Got a good deal on this truck and it is way too nice to take it to the scrap yard so i thought i'd see if anyone here can help me out. It runs very weak like it is missing on 2 cylinders but i'm not getting the shaking out of the engine like a 2 cylinder missfire would show. It idles rough and dies sometimes at idle. Very little power under 2000rpm then it seems to smooth out over 2500 and runs a little better but still not anywhere near 100%. Gets worse after engine is fully warmed up. Transmission is acting very strange also. Wont shift till 4000+rpm but when it does shift it sets you in the seat hard so i dont think the mechanics in the trans are bad. Transmission is 4 speed auto. The transmission also kicked out of gear on the 5 mile trip on the way home. It did this a couple times but if i would let off the throttle and shift down into 3rd it would kick back into gear very firmly

I'm leaning towards computer problems but don't know where to start. The guy i bought it from said he was replacing the passenger side exhaust manifold and he accidentally hit the starter power wire and sparks flew. He told me that is when it started running and acting like this. Driver side manifold is either cracked or leaking very bad so it's noisy under the hood. Where do you guys recommend i start?
I appreciate any help very much.
Thank you

 

Did your check engine light come on?

 

No check engine light. I only drove it 5 miles or so though and the battery had been unhooked for around a year before i drove it so i'm not sure if that would have been enough time to set a code. I found a really bad vacuum leak near the throttle body so i'm going to fix that first and see if the engine will run better and then address the trans problem. The guy that i bought it from put spark plugs in it before he parked it and must not have put the tb back on correctly.

 

Ok. Here is what happened now. I found a bad vacuum leak at the throttle body. Someone put the gasket in wrong. Fixed that and now it tries to idle even lower at 200rpm but thats too low and it dies. So i unhooked the maf while i kept it running and idle dropped a little but that was the only change. No check engine light. So next I checked the timing belt. It is correctly timed but the crankshaft sprocket is shot. It has approximately 1 cog of free play on the crank. The key is worn to half and the sprocket slot for the key is wore bad too.

Here are my questions now.

1) When I unhooked the maf should that have set a light and since it didn't does that mean the comp is shot? I ran it for 2 or 3 minutes while I had it unhooked at full operating temp.

2) Is there a good terminal where I can check reference voltage?

3) Does anyone think that much play in the crank sprocket could cause a poor running condition like this?

4) Is this an interference engine? I want to turn the crank w/ the belt unhooked to see if the crank is shot.

Thanks everyone for the help.

 

jcm, welcome to the forums.

Sounds like you got a heap of problems along with your Montero, so let's see if we can't help you get things sorted out. Things to check:

1. Good that you caught the vacuum leak; there may be others. I'd do the usual test with propane or WD-40 around the head and check all your hoses. Good to do anyway on a "new" vehicle. Who knows what the PO did or didn't do?

2. Check resistance of EGR solenoid connections. Follow hose from EGR valve to unit on left side of engine compartment. It should be between 36 to 44 ohms.

3. As far as checking your computer, do you have a code reader or a way to get any info from your ECU? If it's bad, it should be able to tell you that.

4. With a bad/loose cam sprocket it's hard to tell what other demons may be playing havoc with your timing, so that would be a great place to start: making sure the nuts and bolts issues are cleaned up before proceeding on to things like your Idle Speed Control servo and Throttle Position Sensor, both on the throttle body. THIS IS AN INTERFERENCE ENGINE, so don't do anything you'll regret later . My question is what caused all that wear on the cam, as that doesn't seem like "normal" wear to me.

5. Just a wild shot, but I'm wondering if you seem to be running rich at the pipe? Could Mr. Sparks have blown out an oxygen sensor while he was down there hurling his thunderbolts? You could check the plug for continuity between to top right and bottom right connections (as it's facing you). You should get around 20 ohms resistance when cool.

6. Your comment on your MAF is puzzling, and I've got nothing to help you there and can find no way to check it. Help, anyone?

Isn't buying a used vehicle from a total stranger such an educational experience?

 

Thank you. These forums are a sanity saver sometimes.

Definitely always a learning experience and i always seem to get the wierd ones. Maybe thats cause i only buy something if its a good deal. I'll check that o2s and egr resistance. I'm going to try to borrow an old snap on brick scanner from my buddy for everything else.

Crank sprocket not cam sprocket. Not sure if that was just a typo on your end or if you read my post wrong.
Also, just called the dealer for price on parts and that guy told me the new crankshaft sprocket comes w/ 2 pins that come out the back of it to hold the timing blade and the spacer all in alignment. My sprocket does not have these pins on it. It looks like they are broken off and gone. I'm still worried the computer could be bad since it didn't turn the light on when i had the maf unhooked. I keep hoping the computer has something wrong w/ it because i'm worried about the transmission.

Thanks for the help.
I like how you described the po. Perfect. lol

 

Yeow ~ that'll learn me to try and talk on the phone while trying to diagnose engine problems! You are correct, Sir! Crank sprocket it is......

Same reply, though. If that's bad how could your timing be right?

As far as your computer goes, measure your self diagnosis output on your under dash connector. You can hook up an analogue voltmeter thusly — positive to the upper right terminal and the ground to the bottom left terminal. If your ECU's given up the ghost you will get an alternating low and high reading; A-OK is low followed by seven short spikes. Anything else, call us back.

The fun continues...

 

Ok, got the engine running almost perfect. I'm impressed w/ the power this truck has. It was the crank sprocket/timing blade that fixed it. I ended up using roll pins and a new woodruff key. Had to unhook the vacuum to the egr to get it to run smooth, but i'll deal w/ that latr. I'm hoping there isn't a problem w/ oil pressure cause the oil can shaped light keeps coming on after it is fully warmed up and idling in gear. Engine oil is a quart low and i have not changed it yet so maybe that will help.

Now with the transmission. The fluid is almost a gray color, but it does not have a sharp or burnt smell. Is spIII the only fluid that can be used in this truck? Is that a dealer fluid or can i get it else where? I drove it around town for about 20 minutes and the 1-2 shift seemed to get better but the 2-3 shift did not- seem to improve as much. When it shifts it goes into a neutral between the 1-2 shift for a second then shifts into 2nd like normal then the 2-3 shift jumps back and forth from 2 to neutral to 3 then back a couple times. Then it shifts into 3 very firmly. I stayed in town so i didn't mess w/ o/d. When it goes into neutral between gears it does not seem to be slipping it seems like maybe a valve is stuck and it takes it a while to move. It doesn't seem to change if i drive it hard (~1/2 throttle) or if i just barely touch the throttle. I wish there was a better way for me to describe this. When i pulled back into my driveway i noticed the little 4x4 light (that looks like 4 wheels attached by pipes) was flashing so i'm guessing it set a transmission code. I haven't been able to borrow a scan tool yet. Anyone have any ideas? Could it be from bad fluid sitting in there for a year and gumming up the valves? Do you know if Seafoam Trans Tune would be ok in this transmission?
thanks

 

jcm wrote:

I'm hoping there isn't a problem w/ oil pressure cause the oil can shaped light keeps coming on after it is fully warmed up and idling in gear.

jcm ~ that's the only reason that little oil can light exists, to let you know there's too little oil pressure. Hey, I know what you mean — you hope it's only because the oil's low and not something more serious. But drive around with low pressure long enough and guess what? You'll be getting something more serious, guaranteed, so grab a quart of anything you can find in the meantime to stave off an oil starvation situation. You're going to be changing your oil soon anyway to something better, so it doesn't matter in the short run; just get that light to go out. Know what I'm saying?

Glad you solved the crank sprocket follies. That's one less headache to deal with. But what's up with your EGR valve? Have you checked your vacuum hoses for leaks? Good place to start...

So how old is this gray transmission fluid? Do you know? Is there a door pillar sticker or other way to know? Diamond ATF SP-III or Diamond ATF SP-II M or equivalent is recommended. You don't have to use Mitsubishi's brand as long as it's the same type. I'm a big believer in Sea Foam although I've never used it in a transmission it worked wonders in my lifters and engine generally. I'd try that and a complete fluid exchange with fresh and see if that doesn't smooth things out for you. It might be as simple as that. At this stage, it can only help and is currently your most cost-effective option.

Your flashing trans lights could also mean that the switches on your transfer case are bad, as they often are. Have you tried shifting in and out of 4wd and see if the problem rectifies itself? In any case go to a local auto parts store; they'll often read your codes for free (they're hoping to sell you whatever parts you'll need) and you can then see what you're looking at. The switches, should they prove to be the culprits, are attached to the side of the transfer case. Crawl under your beast with a flashlight and a pith helmet and you'll see them, along with the speedo cable. Verify that their connections are clean and tight. This costs nothing. But any codes you retrieve will let you ponder next steps.

Once you've done all that, we can move on to other things....

 

I was hoping you would say mitsubishi had problems w/ their oil pressure sensors giving false readings like ford oil pressure sensors did. Of course i do not have a manual fluid pressure gauge, so maybe i'll change the engine oil first and see if the light stays off and go from there. No reason to fix the trans if the engine is shot.

I think the egr solenoid is bad because if the vacuum hose is hooked up to the plenum the egr is open. Unplugging the solenoid does nothing so i'm sure its shot.

How does mitsubishi alert the driver that there is a problem in its transmissions electronics? Does it have a seperate light for the trans?