Toyota Truck Problems

OK, let me start from the beginning.  Way back in 2005, I purchased a 1985 Toyota 4x4 pickup truck with about 165,000 miles on it.  I drove it for about three years until I hit a deer with it.  It was a great truck, so rather than getting rid of it, I’d figured that I could fix it up in my spare time.  That was six years ago and I am still not done with it, but I am close, really close, so it makes perfect sense to me that now would be the time that I would have a problem with it.

For six years the only running this truck has done has been being backed out of the garage and driven in again.  About two years ago I replaced the plugs, spark plug wires, rotor, distributor cap, filters, etc., and the truck seemed to run better than ever.  Every now and then, I would let it idle for about 15 minutes just so, well you know, it’s better for a motor to run occasionally rather than never at all.  I always tried to keep a very minimum amount of fuel in it so it wouldn’t go stale, adding a half a gallon here and there.

This truck always started right up and ran fine until - just a couple of weeks ago when I was getting very close to actually getting it on the road.  Then, it happened.  No start.  WTF???  I figured that a little starting fluid might be needed to get her going, so I took off the air cleaner lid to spray some in as my son turned the key.  The truck started, but quit right away.  It was then that I noticed that the air vane (that little flapper door) on the airflow meter was not opening very far.  I had my son start the truck again as I held the air vane open just a little bit, and what do you know?  The truck started and ran.  However, as soon as I removed my finger from the air vane, the truck sputtered and died.  After that, the truck would run at idle at any speed, as long as I helped the air vane open at the correct position for any given engine speed.

The first thing that I suspected was a bad airflow meter, but I tested the resistance at the terminals it is all within factory specs.  I also replaced the airflow meter with a different one from the junkyard.  It was off of a Toyota Celica or something, so it was not the correct one.  I didn’t expect that using that would solve the problem, but I bought it to learn how to take one apart without ruining it.  Anyway, I put it on my truck and I noticed that the air vane on that airflow meter didn’t open any further when installed on my truck than the one I originally had.  I began to suspect that the airflow meter was not the problem, and me pushing on the air vane was telling the computer to add more fuel, masking whatever problem it was that I had.

About this time, I went to Just Answer website for help.  I was working with one of their experts who goes by the name of “Toyota Service”, and found him to be quite helpful.  Now here’s where one of those “It only happens to me comes in.”  He’s not online right now, plus everything we talked about is missing.  Stupid me, I didn’t keep track of the password I used and in the meantime, I erased my browser history so there is no way I can get back to my conversation with “Toyota Service” right now.

Anyway here is what I can remember discussing with “Toyota Service”.  I hope I can remember everything so we don’t have to go over any ground we already covered.

One of the first things I suspected was wrong was a major vacuum or air intake leak.  I searched everywhere for one but could not find one.  I used the old trick of spraying starting fluid around the engine compartment to see if the engine sped up, and, nothing.  One thing to consider about this test I did.  I noticed that spraying starting fluid into the air intake while the truck was running actually slowed the truck down, so the test that I did was rather useless.

At that point, I figured I’d better get this possible vacuum/intake leak possibility ruled out, so this is what I did.  I removed the air cleaner lid from the airflow meter and cut a piece of 1/4” plywood just big enough to cover the air intake hole on the airflow meter.  If there were any major vacuum or intake leaks downstream from the airflow meter, the engine would probably continue to run after I blocked off the air intake with the piece of plywood.  As soon as I covered the air intake, the truck would die immediately, so I figure this rules out any major intake leaks.

The thing that really gets me about this problem is that it happened immediately, while the truck was not running.  A week before, I moved the truck in and out of the garage and it ran fine.  The next time that I went to start it, I had this problem.
Out of desperation, I figured I would drain the gas tank and put in fresh fuel.  Obviously that didn’t help or I wouldn’t be writing this right now.

While talking with “Toyota Service”, he came up with the idea that my timing may be off.  Maybe the timing chain jumped a link.  He figured that if the timing was off, the valves would not be closed at the proper time and pistons on the intake stroke would not produce enough vacuum to open the air vane on the airflow meter.  He told me to do a compression test.  This made sense to me.  If the engine is not making enough compression due to the valves not closing at the right time, it probably wouldn’t be making enough vacuum to open the air vane either.

So I did a compression test.  All cylinders are at 165 psi and the factory spec is 171 psi.  Not bad for a truck with 220,000 miles now on it.  Here’s what else I did to try to determine if incorrect timing was indeed the issue.
  1. A timing light indicates that cylinder number one is firing at 6 or 8 degrees before TDC.
  2. I removed the valve cover, and the timing mark on the cam sprocket lines up perfectly with the different colored link on the timing chain.  There is no way I can determine if the chain and the crank sprocket are lined up without removing the timing cover.  (That’s going to be done eventually, as I purchased a timing chain kit, but I want to get this issue resolved before I start tearing the engine apart and adding new variables to the mix.)

Here’s some other stuff:
  1. I don’t know how to do a fuel pressure test on this truck as my Haynes manual says nothing about it and the only thing I could find on line involved drilling and tapping the fuel rail for a gauge, so I did this Mickey Mouse test:  I cracked the banjo fitting on the cold start injector.  Fuel sprayed all over as soon as I cranked the engine, so even though I don’t have any idea how much fuel pressure I have, I definitely have fuel pressure.
  2. I checked the wire harness for the cylinder no. 1 injector, and there is power going to it.  It makes a test lamp glow very dimly as it pulses.  I bought a noid light and will do a proper check on all the injector harnesses later.
  3. I don’t don’t see how the injectors would get so dirty that the truck wouldn’t run when all that it has done is sit there and it ran fine the week before.
  4. I know there is at least some fuel pressure and at least some fuel going through the injectors, because the truck will run when I “help” the air vane on the airflow meter with my finger.
  5. The truck will only run when the distributor is in the fully advanced position.

OK, that’s all I can think of right now.  What’s the problem?  Can you help me?

5 comments:

  1. The very last line tells the story.
    If you have to advance the distributor all the way to make it run then the timing chain has jumped.

    It either jumped when you shut it off that last time or when you started cranking it again the next time.
    Pull the #1 spark plug, the distributor cap and the valve cover again. Move the distributor back to its original position, you should be able to see that easily from the spot where it was at.
    Stick a pencil or something long and soft down the plug hole and SLOWLY, by hand with a socket and ratchet on the crank pulley bolt, turn the engine over until the pencil comes all the way up and both rocker arms are loose on #1 cylinder.
    See where the rotor in the distributor is pointing.
    The rotor should be pointing at the #1 terminal where the plug wire would be if the cap were on.
    If it is and both rocker arms are not loose then the chain has jumped.
    If the piston is all the way up on the compression stroke and your rotor is not yet at the #1 spot in the distributor, your chain has jumped.

    If you wind up changing the timing chain and gears out, change out the chain tensioner at the same time.

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    Replies
    1. Thanks for your comment. I've already been through so much, I couldn't remember to write down everything. Here is some more of what I have done:
      When the timing mark on the crankshaft pulley lines up with the zero mark on the timing tab and cylinder no. 1 is at TDC, The trailing edge of the rotor is below the no. 1 spark plug tower. I understand that it should be the leading edge of the rotor that should be under the no. 1 tower. I believe that would make it about 3 or 4 degrees off on timing. This would lead me to believe that the timing chain jumped one link. because the chain has 97 links as I remember. That's pretty close to 100, and 360 degrees divided by 100 equals 3.6 degrees, so this all makes sense to me.

      So my question is: Is being one link off enough to make the truck not run? Also if that is the case is me pushing on the air vane on the airflow meter the reason I can make the truck run even though it is one link off on the timing chain?

      In other words, do you think that the timing chain being one link off is my only problem. I want to resolve this issue before I start tearing the engine apart and adding more variables to the mix.

      The timing chain kit I bought has everything. Chain, sprockets, guides, tensioner, oil pump, water pump, timing cover, gaskets, and seals.

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    2. One link is a mile in that regard.
      It will run but have no power and is not good for your engine.
      You are familiar with spark advance?
      Checking your timing with a timing light will generally call for the timing to be set at say, six degrees before top dead center at 600 RPM idle speed.
      That chain being off one tooth will actually have the spark plug firing AFTER the piston is at top dead center, this results in no power and is why you can only get it to run by cranking the distributor as far advanced as it will go.
      Do the chain and gear kit.
      Come back to this thread and let me know how it turned out, I will get an Email alert and good luck!

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    3. I'm getting killed here. What do you think? I just can't figure this thing out. Here's a link to everything I've done so far. You may have read some of it already, but I have updated some more at the end.

      http://goldengeesenews.blogspot.com/search/label/right%20side%20of%20the%20road

      What do you think my problem can be? I going to replace the timing chain eventually, but I would really like to nail this problem down before I do that.

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  2. Thank you for everything! I am planning on doing the timing chain this weekend. I will definitely get back to you and let you know how everything went.

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