midiwall

So, driving home last night I jumped on the gas coming off of a light, and ... the engine bogged down, sputtered, and stalled. In trying to restart it, it would run for about a second and then die. No throttle response at all.

It "felt" like fuel issues, so I pushed the truck into a parking lot across the street, and headed out to get a fuel filter. I'd run the tank pretty dry, put in 16 gallons that morning and figured that something on the bottom of the tank got stirred up.

Replaced the filter, but no luck. Same symptoms.

I pulled the plugs (black carbon sooty - but they were clean two days ago, hmmmm...), cleaned them off and put them back in. The engine ran a bit better and I found that I could keep it running if I goosed the throttle. And the more I kept it running, the better it seemed to run, but it would still die.

I started thinking MAF, so I pulled the air filter, pulled the MAF and it looked okay. I put it back together and started it without the air filter in - and had forgot to reconnect the MAF. It ran a lot better. (I was really surprised it ran at all). I reconnected the MAF and it still ran, and I could get it to idle, though REALLY rough.

Okay... I buttoned it all up, cleaned up my tools and figured it was running well enough to finish the drive home.

I made it, but barely.. The engine runs like crap. Getting on the gas produces a TON of ping (it was pinging so loud it sounded like a ricer). As you might expect, I threw a BUNCH of CEL codes. Misfires on every cylinder, MAF circuit issues ('cause I had it running without the MAF), and possibly the telltale sign - a "Bank 1 too lean".

I'm a bit confused at this point on where to start. I think the likely suspect is the gas I put in yesterday morning, but then if it was THAT bad I don't think the truck would be running at all.

I'll pull the plugs and clean/gap them for real, but this has to be fuel related. I'd reset the ECU during my playing with it in the parking lot, so I don't think it's anything like the ECU going south and losing fuel info.

I think the ping, and the fact that I got it running at all, came from pulling the air filter thus making the ECU think that there was a bunch more air which let it crank up the fuel flow, but since it would have also tweaked the timing, and the fuel really wasn't getting there, then that became the severe pinging. (does that sound right? it made sense at 1am )

The original symptoms (stalling at idle and stumbling) will come back if I put the air filter back in. The filter is clean and remember that it will barely run with it out. Pulling it just makes things "better".


So... I'm open to suggestions. What really sucks is that as I write this I'm supposed to be out on a weekend run. My truck not only let me down, but let down my right-seat buddy as well. Big bummer.

Yoter

How's the cap & rotor. Only reason I say that is the multi misfire symptoms/codes.

Yoter

Errrr if it doesnt have that set up how's the ignition coil?

rimpainter.com

Start testing stuff Mark - with a multi-meter. MAFS, TPS, 02, coil packs...

Did you accidentally flip your TB spacer? j/k

Seriously though, have you traced the entire intake pipe to make sure all the air is being "sniffed?"

Could an 02 sensor wire have melted on those pesky headers? How about your tuning system, could anything have gone funky with that?

Sounds like it is "loading up."

MTL_4runner

Mark, also check the fuel pressure on the rail....I remember Gadget had a fuel regulator lock up on him too and might cause a host of problems like that as well. If it started right after you punched it, I would take a look at the fuel system (filter, lines, pump, regulator) and then look for disconnected wires, missing hoses, the usual stuff. Definately something fishy there and fuel system would cause massive plug fouling like you mentioned too.

midiwall

(I love YT... the outpouring of help is incredible! THANK YOU!)

A scatter-shot response...

- I went through the wiring and hoses last night (I still had daylight for a while in the parking lot) but they're on the list to do again.

- The tuning system (I figure you're talking about the piggyback) got bypassed on Thursday when I came out of work to find a dead battery. (it's been an interesting couple of days) The piggyback didn't like the low voltage as the battery died and it scrambled the fuel/timing maps bad enough that it wouldn't start.

- I'll check the B1 O2 sensor... it's an interesting thought.

- The path from the air box to the TB is clean. One thing I did in the lot is pulled it all apart, I even pulled the TB.

- Fuel pressure... hmmm. And I'd just re-read that thread about Gadget's regulator lock-up. I'll grab the service manual and run through those tests. Good thought Jamie.

- Ignition wise... I'm pretty sure I'm okay Ben. I don't think that the truck would have run much at all if it was something that major. When I pulled the plugs last night, the end result was that I got to reseat all the cables and the connectors on the coil packs so I think that's ok. Coming home, I was able to get it up to 40-45mph...



Weird stuff. Having it just happen all of a sudden was really weird.

rimpainter.com

I should have known that after reading your posts over in the 1st gen fan thread. The disconnect of the piggyback would be a big red flag in my book, as far as contributing to this problem goes...it just seems too coincidental that you did something on Thu, and now you are dealing with a sputtering engine. Hmmmm.

midiwall

Yeah... actually I was thinking about hooking it back up to see if it would fix the problem. I have to reconfigure it but that's "easy".

argh.

Okay... I'm off to fight the battle!


Thanks again guys.

dragr1

iTrader: (3)

Throttle postion sensor? I had this same thing happen once on an SE-R that I owned and it was the igntion coil in that case.

AgRunner06

My vote is for fuel pressure and piggyback. I think the pickup for the fuel pump still has a screen on it. If you did get a lot of trash in there it could plug it up to where it didn't flow enough fuel. If the piggyback is "easy" to reconfigure then I would do that first and move on from there.

Don't you hate it when mods sacrifice reliability.

Good Luck

midiwall

Okay... so sit down and get ready for a laugh. Remember though, the most important thing is that it's running again ... (this is kinda' embarrassing)

Keeping in mind that you need Air, Fuel and Fire for an engine to run, and I took care of Air last night ({cough}foreshadowing!{cough}), then I approached the truck with the problem "must be" Fuel or Fire.

I pulled the plugs... cleaned 'em, gapped 'em. I pulled the O2 sensor and gave it a good look. I pull the plug wires, put more contact stuff on 'em. I did the multimeter tests on the MAF, TPS, ignitor packs. I cleaned the TB, pulled the manifold, pulled the injectors... Short of getting deeper into the motor, there wasn't much that I didn't try.

So... I was putting the intake tube back onto the TB. Wrestle, line-up, push... clunk.

Clunk?

Clunk.

What just fell? And did it really fall OUT of the intake tube?

Rummage around the skid plate... and I pull out a plastic plumbing cap.

I look at it; it looks at me; I look at it harder, and it laughs at me.

I grab the intake tube, flip it over and sure enough, there's air space in the hole where there used to be the J tube - which was part of the intake silencer, which I of course removed when I did the "intake silencer removal" mod.

Guess where the plumbing cap that fell out of the intake tube fit back into? Yeup.

Guess how the engine runs now that it's not wedged in the tube blocking the air flow? Yeup.

Guess how hard I kicked myself in the arse for not finding this last night? Yeup - that's gonna leave a helluva bruise.


S.O.B.


So... the post mortem is that the screw clamp holding in this plumbing cap (as part of the ISR mod) had loosened enough that the intake vacuum simply sucked the cap through the tube and wedged it in such that it blocked the flow of air.

I'm REALLY lucky that the cap was big enough that it didn't get through the TB. THAT would have sucked. (hah! bad pun)


And like you said Ag, it was a mod that compromised reliability.
(argh!)


Thank you all for your help and words. I really appreciate it.

MTL_4runner

Glad you got it licked and don't kick yourself for not finding the obvious
.....done it too many times myself!

havic

Glad you found out what it was, and that it wasn't that serious. I hate things that go wrong with the engine with no warning signs.

rimpainter.com

Somebody didn't read my sticky from a few months back!

midiwall

Oh no Christian... Whad I miss?

Funrunner

Good to hear you got it figured out and fixed. After doing all that work, it should be runnin' like a champ!

midiwall

and I even did another Seafoam treatment just 'cause. It's runnin' real purty now.

(thanks right-seat!)

Funrunner

You're welcome.

I'll still have to kick your butt for this though.

midiwall

Yeah... I deserve it.

rimpainter.com

I had a very slight miss last year when it was hot (see 350 days/year) so I checked out the ISR mod. Turns out one of the end caps was warped from the (at the time) exhaust manifold heat and the pressure of the hose clamp. The clamp was squeezing it into an oblong shape. I posted it, and it was made a sticky for a short time. I have since gone for the threaded black cleanout plug in the primary ISR location. I will keep an eye on that J-tube spot though. I have only switched that one out one time.