Brad.

1993 4runner 3VZE Auto.. 140,000 miles

Head gasket and top end gaskets replaced in this last week, plus new timing belt and water pump.
Everything is back together and we are running into some problems.

Did ISR mod today because the intake hose was all falling apart at the throttle body, new hoses are all sealed except one small spot.

Fuel pump runs constantly when the key is on ACC. FIXED

Idle is too low (& somewhat rough) despite turning idle screw. FIXED
Black smoke is coming out of the exhaust, clouds of it when RPM's are high, and fuel level drops very very fast.

Fixed a fuel leak at the fuel pressure regulator.

We drove the truck around the block, (runs pretty good), afterwards it pulled a Code 24, unplugged the battery and the code went away.

When i stopped in the driveway the brakes were very tight, maybe a vacumm hose mixed up somewhere.

My ideas are something to do with air intake sensors? Causing the computer to push in too much fuel?


I am an avid user of the Yotatech search feature, but I just could really use some specific help on getting my truck back to life!
Any input is greatly appreciated.

bugs1961

The smaller hose (3/8" or so) that comes off the air cleaner and running to the front of the plenum must be connected to filtered and metered air (after the VAFM) or there will be a huge vacuum leak. Check that first. The larger (5/8") hose isn't metered and won't affect engine tune.

I did all the same repairs 18 months ago, with the exception of the ISR an haven't had a single problem. Running great.

Brad.

Yes I have that smaller hose receiving air right after the VAFM directly from the new intake pipes, much like many other people have done with their custom intakes. However it is that fitting that has a small leak right now, I plan on putting some silicon around it to fill the leak in the morning.

Tracey98277

a rich mixture could be a mixed up vac line or computer problem. the running fuel pump points to a computer/electrical problem. check your TPS. are you sure you got the valve timing right on? code 24 is intake temp sensor, check the VAMF.

Tracey98277

oh and check the two vac lines that come off the bottom of the power steering pump, that could be the brake problem.

Brad.

I know it's a possibility I have a vacumm line mixed up, does anyone have a labeled picture of where all the hoses belong on the side of the intake?
And I will check my TPS, but I am not sure where it needs to be adjusted to. I guess I can see how that could result in too much fuel being sent through.
Thanks for the advice I will post back soon with what I find out.

Team420

If the fuel pump runs constantly with the key on, I would suspect that the flapper thingy in the afm is stuck. Pull it out and check/clean it. Fuel pump should only run when engine is cranked or running.

nv4runner

I've also heard of people installing the fuel return line where a vacuum line is supposed to go...that'll make it run richer than its ever done before! I believe that both fuel hoses are at the rear passenger side of the engine. A ruptured fuel pressure regulator can also cause it to run rich. Vacuum lines are such a pain.

harrywat

OutlawMike has 200 photo's that he gave me access to. I was able to locate all my problems from those pictures.
PM him and I'm sure he will do the same for you.

Thanks
Harry

Brad.

Thank you Harry I sent him a message. I'll get back to you guys soon.

thedanned

I would start here, personally.

Brad.

I am pretty sure all my vacumm lines are correct. Code 24 just popped up again, what all do I need to replace or clean that sensor? and could it failing cause the computer to send too much fuel?

Team420

Just pull the sensor off the airbox, and look inside, there is a "door" that moves when there is vaccum, telling the ecu how much air is entering the engine, the ecu uses that as well other info to determine fuel mixture, so if that "door" is stuck it will send too much fuel or not enough, depending on where its stuck. Hence the fuel pump running with the key on... it should only run when there is vaccum...ie cranking or running motor.

Here is a link with info to test the afm as well.

http://www.ncttora.com/fsm/1990-1995...e/volumeai.pdf

Brad.

Ah! nice trick, the door was staying open about half an inch even with the motor off. The fuel pump stopped running when I got it to close all the way.
I am still getting a code 24, so now I am going to get a used part and hopefully the door, and sensor are good on it. thanks 420. i'll report back soon.

Brad.

Got the used air sensor on, truck seems to be running pretty good now, but still too rich. I can still get black smoke from the exhaust when I push the throttle high in the engine compartment. Fuel pump not running anymore.

Brad.

I am hearing a sound that I would describe as a "knock". I feel like I bought a lemon.