Nick91runner

Hello everyone,

I am new to the forum but have used it alot for help trouble shooting problems. I will explain exactly what I have done to this point in hopes someone can help me out as I literally had to get towed 50 miles home tonight

Well here goes, I just bough a 1991 4runner V6 3.0 Automatic trans 198k miles. I am having some major issues. I had a rough running issue, so I ended up having both valve covers change and a new power steering pump installed( wasn't hooked up when I bought it) since then the car has been running poorly, pulsing and shutting off, I did some research and found alot the vacuum lines where leaking and hooked up incorrectly (which I have fixed) l also replaced the main rubber hose of the intake off the throttle body (it was dry and cracked) And everything was running well.

The next day I changed the fuel filter and it hesitated to start up afterwords (I had to cycle the key a few times and then it fired up)

The next few days it was a headache when starting and then I figured something else was wrong. (seamed like it wouldn't fire up if my 4runner tires were higher in the front. my driveway is inclined.)

So after a few days I had it running pretty good and then on the way back from advance auto under load it cut out and stalled leaving me on the side of the road (its only 2 miles away) I popped the hood and realized the main intake hose poped off and that is why it stalled, I reattached and it would not fire back up) so I had my neighbor tow me home with a tow strap. When we got back we were able to get it to fire up but only with starter fluid, once it cleared the fuel it would fire up no problem but would stall under full throttle. (so I turned to yota tech and found that it was most likely the Engine Coolant Temperature Sensor) so the next morning I bought one and changed it out, it actually fixed the issues, it started revved up, and drove very well.

Continued ___>> see next comment

Nick91runner

So Friday night I headed out the 1 and half hours to my camping trip excited to do some off roading. and it ran great (was hesitant to shift until I let of the gas a few times and then it would finally shift) but besides shifting it ran great. As soon as I got close I stopped for some refreshments and when I started it back up (after and about 1:15 on the road it cut off when I stopped at the road to pull out, and then started right back up. I drove about another 12 miles to the camp site and as soon as I got off the tarmac and onto the bumpy road it just crapped out on me (I was going up hill and it was bumpy) I jumped out and it would not fire back up, I checked all the plugs and wires. The only thing I noticed was a wire on the distributor felt like it was loose and popped back in when I pushed it.
I drove down the dirt road and no issues all the way to the camp site (about 3 miles down a dirt road.

Later in the day we went for a drive and as soon as I started going up hill I felt it sputtering and stalling (which it would restart after a few seconds of cranking it up. On the way back down the hill it stalled again and again. This continued to the point the only way I could get it to fire up was with starter fluid) If I was parked on flat ground there was no real issue with starting it.

So today on my way home I made it about 20 miles into the trip until it totally died, and ran like complete crap (luckily I was in Winchester VA, and it limped to the carquest autoparts (this is there main hub and has a store too) so we checked everything again, disconnected the negative terminal and nothing changed. So I want in and bought a new Throttle position sensor and ignition coil (I was frustrated and trying to get it on the road and eliminate likely causes.) Still no dice, so I pulled all the plugs (they were just changed two weeks ago, they were very black and wet with fuel)
I installed brand new plugs, double checked the wire connection, vacuum leaks, spark, and found nothing. I am stumped.

I have done the following repairs/replaced
Distributor cap +rotor button
Replaced Spark Plugs + Wires
Replaced Fuel Filter
Replaced Engine Coolant Temperature Sensor
Replaced Inginiton Coil
Replaced Throttle position Sensor
Replace Main intake tube to Throttle Body
Fresh oil change before issues
Fresh Coolant Before issues
New drive belts (not timing)
New Power Steering Pump

Any help would be greatly appreciated as I have a expensive paper weight in my driveway the wife says I should have never bought.

Nick91runner

Here is a video of the issue if it helps, there is no check engine light on either . http://www.youtube.com/watch?v=LhsmC...ature=youtu.be just stalls out.

Sturmcrow

Just a week or so ago a fellow was having trouble with fuel in his exhaust. He did not really get back to us with the final solution, but the consensus was that he had accidentally plugged the fuel return into a vacuum line. I suspect that is your problem as well. I posted a detailed diagram of the vacuum lines that I found in another post. Search for my posting and you should be on your way.

Ok, fine, I did it for you.
https://www.yotatech.com/forums/f116...t-help-268283/

Here is the relevant bit that I posted:

"Scroll down to the bottom of this thread for an excellent photo with labels of where everything should go. In fact, I will be using it myself to double-check my AC-up and PS-up hoses this weekend.

https://www.yotatech.com/forums/f116...s-here-230638/

As you can see, #2 is supposed to be the fuel return line. If you plugged in a vacuum hose there, big trouble!"

I'm off to bed, but good luck!

Nick91runner

So in the diagrams it shows which lines are which but its unclear,

In this picture there are 2 cluster of 3 lines each, which side should they go to (Meaning if your standing in front of the vehicle the passenger side of the FPU should that go to the top cluster attached to the intake manifold, or to the lower cluster of three https://www.yotatech.com/forums/f116...t-help-268283/ the upper on this right up is marked with a pink dot on the hose)

Mine is like so


Here is the saddest picture ever!

Nick91runner

BTW thanks for your help as well!

Nick91runner

Also what would cause it to finally act up after an hour of driving that it wouldn't do right away upon startup, as I mentioned it was running good until I got off the tarrmac

Sturmcrow

The first thing I would check is that fuel line (#2 in the diagram that I posted earlier). It should connect via hose to a hard line that exits the back of the engine bay and returns to the fuel tank. If it connects to anything inside of the engine bay you probably have fuel going into your vacuum system (and straight into the engine intake).

The photo you posted looks OK, but I cannot actually see that fuel line in question.

The reason there is a fuel return is because the fuel pump sends more fuel than required to the engine. Whatever is not used is bled off by the fuel pressure regulator and returns to the tank. I can envision several scenarios where fuel is getting into your vacuum system but then does not start causing a noticeable problem right at first or until the angle of the vehicle shifts.

If your plugs are covered in fuel you are either getting too much fuel or not enough air. I would not be looking at things like the distributor, plug wires, etc. You need to focus on the VAFM, O2 Sensor, TPS, and cold start injector. There are straightforward procedures to check all of those using a multimeter laid out in the FSM (factory service manual). I could be forgetting a few components, but that is where I would start.

Nick91runner

So upon checking I noticed that the line pictured here was loose (I hate those style clamps)

What does this part do? I am refereing to the valve of sorts with an adjustment screw (it had gasoline in it) and does it have a vacuum?

I also noticed that the bolt that holds all the sensor was broken off and allowing the whole asembly to move (this could explain why the problem happened during bumps)

Sturmcrow

I will go out a check to be sure, but I am pretty sure that is the A/C idle up valve and should definitely NOT have gasoline in it. It is vacuum only. I suspect that may be your problem.

Are you talking about the valve on the left of the photo?

I have no idea which line you are talking about either. Please circle or draw an arrow if you want specific feedback.

Nick91runner

I also just realized the back side vacuum hose was disconnected and jammed into a small hole is the BVSV under the intake manifold super important? I just found that the mechanic who replaced the valve cover cracked off the connector, also what is the proper part name for BVSV when I buy a new one?

Nick91runner

I was referring to the left flathead screw adjustment (its black) below that is a crome fastener that obviously doesn't fasten too well.

Nick91runner

Thanks for all your help as well, I also checked the compression while I was letting the cylanders and intake dry out and it read as follows #1-175, #2-150, #3-180, #4-155, #5 185, #6-150

Nick91runner

Also wanted to note that the A/C has been disconnected before I purchased the vehicle.
I have no plans to hook it back up

Sturmcrow

Have you checked the port labeled #2 in the diagram I linked? I went out and double-checked my truck. Sure enough, that hose loops up past the charcoal canister and back down to a hard line exiting out the rear of the engine bay. If that is going to the valve you referenced, we have solved your problem.

Your compression numbers actually look really good. Minimum is 140, normal is 170. Yours might be a little higher than actual due to all of the fuel in the cylinders.

My connectors were also broken off of the BVSV. I ended up just running the vacuum line from the charcoal canister straight to the hard line that eventually connects to the nipple on the throttle body and have seen no adverse effects from that. In practice my engine is probably running a little rich while cold, but should be just fine once it warms up. IF you do not run it to the throttle body, you're just wasting fuel to the atmosphere, so I consider that the better choice of two that do not involve replacing that PITA valve.

Nick91runner

I will double check the hoses in the morning once it warms up, I out everything back together and rebolted the loose stripped bolt with some fat washers I had laying around. When I started it back up it ran kind of high (idle at 1500rpm) Its about 35 degrees here tonight (great Virginia weather) I only let it run for about 2 minutes due to it being 1am and my neighbors are probably getting tired of me.

Thanks again for all your help, I will let you know how it turns out.

TNRabbit

Fuel in the cylinders can also be caused by a leaking Cold Start Injector or one of the other injectors, although it's much more likely you have that fuel hose connected to a vacuum.

Sturmcrow

Do let us know how it turns out.

We hit 97 here in S. Cal yesterday. I would LOVE a 35 degree night or two!

Nick91runner

So this morning I fired it up and it idled at about 1500 rpms for 4-5 minutes and then dropped down to 1000 rpms with no gas dropping out the tail pipe (still smelled rich) I took it for a quick 5 minute ride and everything seemed to run just fine. When I got back it was idiling at about 800-900 rpms and running fine. I am thinking it was the loose vacum line to the A/C throttle up. (still not sure how fuel got in there)
i tightened it down with a new screw stlye clamp and bolted that whole assembly with the 3 sensors on it (there was a missing bolt) Anything else I should check? I double checked the vacuum lines and everything matched up as close as I could tell

Sturmcrow

That is great news. Did it still smell rich after you warmed it up?