94eg!

iTrader: (2)

Hello all,

I'm looking for info on the JDM Type-R's EVAP system. I know these cars (at least the 96-spec) run an OBD1 ECU program as well as an OBD1 style EVAP system. The problem is I cannot find any info on the EVAP purge control solenoid for the JDM Type-R. On US OBD1 cars (B16A and B18C) it actually screws onto the back of the intake manifold. There is nowhere to attach on the JDM type-r manifold sooooo.......

My question: Where the heck is the EVAP Purge Control Solenoid on the JDM Type R, and how are the vacuum lines routed? It should be the little device hooked up to this hose coming off the corner of the manifold:



USDM OBD1 Purge Solenoid setup for comparison:


The reason I ask is because I currently have my OBD1 EVAP solenoid zip-tied directly to the main harness underneath the manifold, and I would to find a "proper" place to permanently mount it. I haven't been able find this dumb thing in any photos of JDM type-r motors or JDM type-r firewalls. So I am kinda stumped where Honda put the thing (or if that hose simply runs straight to purge control diaphragm on the charcoal canister).

PS: The USDM Type-R's OBD2 EVAP system is different so the US manuals and parts diagrams are no help.

94eg!

iTrader: (2)

Well for the future generations, here is what I found....

It looks like the JDM R doesn't have an EVAP purge control solenoid. That means the manifold is connected directly to the purge valve on the Charcoal canister. Essentially the valve is opened whenever the engine is on while the US version requires the engine be at operating temp before opening (hence the solenoid).

Here is the JDM Throttle Body diagram.

subtlecuddle

iTrader: (6)

Just came in to say thank you for posting this, I have been looking to an answer to this question for quite a while.

Tom B

Where did you source this?

I cannot find a JDM Manual anywhere.

tony_2018

You can go to any jdm honda parts site to find that diagram.

tony_2018

you can add the usdm one and run it to the evap canister.

94eg!

iTrader: (2)

Yes this is how I used to have it hooked up. The problem I was having is that on really hot vegas summer days, with the AC blasting, the EVAP system starts to overflow fumes out the fresh-air tube underneath the car. I wanted to confirm how the JDM ITR EVAP system was plumbed to see if it might help reduce these occasions.

It does not help.

The standard Pre-OBD2 evap systems simply get overwhelmed and eventually vent fumes to atmosphere. This is the reason the US regulations required a fully sealed system since 1996 (OBD2).

Tegra206

iTrader: (2)

So since you switched over to the usdm system no exhaust fumes being smelled?

94eg!

iTrader: (2)

No.

I origianlly had it hooked up the USA OBD1 way....it smelled like gas.
I switched to the JDM 96-spec Type R way.... it still smelled like gas.

The system is functioning correctly, I've tried multiple charcoal canisters with the same result. I've also verified all EVAP components are working correctly. Keep in mind this only happens when it's very hot out, and I'm running the AC. It has also happened on my Bone-stock CRX Si under the same conditions.

Tom B

Can you link some that you have used?

94eg!

iTrader: (2)

jp-carparts.com

wxman94ej1

Hey very glad I stumbled on this thread. I have a 1994 Civic EX coupe (USDM) with a JDM B16A engine in it (OBD1). I still have the USDM charcoal canister, but there is no purge valve on my JDM B16A intake manifold, similar to what you show.

My understanding is I need a charcoal canister that's different than the USDM one, like the one shown here:




Image source is here:
92-95 Civic Eg6 Purge / Charcoal Canister

However, I cannot source a charcoal canister like that anywhere. Seems like the "PURGE" hose would connect to my throttle body (always purging when engine is on, like you describe) and the "TANK" hose goes to my fuel vent line on the firewall. Problem with the USDM canister is it requires the purge valve I think to evacuate the accumulated fumes which is not happening. The JDM one (shown above) just allows fumes to accumulate when the engine is off and then the throttle body connection evacuates the fumes when the engine is on.

Did you ever have a canister like the one above? Does anyone know where I can source one? I called JSH and they don't have any right now.

94eg!

iTrader: (2)

So does your JDM intake manifold have the small nipple on the back side (closest to the brake booster)?

I put a JDM 92-95 B16A in my friends 92 CX. I remember hooking up his stock USDM EVAP system (3 hose). I believe we just zip tied the purge solenoid underneath the intake manifold because there was no mount for it on the JDM manifold.

wxman94ej1

My intake manifold does NOT have a small nipple on the back closest to the brake booster (it's a little different than the type-R one shown above).

There is also no mount for the purge solenoid. I think even if I hooked up the purge solenoid and zip-tied it there it wouldn't do anything since I think it's ECU operated, correct? I'm running a JDM OBD1 P30 ECU which I don't think knows anything about a purge solenoid or how to use it. I could be wrong though.

I also came across your other threads you've commented on about this, which have been very helpful, BTW:

https://honda-tech.com/honda-civic-d.../#post50169059

https://honda-tech.com/honda-civic-d.../#post49755715

Thanks for sharing all your experience with this!

94eg!

iTrader: (2)

Well then yes the JDM EG canister would make for the cleanest install (hooked up exactly as you mentioned). Have you tried contacting HMotorsOnline.com about one?

To make your US canister function again, all you need to do is the following....
- Remove the purge solenoid
- Take the hose that used to connect the canister to the solenoid and tee it into some other small vacuum hose

This will open the canister valve whenever the engine is running (just like the JDM type-r EVAP system), and allow fumes to be drawn into the throttle body.

Thanks for the kind words. Always happy to help.