(800) 853-2651
SHOP NOW

Mitsubishi Truck problems again

O

old

Well-known Member
Location
Camdenton Missouri
Well not sure what the heck to think of this little truck. Did the fuel pump and it ran real well, then tonight when I was driving home it started to run just like it did before I did the fuel pump. It will not o up to RPMs like it should and will some times die. Exhaust seems to smell like it is hot but is not getting red hot. Thinking maybe the catalytic converter might be plugged up or getting that way. Also seem to run ok till it is good and warmed up then it does not want to run well enough to pull its self. If your lucky when it does mess up if you get the RPMs up and can keep them up it might go but other wise will not pull its self.
So any ideas what might be wrong. 4 cylinder auto, EFI 1993 mighty max
 
If it is the cat, you can find out by pointing a laser thermometer at it, when the problem is occurring. Cat should be about the same temp as the manifold and rest of front pipe, if its way hotter, its plugged.
 
My 91 ford pickup was doing something real similiar and it was the cat converter. Not such a drastic loss in power but more than noticeable and stunk real bad. Can you disconnect it and run it for about the same amount of time without causing other damage?
 
It's possible it it the cat. Using a non-contact laser thermometer can help. The cat should be approximately 150 degrees hotter at the OUTLET. That way you know if the catalyst is working. You can also put a vaccum gauge on it when it acts up (manifold signal)then rev it in neutral and see if the vaccum signal drops slowly as the engine labors. Sometimes they break apart and pounding on them from below makes them rattle.
Gerard
 
Hey Old. That truck is new enough to have a diagnostic port on it. If so, take it someplace where they'll do the test for free (Advance Auto,etc) otherwise you're going to be throwing parts at it. My old Tacoma (my son has it) was doing that and it turned out to be the charcoal canister. Or, it could be the O2 sensor, or, who knows?
 
I forgot to add to make sure the truck is at operating temp. before the temperature test. They call this "light off" and it occurs around 650 degrees. If you don't have a non contact thermometer, sneak into the kitchen and get one.
 
How did you fix the fuel problem?I remember you had trouble with the lines,but you didnt say if you put in a new fuel pump or one from a junk yard.Maybe you need to test the pressure on the fuel pump somehow.Could be the catalytic converter.You could unhook it and see if it ran better.
When I did my Chevy I got a fuel pump from a junkyard,but it didnt last but maybe a couple of months.Then I had to get a new fuel pump.So far its been working a couple of years now.I mean you could just change the fuel pump on mine.Plus for a Chevy pickup I think it was 55.00 dollars for a new fuel pump at American Auto.Since my lines were rusted out I bought that part at the junk yard with a fuel pump for I think it was 30 dollars and it lasted a couple of months.When I put the one in from the junkyard I put them down in a bucket of gas and hooked the pump to a battery and the one from the junk yard pumped way more than my old one that day,but it soon got to acting up once I started using it.Thats the bad thing with buying stuff from a junkyard is that you dont know if its any better than yours or not.
 
I posted the other day the fix I did for the fuel pump mount and all. Yep new pump and I did have to rig up the lines but I used approved fuel injection rubber hoses to make it work so I'm pretty sure the pump is not the problem since it is new. Ya I know could be bad right out of the box
 
93 Mitsubishi does not have any port that the local guys can check the system out. That was the first place I went when the problem started not long ago. Even asked the local shops what your believed was wrong with it and they all told me the fuel pump and yes it did seem to check out low on pressure but my gauge does not really read high enough to check it well so the pump may not have been bad.
 
I have a vacuum gauge which is also a fuel pressure gauged which I used to test the fuel pump only thing is it does not read high enough to test the pump like it should be tested. But I know it should read the vacuum since I don't think engine vacuum has changed over the years. As for a thermo not sure what your saying there about the kethcen
 
I've had vacuum leaks drive me straight up the wall a couple of times, but I wouldn't think it would occur at other than idle or part throttle conditions. Maybe throw a vacuum gauge on it so you can watch it while driving? Might help detect a blockage in the exhaust too, but I'm not sure about that. Just a thought ....
 
Well I have tried all day to get this stupid truck to mess up and it isn't doing it. I have checked the vacuum on it and that seems fine right now as in 20 when at idle then if you floor it it drops almost to 0 and then comes back up just like it should. If you open the throttle up slowly it drops and little then back up just like it should. I did do an old hot rodders trick in hopes that it will help. I got it good and warm and then sprayed the exhaust with water with it running. Then let it heat back up shut it off and filled the exhaust with water and then started it back up., I did that a couple times don't know if that helps or not but worth a try I guess
 
and the worst part is,. after you get done fixing the pickup you have the brakes to fix on your dads dump truck, then after you fix them your son wants you to restore his old chevy pickup in between you have to keep a mower working for your nephew I wish you good luck!! lol
 
Ah but you forgot the hay and the garden and the canning which by the way I have a pot sitting right now that later tonight will be home made sweet pickle relish
 
If you don't have a non contact thermometer maybe you have a thermometer inside that will read that high. I don't can, my wife does, and I don't know how high those go. A quick rev won't do on checking the vaccum level. You will need to hold it at about 2,000 to 2500 rpm for about 1 minute. It should drop from throttle opening then stabilize not continue to drop. Bad cats. are usually predictable and don't usually just clear up and run fine for a while unless they are cold.
 
Rich, just got off the phone with a buddy, that last fall was having the same problem with his truck that you are having. I had to go out in the middle of no where and haul it home for him. All it was, was a plugged up catalytic converter. He told me to tell you ta check on how much exhaust is coming out of the tail pipe after it gets warmed up.

Keith & Shawn(Gold Medal Winner)
 
When it runs bad unplug the map sensor and see if it runs better. The controller should go into a default mode. I don't remember how the Mitsubishi determines air flow on that engine. Some used a hot wire, literally, which can be cleaned and some used a mass air flow sensor. Is the MIL light on?
 
Fuel delivery is controlled by sensors telling the computer what's happening since the computer can't see it. The map (manifold absolute pressure) sensor measures manifold vaccum. The map sensor should be near the top of the engine and have a short vaccum line with an "S" curve in it. It will have three wires going to it. When your truck acts up unplug it to see if it runs better. You will turn on the check engine light when you do this because the key is on. Is your check engine light on now?
 
Check engine light has been coming on and then going back off depending on which bump you might hit. But yes as of the last week or so the light has stayed on and I tried yesterday to see if I could make it go out by unhooking the battery for a couple hours and that did not work. Oh and by the way most of the time the truck will run ok for about 30 minutes or so as in gets warmed up then it messes up. Of course it doesn't do it all the time. Like the day I got the tank back in it ran fine all the time I was driving it then on Sunday I drove it 4 miles or so to a place an about an hour or so later home. Then an hour later back and then went to come right back home and it was all I could do to get back home because I could not get the RPMs up
 
Well I looked for that part and did not find it. Ya I know it maybe there but I do not see anything like your talking about but ya who knows maybe I looked at it and did not see it. LOL
 
Start it and wiggle the wiring , trying to duplicate the "bump" on the road. Getting that code would do a world of good for you. Just for grins, cycle the key on and off three times to see if that causes the check engine light to flash. If it does, The long flash is 10 and the short flash is 1. Add them together for the code. This may not work, but we need the code otherwise we are shooting in the dark which might get expensive. Was it raining when the problem happens or was it dry out?
 
Well in the past if it has been wet out it is more likely that the check engine light will be out but dry more likely it is on. But today when I started it up but did not drive it the light went out. I had tried to wiggle all the wires I could on it but again who knows. I did have it at O'reilly's not to long ago to see if they could read the code and they could not hook up to it with the stuff they had so again goes back to how do you check why the light is on if you can not find a person with the right stuff to check it
 
The reason they cannot check it is because it is OBD I. Which means every manufacturer was able to make their own Data Link Connector (DLC) and have their own codes and put it wherever they wanted. Pure stupidity for mechanics. Auto parts stores have OBD II scanners which was required in 1996 and newer and the port was standardized in one location with codes that were mostly generic. I can stop by on my way to Springfield for instructor training with my scan tool and maybe we can figure something out. I will leave probably Sunday around noon on the 26th if you can wait that long. Gerard
 
Mitsubishi mighty max 1993 and if am reading it right it is a 2.4 four cylinder with automatic. You do know I live up here by the lake of the Ozarks don't you
 
Yes, You said I would have to get off at the Lebanon exit. How far are you from that point? Oh and the directions would help. I'll send an e-mail.
 
Well if coming in from the east it would be the Richland exit on I44 if from the west it would be the Lebanon exit. Either one puts me about 20-25 miles north off of either Hwy 5 from Lebanon or Hwy 7 from Richland
 
You must log in or register to reply here.

Similar threads

Hdonly
Toro 223D with Mitsubishi L3E engine
Replies
10
Views
282
jrsavoie
J
M
NAA problems
Replies
9
Views
277
old
O
S
Ford 3600 gas Governor problem?
Replies
10
Views
253
Mark-Ia
M
M
D-17 gas series I stalling
Replies
4
Views
332
old
O
B
Kubota M4030SU
Replies
1
Views
71
Blackhole49
Blackhole49
Tractor Parts Tractor Manuals

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Copyright © 1997-2024 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters
Website Accessibility Policy

Back
Top