L2ILL

Well I went ahead and bit the bullet on swapping out the rear motor mount on my 92 accord Ex 4cyl. Which I've been told is responsible for the horrible idle shaking this car has..due to broken mount and vacuum hydraulic.
It was no easy task and I did by removing throttle body and oil filter. As I did not want to remove the intake.

Right around completing and attaching hoses and what not...I happen to place my hand on the plastic black box under the intake manifold on the drivers side and a small little tubing area in the corner broke off with very little effort but yes it is my fault..I dont know why I placed my thumb there. So I manage to find the little spring and small piston inside it and put it back in and since the plastic elbow that houses them had snapped off I was able to glue it all back together using epoxy. I gave effort to make sure glue wouldnt be introduced to the spring and piston area so it would operate as intended and supply vacuum or whatever to the back egr or purge sensor(i think) it goes to. While I had it out I saw on the top side it had something like a breather type vent with a black plastic cap. Well it looked incredibly dirty so I blew it with some air and the whole dirt clump thing came flying out...in hindsight maybe it was not dirty but was possibly a dirt colored paper element of some kind. While I surely did not have anything to replace it with so on went the black cap without dirt or possible paper filter element(its the size of a nickel). And back in went this mysterious plastic box X.

Unfortunately I had already removed the O2 sensor and had it soaked in gas just to clean it up some.

I say unfortunately because to add to all this upon removal of the rear mount the old looked perfectly intact and it's rubber was not broken and seemed to look fine anyway.....which was really the beginning of bad news. And likely where I would have chosen not to remove the 02 because bad news likes to start then build up.

Long story short. My car is still shaking possibly even worst. Only now I am coding 43.
I am not sure if maybe the 02 did not like the gas solution for cleaning. Or if mystery box is the true culprit to Code 43.

The car shakes it's worst while idleing and the ac clutch kicks on. When I give it gas in park while watching motor it seems absolutely fine and really does not seem to move or nudge badly which is why I almost dont think the other motor mounts are to blame and am starting to think my problem is possibly the convertor. I thoroughly inspected all the other 3 motor mounts and they seem fine the 2 side ones show no tears...the front one does seem to have a tear in it...but like I said when the AC clutch comes on...the engine does not seem to shake at all at any of the 3 motor mount points....ALL 3 look perfectly still while it's shaking. I checked all ignition wires while it's on...and they all made the motor shake bad as I pulled each one out so the car is NOT misfiring.

Please help with mystery box and code 43....ill deal with the shaking later.
I'll buy another 02 sensor if need be..i just dont want it to end up being the plastic box X that's throwing the code.

I was expecting better results from this project...the only good thing I gained thus far was discovering the idle screw on the throttle body was completely closed up and needed new o-ring also...I have been able to bring the idle to 750-800 with AC on and it's rock steady..this has cured it being from where it was too low in the 500-600 rpms but has not cured the shaking.

Please help with the code and black box...id appreciate it.

Lost Again

Got any pic's of the "black box"?

And just my opinion, cleaning an O2 is something that should not be done.

For the vibration....I would have gone for the front mount before the rear. Next, what can/have you tested for the issue? What is the rpm at idle?

L2ILL

I've discovered it is called the IAB vacuum box....the intake air bypass box.
It seems many go around removing or disabling this. I have found this is an incredible feature that lets the engine use smaller intake plenum runners and keeps the bigger ones closed until high rpm. I cant beleive honda thought this up way back in 1992. I ran outside to check if I could catch the vacuum close the butterflies at idle and sure enough it is working. I am not positive this proves the IAB box is fully working and my epoxy fix is holding up...but at least I know at idle it's working to close them.

I took it out for another spin since the check engine light was now off. And after about 5 minutes it did not come back on. Im tempted to lean if it does turn back on it's the 02 sensor. I don't know why I did that I've never done it before to any other car...it was one of those stupid things you read about on the internet and well i went for it.

Anyone know any additional tests for IAB box functions?...I know it goes to another solenoid on the firewall which goes to the fuel evap purge and one to the rear motor mount....how can I test that solenoid is working right?

FurryBalls

+1

Whats the idle RPM reading? I 've cleaned O2 sensors with a variety of results... Some times it helped, most of em, it did not. In my case there was a vacuum leak at the intake so the shaky idle was realted to that. Also, check the IACV is delivering what it should. As for the IAB, I took it out and disabled it. F*** you, fuel efficiency; hello, steady idle.

L2ILL

I am idleing at 750-800 with the ac on. 700-750 with it off.
It is steady even while the engine is shaking the tach needle is showing pretty steady. When the ac clutch kicks on is when the engine rattles the most. Outside of that the vibration is better when the clutch is off.

But if I watch the engine mount and their collars...it does not seem to be shaking there. And when I rev it up the engine doesn't flex up much if at all.

This is the best it's ever idled...the one thing good that did come out of taking throttle body off is there was a screw that had been covered with grey silicon or gasket. And that screw turned out to be the base idle screw since it was hidden I never knew of it. And I usually dont like to open or close the manual throttle blade idle adjustments on any car. Before this it was idling like at 500-600....and it would stall off the line. It's running champ now...smoothest ever...off the line is almost like new car. Maybe someone did that to save gas?

Im probably gonna order the front mount and the O2. I may try to run straight vacuum direct to the rear motor mount just to see if it's "hydraulics" are working.

I dont see how the front motor mount is gonna resolve the shuddering but maybe it's not something I can see. Any other ideas about the shuddering? I've bumped into several reports where motor mounts didnt resolve. So im def. in doubt. Im gonna spray brake fluid around the intake manifold to see if there is a vacuum leak....but I've gone around unplugging things and the engine truly acts up then. even the spark plugs...so it doesnt seem to be a vacuum leak or ignition.

also i have cleaned out the IACV and the fast idle adjuster screw was tightened...both of which helped a lot....but the car never really had a surging or hunting idle.....it just seem to idle rough when ac clicked on because idle was set too damm low. Now when ac kicks in it shudders still but the idle stays put and it seems far from going to conk off. also cleaned out the egr valve. the passages that it bolts too were not blocked off or too bad with build up.

holmesnmanny

The only time I've seen a code 43 myself is when one of my oxygen sensor connectors came off before I did a real job of connecting everything down properly when I rewired my oxygen sensor wiring. I believe it was the ground wire.

You can't clean an oxygen sensor. They are too sensitive to contamination. Get another Denso. Also get another vacuum control device or whatever it was that you broke from the junkyard. Those things are a dime a dozen.

L2ILL

This is IAB operation basically:

Symptoms of a shot IAB solenoid are nonfunctional secondary butterflies.

Proper operation is as follows: under 4800RPM, vacuum is applied to the IAB diaphragm. Secondaries are closed. Above 4800RPM, the ECU tells the IAB solenoid to turn off vacuum. Secondaries are open.

If your IAB solenoid dies, then you will never have any vacuum at the actuator (you can test this like any vacuum hose) and your secondaries will be open all the time. You will not notice any change in top end, but all power below 4800RPM will suffer.

Now on this car it also feeds vacuum to the purge & motor mount solenoid(on firewall)....so I have to now check that the iab is sending vacuum to that solenoid.....if that is failing it's possible the motor mount isn't getting the vacuum it needs because IAB isnt providing it...or other purge solenoid is failing.


Correction: The solenoid for the motor mount has nothing to do with IAB...IAB is fully operational if your secondaries close at idle.
I was confused with the tubing. Sorry. Motor mount solenoid also picks up vacuum straight from intake manifold and sends it only to the motor mount.

holmesnmanny

The iab is nowhere near the black box, it's underneath the intake manifold.

http://www.hondapartscheap.com/parts...el/control-box

http://www.hondapartscheap.com/parts...g/engine-mount

What part in either of these illustrations did you break ?

L2ILL

Think you might be confused or skipping the posts. IAB is under the intake manifold we know that. I had chipped off a white hose inlet in the corner of it. I successfully used epoxy on it. It is closing the butterflies in the manifold.

The only remaining problem is the vibration while at idle in drive and reverse.
That the rear motor mount did not cure and now I will be getting a front motor mount to install and basically pray because I now know that this is a common problem that goes uncured for many.

When I install the front motor mount if it does not cure I will try to adjust the 2 side ones but if no cigar...i guess this honda phenomena will just have to be lived with as many have been forced to after spending much money and effort to try to cure.

holmesnmanny

Is it vibrating while at normal idle rpms or does it vibrate because of irregular(low) rpms ?

L2ILL

Manny it vibrates while at normal idle...harder when ac comp clicks on at that point the idle needles barely blips a little....but my idle doesnt surge or go too low.

The engine basically shudders while needle is still and solid@750-800.

I got the front mount out the top of it was broken up. Tomorrow ill be putting in the new one. And ill also be troubleshooting the vacuum on the newly installed rear which does not seem to be holding vacuum(unreal how new parts come f'ed up) unfortunately I installed it before realizing how the vaccuum works. After that if it still shakes im gonna try to adjust the side mounts.

If anyone has instructions for side mount adjustments please post.

Thank you...and I hope I get lucky.

holmesnmanny

It could be the side mounts. For the tranny side just put something in between the jack and the tranny and jack up the tranny enough to remove the through bolt then I believe you need to let the jack down enough to slide out the mount. To reinstall it you may need to use a crowbar on the drivers side in between the chassis and the mount to be able to line up the through bolt on the tranny side. For the drivers side it's a bit easier. You just need to make sure you have the engine raised up when you install a mount so that the mount and the through bolt are straight so nothing is kinked or slightly bent. This allows the bushings to last so they aren't twisted, causing breakage. Tighten all the bolts on a particular mount side before letting the jack down.