mike03,95civic

I have a '95 civic with a B18b motor with P75 ECU and i'm having emissions issues.
I bought the car with a B20 and I know the guy had a B18 in it before. I swaped the B20 out for a B18b at a shop. They used the same harness.
So I was wondering if the wiring harness would be different between the different motors and if so how could you tell? I was also wonder how much it would effect emissions? If this could be a problem how much would a new wiring harness probably cost and how hard would it be to hook up?

Thanks for any info on this. And just in case you are wondering I've checked all the main problems that would cause my high numbers.

mike03,95civic

One other thing the P75 ECU is for OBDI right?


Modified by mike03,95civic at 5:41 PM 1/22/2008

z6hatchboy

P75 ecu is the obd2 integra ls/gs ecu

mike03,95civic

really... does anybody know if that would affect my having high emissions. I have an OBDII cat. and only one O2 sensor. I'm surprised the guys at the BAR missed that.
(sorry in my post before i put OBDII But I ment OBDI)

z6hatchboy

Isnt the b18b the integra ls/gs motor? Since its obd2 though, It should have 2 o2 sensor's i think. That could be part of your emissions problem.
*edit*, obd1 only uses 1 o2 sensor. So are you obd1 running a P75???

mike03,95civic

Yes it is an ls motor. I know that if it's OBDII it should have 2 o2 sensors. I was told the ECU was for a OBDI car.

z6hatchboy

It can be as long as you have the conversion harness and a obd1 ecu, is there another small black harness between the ecu and car's harness? But the P75 is deff a obd2 ecu for sure.

mike03,95civic

I'll have to look later when its light out...so i'm not sure. It's good to know its for a OBDII though thanks for that info. The only difference between OBDI and OBDII is the cat and o2 sensor's?

z6hatchboy

I dont know if those are the only diff. I know with d-series another obd diff. is the use of a knock sensor, but im thinking all the b-series have those.

mike03,95civic

Do you know if a B20 and B18 harness is the same?

mike03,95civic

Also how is it possible if i don't have wire harness conversion to run the p75 ECU?

z6hatchboy

I've read that b20 swap is exactly the same as any b-series swap, if that helps. I think they are as long as the obs's of the 2 motors correspond with each other.

mike03,95civic

Alright thanks that helps. How about the p75 ECU running off one o2 sensor? Wouldn't this cause my CEL light to come on.

z6hatchboy

You wont be able to run the P75 without some kind of conversion harness. Most people dont go from obd1 to obd2 however. If it is running a P75 (stock) though, it will though a code for the missing o2 sensor, whether primary or secondary.

mike03,95civic

Then it must have a conversion harness because the ECU is stock and no code for o2 sensor

mike03,95civic

Ok so i checked and my ECU is good and it everything is OBD1. I took my car to a CAP station and the diagnostic. They said it is my wiring harness. They say that there are wires have shorted out somewhere. The wiring is bad they're all spliced together and taped with electrical tape and it would take to much work to find out what particular wires are bad so i just want to get a new harness.

I need to know how hard is it to put a new wiring harness on? Is everything just unplug and plug back in?

92bubble

then why do i have a obd1 p75 in my car?

93egSLEEPER

what car/engine do you have?

mike03,95civic

What i was saying is i found out my set up is OBD1. In another post i put up asking what OBD is a p75 i found out that there is OBD1 and OBD2 for the p75.

Does anybody know how hard it is to switch a harness?

Dead CIVIC

iTrader: (1)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by z6hatchboy &raquo;</TD></TR><TR><TD CLASS="quote">P75 ecu is the obd2 integra ls/gs ecu </TD></TR></TABLE>
i havea p75 and it's obd 1

Dead CIVIC

iTrader: (1)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mike03,95civic &raquo;</TD></TR><TR><TD CLASS="quote">What i was saying is i found out my set up is OBD1. In another post i put up asking what OBD is a p75 i found out that there is OBD1 and OBD2 for the p75.

Does anybody know how hard it is to switch a harness?</TD></TR></TABLE>
well you dont really switch harness completely you buy jumpers.

mike03,95civic

When you switch the harness is there any thing that can be hooked up wrong or are all the conectors different?

mike03,95civic

I would have to do this with the motor in the car...Would all the conections be pretty easy to get to?