1993 MM questions

[cubcadet621]

Hello everyone this is my first post hoping to get a little information from the experts. I just bought a 93 mm 2.4 with 200k miles. The truck was running terrible so I changed plugs,wires,cap and button. That did help but its still not right very rough idle a lot of smoke at start up its either blue or white or both. I found at the back of the intake plenum is a vacuum port that isn't connected. If I put my finger over it the idle is a lot better but looking through the book I can't figure out what connects there. If anyone could help I would appreciate any advise. Thank you

[turbomax]

blue smoke = burning oil
white smoke = burning coolant
black smoke = running rich

Does the smoke clear after running a few minutes?

[turbomax]

Also if the smoke smells sweet, it will definitely be coolant burning.

[cubcadet621]

It does clear up after a few min I tried to smell it it just smells like gas to me not really a sweet smell that I could tell. Have any idea about that port on the plenum? Does it just need to be capped?

[joey_crandall]

go to the helpful links section, find mitsubishi links and go there, the factor servie manual for your truck is int he list somewhere, it should have the vacuum diagram.

[cubcadet621]

Thanks Joey that's great information I've looked at the one under the hood also it just doesn't show that port. I'll look at some of these manuals and see if I can find it I'm hoping someone has the 2.4 and can chime in.

[camoit]

Experts???,,, Were just a bunch of guys that spent way too much time under the hood in high school instead of chasing girls like we should have done.. If I spent as much time on girls as I did on cars I would have made a Hue Hefner look like a small time pimp.

get us a picture of it. sounds like a brake booster port. If it's at the carb then it's the EGR port or charcoal can purge port.. about 1/4 inch.

[cubcadet621]

Lol I hear ya. I'm not sure how to post a picture yet haven't gotten that far. I spoke with another mm owner and his is capped off with a screw at the end ... I looked at ever manual I can find and nothing points to that area having a vacuum port. I know its hard to picture what I'm trying to explain I can email a picture of it if anyone would like to be kind enough to post it in he thread. Thanks for all the input so far I'm just having a hard time making myself belive it was capped from the factory. Thanks again

[cubcadet621]

I added two pictures of where its located it was dark so a bit hard to tell they are in my photo album that's as far as I could get them lol sorry

[blindeyed]

I know exactly what you"re talking about. It's a little nipple coming off the plenum towards the firewall. My last 95' had it capped off, and my current 95' didn't have it capped off. There's nothing that's supposed to be connected to it. My best guess is that it's for an accessory such as a vacuum gauge, which could be useful for monitoring or problem solving. If you just want to cap it off, I would recommend going to an auto parts store and looking in the "Help!" isle for vacuum caps. It's only a few dollars for a dozen or so different sizes. That's where I got mine.

As for the smoke at start up. I can almost guarantee you it's your valve seals. Both trucks I've had, have had that problem. If you don't take care of it soon, it'll end up blowing smoke even while driving down the road, which can get quite embarrassing.

[cubcadet621]

Thanks so much exactly what I needed! Would you pull the head or use the procedure they have in the manual to replace the seals? Thanks again!

[camoit]

There is a how to in the sight news and support section on uploading pictures and working with attachments.

[blindeyed]

Not sure what procedure they have in the manuals.. I didn't remove my head to do it. I removed the spark plugs, and used an air compressor with a spark plug fitting to pressurize the cylinder. If you don't have an air compressor, you can use a rope by stuffing it in through the spark plug hole. The purpose of either one of those methods is to keep the valves lifted up, so when you use a spring compressor, and remove the valve keepers, it won't fall into the cylinder (like it did to me ). Once the spring is out of the way, I just used some vice grips, and yanked the old seal off, and tap the new one on with a deep well socket. Do the next valve.. re-assemble, and repeat.

Just gotta be careful with reassembling those brackets that hold down the camshaft. The Haynes manual told me to start tightening them from front to back.. but I ended up breaking one that way. 2nd time I did this, I reassembled them by tightening them from back to front, and had no problems. Those things are very fragile.

[turbomax]

It does clear up after a few min I tried to smell it it just smells like gas to me not really a sweet smell that I could tell. Have any idea about that port on the plenum? Does it just need to be capped?

With 200k+ miles, it's probably your valve seats since clears after a few minutes. When your cars sits overnight, oil leaks into the combustion chamber and your just burning the oil at startup.

[cubcadet621]

Thanks I guess thats the next project how long does that usually take to do? The only thing that worries me is adjusting the valves correctly when I put it back together. I've read the haynes manual on it and doesn't seem like its to difficult...hopefully I can get it back together lol

[pennyman1]

With hydralic adjustors, the only things to adjust are the jet valve lash if you even have them - if you do, remove the adjusting screws entirely.

[cubcadet621]

Ok sounds good! How long do you think this should take and while doing the seals do you recommend doing anything else while I have it apart? Thanks again

[cubcadet621]

Well guys I changed out the valve seals and one lifter and no change still smoking until I drive it a mile or so. It's either light light blue or white smoke I can't really tell. I've watched the coolant level and it hasn't moved a drop and the temp gauge stays steady so I don't think its the head gasket. When I pulled the plugs the #3 was wet so does that point to a faulty injector? Or is it just time to look at a rebuild ...

[LSR Mike]

I just wouldn't worry about it and watch your oil level...

[blindeyed]

My only other guess would be you've got one or more bad piston rings.. If that happens to be the case, then I would agree with Mike on that one