I posted up a while back as to why I kept on having this loud *** wooshing sound (which was in effect a vac. leak)

I knew from sgT what I had to do to eliminate it but I wanted to understand why it was making this "running hose" sound every time I started the car when it was cold.

The thread is located here....:

https://honda-tech.com/zerothread?id=321232

There is a vid attached.

And the solution/explanation is:

"The P28 ecu turns on the purge control solenoid at idle; with a type-r manifold, that means a large vacuum leak. On the D16 SOHC engine, the purge vacuum source is ported vacuum coming off of the throttle body, as opposed to the type-r which uses straight intake manifold vacuum. The type-r ecu only allows purge control activation above a certain rpm/manifold pressure (I'm not sure which, I would have to look it up ). The big vacuum hose going to the purge control valve on the firewall is where leak is. Unplug the electrical connection to that valve and see if you still get the symptoms. Or pinch the hose with needlenose pliers. Good luck."

This was brought to my attention thanks to b19coupe aka Todd Jones. Many thanks to him and all who participated in helping me understand what was going on under the hood.

I'm a little surprised nobody else has experienced this anomaly or maybe I'm just ignorant to the fact it has been solved many times over.

Special thanks to G3-TEG/Crescent Kao of c-speedracing for hooking me up with the hondata.....I will be in touch for more tuning!

Hope everybody finds this info useful to some degree! DIE ALL YOU STRANGE NOISES!



[Modified by RagingAngel, 4:24 PM 11/8/2002]

 

forgive me for being "slow" but do you just leave the electrical connection unhooked? thanks for the info

 

Just read your post here and the attached thread. I don't get it. What is the fix? The decription by b19 seems to diagnose the problem, but where is the permanent fix??

How come all these Hondata/Kenji's p28 people have never said anything about this if it is the p28's fault????

Chris - who feels 'slow' also since he obviously just doesn't understand.


[Modified by 1107, 8:09 AM 11/8/2002]

 

does this apply to other obd1 ecu's? like gsr?

 

Any answers to the questions above??

 

no. it shouldnt

 

I got the same noise. Sorry but where is the purge control solenoid ?

Also, what does it do ?

 

its on the firewall. has a hose going from it to the back of the plenum

 

sgT - Is this problem (the one in the original post) synonymous with p28's? Is there a 'fix'??

Chris - who is still not understanding the original post's explanation of the cause/fix.

 

I won't pretend to know but the explanation is obvious with how b19coupe explained....

sgT also mentioned in the original thread that it is a OBDI/OBDII "problem" from what I know, OBDI cars didn't have the EVAP canister so that's a good reason why the ECUs (OBDI) wouldn't control this whole mess that OBDII cars have.

the fix? Remove the entire Evap system ...that or hondata has to have a "new" feature to address this leak at cold start.

 

I ran into this problem on my B18C powered Civic when I switched out the stock SOHC throttle body for the Type-R throttle body. The purge hose on the Civic was ported vacuum from the throttle body. The Type-R purge hose uses direct manifold vacuum. Both vehicles have an evaporative emissions system which uses an evap. cannister that collects raw hydrocarbons (fuel vapor) from the fuel tank. The raw hydrocarbons are then sent to the intake manifold via a "purge" hose.
The ecu controls when purging (the burning of the fuel vapor) takes place by sending a signal to the purge control solenoid.The P28 ecu allows the purge control solenoid to activate at idle, and I believe it is a simple "on/off" solenoid. I believe the Type-R purge control solenoid is actually a frequency control solenoid (it cycles on and off repeatedly) to modulate the flow of hydrocarbons into the intake manifold.
Thus, the P28 turns on the purge control solenoid, in effect creating a large vacuum leak through the purge hose. The Type-R ecu does not allow purging to take place at idle and I think modulates purging off idle. Ain't emissions controls grand?


[Modified by b19coupe, 4:34 AM 11/9/2002]