This is what I need to do....


Intake manifold hose - MBWorld.org Forums

 

Wow. took me 3 hours to remove manifold and I was in no rush.

It went back on in like 15 min because I knew where things went. I used a small brass double barbed nipple from the hardware store. I drilled a fresh hole in the remaining hose in the bottom of the manifold and hammered the nipple into the hole. It took some effort to get the nipple in so it should be air tight. It went in so snug that I didn't want to pull it out to put some sealant on the outside of the nipple. Had I known it was going to work so well I would have put the sealant on. I used a healthy fuel line 3/16 as vac tube for this connection. I should never have to worry about it again



One last hose of the back of the manifold goes where???? Does it connect to a skinny white plastic tube originating behind the fire wall?

 

Just top and drivers side of the throttle body.. that nipple off the manifold does connect to the plastic tube..

 

Thanks Mr Miata. and the little black circle thing that is hanging off the back of the back passenger side of the engine? It's a black disk that looks like it plugs in somewhere? It's attached to a pressure regulater looking thing all plugged up with vac tubes hanging off. One of the tubes has the black disk on the end.


Yellow plug in the wiring harness! please tell me it just dangles and doesn't belong inside the manifold.

 

Yes it does. That is the vacuum for operating the heater/AC doors.

 

black disk hanging from the vac tube on the yellow harness plug? It looks like there is a place for it to sit in the manifold wall but the hose won't reach. Anyone?

 

all back together now and running strong. 3 days no check engine light. I had a stumble at take off, intermittent, before the line replacement. Now, reliable launches every time. I thought it my be a side effect of the SCAI during takeoff. Car feels faster than ever with this line replacement and barbed nipple replacement.

 

More news. It appears like an intermittent vibration that I thought was in my drive line, may have in-fact been the engine vibrating. The vac tube in the front of the motor apparently opens and closes valve flaps in the manifold. It is my theory that these flaps have been fluttering at cruise speed. I've been chasing this vibration since I started driving the car. Thrumming, oscillating , rhythmic in 6th gear at about 65 mph to 70. The trick is it doesn't happen every time but when it does, it's always the same. No matter what speed, you can set your watch by the rhythm so I concluded it wasn't wheels/tires.

My next best culprit would be the flex disks & drive train support. I have it in my cart from rock auto and the car has completely stopped doing it since the vac tube repair????


I hope it stays away! I will prob still update the drive train parts as well.

 

Sounds perfectly feasible, You have a manual, correct? IF it does happen again, not what speed and RPM. If say 67mph in 6th gear, set the cruise while it is happening, and drop to 5th. If you are correct about the engine itself being the cause, it should go away or change at the higher RPM.
Or say 67 in 6th is 2200 RPM (just guessing), put it in 5th and drive 2200 RPM (55ish?) and see if it happens.

 

I've done that already. The frequency doesn't change no matter which gear or which speed. It's always the same. Damn camshaft position sensor is faulting on me now. Just replaced mine with cheap Chinese replacement parts.

 

im still fighting with the issue, changed MAF again, fuel trims became normal for while but now they back again... the main problems are power loss and fuel consumption...