Hello, H-T! This is gonna be a semi-large post, thanks for reading.

Some information:

Alright, so I swapped a B16A w/ S4C hydraulic tranny into my 1998 Civic DX Hatchback

Hatch was automatic and was converted at the same time as swap.

Hatch originally had a D16Y7 with automatic transmission in it.

Donor car: 1999 Civic EX Coupe, originally manual even before the B16A.

B16A swap uses a B16B ECU from the Type-R. I know it's not correct but it works without issue.

B16A swap works and runs and drives in the hatch.

Charcoal canister plug isn't there and one of the lines from it is disconnected.






The problems:

1. Car runs but has a surging idle - tach. doesn't work but engine revs up and down from probably about 1k to 2k. Similar to when IACV is clogged or unplugged

2. Tach. doesn't work

3. Speedometer doesn't work

4. Cooling fan won't come on

5. VTEC will not engage

6. Car turns on and drives but main relay does not click anymore

7. A few plugs that don't seem to have a home and I don't know why

8. OBD diagnostic port has power but cannot connect to the ECU.

A question - do I need the manual dashboard harness for my instrument cluster to work properly.... or for everything to work properly? My friend who helped me with this whole swap capped 3 wires together from the automatic dash harness if that makes any difference.

Attached are some pictures and I wrote on the pic some info.

If anyone has experienced all this on a swap and can weigh in, I'd appreciate it.

 

99 harness in your 98 is the issue. find a '98 ex harness, modify your old one (heavily) to work.

 

I'm not quite sure how that would help exactly? Literally the only difference here is the dash harness and floor harness because no power doors.

Or do you mean that it's incompatible with my 98 dash harness? If that's the case, would the 99 dash harness resolve these issues? Thanks.

 

Also, if someone who has diagrams or electrical knowledge, I would like to know what these plugs are for.

 

i mean obd2a and b engine harness do not interchange, your problem is the engine harness. im not sure how to be more clear than that. go buy a 96-98 civic ex m/t harness and a distributor conversion harness, plug and play problem solved.

 

The engine harness itself cannot be the problem. It is the same harness that worked in the 99 coupe, nothing was changed or modified. When we pulled it out, we didn't even undo it, just unplugged the ECU and pulled the end out through the firewall. It has to be missing something. I suspect the dashboards automatic harness is to blame but am not sure.

 

you're not getting it. your car (obd2a) is not compatible with a harness from an obd2b civic, aka 99-00.

 

Yeah, that's what I'm saying, too. I realize now that obd2a doesn't work with obd2b but is buying a 99-00 EX dash harness the only way? Can i trade my ecu and engine harness for an obd2a ecu and engine harness? Or does that not exist?

 

like i said, use a 96-98 civic ex engine harness.

 

Alright, which ECU should i use with this? USDM P30? Or should I convert to OBD1?

 

obd-1 ecu's give you the most flexibility for tuning and potential future mods. xenocron and phearable both offer ecu mail in services where they chip and add a basemap set up to your car and parts.