RAVE valves stuck open

[geeps_24]

Re: RAVE valves stuck open

Okay Bill, tried the 12 volt thing, and I heard a click when I applied power to it. There are 3 outlets. One for air pressure intake, one to crankcase and the third goes to the raves. When no power goes to the solenoid, air pressure is blocked off, and the other two let air flow between them. When I apply power, the air pressure is let in, the crankcase hole gets blocked and the rave tube lets air through. It sounds like the solenoid works good. Now what could possibly tell the solenoid to open up the valves right at idle? In another board, I saw you mentioned a sensor for the throttle that tells the engine when to open the solenoid. Do you think that is the problem? Sounds like I have to take the muffler pipe off to get to that... The more I think the more I get lost. Please help!!!!

[Bill O'Neal2]

Re: RAVE valves stuck open

The MPEM activates the solenoid which directs air from the air compressor to open the rave valves. To close the rave valves the MPEM deactivates the solenoid.
There are no adjustments that can be made to this system.

For some reason, it appears that your MPEM is not allowing the solenoid to switch to release the air pressure to your rave valves, thus they stay opened.

Other than making sure the wires are attached and all connections are clean, I have no other advice about getting them to work correctly again without replacing the faulty part.

As an aside, we sometimes drill the rave valve base pod on some racing 947 engines like on a 787 engine. This eliminates the need for a solenoid and the hoses from the engine to run the rave valves. This may be a cheap alternative for you to pursue to run your DI rave valves. I have never done this on a DI engine, but it may be that you could do it just like we do it for the carbureatored model clyinders.

I am assuming that your problem is not because someone put the rave valve assemblies back together wrong after cleaning the rave valves ??

[John Kubiak]

Re: RAVE valves stuck open

Check the terminal pins at the MPEM end of the wiring harness...they have a tendency to recede from the locks in the connector shell...When this happens, these "captive" terminals do not make contact...Also if anyone has probed the wiring harness MPEM connector terminals,they are quite fragile and there is a 99.9% chance that they damaged the terminals and they are making marginal, at best, contact with the pins on the MPEM....This can cause the problems that you are experiencing

[geeps_24]

Re: RAVE valves stuck open

Well, thanks Bill and John for your advice. As for the wires getting a bad connection. If they weren't connected, there would be no current, which means the solenoid would be closed and the valves would be stuck in the down position. What I will try to do tomorow is punch one or a few pinholes on the plastic hose near the solenoid to try to get the initial pressure low, and higher as the RPM's go up. That way, I'll try to get the valves to at least stay down at idle, and come up with some throttle. There is no way I am spending $1000 for a new MPEM on this used machine, when I don't even know if the MPEM is the problem in the first place. It might be a sensor from TPS, or fuel... who knows. I'll let you know what happens!

[John Kubiak]

Re: RAVE valves stuck open

If the terminals recede out of their locked positions, it is possible that they can touch other terminals, possibly ones with enough voltage/current to permit energizing the solenoid on the RAVE system.

[geeps_24]

Re: RAVE valves stuck open

Thanks again John. I cheked the harnesses, and they seem like they are in good condition. The wires go deep inside of the holes, and they look watertight. I also made sure they were on their locked position. I am at a loss at to why the MPEM is telling them to say opened. I may take it to the dealership, but they have no legal obligation to fix it because I bought it used from them this year. Hopefully the pinhole idea works, I'll let you know.

[geeps_24]

Re: RAVE valves stuck open

Well, I had to put quite a bit of holes in the tube, but finally, she works real good now. The only thing I have to put up with is real low RPM at idle right after I give it some gas because the raves all of a sudden open up (I think). It only happens rarely, but overall, it is way faster, and top end is still awesome. Thanks guys you've been great!