Fezous

Hello,

I am from the UK and I am posting on behalf of my friend to try and see if we can get some advice and some technical knowledge to get his 1997 Civic hatch back on the road, as he has missed out on a few shows this year such as raceism in Poland.



About the Hatchback:

• Originally was a UK D14Z4
• Now has B18C4
  

Issues:

• No Spark
• Fuel Pump not Priming
• Fuse 44 blowing every time the key is turned.

whats changed:

• engine loom from stock to rywire tucked b series.

Only thing that has been changed recently is the engine loom which is a second hand tucked rywire which was proven to work before we bought it.

before we removed the old engine loom we noticed we had to use a conversion harness in order to plug the ecu in but with the rywire loom we don’t. So I’m guessing the rywire loom is different to our interior loom?

im guessing the original loom is obd2a and the rywire is OBd1 which is what causing our issue or I could be wrong, I’m only thinking that as we had to use a conversion harness on the original stock loom to plug the P28 ecu in.

here are a few pictures of the everything.


First off all we need to fix, we accidentally removed all the pins from the rywire block which is just like the standard loom I’m guessing, so we need a diagram to put them back to the correct position on the grey connector blank.

What we have noticed is that the green 20/22 pin connector has way more pins than the rywire loom it connects to.

When there both connected there’s about 2 pins going to no where.

This is the rywire loom side of the cabin connector 20/22 pin.

This is everything connected up, even though I believe personally is that we have two different generation looms, everything still connects up personally just some pins looks like it goes to no where.. possibly obd2a going to an OBD1 engine/ecu loom?

if you need more pictures, close ups, etc just ask as I can provide them ASAP to get this issue fixed.

thank you.

muellersfan

Unplug the fuel injectors, ECU, and IACV.

Does this stop fuse 44 from blowing?

Fezous

Still blows, but only if you unplug the grey block from the grey connector it doesn’t.

we found out we could have an OBD1 engine loom to OBD2a/b mix up. Not 100%

mk378

The jumper block joins several live wires together to distribute power from fuse 44 and the main relay to different places like the 4 fuel injectors and some sensors. I think there are also ground wires in the block similarly joined. Obviously if you have it pinned wrong the power and grounds could be crossed and there is a short. This would be more apparent in the stock situation where the wires are color coded-- live wires yellow/black, grounds black. With all white wires you'll need to identify each wire and pin it into the connector properly.

Fezous

All the wires were in the correct position of the grounding block we accidently tried to remove one wire and they all came out so we need a diagram to put them back in.. I believe that loom is OBD1 and they do have Writing on the wires.

i believe with the obd1 rywire loom and the interior loom being obd2a/b there is a grounding issue you stated as when the block(grey adaptor) is removed from the loom nothing blows.

mk378

You should consult with Rywire for what the numbers mean.

Fezous

We have but they want us to ship our entire loom over, for them to re pin it and apparently they don’t have diagrams for us to do it.. 😓

don’t want to ship our entire loom to the US and then having to receive them back.. if we have diagrams we should be able to find an electrician who knows what he’s doing.

a part from the jumper block, the engine loom is obd1 and out one is either obd2a or obd2b interior loom yet everything still connects up just some wires go to no wherebso im guessing this is the issue. Everything needs the pinning

muellersfan

See first two wiring diagrams below.

In the original OBD2a wire harness, there are three relevant connectors in the fuse 44 circuit:
C101
C130 (brown junction connector)
C116 (gray junction connector)

As the Rywire connectors almost surely are pinned the same as they are in the original OBD2a wire harness, you likely removed the cap from C116, which prevented fuse 44 from blowing.

C116 distributes power from fuse 44 to the injectors and IACV. See second to last diagram below.

With simple electrical tests and logic, you should now be able to pinpoint the cause of the short.

My guess is that the C116 power bus bar is shorted to the separate C116 G101 ground bus bar.

Fezous

Thank you! We will try to pin back the original grey connector back, only question is..

are these diagrams just for obd2a/b because rywire is obd1 so we need the other diagrams to match each pin

muellersfan

By the way, there's no specific pin order required for power wires or ground wires in the C116 junction connector. All you need to do is make sure all power wires run to one bus bar and all ground wires run to the other bus bar.

That's how all junction connectors work.

Fezous

Thank you! I could be mistaken but when we tested it before we accident pulled the pins out. One side was all ground with ones positive, and all the positives other side had one ground.. which is why we thought when we removed the block it didn’t blow the fuse

muellersfan

Maybe you accidentally pinned the power wire from fuse 44 to the C116 ground bus bar? That would immediately blow fuse 44 when key is turned to ON(II).

Easy to figure out with a multimeter.

Fezous

Do you mean the two wites the bolt onto the fuse box?

muellersfan

No. The ground bus bar located inside C116.

Remove cap from C116 and post pics of the inner side of C116 cap and the internal side of the C116 connector.

Fezous

I will post that tomorrow when I’m down the garage with the car, I’m there around 5 GMT UK time.

I know what you mean now I think but that pins was already connected to the previous car which had no issue before we had it.. plugged in blowing fuses.. I will post pictures tomorrow

muellersfan

A simple test is to use a multimeter to check for continuity between one Yel/Blk power wire and one Blk ground wire that feeds into C116. Finding continuity would confirm a short between power and ground inside the C116 connector or alternatively in one of the Yel/Blk power wires running to the injectors or IACV.

Fezous

Thanks buddy you seem to know a lot about these wiring.. you got a WhatsApp or something you could pm me? Easier to send pictures etc

Fezous

Im back down the garage tomorrow, but when I was down there earlier I noticed that the C101 connector rwywire side has 1 less wire than the original loom.. so does the dizzy; dizzy has all 10 but loom has 9..

here’s the C101 from inside the car..


Rywire colours don’t match, different locations or completely different colours. Car is either OBD2a or B and I think the rywire is OBD1.

hard to actually know which colour wires go anywhere.

muellersfan

96-98 Civics are OBD2A.

See C101 pin out in post #8.

All stock 96-98 Civics would have a Brn/Blk wire at C101 pin 4. OBD2B 99-00 Civics would not have a wire at C101 pin 4.

Perhaps Rywire incorrectly gave you an OBD2B 99-00 Civic wire harness?

Fezous

Ive noticed the whole loom regardless of it being OBD1/OBD2 connects up.. OBD2 Dizzy with no adaptors connects to the engine loom yet the ECU is OBD1 no conversion harness.. its like everything been made to fit correctly just pins dont match up.
its hard to explain but it my head makes sense..

if you look at this picture the engine connectors to every sensor/dizzy is obd2 but the ecu is OBD1? maybe this is my issue?

muellersfan

It's possible that the aftermarket harness is designed for an OBD2B engine that will be run with an OBD1 ECU.

What I'm saying is that the C101 connector you posted is pinned for an OBD2B car, but you have an OBD2A car.

Post a picture of the distributor connector and the pin that is missing a wire there.

An OBD2B distributor connector does not need the blue tachometer wire found in the OBD2A distributor connector because the rpm signal comes from the ECU.

As an aside, the fuse 44 circuit short in your car may be a separate issue. Did you solve the latter problem?

Fezous

I haven't solved nothing yet, still struggling.. i've messaged rywire my issue too so awaiting a reply.
sorry to ask again but do you have a whatsapp i could chat to you on easier to send photos etc can pm me it, if not no worries.

So how do I wire the OBD2B part of the loom to my OBDA Civic loom whilst its connecting to an OBD1 ECU.. this is all confusing :/
nothing matches up colour wise.. all the diagrams you sent to me that side is correct but the rywire side isnt meaning the colours of the rywire are different

muellersfan

Unlike Rywire, continuity tests conducted with a multimeter would quickly and reliably answer all of your wiring questions.

Fezous

Fezous

Right so let me get this straight.

Car is OBD2A (non-VTEC)
Rywire is OBD2B (VTEC) but adapted to fit an OBD1 ECU without any harnesses.

so I just need an OBD2A 1.5 EK3 / 1.6 Ek4 Interior Loom?