Q: Vehicle failing to pull, smoking black

asked by on

I am driving a Isuzu Big Horn 4JG2, 1994 model. When driving on plains (.i.e flat surfaces), the vehicle accelerates up to a maximum of 90Km/hr. However, when driving up steep slopes, the vehicle slows down to around 10 to 20Km/hr. It produces black smoke when driving up steep slopes. My Mechanic has tried replacing the turbo and serviced the injectors, replaced fuel and air filters but there is no improvement. What could be the problem? Daulos Mauambeta, Malawi

My car has 215000 miles.
My car has a manual transmission.

Hello. If the vehicle is struggling when traveling up inclines then it may be possible that there is issue related to the engine, or possibly transmission. Black smoke is produced when the engine is unable to properly burn all of the fuel that is being delivered into the engine. This can be caused by excessive fuel or lack of air. If the you have already serviced the aforementioned components then the next things I would look at are the vehicle’s fuel system. A malfunctioning fuel pump or fuel pressure regulator may be sending excessive fuel to engine, causing your issues. The same can also occur if there is an issue with one or more of the engine’s sensors that causes the computer to deliver excess fuel incorrectly. I would also make sure to use lower gears when driving up any steep hills or through heavy loads, as using higher gears may put an excessive load on the engine, potentially causing your issues. As these sorts of diesel engine issues can sometimes be difficult to diagnose, I would recommend having a professional technician, such as one from YourMechanic, visit your location to diagnose what the cause of your black smoke may be.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Vehicle failing to pull, smoking black

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: what is the function of this LOCK PLATE , COLLAR NUT, BEARING RACE, SHIM X, output FLANGE?

The output flange is to connect the driveshaft or axle depending on the type of rear end you have. The lock plate holds in the bearing using a shim to pre-load the bearing into the race. The collar nut holds...

Q: Q: Problems with idle

Unfortunately, this is something that older cars suffer from. Vacuum lines are made of rubber. Over time, the rubber in the engine compartments begins to get hard and brittle. Once this happens it no longer performs its job properly and...

Q: Misfire but when get up to 60 to 70 miles and hour, it runs smooth

Hi there. When I get these readings during an emissions test I usually start by checking the fuel pressure. A lean running condition from a weak fuel pump will cause this. If the fuel pump is fine, then I install...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.