Honda Prelude Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
241 Posts
Discussion Starter #1 (Edited)
I recently swapped in a complete Jdm H22 into my type SH BB6. I kept the USDM Ecu and USDM Wiring Harness and kept the car OBD2 for the sake of ease. The only real issue I’ve had since completing the swap is the code, P0441. Basically it means that the evap purge switch isn’t sensing enough of a vacuum when it tells the evap purge solenoid to open and empty the charcoal canister… I’ve been fighting with it for a couple of weeks now and I’ve completed the whole section in the factory service manual on troubleshooting that code, IIRC it starts at page 11-188.



Here is what the FSM lists as causes for this code:
EVAP Purge Control Solenoid Valve
EVAP Purge Control Solenoid Valve Circuit
EVAP Purge Flow Switch
EVAP Purge Flow Switch Circuit
Throttle Body (purge port)
Tubing
ECM



Anyways, here what I have done so far:
I’ve tested the solenoid and do know that it works, it opens and closes and holds a strong vacuum and it doesn’t appear to stick. It also opens when the switch tells it to.


I’ve also tested the voltage of the evap purge switch according to the numbers in the manual it is right on point as well as the voltage at the pin-out of the ECM.


I replaced all my Intake Manifold vacuum lines before I swapped the new motor in, I went over everything about 50 times now with a flashlight, carb cleaner and a mirror and I am certain there are no vacuum leaks, especially any having to do with the evap purge system.


So I thought about it some more and realized how much smaller and slightly different the nipple is that goes on to the JDM throttle body as compared to the one on the USDM throttle body (the nipple that pulls vacuum for the evap purge system). I took the vacuum line off going to the nipple while the car was running and noticed that there was no vacuum what so ever that I could feel coming from the nipple at idle. It is only when I open the throttle up to a 2500+RPM that I can feel a bit of a vacuum. This is because the hole that runs to the nipple, the hole inside the throttle body section is before the throttle plate.


I believe that the JDM Prelude doesn't even have an EVAP purge solenoid from what I've read? So it seems quite possible that the JDM throttle body is giving me enough vacuum for my USDM EVAP system to work with.



So I checked with my friend that has a BB6 with a H22A4, and on his throttle body nipple, even at idle you can feel a decent vacuum, and it’s even more apparent when the throttle is opened up. So I came to realize that the vacuum was insufficient for what the evap system required, so I re-routed the vacuum line for the evap purge solenoid to another unused vacuum port on the driver’s side of the intake manifold.


This made my P0441 code go away, YES! But the problem is now that my idle is surging whenever the evap solenoid is open, like it would when you have a vacuum leak. Looking at it now, maybe this is the reason why on the stock set up the hole in the throttle body for vacuum is before the slide plate, otherwise when the solenoid opens its going to be basically like you have a vacuum leak at your intake manifold.
I’m not quite sure what to do at this point, I was thinking about seeing if I could remove the smaller throttle body nipple and drill out a slightly larger hole to hopefully draw a larger vacuum, but I’d rather not drill into my throttle body xD


I’m also open to disabling the evap system or somehow tricking it if that is possible, I don’t really care as long as it doesn’t throw a code and I can get rid of my annoying bouncing idle. Anyone got any suggestions? For right now out of curiosity I have just connected the vacuum line directly to the purge valve switch that detects if there is a vacuum, I'm thinking this will still throw a code since it will see a strong vacuum even when the solenoid is being told to open, it just depends on how exactly the switch works., gonna go for a drive and see what happens.

EDIT: Well I drove another 250+ miles today and got no codes so far since I hooked the line directly to the switch... So hopefully its gonna stay away. Maybe this will help someone.
 

·
Registered
Joined
·
241 Posts
Discussion Starter #2
Sad bump, the code is back lol. Back to the garage to stare at this some more.
 

·
Registered
Joined
·
241 Posts
Discussion Starter #3
Hopefully last bump--- Long story short I checked the code just to make sure it was the same and well it ended up being the lovely knock sensor code Instead! So I got to do the knock sensor replacement for the second time in my history of owning a prelude... and what a fun time it is on the SH. :D

Anyways it seems like routing my evap solenoid vacuum line to another nipple on the intake manifold with higher vacuum actually solved my problem, apparently the location on the JDM Mani that is in the intended location for the purge port on the USDM version does not pull enough vacuum. I'm not sure what that spot is used for on the JDM version but it must not require a high vacuum.
 

·
Registered
Joined
·
241 Posts
Discussion Starter #5
Thanks for updating! I have this same issue with my car and it drives me nuts, I'll have to try your fix.
Here are some pictures to show where I routed another vacuum line to the empty port on the driver side, ran it behind the IM and just adapted it to the oem evap solenoid hose with an irrigation line adapter.
http://imgur.com/a/mG4cn

But yes it has been slowly driving me insane. A little bit after fixing my poor vacuum issue my evap solenoid shit the bed, I replaced it and it was good for a couple weeks and now my evap canister appears to be leaking out the bottom port that leads to the drain line.:wzbigcry:

At least I assume the evap canister is supposed to hold a damn vacuum right?!?!?!? Because now the leak on the canister is so bad it barely can hold .5inHG vacuum, when the vacuum purge line going into it is strong at 19inHG. This is causing there not to be enough vacuum to energize the evap switch (which is basically a vacuum activated switch) so this is in turn causing a code to be thrown. Basically the big port on the bottom appears to be leaking... I would assume its supposed to have a one way diaphragm or something.

Please have a look at these pics of my evap canister so I can figure out if I need to order a new one.

http://imgur.com/a/7chMQ

If I plug one of the top ports and plug the big one on the bottom and make a vacuum on the empty port it will hold a vacuum. But as soon as I unplug the large port on the bottom it will loose vacuum fairly quickly. I'm not sure how this thing works so I don't know if it is operating correctly.
 

·
Registered
Joined
·
241 Posts
Discussion Starter #6
Bumpity, well I ordered and received a new canister, thankfully I found one for super cheap on eBay, and even brand new it behaves the same as my old one so apparently they are supposed to lose some vacuum to the "fresh air port" on the bottom. But I did find that the evap purge switch only requires very little vacuum to operate. (something less than 1inHG, it barely registers on the vacuum gauge.)

But when I activate the switch with vacuum, it only intermittently gives the proper voltage (according to the manual it should be at least above 1 volt). Mine sometimes lingers around .03 to .06 then will jump up to were its supposed to be for brief periods and fall back down. All while under a constant static vacuum.

So according to the Honda manual troubleshooting flow chart the next thing to do is to replace the damned evap purge switch switch.
 

·
Registered
Joined
·
241 Posts
Discussion Starter #7 (Edited)
Another update.
I’m sort of surprised not being able to find more results of this happening after a swap, really I was only able to find one other similar instance on Google from a guy doing a b series swap in his civic.

Anyways, I have come to the conclusion that something in intake manifold of the jdm motors behaves differently (relating to the vacuum port on the throttle body) and gives a completely different vacuum at a different time to the evap purge port. I have swapped a USDM throttle body onto the jdm manifold and it still gives different readings then those on my friends h22a4.

I have also gone through and replaced all the components of the evap system that are affected by this code: the canister the purge switch, the purge solenoid and the vacuum lines. I also tried rerouting to different vacuum port directly on the intake manifold itself. First I tapped into an extra nipple on the driver side of the manifold which gave a strong 18-19inmg vacuum all the time but the code still came up.

I then tried tapping into the much larger brake booster line with a T-fitting, while it seemed like it allowed for a higher amount of air to flow through, and it still held the same vacuum and ultimately the code came back up. I then attached a USDM throttle body back on the intake and connected the line back to its original spot to see what it would do and the code came back up.

With the usdm throttle body attached, I then measured the vacuum at the port at idle on my car it was zero, which makes sense since it is forward of the throttle butterfly. Then I tried opening the throttle, it only gives a brief period of vacuum if you blip the throttle open quickly. If you slowly raise the throttle it will have no vacuum all the way up to red line.

Now on my friends stock USDM h22a4, I measured how his vacuum worked. He also has no vacuum at idle on his evap port but as soon as you open the throttle even a little it will raise and hold steady around 18inmg. This makes me believe that somehow something on the intake manifold of the jdm h22a is causing the vacuum at the evap port to behave differently.
It makes sense since the evap system isn’t a jdm feature as far as I know but I really don’t know where to go from here, this code is driving me nuts. Maybe someone out there can chime in that has done the swap if they have experienced anything similar????
I really appreciate any responses.
 

·
'01 Milano Red - BB615
Joined
·
982 Posts
I just ripped all that crap out when I did my H23A VTEC swap. So much cleaner with no issues.
 

·
Administrator
Joined
·
6,799 Posts
If the intake manifolds are different, swap them. You're already aware of the throttle body differences.

Probably only need to swap the upper portion of the manifold if anything.
 

·
Registered
Joined
·
241 Posts
Discussion Starter #10 (Edited)
I just ripped all that crap out when I did my H23A VTEC swap. So much cleaner with no issues.
Are you running obd2? edit: nm reading your thread

If the intake manifolds are different, swap them. You're already aware of the throttle body differences.

Probably only need to swap the upper portion of the manifold if anything.
This seems like a logical step, I will figure out if I can mount up the upper usdm plenum to the jdm lower. I do wish I understand how those ports forward of the throttle plate worked better. It was my understanding that you can't run a vacuum forward of the throttle plate naturally because the air filter is open to the atmosphere. But the evap port definitely uses two tiny holes that are forward of the throttle plate.
 

·
Registered
Joined
·
241 Posts
Discussion Starter #11
Bump...

Well I swapped out only the JDM throttle body with the USDM throttle body and the code has vanished now for quite some time. (knock on wood)

The USDM throttle body has a different setup for the holes that pull vacuum forward of the throttle plate that definitely give different vacuum readings than the JDM counterpart at the same RPMS. The ECU seems to be incredibly picky about what vacuum it wants and when.

Only time will tell if this was a true fix finally once and for all and I can quit ripping out my hairs.
:D
 

·
Registered
Joined
·
40 Posts
Hi G-Wiz….
Have had the same occasional code issue ever since my swap finished in Feb 2014.
Have to say, it drove me bats, but I've just lived with it.
Never went to US throttle body because it is much smaller.
Did (also) just get a knock sensor code that IS a serious issue….have a month and a half to fix ;-(
My swap experience is the H22A is a much better engine. More power, better fuel mileage. No problem with emissions when using US harness and changes to OBD11.
Cheers-
 

·
Registered
Joined
·
241 Posts
Discussion Starter #13 (Edited)
Gonna bump this thread back from the dead just to say 2 years later an I am STILL fighting this code. It comes on sometimes within 5 miles of driving and sometimes it takes 20 or more. I can bring the code on almost instantly if I short shift from 4th to 5th anywhere below like 3k RPMS.

I've followed the complete troubleshooting procedure for this code about a dozen times in the manual. The only thing I will be honest that I haven't really looked into all too much is the fuel vapor line coming from the fuel tank itself. I have verified that it holds vacuum but there is another line I found that I haven't tested. That is next on my list. Although I am very doubtful about this being the problem as my fuel system always seems to hold pressure decently. At least when I open my fuel cap on a low tank I get a quite audible gasping noise.

I still feel like there is something stupid simple that I am missing that is probably staring me right in the face but for the love of god I just can't figure out what it is. When and if I ever figure out what is causing this code it will feel... probably like the first time getting laid... MAYBE even better. I've also got desperate enough I actually started throwing parts at it like a fool without even having confirmation that it was even faulty. (None of the troubleshooting tests showed that any component was at fault but still I've replaced the solenoid, sensor, canister and vacuum lines...)

Anyone else happen to have a 1997 5th gen I could get some detailed shots of the vacuum hose routing around the EVAP canister area (the black tank next to the cruise control actuator). If you need details I can take a picture myself kind of what I'm looking for.

And to clarify I REALLY, REALLY wish I could just rip all this shit out but I am stuck on OBD2 where I am at. RIIIIIP

One last edit: I also went back to the full USDM IM, now the only non USDM part on my car is basically the block... still the code persists
 

·
Administrator
Joined
·
6,799 Posts
What all have you replaced at this point?


I actually just stripped a 97/98 parts car if you happen to need anything evap related.


When I was having evap codes - the issue was a cracked valve. Ended up replacing every single vacuum line until I figured it out. (including the ends for the main line to the tank). Thankfully since you're 97/98 - the system isn't as much of a pain as the 99/01.
 

·
Registered
Joined
·
241 Posts
Discussion Starter #15
I have replaced the solenoid, sensor and the cannister. I've went through and checked all my vacuum lines related to the evap and tested each one they all are in good shape. I swapped back on my whole intake manifold/TB from my USDM h22a4. The JDM throttle body definitely was a problem as it was causing the code to be thrown instantly, the main port going to the solenoid drew vacuum differently then the US version. So switching it caused the code only to be thrown in 5th gear at low rpm.

Ive ran through the troubleshooting procedures a couple times in the manual. It passes teh vacuum tests, and probing all the connectors results in the proper voltages etc... but it always leads me to the end which says replace the ECU with a good known ECU lol.

I think Im gonna run the the troubleshooting once more.
 

·
Registered
Joined
·
1 Posts
Hey GWiz just bumping your ancient thread don’t mind me ?

I’m having the same problems you are with my jdm h23a vtec swap. P0441 comes on seemingly randomly. Changed the gas cap and purge control solenoid and did all the steps in the helms manual a couple times.

Have you had any luck with this? Any update?
 

·
Registered
Joined
·
1 Posts
Hey GWiz just bumping your ancient thread don’t mind me ?

I’m having the same problems you are with my jdm h23a vtec swap. P0441 comes on seemingly randomly. Changed the gas cap and purge control solenoid and did all the steps in the helms manual a couple times.

Have you had any luck with this? Any update?
so I am running down the same thing currently..don’t know if you still have this car as this an old thread...
I am having the same issue put a 99 h22a4 into my 97 prelude got this fault..this was new after the swap and was not there previously...I have found that the throttle bodies are different...manual says that there should be no vacuum at idle and vacuum with throttle open...the 99 engine has tons of vacuum at idle...I compared the throttle bodies and the 97 throttle body evap port is forward of the throttle plate...did you fix your problem?
 
1 - 17 of 17 Posts
Top