HARMON]

its bc the 2 ecu's are a different OBD. i ran into the same issue with my ecu for 5 spd swap. the stock ecu is an OBD-2A however the new one ur trying to intall is OBD-2B. They have the same harness clip setup, however the pins are in an entire different setup. they sell conversion harnessess to save you from the nightmare of cutting and splicing all those wires.

what year did the new ECU come from?

 

[FAC3L3SS]

The new ECU is a 1997 EX 5-spd VTEC ECU, going into a '96. They are both OBD2a, so that's not the problem I'm sure. Also, I think I'm a newb...where is the IACV?

 

[Jersey8]

did you swap in a y8 intake manifold or did you keep the y7?

if you went y8 mani, is it an auto manifold or manual manifold? (they're different)

auto has a 3-wire iacv setup bolted onto the throttle body
manual has a 2-wire iacv setup bolted onto the back of the manifold

im trying to get more info about your setup to help you with the best route to take to fix this

 

[FAC3L3SS]

Well after looking, I've got a 2-wire IACV on the back of the manifold, with just the wires hanging off it. The Y7 TB is still on, and everything else appears to be a 3-ire setup. Now comes the REAL question(s)...

Which 3-wire plug do I unplug to rewire to the 2-wire on the IM? I've got a 2-wire plug already wired up, spliced off the 3-wire one that's currently plugged in...do I unplug the 3-wire and plug in the 2-wire? What should be unplugged and rewired? lol that's the ultimate question.

Also, after this rewire, do I swap A14->A12 and unplug A13?


EDIT:

The 3-wire IACV on the Y7 TB is on the bottom of the throttle body, correct? I found the 2-wire on the back of the intake manifold...so I unplug that 3-wire one from the TB and wire it into the 2-wire on the IM? THEN do I do any swapping @ the ECU?

 

[Jersey8]

ok, well correct me if im wrong but it appears you have a manual y8 manifold, and a y7 auto TB, so you have 2 IACV's. one with a 3 wire (TB), and one with a 2-wire (manifold).

it seems like the 2 iacv's are interfering with eachother and you're not sure which one to use. sometimes when iacv's are not plugged in they can fluctuate in the manner you previously described
what you need to do is eliminate one of the iacv's and decide which iacv you want to keep. you can:
1.) take the manifold iacv off and block off the port with jb weld, utilizing a 3-wire setup
2.) get a y8 MANUAL throttle body and stay 2-wire. then you will have to move a14 to a12 and remove a13.

if you ask me i would say 2 is the easiest option, cause then you'll have a manual y8 TB to go along with a manual y8 manifold, and it appears that there is already a 2-wire plug available.

 

[FAC3L3SS]

Correct, I currently have the Y7 ATX TB on the MTX Y8 IM. The two wires are just hanging off the plug on the manifold, and I'm using the 3-wire. I was told over on d-series that I can just splice the 3-wire into the 2-wire and leave the 3-wire unplugged. Then do my ECU pinout moving. Is THAT a possibility?

Also, the reason I believe I need to run the 2-wire setup is because my P2P ECU, when plugged in all wired up, idles terribly and throttle response sucks. I think it's because the ECU is searching for a two wire setup (the A12 pin) but it's reading a 3-wire (A13 and A14) which also makes me wonder if wiring up the 2-wire and moving the pins works, wouldn't it override the 3-wire sensor (much like it's doing now to the other one) and run properly? I believe that rewiring it to the 2-wire one will solve it, as it cannot idle properly at ALL when the other ECU is in.

 

[Jersey8]

o ok. i thought you said you were currently spliced up for 2-wire. i would convert to 2 wire and see what happens. then if it still acts up start looking around for a manual y8 TB.

 

[FAC3L3SS]

Fair enough. Worst case is I splice back to the three and run it for a bit until I find a Y8. Problem is, he gave me another TB and some other parts when I got the car, but most of it got tossed because it was junk and he told me EVERYTHING was done sans wiring.

 

[FAC3L3SS]

Got the 2-wire IACV done on the back of the manifold. Car starts and idles at about 1800 for 30 seconds, then drops to a grand...then slightly revs back to 1800 then drops back to a grand, then slightly back to 1800...then drops to a grand....etc...etc.. any ideas? All the wiring is done, and it just sort of teters back and forth at idle.

 

[FAC3L3SS]

Haha alright alright LAST series of questions, I swear. The rewire is DONE! Everything is in and it runs great...when I'm moving. At idle, it sort of leaps from 1000 to 1800 slowly. Like in a steady rythm. I read on HT that it's because the 3-wire IACV stays open, even when unplugged or not wired up...so it may be causing leaks (and idle surge). What can I do to keep that from happening? I read someone made a little plate or something to cover it...any ideas? Idk what to do, but I'm 98% that's what making it run funny / idle wrong.

 

[Jersey8]

ive had an iacv surge on me before when unplugged. like i said earlier, it could be interfering with the functionality of the 2 wire. thats why i suggested getting a MANUAL y8 throttle body, cause then youd be getting rid of that 3 wire iacv. or you could fab up a plate yourself

 

[FAC3L3SS]

So blocking it off could solve the problem? I'm like 98% sure that's what making it surge since I read that it stays open.

 

[Jersey8]

well yea if you blocked it off then it wouldn't allow any air to go through, and the entire intake system would be fully sealed, with the exception of the functioning iacv on the manifold

 

[FAC3L3SS]

Alright, temp solution until I buy a Y8...I've got it partially blocked off with a few holes to adjust the idle rofl. It'll hold until I got a TB.

 

[FAC3L3SS]

Alright, I've got a line on a manual Y8 TB, but until then here's an issue...

After I made that block plate w/ some holes in it the other day, it ran fine except after about 20 minutes the driving below 2k (taking off, granny shifting) got super rough and choppy again...like how it did when the IACV was messin up. Tonight I drove into town fine and when I left the drivethrough it did it again (another 20 minutes or so). Could it be that after a while my wiring comes loose? I re-checked it this morning and it was fine and drove fine, but then it acted up again. It idles fine, so I know it isn't my plate. It's acting JUST how it did w/ the bad wiring. Maybe I just need to strengthen my wiring (taped for now, FTL I know) because when the engine moves it's shorting it out? Hell Idk.