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Doug
Doug, ASE Certified Technician
Category: Mitsubishi
Satisfied Customers: 8568
Experience:  Mitsubishi employed and Factory trained ASE certified technician
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My wife's 2003 mitsubishi outlander loses power when I hit

Customer Question

My wife's 2003 mitsubishi outlander loses power when I hit the gas hard to pass and sometimes backfires. I replaced the throttle position sensor, but now it is still doing it.
Submitted: 1 year ago.
Category: Mitsubishi
Expert:  Doug replied 1 year ago.
Hi,
Is the Service Engine Soon light turning on, either all the time or even just when the problem occurs?
Customer: replied 1 year ago.
sometimes when the problem occurs.
Customer: replied 1 year ago.
Hello?
Expert:  Doug replied 1 year ago.
Thanks.
Sorry for the delay. Are you able to get the system scanned (most auto parts stores will do this for free) close after the problem occurs so we can see what fault(s) set?
Customer: replied 1 year ago.
I had it scanned, but the service engine light was off at the time and they read nothing.
Expert:  Doug replied 1 year ago.
I understand.
What is the history of the timing belt, had it been done within a reasonable time frame (They are due every 60k)?
If you run the engine at night and rev the engine some, so you see any red glowing from the exhaust (under hood or beneath the car)?
Customer: replied 1 year ago.
I replaced the timing belt 10,000 miles ago and had no problem. I believe if it was the timing belt it wouldn't be a intermittent problem.
Expert:  Doug replied 1 year ago.
Thanks, ***** ***** not realize the problem came and went.
How about the exhaust glowing in the dark when revving?
And can we induce the engine light so we can scan it again and see why it was turning on?
Customer: replied 1 year ago.
Glowing on the inside? What would that elude to? The light is on right now. I induced it when I replaced the TPS and stompped on the gas and it lost power and backfired, but when slowly pressing on the gas it revs up fine.
Expert:  Doug replied 1 year ago.
The glowing would be either on the manifold or under the vehicle (roughly around the center console area or at the bend toward the muffler). These would indicate a restriction in the exhaust if you saw glowing.
This is probably already been looked at since you were doing a TPS, but there aren't any tears in the intake duct between the throttle and the air filter is there? Cracks/baffles missing/etc?
If you unhook the MAF (right behind the air filter, the big square sensor) will the engine run acceptably, and if so is the problem more or less identical when you stomp on it?
Customer: replied 1 year ago.
No tears, no wire quality issue. When I pull the MAF it actually revs up when I stomp on it, slower then it should, but it don't try to stall out like when it is plugged in.
Expert:  Doug replied 1 year ago.
Hmm.
Looking in the MAF opening, do you see any signs of fuzz or filter material, or any black/soot like gunk in there? Paying particular attention to the pillar like portion in the center.
Customer: replied 1 year ago.
I was away on work. I pulled and inspected, it is clean no soot, looks good.
Expert:  Doug replied 1 year ago.
Thanks. What is the condition when the MAF is unplugged?
Have you set any codes since last we spoke?
Customer: replied 1 year ago.
It seems to not want to stall when it is un-plugged, but it doesn't rev up fast. the only code was P0122 which is a TPS. I replaced that already.
Expert:  Doug replied 1 year ago.
Is the tps fault still present after the tps was replaced?
Do you have a live data scan tool so we can see what that sensor is doing if so?
Customer: replied 1 year ago.
yes the tps code is still present and no i don't have a scan tool.
Expert:  Doug replied 1 year ago.
Hmm. It is pretty hard to discount that fault considering how closely related it is to your symptoms.
Do you have a multi meter? If so, let's unplug the sensor and test for voltage with the key on at each wire and let me know what you see there.
Customer: replied 1 year ago.
Which sensor. I tested the TPS with a multi meter. I got the 5v from computer and when gas is pushed voltage rises. Also I confirmed it had a good ground.
Expert:  Doug replied 1 year ago.
The tps, please unplug the sensor and check voltage with key on, not plugged in. Let me know what your source voltages are.
Customer: replied 1 year ago.
What is a tos sensor? If you ment TPS. It is receiving 5v on one terminal.
Expert:  Doug replied 1 year ago.
TPS. The spell check refuses to acknowledge those letters, so I have to go back and change them each time I post. You must have caught it in the 10 seconds before I changed it.
Please plug the sensor back in and then back probe the 5V wire. Tell me what the voltage is at rest, then the voltage fully opened.
Finally, slowly open the throttle and watch the voltage, is it linear movement?
Customer: replied 1 year ago.
As stated before I got 5v from the computer. On the other wire which tells the computer what the throttle position is, I get 0v to 5v as it is turned depending on how much it turns. It is linear in movement.
Customer: replied 1 year ago.
It peaks at a little over 5v full throttle.
Expert:  Doug replied 1 year ago.
You get 0V when closed? Is that exact?
Customer: replied 1 year ago.
.39v
Customer: replied 1 year ago.
Its .39v at idol to a little over 5v at full throttle.
Expert:  Doug replied 1 year ago.
Thanks.
Please loosen the TPS and adjust it so you are at 0.700V when fully closed. Then clear the fault and see if the P0122 returns or not.
Customer: replied 1 year ago.
The closest I can get it is .71v. The light is still on. I can clear the code, but the code only returns on occasion any ways. It seems to be running better now. Its still idoling a little low about 600 RPM.
Customer: replied 1 year ago.
I was unaware of needing to adjust the TPS sensor.
Expert:  Doug replied 1 year ago.
Thanks.
At this point the only thing I would try before getting it to a shop for a full inspection would be trying a different tps sensor -if the new one was aftermarket-. Mitsubishi and aftermarket electronics do not get along, so this could be a plausible scenario, add it would certainly be far from the first time something like this has happened.
The fault you are getting is literally saying that the voltage for the tps is dropping out. It only sets if the computer sees near zero voltage (0.2v or less).
We know the 5v source is good, and we know the fixed ground is good (as it is shared with the other sensors on the car), which would leave us (again the sensor being ruled out, which if aftermarket we can't exactly do at this point) with either a wire issue between the computer and the sensor on the sensing wire or a problem with the computer itself.
Neither of these are terribly common at all, however an inspection with a full scan tool could help rule the wiring out. If the scan tool sees the same voltage at rest you are seeing on the meter and no dead spots in travel, then you would know the wiring is intact as well. This would only leave the computer itself or again the sensor if it is feeding noise back on the wire or similar scenario like we see with low quality electronics.
If you can not get to a shop with access to a scan tool to test this condition, then I would suggest checking your exposed wiring around the sensor area for signs of damage, and again if the sensor is aftermarket trying a genuine one (even if used) before going further. A computer issue is highly unlikely. Just remember to set the new sensor like we did (0.650-0.720v roughly at closed position).
Customer: replied 1 year ago.
This is the first weekend I have had to work on the car again. It is still doing the same thing. I have the TPS set right, yet the car is still having a rough idle and back fire and it wont rev up without dying.
Expert:  Doug replied 1 year ago.
Yeah with that ruled out it is going to be time to get it to a professional with proper scan tool that can log the engine management and see what is out of place.

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