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verboden1 08-29-2013 12:04 PM

Lots of BLACK smoke
 
Just found this site. Loving it so far. I breezed through the first 25 pages, so I apologize if this question has been asked before.
I previously owned a 1991 Cherokee 4.0 I6, and I erroneously traded it in for something newer. It had 280k and ran like a top. I'm an idiot, and as I drove home in the Nissan Xterra that I traded it in for, I had buyers remorse like never before.
I recently bought a 04 Grand Cherokee Laredo, of course because it was powered by the 4.0I6, and has 102k. Suprisingly (knock on wood), there are no leaks and no smell of burning oil. Oil pressure is good.
I decided to change the spark plugs, due to a slightly rough idle. It only idled rough at a stop and in gear. If I put it into neutral, the idle became completely smooth as it went up about 100-200 RPM. I changed the plugs...the first three (Front to back) they were black as a car tire. The last three showed minimal wear, but no carbon. I replaced the plugs using standard copper core Champions, as I understand, our Jeeps seem to like them. I added the seafoam fuel treatment and took her for a spin. I slammed down on the gas and thought it might have transformed into a deisel. During higher RPM and shifting, it sends out a puff of black smoke.
Questions are:
1. What would cause only three of the plugs to be fouled with carbon?
2. Is the black smoke an indicator of the Seafoam cleaning out carbon deposits?

happy to be in a Jeep again, and better black smoke than white smoke.

I appreciate any advice.

Peace

lstowell 08-29-2013 12:41 PM

Re: Lots of BLACK smoke
 
Quote:

Originally Posted by verboden1 (Post 884525)
Just found this site. Loving it so far. I breezed through the first 25 pages, so I apologize if this question has been asked before.
I previously owned a 1991 Cherokee 4.0 I6, and I erroneously traded it in for something newer. It had 280k and ran like a top. I'm an idiot, and as I drove home in the Nissan Xterra that I traded it in for, I had buyers remorse like never before.
I recently bought a 04 Grand Cherokee Laredo, of course because it was powered by the 4.0I6, and has 102k. Suprisingly (knock on wood), there are no leaks and no smell of burning oil. Oil pressure is good.
I decided to change the spark plugs, due to a slightly rough idle. It only idled rough at a stop and in gear. If I put it into neutral, the idle became completely smooth as it went up about 100-200 RPM. I changed the plugs...the first three (Front to back) they were black as a car tire. The last three showed minimal wear, but no carbon. I replaced the plugs using standard copper core Champions, as I understand, our Jeeps seem to like them. I added the seafoam fuel treatment and took her for a spin. I slammed down on the gas and thought it might have transformed into a deisel. During higher RPM and shifting, it sends out a puff of black smoke.
Questions are:
1. What would cause only three of the plugs to be fouled with carbon?
2. Is the black smoke an indicator of the Seafoam cleaning out carbon deposits?

happy to be in a Jeep again, and better black smoke than white smoke.

I appreciate any advice.

Peace

Where you are driving might be a contributor, particularly on the 4.0.

I would do a couple seafoam treatments, then use it as an additive on a somewhat regular basis.

Oil smoke is bluish, not black.

I'd suggest having someone who knows Jeep 4.0s check your TPS, the oxygen sensors, your cat, and clean the throttle body and map sensor. Plus the plug wires themselves should be changed unless you know how old they are. They do get old and misfire a bit. If this condition has lasted long, you can probably expect your cat to not be healthy. They're cheap.

The reason I noted where you live is I just got rid of a 4.0 that never gave a bit of trouble, passed smog with flying colors, light greyish brown exhaust pipe etc.

Took it to Los Angeles area and I have no idea what concoction is sold at the pumps, but the thing absolutely refused to run smoothly at stop lights on the local gas.
Ran so rough I was putting it in neutral and only shifting into gear as the light changed. Once it was up a few RPM, ran smoothly like the 4.0 always does.

Ran that crap down to near empty, filled up in Barstow, and the problems simply went away even though heading out thru Baker, etc. which is as lower or possibly lower than LA altitude.

verboden1 08-29-2013 12:51 PM

Re: Lots of BLACK smoke
 
Thanks for the reply. I'm in sunny Florida. The smoke is definitely black...no blue, just black. The first start up after the seafoam treatment, it left a short black strip of residue on my driveway.
The idle while stopped and in gear has smoothed over, but still a little bumpy, but way smoother than before. My Jeep has the coil rails, no wires. A new coil rail is my next step, unless a seasoned Jeepster tells me otherwise.
After readin a few posts here, the O2 sensor will be my next suspect.
It otherwise runs fine, and I should probably just shut up and drive it, but my OCD gets the best of me.

Peace

Frango100 08-29-2013 11:15 PM

Re: Lots of BLACK smoke
 
Welcome to the garage.
Does your jeep has the 2 upstream and 2 downstream O2 sensors?

That would be my first suspect, check the O2 sensor voltage and see if they jump up and down very frequently. If not, the respective O2 sensor is shot. (most probably the 1-1 sensor).
By the way, eventhough you live in Florida, do you have anything to do with Holland (because of your name)

verboden1 08-30-2013 06:48 AM

Re: Lots of BLACK smoke
 
Frango!!! Thanks for the reply...
O2 sensors are on the list to replace if I can diagnose which one is bad. I'm just wondering why the "check engine" light hasn't come on yet....either way it drives fine, but smokes like a diesel when I accelerate hard.

As far as my screen name, My mother and father are from Germany, near Ehrfurt. I was born over here, and the name just came to me one day....lol.

Any other suggestions are welcome, as I will be crawling under the Jeep tomorrow (I'm not mechanically inclined, but I refuse to pay the ridiculous shop fees, so I'll learn to fix minor things myself).

I'll report my success or disasterous outcome this weekend.

See ya'll around the sandbox

Frango100 08-30-2013 09:27 AM

Re: Lots of BLACK smoke
 
I'm not sure if the.black puff could be from the seafoam, because when you put it straight into the brake vacuum line, you get a lot of white.smoke. Did you already put some of the seafoom directly into the vacuum line, or only into the fuel tank?
Do you have a scanner which shows live data? You could check the O2 sensor voltage, but also the fuel trims. The trims are shown like this: STFT bank 1 (2) and LTFT bank 1 (2). This are the short term fuel trim ( the actual fuel trim) and the long term fuel trim figures ( an average figure over a longer period) . These figures can show if something is wrong with the fuel trimming.
If you don' t have a scanner and prefers to do your maintenance yourself, you should think in buying one, it can help you a lot in the future. If you have an android phone, you could download an app like "Torque" and just buy a bluetooth dongle which fits in the OBD port.

verboden1 08-30-2013 02:13 PM

Re: Lots of BLACK smoke
 
Seafoam went directly into the fuel tank, which was only half full.
Good call on the smartphone app!! I already downloaded it, and will look for a bluetooth dongle this weekend. I am a mechanical reeetard, but I'm looking forward to learning all about my Jeep. Being able to get the codes from my phone will go a long way!

I'm going to replace the front upstream O2 sensor this weekend since the oly plugs that were caked with carbon were 1,2, and 3. Probably due for a replacement anyways, and I'll put a new fuel filter in while I'm under it.

You guys rock....thanks for all of the info....keep it coming!!

Frango100 08-30-2013 08:49 PM

Re: Lots of BLACK smoke
 
You could try some seafoam into the brake booster vacuum line, seems to be cleaning the cylinders up quite a bit. There are some writeups overhere on howto.

xJoshxx 08-30-2013 09:08 PM

Re: Lots of BLACK smoke
 
Quote:

Originally Posted by Frango100 (Post 885307)
You could try some seafoam into the brake booster vacuum line, seems to be cleaning the cylinders up quite a bit. There are some writeups overhere on howto.

Amsoil Power Foam if you can get it. Worked 10x better for me than seafoam because instead of a liquid the foam expands and reaches area's the seafoam doesn't.

Amsoil Power Foam 00 WJ - YouTube Me when i did my 00 WJ Also great for finding exhaust leaks haha. Long ago lol roughly 3 yrs or better

verboden1 09-03-2013 07:56 AM

Re: Lots of BLACK smoke
 
Took it to a buddy this weekend who has a diagnostic computer....only showed bad IAC and bad O2 sensor. Next weekend I'll replace those, although I've seen many posts about cleaning the IAC before replacing it. I'm sure it's caked with carbon, so I may just try to clean it off first.
I did purchase some CatAclean under the advice of my mechanic buddy. I bought it, but most of those miracle compounds are "snake Oils" from what I understand.
All in all, it's fun when someone is tailgating me and I dump the accelerator and coat them in a nice cloud of black carbon.

I'll post any results of the catAclean, if any, and report on my IAC and O2 sensor. BTW, the code was for the front upstream O2 sensor.

Any thoughts on cataClean or cleaning the IAC?

verboden1 09-03-2013 07:59 AM

Re: Lots of BLACK smoke
 
Hey josh, an neighbors call out the Fire Department?? lol....

What, if any, improvements did you notice after using the power foam??

Frango100 09-03-2013 10:15 AM

Re: Lots of BLACK smoke
 
Yes, try cleaning the IAC first before you replace it with a new one. For sure the IAC stepper motor plunjer is very dirty and maybe even stuck in place. You can easily take it out from the throttle body removing the electrical plug and two torqueX screws.
Take care when cleaning the IAC plunjer to not rotate the plunjer head. Two very small plastic ribs are preventing it from turning when operated electrically and these ribs break of very easily and then for sure you have to replace the IAC motor.Also clean very well the IAC air passage in the throttle body. You could remove the throttle body for that, or spray some carburetor cleaner into the air passage with engine in idle. Bit by bit, so that the engine will not starve. You have to remove the air duct to the throttle body to spray directly into the air passage.
The front upstream sensor is the 1-1 (bank 1, upstream sensor) and was indeed suspected.


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