Mitsubishi Montero Fail Safe Issues

Truck Starts fine,but will not go more then 30 KMph


Customers Issue:-----

My Mitsubishi starts fine,but will not run more then 30 Kmph,is it a fail safe issue.Its 2003 Montero Truck.
The acceleration is very poor.

Garage Experts Reply:---

I dont think so,as per your problem,i suggest you to get the vehicles Engine computer module checked,such problems are very common on these Mitsubishi vehicles.


As per your vehicle model,there are two fail safe systems on these trucks.
One is transmission fail safe issue.The transmission fail safe provides Reverse and 3rd gear only (and some harsh engagement as electronics are shut down), but that doesn't fit your issue.
The other fail safe issue is electronic throttle control.On late 2003 year model vehicles went to an electronic throttle  just snaps the throttle shut to about 5% opening and you lose all throttle response.... again it doesn't fit your issue..... plus any throttle body anomaly should set a fault without fail.
So if in your case,is there any check engine light coming up on dash.Is there anmy warning indicator light showing on dash.If yes,get the engine module scanned and see what codes are set in module.As per that you can continue further.


Customers Reply:---

What if the Warning light comes after sometime.

Garage Expert:---


Suppose if its a skewed ECT reading lets say 40F low, then you could have over fueling that under load just floods it too much....this is something that could take a long time to set a engine light as well, though I would expect some idle quality issues especially on cold start were that the case.

You can try these,

Unhook those pre-cats. These cats are notorious for failure, and that would certainly give you poor acceleration and very low top end. As per level of performance received, you should probably even be able to tell from putting your hand behind the exhaust to feel for flow.


Customers Reply:----

I will try these troubleshooting,Thanks.

Users Who Viewed This Problem Also Viewed:

Fail smog test due to gas filter hose?

http://repairhelpcenter.blogspot.com/2012/01/fail-smog-test-due-to-gas-filter-hose.html

Check Powertrain message and Safety Mode Reduced Performance on Holden VZ Commodore?

http://howtobyme.blogspot.in/2012/02/check-powertrain-message-and-safety.html

2004 Dodge town & country: Jerks and Hesitates During Acceleration?

http://technoanswers.blogspot.in/2012/07/2004-dodge-town-country-jerks-and.html

Engine accelerates when brake is applied?

http://technoanswers.blogspot.in/2012/02/engine-accelerates-when-brake-is.html

Loss of acceleration?

http://technoanswers.blogspot.in/2012/02/loss-of-acceleration.html

1993 Pontiac Firebird V8: Very slow to Accelerate?

Common complain on these engine models.

Its a old model car.

There are few tests and inspection necessary to confirm the fault causing the problem.


On 1993 Firebird formula didnt have alot of get up and go to begin with. Although the 6sp manual transmission version did have a top speed of around 150mph, the 1/4 mile time is only 14.9 seconds, which is not very fast. It only has 275hp and 325ft lbs of torque.

So if you are referring to take off times and fast acceleration, it really wasnt there to begin with.

If you just mean that it barely accelerates and seems to be bogging down on acceleration or hesitation,then parts needs to be checked out.

Check and confirm this information:---------

Is the check engine light on?

How does the engine run at idle - smooth, misfiring?

Any exhaust smoke while idling or accelerating from a stop? If so, what color and does it smell like fuel, coolant, or oil?

The first 2 steps at this point are to first pull the plugs and inspect them for being not just worn, but for signs of running rich(black and sooty) or too lean(whitish) and go from there in of course replacing the plugs, but then testing for vacuum leaks, check fuel pressure regulator vacuum line for fuel in it(replace regulator if found), and if ok, check O2 sensor for being black from soot and replace if needed,


2nd step would be to test engine compression. A worn out engine with low compression will be slow and loss of power on acceleration. if compression on any cylinders are under 100psi, or more than 10% difference between lowest and highest number, then unfortunately a rebuild is in order.

Start by troubleshooting this possibilities.This will help to confirm the issue.

Thanks.

For All types of Car models and brands help 
Go to Newly Launched

FREE Car repair guide? 
http://technoanswers.blogspot.in/2012/03/car-repair-guide.html 

& 
Complete Car repair Help FREE? 

http://repairhelpcenter.blogspot.in/2012/03/complete-car-repair-help.html

poor acceleration problem?

Check engine light was steady "ON" on dash.Getting car module scanned showed error P0141.
Error P0141 is for oxygen sensor problem.
If the air filter is plugged it can cause increased fuel consumption and in severe cases it can cause running problems. The O2 sensor code you have is for the heater inside the coil. In order for the O2 sensor to work properly you need to have the sensor hot. In the past the engine would run in a predetermined fuel map until the O2 sensor was hot and started working. At that time it would switch and add/subtract fuel by using the O2 sensor. That few minutes or so when this was happening (engine running off fuel map before O2 sensor was hot) was causing increased emissions and to stop this they started making O2 sensors that have a heater inside. It's similar to a toast coil. It's a wire inside that gets really hot as soon as the engine is started to reduce the time the O2 isn't working.

What usually happens is that wire inside breaks and the computer doesn't see any change on that wire when it's sending current too and then it sends a code and turns on the check engine light.

But in case if you still get error Check engine light on dash then,

I would take off the cat. after the header and check for a plugged exhaust. You should be able to see light through it. Looks like a honeycomb just smaller cells. It should not look melted or anything and should not have chucks of anything falling out or anything.
If it looks good then you need to check the header for blockage. I think you may have a blockage.
Another thing you can do is put a vacuum gauge on the intake manifold and watch the needle after you rev the engine up and let it idle. It will drop down on the gauge if it's got a blocked exhaust.