Shaggybenz04

1993 4Runner 3.0L Engine, 4WD, Automatic Trasmission, Cruise Control.

First of all Thanks to all the pros that help the rookies, its much appreciated.

The Story
I had leaking Valve Cover Gaskets, my covers were leaking oil all over the engine. I took it upon myself to read a many threads, read through the FSM, and speak to some friends about doing the job myself. After my due diligence, I Got in there and replaced the Valve Cover Gaskets.

The Symptoms

After reassembling all the parts and starting the 4Runner,

• The engine idles only at 500 RPM,
• Has noticable power loss while driving,
• The exhaust smells rich of gasoline
• When I press harder on the accelerator the exhaust comes out dark.

What I Did


1. Project Materials Used

• RTV Sealant (copper)
• New PCV Valve & PCV Hose
• New Valve Cover Gaskets
• New Plenum Gasket
• Acetone for mating surface cleaning
• Torque Wrench (Ft. lbs.) & (In. lbs.)

2. The Process

• First I took off the intake assembly. In retrospect, when I was disconnecting the Mass Air Flow Meter I started to unscrew it from the top of the MAF, but after hearing spring like sounds I realized that the connector simply needed to be pulled off, so I retightened the screws. (This may be of some importance?)
• Second, I Labled and disconnected all vaccuum hoses and wire connectors from the Plenum and Throttle Body
• Third I removed the Accelerator cable, Automatic Transmision Cable, and Cruise Control Cable from the Throttle Body. (I taped the nuts in place so that I would be able to properly reassemble them)
• Fourth, I removed the EGR Valve. When I took it off, I saw that the stem that goes into the plenum, was covered in carbon deposit. I scrapped it off and found out that there entire thing was clogged! But my engine did not seem to have any idle or fuel efficiency problems before!
• Fifth, I unbolted the plenum, and lifted it off.
• Sixth, I unbolted the Valve Covers, (they are made of plastic, Wierd.) Cleaned the valve covers and replaced the Gaskets with the Blue FelPro Gasket type.
• I cleaned the mating surfaces, and added four nickel sized dots of Sealant at each corner of the Cylinder heads.
• Tightened the Valve Covers to 48 in.lbs. with bolt sequence.
• Replaced the Plenum Gasket.
• Reassembled Intake Chamber
• Reassembled EGR Valve
• Reassembled Vaccuum Hoses and wire connectors to the cold start injector connector, and accelerator/throttle/cruise control cables.
• Reassembled Intake and connected the MAF sensor

My Theory about where I messed up

1. MAF. I could have broken it by unscrewing the connector jack instead of just unplugging it.
2. Ignition Timing. I might have messed it up somehow?
3. EGR. Cleaning it may have broken it?
4. Accelerator/Throttle/Cruis Control Cables. What if I didn't place the nuts back with the correct calibration? What would this affect?

WELL, thats it, thats all I can come up with. I dont know which to try first because i don't know what would be best to fiddle with first.

The 4RUnner is Running and getting me around, but I need some advice.
The Gas Mileage right now is at 6 MPG! I'm Getting screwed bad.
My question is WHat else could it Be?
And would any of the things I am unsure of, be causing the symptoms that I am getting?

Thanks everyone.

TNRabbit

VAFM (not MAF) is my guess. That would certainly cause the issues you're describing.

edwinb4x4

2nd TNRabbit...after reading your process that was the thing that came up. ... VAFM.

You mentioned a spring sound when you mistakenly removed the vafm connector. It's possible that you shorted or loosened something inside the meter. My suggestion is to inspect the meter. First disconnect the neg bat cable then uplug then replug the female connector (not the one you unscrewed) . Start the engine, if problem still present - you might need to open the meter - use a sharp blade to cut the silicone seal then use a small flat tip screw to pry open the plastic cover (be very carefull) if ur not sure about this, do a search on how to remove the plastic cover. Once u have the meter open, carefully inspect the pins/wirings for opens/shorts. If everthing is OK reseal the cover then start the engine again. If problem is still present...u might need to double check the hoses again but at least at this point you've eliminated the meter from the equation.
'hope this helps...

abecedarian

If the VAFM was not damaged from partial disassembly, if the battery was left connected while you worked on it, it's possible that the ECU is using the fuel trim adjustment from when it had the vacuum leak (a consequence of leaking valve covers allowing air in through the PCV / breather) and injecting too much fuel. It should eventually re-adjust / lean the mixture out after a dozen or so start / stop the engine events, or you could reset it by pulling the EFI fuse or disconnecting the battery for a minute or so.

Shaggybenz04

OF COURSE!

I opened the plastic cover from the top of the Vafm and saw that I had ripped the three main terminals from the electronics inside. These three terminals had been torn off when I attempted to remove the base of the connector instead of just unplugging the wires on the harness.

I have soldered many electronics in my day so I simply soldered the corresponding connectors back onto their corresponding terminal end on the board. These three are the only ones that touch the board so the rest of them I simply reconnected from the inside before closing it up again.

I turned the 4runner on and immediately saw
RPMs go back up to 800
No dark smoke from exhaust and
The fuel mixture returned back to normal !
It is ridiculous how much the ignition system can change from just three little wires being disconnected.

Thanks for the advice
abecedarian,
edwinb4x4,
TNRabbit,

That just saved me $189.99 for that one part!

**I'm no electronics expert so what worked for me may not work for someone else, but Ill post some pictures of what it was like inside the Meter.**

Picture 1- The VAFM Lid removal
Picture 2- The three terminals that the prongs needed to be soldered to
Picture 3- The prongs firmly soldered to with the rest of the terminals plugged in.

edwinb4x4

...glad it got resolved!!

abecedarian

I don't deserve any credit here. TNRabbit and edwinb4x4 pointed you at the VAFM before I showed up. I'm still glad you found it easy to fix. Several have torn apart the VAFM and left it beyond repair.