98vtec

Ok so i am converting my 1998 prelude to OBDI engine harness and OBDI distributor. I am using a chipped p28 over the stock ecu as well.
I am confused on what to do so i am creating a thread. I have looked through the faq and found some information but still a little confused.

As we all know, the OBDII h22's have the CKP sensor and TDC sensor on the oil pump and the CYP and pickup in the distributor. Now in the OBDI h22's, all the cam sensors are in the distributor.

I'm really just not sure what really needs to be done as electricity is not where i am known to be knowledgeable. Any help here would be greatly appreciated as i am trying to get my motor running and broken in.

also, when i connect the OBDI engine harness to the OBDII sub harness, one connector on each side is unable to be connected because the plugs are different. Its 8pin on the subharness side and 4pin on the engine harness side. I wish i had a camera to make this easier, but i'll have to wait til my roommate gets home.

98vtec

- Ok, this is what i have so far:

OBDI ecu connector B

B11 = CYP P - input - Orange
B12 = CYP M - ground - white
B13 = TDC P - ground - input - orange/blue
B14 = TDC M - ground - signal - white/blue
B15 = CKP P - ground - input - blue/yellow
B16 = CKP M - ground - blue/yellow

OBDII ecu connector C

C2 = CKP P - CKP sensor - blue
C3 = TDC P - TDC sensor - green
C4 = CYP P - CYP sensor - yellow
C12 = CKP M - CKP ground - white (silver dots)
C13 = TDC M - ground - red (silver dots)
C14 = CYP M - ground - black (silver dots)

mgags7

Blake, you'll need one of the 8pin plugs off an obd1 engine harness, and you'll need to de-pin the one on yours, and reinsert the pins into the 8pin plug when you figure out the right order.

I found that on my car, the obd1 engine harness was not going to work at all, so I kept the obd2 harness and did the necessary wiring.

Here's how I did it:
Take any 4-pin square plug, male side IIRC, and get 4 wires for it, about 3 feet long just to be safe. Solder the pins onto each end of the 4 wires, and pin them in according to the wiring you have above.

Then run them all the way up to the dist plug, and pin them in, along with the ICM wire, and the two wires for the CYP.

98vtec

gonna get to work more on this more tomorrow. But right now, its time for keg wars.

hopefully someone will come up with something clever.

mgags7

keg wars?!?!?!?

I want a piece....we had a pony keg race a while back...that **** was fun.

later holmes

kulrevon

Well The Other day I had to put a OBDI external distributer on a 1996 OBDII which has an external Dizzy.

98vtec I know you are smart and probably know this information that I am about to tell. But just letting you know my experience.

So This is what I did. I extended The sensor wires That go to the TDC and CKP. On the obdII they are done on the timing belt side.

so for the CKP and TDC wires that needed to be extended and connected

--------OBD II----OBDI dizzy
CKP P Blue ------Blue/Green
CKP M White------ Blue/Yellow

TDC P Green------Org/Blue
TDC M red --------Wht/Blue

The CYP is in the dizzy for both but the colors are different

-------OBD II---OBDI dizzy
CYP P Yel ------Org
CYP M Blk -----White

The other wires are

Power Blck/Yel
IGN input icm Yel/Green


Once I connected all of these car started immediatly.


98vtec is the 98 dizzy internal or external coil?

Modified by kulrevon at 2:51 PM 2/16/2008


Modified by kulrevon at 5:04 PM 2/18/2008

98vtec

........

98vtec

Kul,
Were you using an OBDI engine harness or OBDII?

what do you mean by "OBDII OBDI" Dizzy? Sorry, had a lot to drink last night and im not fully recovered yet

edit:
My distributor is external coil off a USDM H22a1

98vtec

after a little bit of cross referencing pinout schematics, the guys writeup has some of the pinouts messed up (or i am just reading it wrong) So i guess its back to the drawing board of having to do this myself.

I found another OBDII harness too. 35 dollars in CA.

kulrevon

I tried to fix my post. The obdII is the colors on the 96 harness. and the OBDI dizzy is the colors on the Distributer.

98vtec

is that wiring for external coil?

and im assuming that he was using the OBDII engine harness?

98vtec

.......

98vtec

i have two plans for doing this:

removing the pins from the OBDI engine harness connector and moving them to the corresponding pins on the OBDII side.

my other option is to bypass the conversion harness and use OBDI ecu connectors in place of the OBDI connectors. Just connect the dots basically.

for instance, take connector A on the OBDII harness and remove pin8. transfer that pin over to the OBDI A connector at pin4, and so on with the rest of the pins.

I'm honestly kinda leaning towards using the OBDI connectors and getting rid of the conversion harness.

kulrevon

Sorry 98. usually I am very good at electrical.

But I am not even sure I understand what you are doing or what you are trying to accomplish.

So The questions I have are.
1.Why are you switching to obd1?
1A. why do you want to run an obd1 dizzy and internal sensors?
2.Are you using a conversion harness from the ecu to the cars computer connectors? like this http://www.boomslang.us/obd2to1.htm.
3.Are you using the 1998 car harness?
4.Why are you changing the engine harness to obd1?

If you are going to run a obd1 engine harness, you need an injector resistor, and to change the injectors, or fix the harness.

I will help as much as I can as long as I understand what you are doing.

98vtec

.....

98vtec

anyone happen to know what A8 is on the OBDI system? its a green/black wire and on technet it shows this as an empty location. I guess i could find it on the harness if need be...lol

Sam_J

Good job with the plan of doin the conversion so far

Blake, dont forget to mock assemble the harness and make sure everything plugs up fine, since its obd1, you'll have to change the injector clips and bypass the main relay with a jumper plug.. Also check to see if your iacv is 2 or 3 wire..

98vtec

Thanks for the help Sam

I just finished with the mockup on paper for the ECU connectors and i have found all the necessary pins for direct hookup with the OBDI connectors except for two pins:

D7 = diagnostic data link
D20 = voltage for TPS

Now on the OBDII harness, there is something called K-line: OBDII scan tool signal. I dont have the slightest clue if this would correlate to the diagnostic data link on OBDI.
On the OBDII harness, there is a voltage for MAP at D4 but there is nothing for the TPS, however, the OBDI pin out calls for a separate pin for TPS voltage.

I'm beginning to feel really confident in doing this as it all unfolds. Its very time consuming but the level of difficulty really isnt that bad.

The worst part is going to be repinning where the subharness and engine harness meet, but i will have pinout diagrams for that as well.

kulrevon

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98vtec &raquo;</TD></TR><TR><TD CLASS="quote">
About the injectors:
I am running RDX injectors, which are saturated. Is there anything i need to do to the OBDI harness in order to run them properly?</TD></TR></TABLE>

you are going to need to cut out the wiring for the injector resister. Which is the green plug over by the driver side firewall.

I am pretty sure you just need to take all five wires and connect them together. 4 go to the injectors and one goes to the main relay.

98vtec

yep, sam suggested that i make a jumper plug.

98vtec

ok i found TPS voltage. Its labeled a little differently than the map voltage.

MAP voltage is labeled VCC1 at D4
VCC2 is located at D10. Taking a look at the TPS sensor, its a 3 pin connector. 1 is ground, 2 is signal, 3 is VCC2 aka TPS voltage.

w00t.

98vtec

This is the OBDIIA to OBDI pinount diagram for the OBDII subharness to be wired directly to the OBDI ecu connectors.

OBD2A - OBD1
A1 - A2
A2 - A5
A3 - A3
A4 - A1
A5 - X
A6 - A6
A7 - A11
A8 - A4
A9 - A26
A10 - A23
A11 - B1
A12 - A9
A13 - X
A14 - X
A15 - A20
A16 - A7
A17 - A15
A18 - A13
A19 - A16
A20 - A21, A22
A21 - X
A22 - B2
A23 - A24
A24 - A25
A25 - A19
A26 - A17
A27 - A12
A28 - X
A29 - X


OBD2A - OBDI
C1 - X
C2 - B15
C3 - B13
C4 - B11
C5 - B5
C6 - B9
C7 - D4
C8 - X
C9 - X
C10 - D1
C11 - X
C12 - B16
C13 - B14
C14 - B12
C15 - D6
C16 - B8
C17 - D9
C18 - B10
C19 - X
C20 - X
C21 - X
C22 - X


OBD2A - OBD1
D1 - D11
D2 - D13
D3 - D17
D4 - D19
D5 - D2
D6 - D3
D7 - D14
D8 - D15
D9 - D12
D10 - D20
D11 - D22
D12 - D21
D13 - X
D14 - X
D15 - X
D16 - D10

I'm going to double check these pinouts again tomorrow.

jdmlude5

not sure if this helps u but my lude is a 96 i put an obd2 to obd1 adapter and i used a obd1 dizzy. i just got obd1 dizzy plugs and ran the crank sensor wires to the dizzy. but i am useing my obd2 harness.

98vtec

thats what is cool about doing it this way. I dont have to do any kind of wiring. just repinning. dont even have to mess with the distributor.

jdmlude5

i agree with u there. i hate messing with wireing. and it was a pain in the butt. i did my swap in 2001. and it was my first. i should have just used my obd2 oil pump. but goodluck.