My 4Runner rather suddenly started running very rough, blowing black smoke and shooting some soot out of the exhaust pipe. Up to this point it ran pretty well, I put a new OEM distributor cap & Denso plugs in it in Jan or Feb, new TG Rockripper header in about the same time, no exhaust leaks.

- After seeing the smoke, I checked all the vac lines, don't see any leaks.
- Threw in a fresh air filter since I had one.
- Last night I put in a new Denso O2 sensor b/c I was certain my 2 year old Bosch was the problem. Reset ECU and still runs exactly the same.

I adjusted my TPS over a year ago, and this running poorly was kindof sudden so I don't really suspect it, but I will check it.

Could this be a leaky cold start or a leaky injector(s)?

I've never messed with the AFM, I know somehow measures the air but I'm not sure what to look for or how to even check it.

 

The only time my 87 22re acted like that was when the AFM wasnt getting the right info and allowing the little door to open. I think mine was a bad TPS and replaced it but there was a lot of other stuff that was also straightened up at the same time (teenagers put a new head gasket on and didn't make ANYTHING)

 

Thanks for the response.

I'm going to check the AFM tonight as per Roger Brown's page: http://www.4crawler.com/4x4/CheapTricks/AFM/index.shtml

If that checks out, I'll see if it could be the Fuel Pressure Regulator. I was planning on taking a little road trip to do some offroading next weekend, but not looking like it now unless I can get this thing back in top form.

BTW - Last night I pulled all 4 spark plugs to look at them and all 4 show black sooty crap on them, so all 4 are getting too much fuel. To me that says either

A) AFM reading wrong or not letting in enough air

B) Fuel Pressure regulator not working, I guess too much pressure dumps too much fuel into cylinders on each injector pulse (but I would think that the ECU could shorten the pulse duration to account for this when it reads the rich condition from the O2 sensor)

C) Leaky Cold Start Injector which dumps fuel right into the intake and it gets into all 4 cylinders

D) All 4 injectors leaking...this seems remote because the condition was fairly sudden, but who knows

Anyone have any direct experience with an internally leaking injector? The search turns up mostly external leaks.

 

My '90 pickup (3vze) went through the same thing a few weeks ago when the harmonic dampener (crankshaft pulley) failed.

The rubber layer sheared apart and the alternator belt running surface had almost zero traction against the inner drive hub and the crankshaft. No/low alternator output tanked the engine efficiency. Engine would shut off at idle or idle very poorly, blowing black smoke, pretty much venting fuel out the tailpipe...really fun since it happened in bumper to bumper on the freeway
Swapping the pulley off my parts vehicle was all it needed but I went through the same troubleshooting procedures before actually pulling off the pulleys to check the belt timing hadn't slipped...bingo.

The fact that your problem seems to have happened so acutely, to me, suggests a similar (or the same) sudden mechanical failure. If its not a pulley issue, do a leakdown and check the internal seals. A complete failure of a sensor or injector could theoretically cause such a sudden failure, but I'd check the mechanical stuff as well.

 

if it happen suddenly i would lean towards t chain pull valve cover and check the t marks

 

ps. hope you get this solved for the weekend!

 

Hmm, I did not think of that. Tchain is not yet 2 years old, but I will pull the valve cover and make sure the cam sprocket is lined up. I was going to adjust the valves anyway, so that's a good point, thanks.

I will check the alternator output. I put new brushes in it under 1 year ago and it seems to charge fine, but I'll look at it. I don't think the 22re crank pulley has a rubber center like the 3.0, but still could be my alternator, low spark energy could certainly be the problem. Thanks.

 

disconnect the cold start injector connector, i had a first gen runner that had the cold start timer switch go bad and it would intermittently kick in the cold start injector and make it run like crap, super rich and load up horribly. if the problem goes away without the cold start injector hooked up you've found the problem.

 

Checked the AFM this afternoon per Roger Brown's instructions. Went thru the static tests first and noticed that the final test, E1-Fc read as shorted on my meter, the spec is infinite resistance. Pulled the whole contraption off the truck and looked in there, the flapper was stuck open. I sprayed some carb cleaner on a rag and wiped around in there, worked it back and forth a few times and then went thru the tests again. Tests out fine now for all the static tests and the dynamic ones too.

Put it back on truck, and holy crap problem solved! Truck runs great, drove it around the block and I am one happy camper. Looks like I'll make the wheeling trip next weekend.

Thanks for all the replies.

 

My 1990 4Runner is producing black smoke and idles very low. The start of the problem was I cleaned the butterflies in the throttle body and when I shifted the air intake hoes I broke a wire in the AFM connector. I replaced that and have know have black smoke and low idle. If anyone knows what's going on and how to solve it please let me know.