Lets see i did an obd0 to obd1 conversion myself. I repinned the ecu plugs and injector plugs to obd1. I made a jumper harness for my distributor. Turned the key dash lights up and i dont hear the fuel pump prime. I assumed maybe i just didnt hear it and tried to crank it, it turnes over fine but wouldnt crank. I pulled spark plug wires and used a known good spark plug to check for spark. And no spark at all. The distributor has power and the harness is correctly made for the jumper (me and my bro both triple checked it after it wouldnt crank). I did some research on here for about 2 hours and came across a few things to try:

Main relay - I couldnt hear it click or feel it click when i held it and cranked the car, so i took my working one out of my running car and plugged it in and still couldnt feel it.

ECU wiring - I used the diagram from https://honda-tech.com/forums/showth...d0+obd1+wiring read through the comments and a few people had issues with A21 and A22 needing there wires swapped (both are ICM) and after swapping didnt effect anything. Checked a random handful of wires (not everyone just yet) for there colors and to make sure they were in the right spot and there where)

Thinking back i should have bought the jumper harness and saved me the headache but what is done is done (dont flame me for attempting to DYI it). Any thing else that could be wrong? Or anything else i could try? thanks alot

 

Forgot to add that the check engine light is on but not sure how to check them since it converted to obd1. 1989 civic hatchback SI with b18a1 1993 Integra Gs pr4 ECU. Thanks again

 

Another update:
Spend most of the afternoon trying to figure out the issue. The main relay harness checks out ok, the ground when i Check for continuity i dont get 0 but i get a 2.3 which i believe is ok. I can jump the fuel pump there and it works as it should. I open up the original main relay that came with the car, check the solder points and redid a few that didnt look too great. Still no spark and the fuel pump still wouldnt prime. Did i pulled up the ecu wiring diagram for the obd0 and the pin diagram for my pr4 and double checked my conversion, checked good. Pulled diagrams for my distributor jumper harness, it checked out good aswell. I remembered that sometimes bad engine grounds could make things wonky so i undid them all (valve cover, negative battery terminal/where it grounds) then i read i should have one on the thermostat housing, which i didnt have so i made a body ground there. I gave it 1 more crank before calling it a night and still no spark or fuel prime. Im at a lost. The lady who i bought the car off of to do my b18a1 obd1 swap in, had parked it due to it wouldnt run. A mechanic shop she took it to about 6 months back said it needed a new distributor due to no spark. Im starting to think it was something much more and here i am trying to find it : / . Any ideas on what to try next? Any ideas/advice are much appreciated.

 

I ran the same problem for 8 months couldn't figure it out, finally I started guessing.. found a couple pins on the obd1 ecu that are grounds and ran a jumper wire I'll go take a photo for you if I can get enough light.

that worked as a temporary solution, then my fuel pump quit working, so now that's on a toggle, works fine and probably a good anti theft device also.

 

image free hosting

its the green wire in the photo.

I must say, this is not the correct fix, but should get you going for now.

I would suggest chasing the wires that connect to these with either a continuity tester to ground or a ohmmeter to ground to ensure all ground wires in fact have a ground connection.

good luck and let me know if you need any other help

 

I have the same engine in an 89 crx si was running a p75 now a p28 with a modified pr4 burn I really just got rid of the speed limiter and added fuel since I have a str8 through exhaust and cai

 

cool i spent today working on it and every ground tested good. So i desided to check the ignition switch...on I it passed, on II they failed (which i believe tells the ecu the key is turned), and on II it passed. Still no fuel prime or spark so i believe this maybe the issue. I read i can steal the switch off my DA and either plug it right in or splice the wires to the way the 89 plug is (all wire colors are same, testing is the same color wires, but they are located on different pins) so imma double check and see what i can do. thanks Im no a tight budget for the next month (immagration to pay for) then ill be back to my normal budget so if i can rig my DA switch to work temp. then i can order a new one in about 3-4 weeks


"edit" forgot to add i desided to check the ignition cause i got a bright idea and remember to see if the ECu was turning on and it wasnt but the fuse had power going to it, and i believe the ignition tells the ecu when the key is turned so it "boots up". But i could be mistaken (hopefully not haha ignition switch is an easy repair lol)

 

if it tested bad, that's most likely the problem. It's kinda hard to believe that the bad switch worked with the old ecu and not the new one, but it's possible.

also, you're distributor is obd1/2 correct? the obd0 will not work, the ring has less teeth than the newer style so the computer will just be dumb.

 

Yup it's obd1 and it didn't on the other when i bought it the mechanic had looked at it a few before and said it was a bad distributor because it had no spark so my guess is it had the same issue as now being no spark and fuel pump didn't prime

 

what pin numbers is that jumper in?

 

When you turn the key from off to ON(II), does the CEL turn on and stay on or does it turn off after 2 seconds?

Do you have an OBD1 main relay and connector? If so, unplug the main relay and turn the key to ON(II). Use a jumper wire to short term 1 to terminal 7 in the plug. Does the fuel pump run? Do the same jump test for terminals 1 and 5.

 

yea ive tried an obd1 main relay and the obd0 one ( i thought they were the same) and that didnt do anything just 1 click and no fuel pump prime. I have jumped the main relay harness (did a main relay harness test) and everything tests fine. I did just pull the pin locations to double check my ecu grounding (pins: A1,2,3,5,26,23,24 B02) didnt do the injector part since i wasnt getting spark (going to do it now) the ecu grounds which are A23,24,26 and B02 only A26 was grounded, i tried to locate where those grounds run to just now but didnt see anything so once i test the last 4 pins (injector grounds) ill see about doing a temp chassey ground until i can trace the end of the wire.

CEL stays on will double check but im 99% sure it stayed on.

Re read my 3rd post and itll tell u what i have done for the most part it is up today so people know what could be left

 

Yep, this^ is clearly a major problem.

They all eventually ground at G101 on the thermostat housing.

Good idea.

Also install the two wires for the service connector so you can pull CEL codes.

 

I keep hearing this G101 Thermostat housing but on the 1989 si harness i can not find anything on the harness that could or would be able to bolt on it for a ground..
as far as the service connector, i would been to pin in 2 wires to touch to make the codes flash on dash or they are already there and just need a jumper?

 

It's called G151 on the Si harness:

 

yup just found was soo excited ive looked for 2 days and couldnt find it (2 days= like 3 hours max lol) going to hook it up and see if that cures my car ill post back in 10mins or so and let u know

 

 

The 89 Si harness would not have a service connector, so you'll need to add the two wires, if you haven't already.

One wire pins to D4 and the other wire shares the common sensor ground that pins to D22. Touching the two wires together will make the CEL blink codes, if the ECU has any stored.

 

omg it fired it and no cel ))) im soo happy g2g adjust valve and test drive tyvm

 

Sweet