Black smoke from exhaust

I need to know what i can do to stoop the black smke from coming out of my tail pipe, this has reduced my gpm badly, i also want to know where i can get a new brain box for my isuzu trooper 94 (SOHC, IEFI)

Do you have the Isuzu 3.2L engine installed like I do? The Oxygen sensor was causing the black smoke in my Rodeo.

http://www.automotiveforums.com/vbulletin/showthread.php?t=258045

I'd check the oxygen sensor and other inputs to the ECM ("Brain box") before replacing it. The ECM is expensive and not likely to be the source of your problem.

Is the check engine lamp lighting up on your Trooper?

Dale

I need to know what i can do to stoop the black smke from coming out of my tail pipe, this has reduced my gpm badly, i also want to know where i can get a new brain box for my isuzu trooper 94 (SOHC, IEFI)

I diagonised the original ECM in the car, it did not give any errors, I tried another ECM, but the car could not drive, it was showing "check transmission". but when i replaced the ECM back to the original one it stopped smoking considerably, but them the MPG is still bad. Also my engine oil was loosing viscousity. I still would like to know how much an ECM for this would cost?

Heeeeeeeeeeeelllllppppppppppp
I need to know what to do
the smoke is killing me

you can buy a used ecm at www.car-parts.com

I agree with the change the O2 sensor advice. Computer boxes very, very, very rarely fail out of the blue. Now if you had spilled a soda on the box or shorted a wire and then had a problem I can see the computer as being a likely culprit.

02 sensors on the otherhand can yield exactly your symptoms. They, and their electrical connections, routinely fail because of the harsh environment they are in.

Travelman,

If the O2 sensor is bad it would show up when you run a diagnistic on th ECU right, but them i dont get any errors from the sensors. How can i find out if the O2 sensor is bad?

When my oxygen sensor went bad, the check engine lamp did not light up and there were no codes stored. You need a scan tool or a scope to test the oxygen sensor.

I believe the replacement interval for the oxygen sensor is every 60,000 miles (96,500KM).

If your Trooper has more than 60,000 miles, change the oxygen sensor. It is much less expensive than the ECM, which rarely fails.

Does your engine oil have a very strong smell of gasoline? If it does, that would explain why the oil is losing viscosity. The oil is saturated with gas from running too rich all of the time.


Again, what size engine do you have in your Trooper?


Dale

Dale,

Thanks a lot, i have a 3.2L engine, is the O2 sensor different from the ones you find in honda cars cos i have spares for my honda 88.

Rgds

jungleman

If it were me, I'd only replace it with a Bosch oxygen sensor manufactured for my vehicle.

On the other hand, if I were in the jungles of Nigeria, with no auto parts store within 100 miles, I might try one from the Honda. :)

Provided-

You have a new or gently used sensor from the Honda.

It is a 4 wire oxygen sensor. If the Honda sensor is a 1 or 2 wire, I'm sure the Trooper's ECM will toss a code at you.

You will have to rewire it to your connector. You will need to know what the 4 wires on the Trooper connector do and what the 4 wires on the Honda sensor do. It is very important that you wire this correctly or you will make more problems for yourself.

It screws into the hole in the exhaust.


How many miles do you have on that Trooper? Does the oil smell like gas?

Just curious, how much does it cost to buy gasoline in Nigeria?

Dale

Dale

My car has over 150,000miles, it is a 3.2L, I brought out the O2 sensor and had it cleaned, the smoke comes intermittently now, but not as bad though. When i take of the ECM fuse it stops smoking for a while the starts to smoke again.
My fuel consumtion is like 7 miles a barell (In Nigeria we buy at $1.5 a barrel) that seems bad to me. What is do you think is the normal consumption for my engine?

Jungleman

Jungleman,

If I were you, I would install a new Isuzu or Bosch oxygen sensor. The sensor is not something that can be cleaned and made like new. When they wear out, you must replace them. The money you save in gasoline will eventually pay for the sensor's replacement. Be sure to pull the ECM fuse for 15 minutes after installing the new oxygen sensor. This will reset the ECM back to the leaner factory setting.

That is what is happening when you pull the ECM fuse. The computer will run the engine lean at first until the bad oxygen sensor tells it to richen up.

You mentioned your oil is losing viscosity. Does your oil smell like gasoline? If so, I would change the oil and filter especially if you have driven your car a lot while it is blowing black smoke. The unburned gasoline has to go somewhere and that somewhere is out your tailpipe and into your oil pan. Be sure to do this, the unburned gasoline is washing the oil out of your cylinders, causing increased wear.

I get 14 miles per gallon in winter and about 16+ in the summer. This is all city driving. I don't know how to convert miles per gallon into miles per barrel.

Is a barrel about a liter?


Good Luck,
Dale

Dale,

Thanks a lot, i will make arrangments to get another O2 sensor.

Rgds

Obinna

You are welcome.

Let us know how things work out for you.

Dale

Guys,

I was able to get a brand new O2 sensor and it worked quite well.
my MPG went up but somehow it is not as good as the initial time.
I noticed that the engine gets sluggish once i start to move after
starting, sometimes it even stalls, but it does not repeat again.
ai would like to know why i get such sluggish response from the car. Also the RPM goes high (2600) before changing to the next
gear. This does not seem normal. any ideas from you guys?

Rgds

Jungleman

Did you reset the computer after you installed the new oxygen sensor?

If not, remove the ECM fuse (located in the engine compartment's fuse box) for 15 minutes then reinstall it. Resetting the ECM may clear up some of the issues you are having.

Sometimes my Rodeo will try to stall when the engine is cold and I don't warm it up enough. I don't remember it doing this before I installed the new oxygen sensor.


Dale

Thanks,

It worked, after resetting it it stopped stalling, but the issue of reving up to 2600 before the it shift gear is still occuring.

Rgds

JM

Good to hear you are making progress on your Trooper.

Do you have an automatic transmission installed?

If so, shifting at about 2600 RPM is normal only when the engine is cold. The computer is programmed this way to warm up then engine sooner thereby cutting down on exhaust emissions. When warmed up, the shift point should occur at a lower RPM.


Dale

you are correct, I have an auto transmission, it operates exactly as you said, most times i dont use it in the mornings, and when i do in the afternoon when it is hot i dont notice this.
Thanks

You are the "MAN"


JM

I have changed the head gasket (valve cover gasket)for the second time and i still have oil leaks.
I also have oil leaking from the oil filter seat, could there be something loose there???

Double check your valve cover gaskets to be sure they are installed properly. It is easy to for them to get "out of place" during installation and cause a leak.

If they check out OK, you may have a bad head gasket like I do on my 3.2L. I lose about a quart of oil every 1000 miles due to this problem. I'm not real happy that I have to replace my head gaskets, they should last for the life of the engine. I'm sure the job will be an extreme PITA due to the design of the engine and the lack of working space to get your hands / tools in there.

The oil filter base has a rubber O-ring inside which can harden up and leak. I installed a new O-ring and it fixed the problem on my Rodeo. It was one of the few repairs I've done on this car that was easy to do.


Dale

Did you reset the computer after you installed the new oxygen sensor?

If not, remove the ECM fuse (located in the engine compartment's fuse box) for 15 minutes then reinstall it. Resetting the ECM may clear up some of the issues you are having.

Sometimes my Rodeo will try to stall when the engine is cold and I don't warm it up enough. I don't remember it doing this before I installed the new oxygen sensor.


Dale

Do you need to let the car run for 15 minutes when resetting the ECM? Also I just bought a really old and really used 91 Trooper and gave it a basic tune up. Should I reset the ECM?

Kermit']Do you need to let the car run for 15 minutes when resetting the ECM? Also I just bought a really old and really used 91 Trooper and gave it a basic tune up. Should I reset the ECM?


The car will not run with the ECM fuse removed.

You can if you want to. I think that the only time it is necessary to reset the ECM is when I install new engine parts or need to clear out fault codes.


Dale