4g69 Intermittent Choking

hornunga

hornunga

Active Member
Hey guys,
having a bit of trouble with the wagon, 4g69 manual. Ive taken it in to Mitsubishi with no success, just wondering if anybody has had similar problems or can help out.
Problem I'm having is the car seems to choke or lock when the revs drop down to around 1500 while in gear, it will stick to the 1500rpm regardless of what i do to the accelerator for around 2-3 seconds and then it will launch. Mainly happens when going through roundabouts, drop the car back to second before entering roundabout, turning corner go to accelerate out pause then will accelerate. This is the main offender, again it is intermittent, has happened in slow stop start traffic, has happened in second and third gear.
Mitsubishi could not find this fault, i even took a mechanic on a drive with me to try and replicate the action with no result and was told there was nothing wrong, don't worry about it the car drives fine, try to keep my revs up and/or only bring it back if it gets worse or i can find a way to replicate it. My driving style hasn't changed from owning a sedan to a wagon with the exact same engine/drivetrain. I know there is something not right!

Ive swapped or replaced parts with no results.
Coil packs
Spark plugs
fuel rail
injectors
fuel filter
fuel pump

And now im at a loss, any help would be appreciated.
 
its worth having a look-see at the throttle body valve make sure its not sticking. Usually only see this is in older vehicles due to a build up of oil and junk accumulating around the valve acting as an adhesive. (not likely in your car)

most likely its your ecu and electronic sensors letting you down, 4G69s came standard with electonic throttle control or "fly by wire" setup. This means if there is an issue with the engine the ecu can and will lock the throttle body. It seems to be what you are experiencing...

electronic_throttle_control_2.gif
 
The throttle body is still golden and spotless.
I have had throttle lock before when changing out my fuel.rail in the sedan not the wagon which threw a check engine light and locked the throttle to a maximum 2500rpm, thats what it feels like.it is doing but unsure what is causing it. Trying to problem solve with the fly by wire will be like finding a needle in a hay stack.

The wagon doesnt seem to have as much go as the sedan which i just put down to added weight. Which now i believe could be to do with what is causing this.
 
hornunga said:
Trying to problem solve with the fly by wire will be like finding a needle in a hay stack./quote]

i hear you there!!

i would be checking all the sensors and wires for damage or loose connections, the CG came out with miriad of new complex electronics that differ to previous Lancers so theres plenty to look for.
Im really not a fan of the electronic throttle control, any minor issue can turn into an annoying large problem.

Good luck with it :thumbup: .. hope i've been some sort of help haha
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We've had the same issue with our 4G69 manual wagon from new. Something to do with fuel pressure regulation that only affects the manual cars apparently. Mitsy have reduced the problem by reflashing it with an updated factory tune every time we have it serviced, but have never had a permanent solution. We keep getting advised that it's a 'characteristic of the vehicle' and have learned to live with it. I have been told that replacing the fuel rail with a bigger bore rail and replacing the ECU with an aftermarket one can fix it, but I'm not willing to spend that cash for that on a car that is just our family hack.
 
Its just strange beacuse ive got a 2.4 in the sedan aswell as the wagon and the sedan doesnt do it.
I have learnt to deal with it for now but it is still a concern.

I am glad to hear im not the only one who has it though.
 
That is a possibility. But won't i run into immobilization issues without changing key barrel etc?
 
hornunga said:
That is a possibility. But won't i run into immobilization issues without changing key barrel etc?
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You can swap the immobiliser chip from the sedan key when swapping the ECU because the chip and ECU must match for the car to start.
 
For those who are interested. I fixed my problem. It was the air flow sensor. Swapped it out with an old one i had and reset the ecu. Dead spot gone!
 
Slee96 said:
I have this problem :( How much is that set you back?
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I picked mine up from a member on here that was wrecking for $30 so happy dayz.
If you have a pick a part of similar in you area i cant see them charging too much more.
 
hornunga said:
For those who are interested. I fixed my problem. It was the air flow sensor. Swapped it out with an old one i had and reset the ecu. Dead spot gone!
Click to expand...
MAF sensor right? the one on the air box?

I am having some sort of hesitation issue sometimes after the car has been running for long periods of time. I press the accelerator and it doesn't take off quickly enough, stays around 1200rpm for a second or two then takes off like crazy. :think:
 
ABS said:
hornunga said:
For those who are interested. I fixed my problem. It was the air flow sensor. Swapped it out with an old one i had and reset the ecu. Dead spot gone!
Click to expand...
MAF sensor right? the one on the air box?

I am having some sort of hesitation issue sometimes after the car has been running for long periods of time. I press the accelerator and it doesn't take off quickly enough, stays around 1200rpm for a second or two then takes off like crazy. :think:
Click to expand...


Yeh the MAF sensor. Thats exactly what i was having. But temperature didnt matter. Mind you i havent taken my car for a long run (40+km) since replacing the sensor.
 
Sounds similar to what I'm experiencing.. Do you have to reset the ECU after changing the MAF? How do you do that :O :think:
 
I just did it for *poo*s and giggles to make sure the computer recognised the change.
Dissconnect the negative terminal off the battery for half hour while changing the sensor. Once all done and dusted. Connect her back up and let the car sit at idle for 5 or so mins then take it for a spin or two around the block.
Dont forget to take note of any stereo settings you have. You will loose them.


I still feel there should be some form of an update for the fly by wire for these cars to increase the responciveness of the pedal. Ill pop in and ask oneday at the local mitsu shop.
 
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