eltexmexalex

Ok first of, this is a Honda civic 98 DX (NON VTEC) and we swapped the transmission to a VTEC transmission. So this car has a VTEC transmission (96 EX) on a non vtec motor. The car was running fine for a while but after running up on hills, it started failing to shift gears (muffler got louder). Then we scanned the transmission and it said it 2nd gear out of range. So we replaced both solenoids and the transmission oil was dirty. So then it stated working, but now it happened again, but this time it might have been because we fixed the ac compressor and it started acting up again. I heard that this code appears when swapping transmissions that is a different model any ideas of what's going on?
Error codes: P0700, P0740, P0730, P0758

tony_2018

Not gonna work. If you had done some research you would've seen that I've went down similar path already.

eltexmexalex

Can i jump A4 to D6 on the ECU to fix this problem? Or can i just swap the head for a vtec, so it can work?

tony_2018

You need to swap ecu's to make it work, just don't hit vtec. But if you want to add vtec than yes swap the head.

94EG8

I also went through this a few years ago. You can't use a Y8 transmission on a Y7 or vice versa for this reason.

tony_2018

Thanks for the double confirmation. I really wish Honda just standardize one auto transmission for the civics back in the days.

eltexmexalex

Ok, so if i put a vtec ECU it will work but i don't have to put the vtec head right?

tony_2018

Right, you might have to change injectors to, its a hit or miss.

eghatch9295

iTrader: (1)

the injectors will work, but swapping to the larger y8 ones is ideal. since they're both auto, they both look for a 3 wire iacv. you will have check engine lights over the vtec system, which may or may not put your car into limp mode. its been a long time, but grounding the pressure switch might fix this.
edit: you'll have to deal with the y8's knock sensor as well.

eltexmexalex

Alright i just swapped the ECU for a vtec ECU and now it seems to work better, but it still has the same problem. So i would have to put the pressure switch and knock sensor on ground? Is there a diagram that explains this?

tony_2018

What pressure switch? OH right the oil pressure switch, yes ground the vtec oil pressure switch, and you still need to wire in the knock sensor.

eltexmexalex

Alright, i jumped the pressure switch to the knock sensor and like he said the car in limp mode so i have to fix the 3 iavc?

tony_2018

Who the **** said jump the oil pressure switch to the knock sensor?

eghatch9295

iTrader: (1)

you shouldnt need to anything with the iacv. both the auto y8 and y7 use a 3 wire. you need to wire in knock and deal with vtec.

eltexmexalex

When you say wire in knock, what exactly do you mean? Where do i wire it to?

tony_2018

You need to install a knock sensor that is hidden under the intake manifold and plug it in.

eltexmexalex

I installed the knock sensor and put the pressure switch to ground. It seems to run much better, but it feels like it's jumping when idle. I just need to put the iacv back to 3 wire.

tony_2018

Yeah you do..Good to hear its finally running somewhat properly.

eghatch9295

iTrader: (1)

its weird that it isnt 3 wire already. y8 auto and y7 both use 3 wire

tony_2018

Not everybody is forthcoming about there issues. People tend to want to waste peoples time to figure that **** out for them and leave out details.

eltexmexalex

Let me guess that's why it jumps when is idle? I read in some other forum to make it into a 2 wire but then i realized that was for standard only.

eghatch9295

iTrader: (1)

if you're running a 2 wire iacv then yes. a y8 AT ecu will always look for a 3 wire.

eltexmexalex

Ok i have the 3 iavc back to normal, knock sensor installed, and oil pressure to ground. So it ran better, i hit the freeway and went back to low speed and now i have the same problem (stops running). I am supposing if i put the vtec head, there won't be another problem? If not then i can just put the non vtec transmission.

eghatch9295

iTrader: (1)

post all current codes thrown.

eltexmexalex

P1259
Vtec system fault
P0700
Transmission control system
(MIL request)
P0715
Input/Turbine Speed sensor a circuit
Do you recommend the vtec head?