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420A Limp Mode?

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ChristianP2506

Probationary Member
15
0
May 18, 2023
Brownsville, Texas
Hello, I need some help and advice on some issues I'm experiencing. To start, I have a 1997 Automatic Mitsubishi Eclipse GS.

It all started one day when I got into my car and noticed the handbrake light on. I went to tug on it and realized it moved freely without having to press the brake. It still remained functional and everything however, it did not lock into place when put fully down, and the light stayed on.

The car drove fine for a few days until one day on my way to school I realized the car sounded different. It sounded completely normal from 1st gear through 2nd gear, however, sounded extremely strained from 2nd to 3rd. The car felt as if it did not want to accelerate and go past 3k rpms. I continued driving it until one day I decided to test what would happen if I floored it. The car then proceeded to shut completely off. All the lights on my dash turned on and I heard a huge pop (backfire?).

One second later it turned on by itself and was able to drive it all the way home. The "limp mode" persisted until I discovered that the car may be in limp mode after doing some research (Did not know limp mode existed) and stopped driving it.

After a week, I decided to take it for a drive and it shut off at idle. I had to push the car to somewhere safe and immediately popped the hood. I took off the intake and sprayed carb cleaner and was able to start it. I'm pretty sure that means I have a fuel issue right? The injectors, fuel filter, and fuel pump are all fairly new, so I'm at a loss. Not to mention, I've tried many different cleaners and treatments.

My main concern is the limp mode. I've rebuilt the 420a before but unfamiliar with transmissions. I've looked into buying a throttle body position sensor (when spraying starting fluid and pressing the pedal I was told that the flap barely opened) and should be here in a couple of days, but also thinking of buying a shifter solenoid. Can someone point me in the right direction and also include a diagram of where the shifter solenoid is located and which one I need? Is the one I included the right one?

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Hello, I need some help and advice on some issues I'm experiencing. To start, I have a 1997 Automatic Mitsubishi Eclipse GS.

It all started one day when I got into my car and noticed the handbrake light on. I went to tug on it and realized it moved freely without having to press the brake. It still remained functional and everything however, it did not lock into place when put fully down, and the light stayed on.

The car drove fine for a few days until one day on my way to school I realized the car sounded different. It sounded completely normal from 1st gear through 2nd gear, however, sounded extremely strained from 2nd to 3rd. The car felt as if it did not want to accelerate and go past 3k rpms. I continued driving it until one day I decided to test what would happen if I floored it. The car then proceeded to shut completely off. All the lights on my dash turned on and I heard a huge pop (backfire?).

One second later it turned on by itself and was able to drive it all the way home. The "limp mode" persisted until I discovered that the car may be in limp mode after doing some research (Did not know limp mode existed) and stopped driving it.

After a week, I decided to take it for a drive and it shut off at idle. I had to push the car to somewhere safe and immediately popped the hood. I took off the intake and sprayed carb cleaner and was able to start it. I'm pretty sure that means I have a fuel issue right? The injectors, fuel filter, and fuel pump are all fairly new, so I'm at a loss. Not to mention, I've tried many different cleaners and treatments.

My main concern is the limp mode. I've rebuilt the 420a before but unfamiliar with transmissions. I've looked into buying a throttle body position sensor (when spraying starting fluid and pressing the pedal I was told that the flap barely opened) and should be here in a couple of days, but also thinking of buying a shifter solenoid. Can someone point me in the right direction and also include a diagram of where the shifter solenoid is located and which one I need? Is the one I included the right one?

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It's customary to provide additional information to an existing thread rather than repost the exact same in a new thread if you're not getting responses.

There are two different types of "Limp Mode" with these cars. The first is an ECU/PCM fault mode when it detects an issue with one more more of it's sensors. The second is when the computer for the automatic transmission senses a fault in one of it's sensors. In both cases the computer in question reverts if possible to a mode of operation that allows you to "limp" home.

I can't tell which you think you are dealing with. It sounds more like you have some sort of engine problem. Have you checked for any fault codes?
 
Many things here aren't making sense to me.

I went to tug on it and realized it moved freely without having to press the brake.
Pressing the brake pedal is not necessary to engage the parking brake.
It still remained functional and everything however, it did not lock into place when put fully down, and the light stayed on.
It shouldn't lock into place at full release. The button (lock) is only necessary to disengage the brake, at full disengagement you can pull straight up with no button.
One second later it turned on by itself and was able to drive it all the way home.
Actually a full second, or just milliseconds? A full second is almost enough time to reach zero rotational speed, and definitely enough time to fall below the operational threshold, unless it were revved high. Which would potentially mean the ignition switch has gone wonky. If much less than a second, you simply lost a requirement for engine operation which returned before the engine fully stalled.
(when spraying starting fluid and pressing the pedal I was told that the flap barely opened)
Pressing the throttle pedal how much? If the throttle plate is not opening fully, you may need to adjust the tension of the throttle cable. It seems to be too loose based on this description.
I took off the intake and sprayed carb cleaner and was able to start it. I'm pretty sure that means I have a fuel issue right?
Possibly, but the other issues you've described point to the opposite side of this spectrum. If you're popping and backfiring it isn't because of a lack of fuel, rather the mixture being too rich. Whether the timing causes this or not needs to be diagnosed. My very first step would be checking the mechanical timing to see if it has jumped. It will backfire, misfire, and lack power if the timing has jumped backward by even one tooth. And please note that the parking brake/emergency brake ("BRAKE") light indicator is entirely unrelated to any functionality of the engine or transmission. This is simply to notify the driver that the parking brake is engaged so you don't try to drive off and burn up the shoes. Totally different issue. For this specific issue, my first place to check would be the 1 pin connector underneath your center console. Those can come loose or get cut for who knows what reason.
 
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