Axel Spott

First time posting, but I've been learning a lot of valuable information on here since i bought my first yota early this year. Unfourtunately my first one has the 3.slow 3vze under the hood. It's a 90 4runner and I'm in love with this thing but like most loves, it has turned into a painful fight everyday. It all started when going down the road it just died on me. I waited for a little bit and got it to start back up but it was lacking power, like not able to go over 20mph and stalling if i let off the gas. I got it home and pulled off the egr and cleaned it. Reinstalled it and it started knocking (top end). Now it starts and idles and drives fine until it warms up and then it loses power and stalls. I can be on the highway and it wont accelerate even at 4000rpm and will stall out. It will be hard to start if it starts at all until it cools back down. I've replaced the distributer, VAFM, throttle body and sensor. Coil resistance is in specs. I'm not throwing any cel codes now and still the same problem. HELP! I'm losing my mind on this.

TNRabbit

Would it be possible to post a video of what it's doing?

See if it's this:

Axel Spott

Video won't play on my phone so I'll have to check it out when I get home from work. I work at a classic car restoration shop in RI and we're going nuts getting prepared for this hurricane this weekend. I'll see if I can record the engine when its dying. If I just start it and leave it idleing without ever hitting the throttle or putting it in gear, it will slowly idle lower and lower til it stalls. I'm thinking this is valve related since it has that loud top end knock but honestly, I have no clue anymore. I've been chasing it for a while.

TNRabbit

The video I posted was a bad vacuum distribution puck that allows the EGR to stay open all the time. Sounds a LOT like what you're experiencing.

vasinvictor

iTrader: (3)

Quick test: Could he just pull the vacuum hose going from the vacuum distrubtion puck to the EGR valve and see if problem persists? (and plug the pulled vacuum hose, of course)

TNRabbit

Exactly. Pull the vacuum hose that goes into the top of the EGR valve.

Axel Spott

So in theory I should just be able to make a blockoff plate for the EGR and problem solved? I can tell you that when the problem first happened I took off the EGR and plugged the hole in the plenum and ran it ( I also had a spark plug out of one cylinder at the time) and within a minute of running it the knock started for the first time. Like someone was hitting the plenum with a hammer. I don't know if it was something wrong that I did. I pulled the oil and there was no metal shavings.

vasinvictor

iTrader: (3)

So you actually ran the motor without a spark plug in it? Washed out cylinder? Maybe not in that little time. Don't block off the EGR until you try to pull the vacuum line first. That thing will stay closed if you just pull the line. No need for a blockoff plate if the EGR valve is properly closing, unless you are just trying to clean up the engine bay.

Sounds like hitting it with a hammer? Wow, well I don't EGR is the problem now anyway. A video would be useful.

Axel Spott

Yes, not gonna lie, I don't even remember why I was running it with no plug but it was for probably a minute. So my mission is to pull and plug the vacuum line at the top of the EGR and make a video of the horrible sound it makes and of it dying when I get home.

Axel Spott

Alright, so I pulled said vacuum line to the top of the egr and plugged it with my thumb and unfortunately no change. I did record the testing so now you can share in my joy of the horrible sound that is my 3vze. However this was recorded with a cell phone so I appologize in advance for the s**tty quality and don't get me started on the lack of cinematography lol. It stalls out at about 4 and a half minutes in. I was goosing the throttle to speed up the process some. And another problem with a cell phone camera is the knocking sounds more like a diesel engine running as opposed to a knocking and also the fan sounds like an air leak.

<iframe width="420" height="345" src="http://www.youtube.com/embed/pbFtw1ixCnw" frameborder="0" allowfullscreen></iframe>

Axel Spott

Guess the embedded video didn't work. Heres the link.
http://www.youtube.com/watch?v=pbFtw1ixCnw

Axel Spott

ok... lol

vasinvictor

iTrader: (3)

Man that is a SICK soundin veezy. Sounds like bad lifters or bad out of spec valve shims. Also sounds like an exhaust leak? It sure seems to die and get worse sounding when it has come up to operating temp. You sure that EGR valve is fully closing?

Axel Spott

Yes sir. Typical catalytic robbery so I've got a straight pipe hanging in place right now however this was exactly the same before said theft. It'll actually run fine despite the noise until closed loop. Then you get that... I've got another set of heads that I was hoping to avoid having to use but I guess no chance of that at this point. And as far as the egr I couldn't really tell ya unless i try it with no egr in place. Guess I could try that tomorrow.

vasinvictor

iTrader: (3)

Is the o2 sensor(s) before of after said stolen cat?

Axel Spott

Bout 6 inches before the cut out cat.

thook

You need to check the fuel pressure as you allow the engine to go through the warm up cycle until it finally dies out on you. That horrible knocking could very well be caused by an extremely lean condition/lack of pressure.

Until the engine reaches operating temp/closed loop, the ECU is running through an enrichment cycle. Then, as it reaches temp, the ECU leans it out. Possibly the enrichment cycle is keeping enough fuel, and therefore pressure, in the system to keep it running up until it's at temp. I'd say it could be injectors, but with it happening all of a sudden like you described, your fuel pump could just be in the beginning stages of crapping out.

On the other hand, it could be a pressure regulator problem. Do you see any signs of black smoke or overly carbon coated spark plugs? If the regulator goes bad, it either leaks fuel past the internal diaghragm or sticks shut. Pulling the actuating vacuum line off will tell you if it's leaking. There will be fuel in it.....and, that leaking fuel is drawn into the plenum. If you were to pull the fuel return line at idle, there should be fuel coming from it. If there's no fuel, it's stuck closed. If it's sticking somewhere in between....neither fully closed or open (as it should be at idle) the only good way to tell is by testing the pressure with a guage. Note.....in many testing suggestions you might read, it's recommended to pull the vacuum line at idle and observe if the idle condition changes. That only works if the regulator is the on the pressure side of the rails. On the 3vze, it is not... so that test doesn't work. You just have to use a guage......or throw some known working parts at it and see what makes a difference.

thook

Oh....and, then there's the coolant temperature sensor. That's an easy thing to check. With a volt meter, hook up to the TWA and E2 terminals at the back of the connectors on the ECU. Start the vehicle and have someone make sure it stays running with the throttle. Note the the amount of voltage at start up while the coolant is still cold. Watch the meter as it warms up. Voltage should steadily drop. If it doesn't drop or drops erratically or does not fall within voltage specs in any way, there's your problem.

ECU diagram: http://personal.utulsa.edu/~nathan-b...e/102engin.pdf