Hi All,

I have 99 Civic hatch running obd2b engine harness with obd2b cabin harness all connected to a p28 ecu. I came across a really good deal on a mil spec engine harness but its obd2a, I've read several threads and some ppl say yes it will work and some say get the harness made for the car.

My idea is to run 2 adapter harness in this order

Obd2a --> obd2b jumper harness --> obd1

I already own the obd2b to obd1 harness in theory it should work but any advice would be appreciated.

Thanks in advance !!

 

it doesn't work that way. the green plug off the obd2b harness plugs into your dash harness. where is it gonna go in a jumper harness?

 

 

Whats wrong with the harness your running now???

you want the other just because mil-spec???

 

My harness is acting up since it threw a code 8 and 9, I swap out the dizzy and, no check engine light but now my tach doesn't work. Some coolant was leak into the interior and got into the engine harness wiring and jumper harness. I cleaned and dried everything up but now my tach doesn't work and coolant is leaking from a bypass hose still.

That's the main reason why I wanted to swap engine harness. I found a thread about ppl doing a 99-00 dash conversion in a 96-98 and they didnt need to swap out their engine and dash harness but yet it still works ? That's what led me to think I could use the jumper harness to solve my problems.

I'm trying to find all of the data from datapro so I can perhaps repin everything.

 

no tach -- 99-00 Civics are wired to get the tach signal from the ECU not from the ICM inside the distributor.

 

What's wack is my tach works prior to me swapping out the dizzy. I feel like the car teases me, when I first turn it on, the tach jumps to 1000 rpm and then it falls and stay at zero !

I'm just tired of the decade old harness that's why I thought the obd2a harness being new was going to be easy to convert. Apparently I was wrong hahaha hopefully I can get the schematic of how things works and maybe I"ll be able to repin the wires needed.

 

Someone already rewired the tach wires to use the ICM signal in your car because an OBD1 P28 ECU can't send a tach signal. Check whether the blue wire is attached to the ICM and that it is not cut or broken.

 

Thanks for the quick response, I will try this in the am and cross my finger everything will be back to normal.

Well I'll need to get the 96-98 harness thing figure out but for now I need a running car !

 

Thanks to all that have reply, I do appreciate all of the help. Problems solved so this thread can be deleted. Thanks again fellow honda tech members!

 

Please post the solution for the benefit of others.

We don't delete solved tech threads as the information may help others.

 

So the solution was a dirty plug along with a bad dizzy. Once I reset the ecu and reinstall a new dizzy everything works perfectly fine.

Also got a brand new stage 4 harness from http://www.wire-worx.com Xavier takes pride in his work and help answer all of my questions before, during, and after the sales.

Sorry, I'm used to for sale threads so I ask for everything to be deleted lol

If anyone have questions feel free to pm and I'll contribute to the thread.