I did an AdamC.
I tried to remove the green check valve that goes intake manifold-double throttle solenoid. I got the hose off the intake manifold nipple fine.

I then attempted to remove it from the double throttle solenoid, buried under the rats nest. This failed, so I attempted to twist the green check valve to break its seal in the hardened vacuum line. Then the m%&^*(f$%^&*g nipple broke off the double throttle solenoid. F#$%^&*(^& f%$$#%......

This is the first thing I've broken on this car in nearly four years of use. I've just come inside from the garage and I'm not bloody happy about it. Why did Mazda need to put plastic nipples all over everything? Bloody hell... My car now feels that "1% more molested than it did the day before" feeling, and I'm the idiot who did it.

Anyways, if I just cap off the nipple at the intake manifold, and leave the double throttle with no vacuum signal at all, will the double throttle plates rest open?
IE are the double throttle plates spring loaded normally open?

Thats all I really want to know. I'm off to be pissed off at myself now. Just couldn't leave it alone could I.....

 

Okay. So I capped the nipple on the UIM. Basically left the double throttle actuator with no vacuum signal at all. Warmed car up, went for a drive to assess the extent of my stupidity.

Disclaimer: I'm normally a fierce proponent of "leaving things alone" and I don't like pulling things off or modifying something that Mazda added to the car for a presumably good reason. I dont like screwing around with something that a Mazda engineer probably put a lot of effort into designing.

Holy crap. It actually runs better than when it had the double throttle connected. Throttle response from a rolling start feels better. But definitely more noticeable is the midrange to top end pull. You do 100kmh in 3rd, then put your foot down hard. It picks up and its got more oomph, and its doing 170-something kmh and you realise you're running out of road quite quickly, in what was supposed to be a 100kmh zone.

Might also be because I replaced all the old questionable green check valves with Dale's viton valves as well today, but something is definitely a lot better

What I learned:

1. Bypass that double throttle BS.
2. Get Dale's viton valves if you still have those stupid green check valves in there. The green OEM valves need to go ASAP.

 

Yeah, if its disconnected its open. I'd offer to send you a free replacement, but it prob wouldn't be worth the shipping cost to Aus .

 

I did the exact same thing . honestly you can live without the double throttle control. and yes if you cap it it should work fine , also you may want to cap the nipple that goes into the uim and the actuator , which is what I did . well I removed the damn thing completely haha.

 

from what I understand, you don't want to boost the car until it's warmed up to normal operating temperature without the double throttle connected.....

 

yup , but you really dont need the double throttle control , its just common sense LOL which most people lack thats why mazda added it LOL .

 

I tested my double throttle back in the day, it only stays closed when the car is super cold, at like 50-60 deg. water temp it opens and stays open.

I'm amazed anyone still has stock check valves, they all need to go in the trash .

Long term just replace that solenoid. They're also used on 2nd gen RX-7's so they're rather plentiful, I bet you can find one local to you.

Dale

 

Holy ****!! That was soooooooooooooooo long ago. At least 10 years. Doesn't anything expire on this site?????

My car did just fine without it for many years.

 

Thanks guys, it's good to know it's not of a huge consequence.
I did worry a little bit because some tuners were saying that the double throttle blades dip closed for a split second when you floor it, as a sort of acceleration enrichment to prevent a small lean spot when you get on it and open the throttle quickly. Thats what some Haltech guys were saying they found out on a board somewhere.
I think I'll get a replacement solenoid and eventually fix it because it bugs me knowing it's in there busted. A friend of mine probably has some somewhere.. In the meantime I'll just warm it up properly and drive it reasonably

Edit: this is the sentence I found in the FSM, in the Shop Manual (Page F-137) which specifically says its there to prevent lean-out as well as cold start:

"The response delay of the pressure sensor (MAP sensor delay time) following rapid acceleration
temporarily causes a lean fuel mixture. The double throttle control system
prevents this hesitation caused by the lean fuel mixture by temporarily closing off intake paths for an instance, providing momentary enrichment."

Based on that, I think I'm going to repair it

 

Fix the broken solenoid.
All it takes is:
drill,
brass tube,
JB Weld,
intelligence.

 

I've done that many, many times before when I had no alternative spares.

Luckily I just got my hands on a good working solenoid for free. A friend of mine pulled his rats nest to go single turbo, so I have access to many more good, working solenoids now

Either I'll fix the old one or (and I really want to do this) put the sucker in the bandsaw and cut it in half to see whats inside it To my knowledge there are no photos anywhere of what they look like inside..

Hardest part now is taking the old one out. Might leave it in there until I pull the UIM in a few weeks to change spark plug wires, IAT, coolant hoses, etc as I was planning to do anyway. Sorted