Strange stumble/lack of power/idle problem...

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2ndGenToyotaFan

2ndGenToyotaFan

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89 4Runner 22RE 5 Speed. Truck has 220k+ miles on it with a lesser number of miles on a rebuilt engine.

This is a friends truck, and I just got this Email:

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"I was starting to pull the truck and stopped on a slight incline, when I went to go again I stalled out, and when i restarted the truck it was idling ruff. When I went to go again, I rode my clutch but I could feel there was no power, I let the clutch out entirely and was pushing the gas but there was nothing. So we stopped, rolled back to the flat spot, I put it in 4 low and pulled him up just fine.
Like i mentioned from time to time it is idling kind of ruff, and sometimes it is nice and smooth and quiet. what i mean by ruff is that it sounds choppy, not like i smooth purring engine but more like inconsistent with its idle."

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This truck had a bad TPS, and I swapped it out for a junk yard one that tested fine. Aside from that it's in an average state of repair and tune. The problem seems to be intermittent, which is my favorite kind... Thanks for any thoughts on this. :cheers:
 
I had a rough stumble, and no run problem with my truck a couple years ago. Ended up being the ground wire to the fuel pump bracket was corroded, poor contact to the pump. For a few weeks it would come and go, until one day it totally stopped working.

Its worth looking at, sounds like a fuel problem.
 
Loose crap and old clumps of varathane like gas globs getting into the filter also likely.
 
Could also be a loose injector wire, I've heard the solder splices can loosen up on the harness. This would cause the same problem, as the injectors are not always going to fire properly.

Could be something totally different too, but I would probably start by checking for loose wire connections, as well as change the fuel filter like Norcal said.
 
cruiser88 said:
I think "hill" is the key word.............check the fuel pressure
Click to expand...
Agreed... Check the fuel pump and it's wiring.

Next engine ground and other engine wires.
 
Mike C said:
Could also be a loose injector wire, I've heard the solder splices can loosen up on the harness.
Click to expand...

No solder involved. Those splices are crimped which is why they fail. One of mine failed many years ago before I knew anything about my truck and the dealer fixed it. One of these days I'm going to pull out the EFI harness and remove all of the tape and solder/shrink tube every splice. Some day.
 
X2..Ditto the pump connector wiring idea, just said the same in Doug's thread. Connectors corroded and frayed on the top plate of the sending unit.
 
I actually just talked to her on the phone. We're both thinking it's a clogged fuel filter... She had the symptoms a while ago and we changed the filter and it was good for a month or two... Now it's back. So either the fuel lines are leaving deposits and clogging it or the sock on the pump has failed and is letting gunk through... I'm going to see the truck on Monday and will probably be changing the filter then. So we'll see how it goes, and I will let you all know! :cheers:
 
Check the Mass Air Flow (MAF) sensor. It could be corroded up inside and the air gate is not freely moving. Took my 89 22RE powered 2WD pickup acting up again for me to remember that possibility.

The MAF unit can be disassembled to allow easier access for sanding all the surfaces that may rub. When removing the wiring connector, open up the spring clips to allow it to be freely removed. On each side of the connector there is a fine spring wire that wraps around the connector in a grove and engages a catch on the unit. The ends of the wire are visible on the top. I use a small flat bladed screwdriver to carefully push them to the side a bit. Once they are out far enough the connector comes off very easy. The MAF unit has 4 nuts and 1 bolt that connect it to the top of the air filter box. Take a look inside the unit through the air in and out ports. If there is corrosion on the surfaces it may be impeding the motion of the air gate. Flip the unit upside down and you will see allot of tiny screws and some caulk holding the bottom AL plate on. Use a properly fitting screwdriver to remove the screws.(See note below) Carefully pry the plate off as it is also has some caulking holding it in place. That caulking serves to stop stray air flow. Don't try to remove the air gate. Just leave it in place as you can move it back and forth and sand around it. Use some 200 to 400 grit sand paper to remove the corrosion form the interior surfaces and the edges of the air gate. You should be able to slip some sandpaper under the air gate edge to sand it smooth. On reassembly, I've ignored the caulking and just used the screws to hold the plate in place.:hillbilly: You could just use some caulk to seal up the edges after the plate is put on as the joint is under negative air pressure. I figured the gap is so small it wouldn't matter much. The rest of reassembly is the reverse of disassembly.

NOTE: the screws are JIS standard Phillips head. It is a slight bit different than the US standard. Using US Phillips screwdrivers in them is prone to having cam out issues. I just selected the right size screwdriver bit, then used allot of pressure to keep it from camming out. If you do strip the head on one, get a left hand drill bit about the same size as the screw head and use it to drill the head out. Often the screw will start to come out before the head is fully drilled out. Take the screw down to your local fasteners dealer and find a replacement.

NOTE: At no point do I open the plastic covered area on top of the MAF unit. I do use some electronic contact cleaner on the contacts for the connector.
 
Did you "force the pump to stay on" by inserting a paperclip in the B+ and Fp contacts. This will help you check the function of the fuel pump. If this happens to fix it then its the circuit opening relay, maf or starter switch (that are not sending to the relay). Its a lot easier (and cheaper) than swapping a fuel pump or filter.
 
We changed the filter and it did not change the problem. I forgot to try to jump the pump. However she pulled the fuel pump cover off and said everything looked ok in there. I'm now out of teh country for about 5 weeks, so I'll try some of the other things when I get back, or have her try them. Thanks Gents! :cheers:
 
The bent rubber hose part of the intake tube. It's in the lower right corner of this pic:

tbintake25.jpg
 
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