My 93 was recently in the shop for what turned out to be a new coil. After they installed, they told me I need a new Air Flow Meter, which I declined. I then went to AutoZone and picked one up a cheaper price. After I installed, the truck idled irratically, but ran okay...although chk engine light came and went. I then installed a new O2 sensor. Now truck idles for a few minutes then starts cutting out--smells and looks like its running too rich. Code indicates 31, which is either Air Flow Meter or Manifold pressure sensor. I'm thinking of taking meter back to Autozone and picking up a Toyota meter from junkyard (only 75 bucks). Do you think this will solve problem? What should I make of the codes?
Originally, it went to the Toyota dealer because it wasn't running in wet weather. After three hours of investigating, they discovered it was the coil. They installed, saying problem was solved--an hour later I get a phone call saying truck was running bad and and computer tells them it needed a new air flow meter. Told them no thanks.
I picked up my truck and drove it home. Went to AutoZone and bought a reconditioned AFM. After I installed it, truck still was not running great, but got me there. Thought maybe I had to work out the bugs and install an O2 sensor, which was way past due. At this point, CHK engine light was not staying on. It would light up from time to time and engine would "rev" without hitting the accelerator. Last night I installed a new O2 sensor. This did not solve the problem.
Today, I checked my code and found a 31, which based on research tells me Air Flow Meter or Manifold Pressure Sensor. Since finding this out, I took the AutoZone (reconditioned) meter back and bought a meter from the junkyard. It seems to run better, but still misfires. I'm still getting a 31 code.
Also, I'm getting black soot out of the tail pipe. Smoke is clear, but heavy--I could open a dog pound.
Thinking of cleaning the throttle body. Any other suggestions?
You are having the exact same problem I am having! My son got the engine wet cleaning it and it started running terrible, backfire through the exhaust, running rough or not at all, black soot comming out of the tail pipe and will not pass emission testing now. Dealer told me Mass air flow sensor was bad. I have also changed with one from junk yard and replaced O2 sensor, New Toyota plugs, wires, dist. cap, and rotor button. The truck dosn't backfire anymore but still shoots out tons of black soot, and will not pass emissions test. One thing I have been told by many people is that Toyota engines do not run well with aftermarket parts from Autozone type stores. The thing that gets me is that Toyota parts are to expensive to throw parts at the problem without being sure what will fix it. My dealership is clueless. I wish there was some way to try a new sensor before I dished out $400. Keep me updated on what you find.
Yes, there is definitely a connection, as I also cleaned some excess gunk off my engine. I recently changed my valve cover gasket and wanted to make sure there were no more leaks. Using a common engine cleaner and very small amounts of water to rinse (and covering key electrical components). I did this after installing the AutoZone air flow meter. I've tried a blow dryer and the like to dry the area out--and it is getting better.
Yes, I've got several problems working but think (after talking to you) it is water related around the fuel injectors or the like. Wonder if there is a product to remove water or a fresh tank of high-octane or some aviation gas. I should have left well enough alone and gone down the road with a dirty engine!
I have since taken Autozone AFM back (they actually gave me all my money back) and bought one from the junkyard. Runs better and computer flashes normal code -- no more chk engine light. However, when I wiggle the wire harness leading from the AFM to the computer, the engine wants to stall and throws soot out of tailpipe. Must be a short somewhere in the harness. Looks like it might be a mother to change. At this point, I don't think the problem was the AFM, but the wiring.
Any ideas on how to change the harness? I'm wondering if I could splice.
Check all your connections to the components and mde sure they are dry and free of corrosions. It will take a little time but it's all a matter of which you have the most of. Get you a tube of dielectric silicone grease and some electrical cleaner from the parts store and after checking and cleaning connections put a little of the dielectric grease on or in each connection. You will always be ahead of the game to use only Toyota OEM parts on the emissions and ignition parts. And remember the ECM coes just tell you what is happening and does not always mean the the part that relates to the code is bad!! So don't start throwing parts on just because the codes relate to them!!
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94 Toyota PK Ex-Cab 3.0 4X4 Auto
What are your recommendations for a good throttle body cleaner? Should it contain acetone, MEK, and the like or is it okay to contain petroleum distillates?
I've since dumped some fuel injector cleaner into the gas tank and it seems to be running better, but still get black soot out of tailpipe.
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