TOPIC: 1990 Mitsubishi Montero, 3L, Costa Rica

I too looked at the pics and suspected the Groove on wrong side. Thanks to all on this thread. Johnathan just get and use a new TB gasket, might get bulk fiber/paper type to improve sealing and cut to match stock Tb gasket, place between TB and stock gasket.

You already have the right idea to re-route the IAC path. I'd leave the screw adjust idle air path alone to allow for adjustment. Be sure to clean/roughen up the carboned up IAC trench w/ a drill bit for good adhesion, just go slow. I forget the other types of epoxy mentioned before by others, but check around on here and see, and see what's available down in CR. A solid well bonded type is needed as you will probably be Grooving into your epoxy.

TracyG Gadgetman Reno

Hey Tracy,

I have some of that gasket making material you're talking about and am going to follow your suggestion.

I also appreciate the reminder to roughen up the IAC trench with a drill bit. I'll also leave the screw idle adjust alone, but do those leak? If so it's a vacuum leak as it comes in after the groove.

I brought JB Weld and JB Kwik with me from the states, and also bought some UltraWeld here which is made in the US and is supposed to be stronger than CR brands. So I should be set in the epoxy dept. But how do you determine if one is solid and well bonded?

Hi Guys,

I've done enough with the JB Qwik and JB Weld to get a fair idea of how they handle...

The JB Qwik is slightly more porous than the JB Weld.

I'll primarily use the JB Qwik for outside patches and fills.

The JB Weld I use when I want to fill in a Groove that I plan to recut.

Roughing the surface is always a good idea.

For something like the IAC pathway you can use cellophane and modelling clay to fill the back area which will reduce the amount of JB Qwik that you will need.

I find the modelling clay to be a pretty useful tool all around, you can pick that up t a craft shop.

Things that make ya go.... hmmm, I can use that here...

Karl Fortner
Tacoma, Washington

Hi Karl,

I appreciate your distinction between uses for JB Weld and Kwik.I hadn't really honed in on differentiating between the various consistencies of cured epoxies. I may experiment and make some blobs of various epoxies and cut them with the bit to see what each looks and feels like afterwards.

It makes sense to add a cheaper filler, especially on larger cavities, instead of all epoxy. And I like the suggestion I've seen before of remixing the aluminum shavings into the epoxy. I can picture cellophane as filler - like cutting some plastic bags into little pieces and selectively packing them in with the epoxy, is that sort of what you're talking about? The modelling clay throws me off a bit though. Are you saying mix it into the same space/cavity as the epoxy - though with epoxy as the final outer layer? And is this the type of modelling clay that hardens when it dries out (unlike the oil based types)?

As for other uses for modelling clay, I noticed and liked your suggesting some time ago to use it (you mean the Play-Doh type stuff that doesn't dry out right?) to help make a template to get the bit angle right.

Cheers.

Hi Jonathan,

I use the cellophane as a liner to separate the modeling clay from the epoxy.

The modeling clay is the soft moldable variety, I use it to temporarily backfill space that doesn't need to be permanently filled with epoxy. Once the epoxy is cured I would remove the cellophane and modeling clay.

In this instance I would probably build the pathway on the backside to make rerouting the pathway a bit easier and fill the rest with epoxy.





Karl Fortner
Tacoma, Washington

To Jonathan: Your questions are good.

1) I would fill in the groove and recut in the proper position. I don't thing the purge line is anything to worry about, and is easy enough to fix so don't worry about the ports at this point. Wait and see.

2) Throttle Shape-It will enhance the responsiveness and (perhaps) give a little extra kick to The Groove as well.

Sorry, I would write more, but have another client coming in for some added value service.

Ron

Karl,

Thanks, that seems like an excellent technique. I assume you use cellophane because epoxy doesn't bond with it. If so, since I don't have any around at the moment, if I can't find any (I live in the boonies) maybe putting some oil or grease on a piece of plastic bag would do the same thing.

I agree with putting the reroute on the backside. The thicker the wall between the groove and the reroute the less chance it will blowout/crack/whatever.

Ron,

Thanks. I'll fill the old groove smooth it out, leave the purge line alone and do my first throttle plate shaping.

Any feedback about whether the metal gasket is enough or whether it's better to add something like Tracy suggested (and like I'm planning to do)?

Hey guys,

I recut the groove, and in doing so, cut through in a few places. One was the area the TPS is in. I want to pull the TPS off, patch the hole and put it back on. I've never removed one before though and just want to make sure it's not an issue. If I pull it off am I going to be stuck having to retune and recalibrate it? or can I just stick it back on if it's in exactly the same position it was in when I removed it?

Thanks

Make sure you mark the plate position, put marks on the housing to note location.

It shouldn't be off by much if any at all, the shaft itself should be keyed.

Karl Fortner
Tacoma, Washington

Excellent info Chris, thanks. I think once the groove is well cut and there's no leaks, sensors are obviously where the action is, so I'm sure I'll use it down the road.

I just ended up making a mark straddling the sensor housing and the TB that I could use to realign them later. Then I took it off. The throttle axle had a piece with fins on the end of it, so it was easy to line up again later. There was tension on it from a spring inside the sensor housing, so when I put it back on I had to twist it a bit to line it up, but it seemed normal, since I hadn't adjusted anything. The biggest hassle was that it had a rubber gasket that was stretched out and it was hard to cram it all back into its original groove.

I redid the mod in the right place, rerouted and reduced the idle air control path, shaped the throttle plate and did an experiment by blocking the majority of the opening for air to come in through the idle adjustment screw.

The idle went from 1,200-1,300 down to 200-300 on startup, and up to about 500 about a minute. Though it doesn’t idle rough, it does die if I don’t give it extra gas in the beginning so I need to bring the idle up.

The obvious possibilities are to increase the size of the IAC air entry, open the idle adjustment screw, or adjust the idle set screw. Any suggestions about the best way to go?