[Bryan R]

alright well most of us can tell the difference between an obd1 harness/car from an obd2 harness/car BUT over the past few weeks i have been reading through tons of threads and seen where people have been asking how to tell the difference. well, im here to the rescue. i know this wont stop the constant thread making and question asking about how to tell the difference because some people are to lazy to search but at least we will have a link to a thread that we can post along with a little flame for the non searching newb. (i dont condone to flaming newbs )

i have took a few pics and wrote up a few comparisons between the 2 so here it is.

How To Tell OBD1 From OBD2 (For Newbs):

one good way is to know the year of the car. 92-95 is obd1 and 96 and up is obd2. another way is to pull your cup holder and there should be a service port there. if so, then you have an obd2 car but if not then its obd1 (courtesy of slipknot95758 ). now that that is out of the way, lets get to the more detailed stuff.

to really tell if its an obd1 or obd2 harness (say you bought the car with a swapped motor and you want to know what harness they put on. whatever reason you have, i have the answer) then look at the dizzy (distributor will be referred to as dizzy) plug ins. the obd1 is going to be oval with 8 wires going to it and the obd2 is square with only 4 wires going to it.

obd1 distributor:



obd2 distributor:







obd1 on the left and obd2 on the right:



another way is, if your car is obd1 (92-95) then if it was an obd2 harness on your car, it would have had a plug on the harness by the big blue plug that wasnt plugged up because the obd2 preludes have an extra plug by the blue plug and the obd1 doesnt. so if there is a plug on the old harness that was by the blue plug that wasnt plugged up then it is an obd2 harness.

said blue plug and the extra plug that is only on obd2 ludes:



now, look at the dizzy that has been on your car since you got it. look at the holes where the bolts go through to hold the dizzy on the head. if the 2 top holes are oval and the bottom is a perfect circle then its obd2 but if all the holes are oval then its obd1.

obd1 dizzy:



another good way to find out is to take the dizzy cap off and see if there is a sensor on the top, right under the rotor. its going to look like a black box.

obd1 dizzy:



and yet another way to tell is to take the dizzy off and spin the piece that goes in the head that attaches to the cam. if it clicks every time you spin it a little bit its obd1 but if it clicks after you spin it half way then its obd2. also the obd2 dizzy is lighter then the obd1 dizzy.

now on the 92-95 ludes the MAP sensor is on the firewall. on the 96 and up ludes the MAP sensor is on the throttle body.

obd2 lude MAP sensor:



REASON WHY PEOPLE CONVERT TO OBD1:

the reason why people convert to obd1 is because obd1 is far more simple then obd2. obd2 looks for alot more things such as sensors and stuff when obd1 only looks for what it NEEDS to make the engine run. obd2 just looks for alot of bullshit that doesnt really matter and if ONE thing is out of proportion then your engine runs like doo doo. if want to tune your car its gotta be obd1 because no body has cracked the code to be able to tune obd2 ecu's. alot of people like to tune p05's, p06's, p08's, p28's, p72's etc etc and they are all obd1. obd1 is the way to go if you want to tune. well, its really the ONLY way to go if you want to tune.


if you guys have any questions or want to add to this thread please feel free to do so. hope this helps.

[JeremyGTS]

lol. thanks man.. that does clear some things up for me.. rep for you. and im sure this will help alot of others aswell...

Ill get some of my pics posted up in my thread tonight when we get finished up. i cant remember if my dizzy connectors look like that or not but i believe they are... like i said ill get pics, thanks though for this thread.

[Bryan R]

Originally Posted by JeremyGTS

lol. thanks man.. that does clear some things up for me.. rep for you. and im sure this will help alot of others aswell...

Ill get some of my pics posted up in my thread tonight when we get finished up. i cant remember if my dizzy connectors look like that or not but i believe they are... like i said ill get pics, thanks though for this thread.

if you want you can post up some pics in here when you get some. more info the better.

[JeremyGTS]

Originally Posted by Bryan R

if you want you can post up some pics in here when you get some. more info the better.

yeah we will get those updated.. but you did verify my old harness at least was the H22a4 harness. i just think they cut it up and ran wires to their liking at least to get it fired up. just wait till i get the pics lmao.. like i said elec tape mess from the fusebox down.

[Bryan R]

Originally Posted by JeremyGTS

yeah we will get those updated.. but you did verify my old harness at least was the H22a4 harness. i just think they cut it up and ran wires to their liking at least to get it fired up. just wait till i get the pics lmao.. like i said elec tape mess from the fusebox down.

yea the injector plug ins on the h22a4 harness are blue. thats how i knew.

[RWPerlaki]

whys it look like your map sensor is turned backwards. I dont know if it matters but i know most honda map sensors sit the other way around.

[Bryan R]

idk its always been like that.

[RWPerlaki]

you might want to look into that mabey the map isnt getting a good reading because its instaled wrong.

[JeremyGTS]

map sensor looks fine to me. thats how mine is on the TB..

[ludeatik23]

the map sensor pic isnt right, I just bought an obd1 h22a and my map is on the manifold....

or maybe they shipped me the wrong motor?

[Bryan R]

Originally Posted by ludeatik23

the map sensor pic isnt right, I just bought an obd1 h22a and my map is on the manifold....

or maybe they shipped me the wrong motor?

the h22 must be obd2 or the jdm h22's are different.

[slipknot95758]

also obd2 pull your cup holde rout an dyoull find the obd2 service port there if its not your obd1

[hjdanzi]

Thanks for the info man.. really helpfull! reps for you

[Bryan R]

Originally Posted by slipknot95758

also obd2 pull your cup holder out and youll find the obd2 service port there if its not your obd1

added to the info. thanks man i forgot about that. i love my service port

[slipknot95758]

i love my obd1 prelude i can run hondata and not have to swap over, also i can still pass cali smog with it

[ludeicious!]

Wow I feel retarded now that I find this after searcing, than posting another thread lol.

[Bryan R]

Originally Posted by ludeicious!

Wow I feel retarded now that I find this after searcing, than posting another thread lol.

[ludeicious!]

I did but I was asking the wrong question, I was under the impression all 4th gens were obd1. I fail lol.

[execrashnburnexe]

take a look at this jdm h22a


it has its map sensor on the tb and the dizzy plug is 8 wire. this is a random pic of a 97 accord SiR.

after seeing this thread i did a little research into my own engine and apparently the @ssholes i bought my engine from sent me this instead of one out of a prelude , im not sure why but these only have 190 hp and have a lower redline. thats with a P0F ecu , im not sure the specs when they're hooked up to a p13

[Bryan R]

If it's from a 97 then it's obd2. Look at the oil pump and see if it has 2 sensors on it. If it does it's obd2.
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[execrashnburnexe]

could that be why i cant get it to run with the p13 on it? its running on my old p12 (w/o vtec) , but it stoped running after about an hour of use on the p13 , i thought it was because the the p13 just died , oh ,and it wouldnt shift into first when i was useing the p13 a/t , (its an auto)

[Bryan R]

I really have no idea. I've dealt with nothing but manuals but you should just use an obd1 wiring harness and obd1 distributor then an obd1 p13 and you will be set.
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[H22A_lude]

I believe their are 2 different JDM H22A's. One for the prelude and one for the accord. The Prelude one is more powerful, if I remember right.

Also, if the MAP sensor is on the throttle body then it's OBD2. All OBD1 MAP sensors are located else where.