3.4Runner

Check engine light came on yesterday on the way to work, truck seemed to run fine. Didn't get a chance to look at anything but ran into big problems this morning. Truck stalled 3 times immediately after starting, finally got it to idle (very rough) on the 4th try. Started stalling when I'd declutch on my way to a stop. Had to limp the truck back home and now I'm renting a car to get to work.
Used my OBD reader and got the following codes:
P0100
P0101
P0110

I also noticed the truck was spewing a bit of smoke on the way home and smelled pretty bad. Inside of the exhaust tailpipe is coated with black oily stuff.

I hooked up my AFR gauge on the limp home and I was running very rich the whole time (AFR between 10-11). The truck is having severe drivability issues and is lurching quite a bit, hesitating like crazy, and has a VERY SEVERE power loss (didn't think I'd be able to get up hills and the danger of stalling on one in traffic was too much to risk it).

I have very little time to work on this, but any help of where to begin would be very much appreciated.
Specs on the truck: 99 3.4L 4Runner 4WD, TRD S/C with URD kit (spark plugs, FTC, injectors, Walbro pump).

Please help!!

midiwall

ref: OBD II code lookup

P0100, 101 and 110 are all pointing to the MAF. Have you had the intake tube apart recently, have had the MAF disconnected, and didn't seat the connector fully? Is there something stuck in the intake? Do you run an oil coated air filter, have just re-oiled it, and used too much oil?

What color was the smoke? I'm betting black...

Short form... I'd pull the intake tube, clean the MAF and clean the TB to see if it helps. Once you do that, reset the ECU to let it clear the codes and re-learn the airflow.

3.4Runner

Inspected all the hoses and saw the cam cover vent hose had somehow popped off. Didn't help anything after reconnecting it. I went ahead and pulled the MAF sensor, which appeared normal. I also pulled one sparkplug and found that it was coated with a thick black residue.

Anyone know how to clean spark plugs well, or should I just get new ones?

midiwall

Hmmm... you can try soaking the plugs in something like intake cleaner, it makes a great grease/oil cutter - but it wouldn't hurt to buy new ones. Gap them to .040".

But... The "thick black residue" is probably oil and this is a good time to hope that it somehow came through the intake, and it's not blow-by around the piston rings.

How many miles are on the engine? How many miles are on the plugs? What color was the smoke? Are you running the stock air filter or something like an Amsoil?

If the goo got in though the intake, then there's probably goo IN the intake. You'll want to pull the intake tube off and clean it out, then pull the throttle body and check for goo there. If it's there too, then you should pull off the S/C and check to see if there's goo in there as well.

And... if all of that is dirty, then be sure you figure out HOW it got dirty in the first place. That's why I keep asking about your air filter.

If the PCV valve - or the other end of the hose - popped off then it would actually _reduce_ the amount of crap that ends up in your intake. You really need to figure out what the stuff is on your plugs and where it came from.


Here's a scary thought... What if the nose piece on the S/C has a crack in it? There's oil in there, and that will shoot right into the intake manifold, through the valves and into the cylinders.

How many miles are on the S/C? Has it gotten louder since this started?

mt_goat

Is it an oil coated air filter, like K&N?

midiwall

Yeah... that was first thought as well - I've asked him twice now, hopefully we'll find out.

rimpainter.com

I think he has a 7th injector. Any chance it could be dumping fuel for some reason?

midiwall

Hmmm, maybe, but what's the goo on the plugs?

I'm thinking an oiled air filter that's too wet, or... (yuk!) the housing's cracked on the S/C.



C'mon back man! You said "urgent" and you're drawing a crowd now... Help us help you!

mt_goat

His specs say he's got Gadget's URD kit (spark plugs, FTC, injectors, Walbro pump). So that would be those 318cc injectors and 190 LPH fuel pump and 2 step cooler plugs along with a controler that over-rides the ECU settings. That is a system that has the capacity for dumping a lot of fuel into the engine. I'm thinking if that system has a problem with say the air flow measurement couldn't he just be running very rich and fouling the plugs?

rimpainter.com

Well Doug flew out there and helped him install everything, and I could have sworn he told me that he had the 7th injector with the URD controller. I could be wrong though.

3.4Runner

Sorry about the delay in replying. I had an amsoil filter a few years ago but chucked it after it threw a CEL and I found my MAF coated with grime. Been using the stock paper filters ever since.

I don't know who Doug is, and I installed this all myself. No 7th injector here, just the full URD setup.
Plugs had about 25K miles on them, same mileage on the SC--no increase in noise or detectable change in the SC function. Engine has about 85K miles on it and has been running like a champ--synthetic oil since 1K miles and SC since 60K.

Seems like the problem is fixed, at least temporarily.
I pulled the fouled plugs and replaced them with the stock 3.4 plugs (I had a set with 10K miles on them laying around). I also cleaned the MAF sensor, it only had a minimal coating of debris on the 2 small wires. I pulled the ECU fuse to reset the codes. Truck seems to be running normally again, but I've only driven it about 20 minutes. AFR is now at 14.7 where it should be during cruising. Good power when going into boost. No hesitating or stalling, and no dark smoke out the exhaust.

I agree with mt. goat's assessment of what happened. I think the disconnected vent hose let air sneak into the system that wasn't being registered by the MAF, this caused the fuel computer system to dump more fuel in, which in turn fouled the spark plugs. I think the truck was running okay for awhile because the plugs were very hot, it was the next morning after starting a fully cooled engine when I had all the stalling/hesistating issues...presumably because the plugs were very fouled and not able to spark well while cold.
Hopefully it continues to run normally, I'll drive to work tomorrow and see what happens. I'll be ordering a new set of SC plugs, but hopefully the problem is fixed.

rimpainter.com

I got the wrong guy. Sorry about that. (But the Doug story is true, I swear )

mt_goat

Please let us know how it goes, I'm thinking about using your same set-up when I'm done swaping in my 3.4 engine.

Super Doody

Its actually .043 and not inches.

midiwall

Ummm... no, it's inches (are you thinking it's mm's?).

Past that, I'll give you the 3/1000ths (of an inch ) but the material I have in front of me says .038-.043, so when I babbled the above, I split the difference. And I'm pretty sure that the box of Denso's that I bought from Gadget around that time were marked with 'gap to .040"'

mt_goat

Yeah, it is inches. Interesting the way everything on the truck is metric but we spec the spark plug gap in inches.