I've been trying to solve a problem with my car, Mitsubishi replaced the gearbox but lately the gears aren't changing smoothly and the car feels like its lost power and ill have my foot down on the accelerator but it won't pick up the speed. After a few seconds the engine will make a load roar then the car will take off. Has anyone heard of this problem before?

I could be sitting at the lights and the car will struggle to get past 40kms....The car sometimes wont change gears until it hits 4k revs, even in tiptronic the car will pullback and not pick up speed. I have spent alot of money paying mechanics to try and fix it but the problem just keeps coming back.

142k on the clock, no mods.

When was the last time you flushed the transmission fluid? What colour is the fluid currently?
When and under what circumstances was the transmission replaced?

I'm wondering if it may be a torque convertor issue? I can't advise you on it though, not qualified.

I just did a quick google on Torque convertor bogging, got this hit, I have had a TR which had TC issues, very boggy, use to feel like it was going to rip itself of the mounts with flatout shifts, had slip and shudder at highway cruising.



Search result.

Torque converter lockup can have a major impact on how your engine performs. The torque converter is a part of the transmission, and you will notice that the engine will hesitate and be underpowered when it is locked up. There can be many different causes for certain engine problems. However, if you believe that the torque converter is locked up, here are some troubleshooting tips to make sure.

Revving when Idling

One of the prominent symptoms of a problem with torque converter lockup, is that the engine will rev up and down while it is idling. This may result in a stall, but mostly will cause the vehicle to lurch forward when not in park.

Engaging in Gears Randomly

Another symptom of torque converter lockup is that the transmission will shift into gears at random. Also, it will not allow the overdrive gear to engage immediately upon demand. Your car will act like it is bogging down, until the torque converter engages the overdrive.



Keeping Clutch Disengaged

You will notice that as you try to slow down, the transmission does not go into a lower gear. This will then result in not being able to accelerate when the gas is pressed. Most of the time, this is noticeable when you come to a stop sign or stop light, and need pull out into traffic.


Read more: http://www.doityourself.com/stry/troubleshooting-torque-converter-lockup#ixzz2kEqoj4B5

It was last flushed when the gearbox was replaced, which was quite a while ago. I checked the levels which seem fine, the colour seems clear.
They replaced it because the gears kept on slipping.

That seems fairly spot on TV, might be something I need to look into. Doesn't shift into gears randomally though.

Was it a WTY job and the box was supplied by Fluidrive in VIC?

Yeah warranty job. Not sure where the box was supplied from. Just driving to my parents place, lights turn green, put my foot on the accelerator the car just rolls forward with no power at all. Exhaust makes some popping noise then it takes off but doesn't change gears in time.

Yeah, I don't really know, sounds weird, might be worthwhile checking the Throttle position Sensor too.

Maybe needs the MUT hooked up and if it's doing it consistently they can data log it or take snapshots of all the sensors. I had to force a dealer to do that after my last box was replaced with some weird happenings, they thought I was imagining my issue but end result was incorrectly set TPS.

It's hard to find someone with the experience and knowledge but I got the right guy on it in the end who was born and bred on Mitsubishi his whole mechanical life and had owned and driven them.

I'm just over it, been dealing with it over the past 4-5 years. When I think the mechanics fixed it, it always returns. Too much money has been wasted.

I'm just over it, been dealing with it over the past 4-5 years. When I think the mechanics fixed it, it always returns. Too much money has been wasted.

Yeah, I know how you feel. 4-5 year problem? I thought you said just lately. So what's been done in the past and how long does it stay good for?

The last thing that was done which was a few weeks ago, was all the spark plugs and covers got changed as there was oil apparently leaking onto the spark plugs, which fixed the problem for like a week. Other than that the only other work that's been done is the gearbox change and it's regular servicing.

Could be a number of things then, almost sounds like intermittent electrical issue? My third gen is 8 yo yet to face something like this or the dreaded heater core leak on the computer. Touch wood.

Just hope I can get the parts into the future, still heaps of life in it with 140 000, still drives very well.

Yeah, as much as I like my Magna, I can't say ill ever have faith in one let alone mitsubishi anymore. Hope your other car goes well though :D

Have they taken a look at the heater core and ecu?

Moisture may have caused a short..

Also check the Throttle Body.. My GTV went into limp mode because of the TB.. Required replacement!

SuFz

I had them check everything they could, I might drop it into am auto electrician through my work and get them to check to see if it's an electrical problem

If it went it to get new spark plugs and that fixed it for about a week it's an ecu issue. Obviously they touched the battery or ecu or something when they did that and then over the next few days either the trans or the ecu did it's relearning procedure and it went back to being shit. My s15 is doing the exact same thing. Reset ECU and it runs fine, after a bit of driving it goes back to being crap.
I think you should look into that.

Easy way to check that is unhook the battery for 10+ seconds and that will clear the ECU. if your problem clears up - thats your problem.
Once the problem returns, check the codes.

Have they taken a look at the heater core and ecu?

Moisture may have caused a short..


This. Check for moisture in and around the ECU area behind the dash and moisture in the passenger footwell area.

Are there any lights flashing on the dash (such as the 'N' on the gear selector in the cluster, etc.)

New plugs fixes it for a week . . . .

My money is on . . .

Ignition coil!

I am with Max

I can not see why anyone in their right mind would disconnect the ECU or Battery to change plugs. I would be starting with a new coil BUT that is only for the issue with the motor

Reading your initial post it does not sound engine related unless your impression is the fact that the box feels laggy. Problems like these are so damn hard to dignose over the net but I would start with electrical if new spark plugs made the car better for a short time because the new plugs would have had better spark initially and as they get a coating of carbon over them they will not spark as well thus you are back to where you started. Still check the ECU and also the connections on the trans as well as often the later TJ series can get corroded pins on the trans plugs

i hope this gets sorted out for you.

Nothing's flashing no, but i'll get them to check everything that you guys have mentioned so far. I will let you's know the outcome of it all. Thanks :)

A couple of years ago I had a faulty O2 sensor on the car and that really made the car behave erratically! If you haven't had the O2 sensor changed in a long while it would probably be worth doing anyway, but if you don't want to go to the expense there is a simple test to see whether it is the O2 sensor, unplug it! (the electrical connection, not unscrew it from the exhaust). With it unplugged, the car should use the values it does when the car is warming up. Worst case scenario, it will at least give you one less possibility for the cause of the issue! Remember to plug it back in though after you have tested it a while, as you will get a little worse fuel economy with it unplugged.

This is the one I bought, still going great!
http://www.ebay.com.au/itm/120738436183
(seller apparently is away until the weekend and hasn't got any items currently listed).

From memory there is a specific one for the Magna as well which is exactly the same, but just has the plug on it for easier installation. I don't think that was available at the time I purchased that one, saves the effort of splicing.

A couple of years ago I had a faulty O2 sensor on the car and that really made the car behave erratically! If you haven't had the O2 sensor changed in a long while it would probably be worth doing anyway, but if you don't want to go to the expense there is a simple test to see whether it is the O2 sensor, unplug it! (the electrical connection, not unscrew it from the exhaust). With it unplugged, the car should use the values it does when the car is warming up. Worst case scenario, it will at least give you one less possibility for the cause of the issue! Remember to plug it back in though after you have tested it a while, as you will get a little worse fuel economy with it unplugged.

This is the one I bought, still going great!
http://www.ebay.com.au/itm/120738436183
(seller apparently is away until the weekend and hasn't got any items currently listed).

From memory there is a specific one for the Magna as well which is exactly the same, but just has the plug on it for easier installation. I don't think that was available at the time I purchased that one, saves the effort of splicing.

I bought one of those and it died after 8000km. Warranty job and got a refund and fitted one I got from autobarn.

Speaking of that, I had a sound system installed quite awhile ago but I'm pretty sure the guy was dodgy, could incorrect wiring play funny games with the car? Lol

A couple of years ago I had a faulty O2 sensor on the car and that really made the car behave erratically! If you haven't had the O2 sensor changed in a long while it would probably be worth doing anyway, but if you don't want to go to the expense there is a simple test to see whether it is the O2 sensor, unplug it! (the electrical connection, not unscrew it from the exhaust). With it unplugged, the car should use the values it does when the car is warming up. Worst case scenario, it will at least give you one less possibility for the cause of the issue! Remember to plug it back in though after you have tested it a while, as you will get a little worse fuel economy with it unplugged.

This is the one I bought, still going great!
http://www.ebay.com.au/itm/120738436183
(seller apparently is away until the weekend and hasn't got any items currently listed).

From memory there is a specific one for the Magna as well which is exactly the same, but just has the plug on it for easier installation. I don't think that was available at the time I purchased that one, saves the effort of splicing.

I have seen bosch 02 sensors for around $70, i would rather buy a known product imo

I am with Max


Sorry but had to giggle ^ This doesn't happen alot.

Thanks for the quick info guys about the O2 sensor, Im looking to do mine, was looking at that cheapy, ill spend a bit more and get a well known one.

OP yes a dodgey sound system canm but just to give you an idea if something is wrong normally the first place for something to show is in the fuse box either in the kick panel or engine bay. Depending on how its wired it can blow a couple of fuses the most common are the radio fuse in the engine bay or interior light fuse in the drivers kick panel, it takes no time at all to check however if a fuse has blown you would normally know by the lack of accessories active. However with that said it wouldn't normally work for a week, stop and then start again. Howevers its a free and easy check and I know alot of mechanics who would over look the fuse box.

I have seen bosch 02 sensors for around $70, i would rather buy a known product imo

I agree, didn't realise they had come down so much. When I got mine I think a brand name one like Bosch, Denso, NGK etc were something like $120

Seems like it IS the ECU, I reset it and the car was driving perfectly!