Shop can't help. Great.

[santanvalleydirt]

So I finally got the chance to take my truck into the shop, where they cannot find the problem. They said it could either be the vehicle's computer, ignition wiring, or the igniter itself, although the igniter is basically brand new.:tsk: If I can't get a shops help on this, I'll have to do it myself. What would some of you guys recommend? What should I try to do first?



Here is my original post where I described the issue I was having:

http://www.toyota-4runner.org/classic-t4rs/214780-power-fluctuation-check-engine-light.html

 

[flyinhawaiian01]

If the engine continues to run, its not the spark! You have an issue with the key on position.

When this happens again, grab the keys and yank it around a bit, see if the issue goes away or is intermittent. If not, its elsewhere.

As I said before, I can turn my key slightly off from the on position while the engine is running, and the lights come on in the dash, the tach drops to zero, yet the engine continues to run, also with a slightly higher idle when this happens, most likely due to the fact that the alternator is no longer charging and the mechanical load is removed from the engine.

Of course, if you don't want to bother with the issue, take it to another shop. Just because one shop is incompetent, doesn't mean all shops are.

 

[santanvalleydirt]

If the engine continues to run, its not the spark! You have an issue with the key on position.

When this happens again, grab the keys and yank it around a bit, see if the issue goes away or is intermittent. If not, its elsewhere.

As I said before, I can turn my key slightly off from the on position while the engine is running, and the lights come on in the dash, the tach drops to zero, yet the engine continues to run, also with a slightly higher idle when this happens, most likely due to the fact that the alternator is no longer charging and the mechanical load is removed from the engine.

Of course, if you don't want to bother with the issue, take it to another shop. Just because one shop is incompetent, doesn't mean all shops are.

I'll try the key thing right now, but it goes away as soon as I press in the clutch, that's the part that confuses me. Also I'm not sure if the engine is turning off or not, the RPM meter just drops to 0 and then jumps back up after I either press in the clutch or wait about 10 seconds. I'm going to go put in a new ignition coil just to see if that works since its not that hard to do.

 

[santanvalleydirt]

If the engine continues to run, its not the spark! You have an issue with the key on position.

When this happens again, grab the keys and yank it around a bit, see if the issue goes away or is intermittent. If not, its elsewhere.

As I said before, I can turn my key slightly off from the on position while the engine is running, and the lights come on in the dash, the tach drops to zero, yet the engine continues to run, also with a slightly higher idle when this happens, most likely due to the fact that the alternator is no longer charging and the mechanical load is removed from the engine.

Of course, if you don't want to bother with the issue, take it to another shop. Just because one shop is incompetent, doesn't mean all shops are.

Yea it's definitely not the key thing. I shook the crap out of it, and twisted it just a bit, but nothing happens except the truck turns off when turn left too far, but that's what it's supposed to do of course.

 

[Hyde802]

Read through your other thread, have you checked the to see if its throwing a code?

Download the factory service manual, it will tell you how to test the coil and igniter with a volt meter, and the rest of the electrical system.

You could have a bad ground or a wire rubbed raw somewhere that when it contacts whatever its hitting is shorting something out.

 

[Bad_Vision]

Well the first thing to try would be the ECU you could pull one from a junkyard with moderate success rate. The vehicle furnace is a nightmare of long boring hours of chasing wires. The igniter is easy enough to test using the factory service manual. You're going to have to read how to test items using the factory service manual and then devote the time to do the testing


Sent from my iPhone using Tapatalk

 

[flyinhawaiian01]

I'll try the key thing right now, but it goes away as soon as I press in the clutch, that's the part that confuses me. Also I'm not sure if the engine is turning off or not, the RPM meter just drops to 0 and then jumps back up after I either press in the clutch or wait about 10 seconds. I'm going to go put in a new ignition coil just to see if that works since its not that hard to do.

I don't think I'm understanding this correctly. Let's work this through...

The issue is that the warning lights come on in the dash and the tach drops to zero, correct? Any other issues other than this?

Next, if you have to wait 10 seconds for the tach to come back to life, and the lights to go out, that's a long time to not know whether the engine is actually cutting out or not. 10 seconds would definitely be noticeable if the engine isn't running during that time.

Also, if the lights are coming back on and tach comes back online when you touch the clutch pedal, that there tells me there's an electrical issue with wiring very close to the foot well area.

I'm still not convinced its not just a wire that's loose. If it was shorting out, chances are you'd already have had a fire or at least a really bad burnt smell under the dash! But, let's forget about that for now, as I'm sure you'll peeked under the dash to check the area out.

Do you have a tilt steering wheel? If you do, try adjusting it up and down, just like you did for the key thing, see if that changes anything. It could still be the "ignition" thing I'm thinking of, but now that we've ruled out the cylinder switch (your key), let's look at the very next connection, the flat molex plug at the bottom of the dash area that the cylinder key wires connect to.

I'm thinking that whatever wire(s) are bad, are near the clutch pedal, and they're moving just enough with the pedal to cause a break.

Not trying to detract from the other posters remedies to try, but these are free, and if the engine is continuing to run, it surely can't be the igniter.

 

[santanvalleydirt]

Read through your other thread, have you checked the to see if its throwing a code?

Download the factory service manual, it will tell you how to test the coil and igniter with a volt meter, and the rest of the electrical system.

You could have a bad ground or a wire rubbed raw somewhere that when it contacts whatever its hitting is shorting something out.

Well the first thing to try would be the ECU you could pull one from a junkyard with moderate success rate. The vehicle furnace is a nightmare of long boring hours of chasing wires. The igniter is easy enough to test using the factory service manual. You're going to have to read how to test items using the factory service manual and then devote the time to do the testing


Sent from my iPhone using Tapatalk

I don't think I'm understanding this correctly. Let's work this through...

The issue is that the warning lights come on in the dash and the tach drops to zero, correct? Any other issues other than this?

Next, if you have to wait 10 seconds for the tach to come back to life, and the lights to go out, that's a long time to not know whether the engine is actually cutting out or not. 10 seconds would definitely be noticeable if the engine isn't running during that time.

Also, if the lights are coming back on and tach comes back online when you touch the clutch pedal, that there tells me there's an electrical issue with wiring very close to the foot well area.

I'm still not convinced its not just a wire that's loose. If it was shorting out, chances are you'd already have had a fire or at least a really bad burnt smell under the dash! But, let's forget about that for now, as I'm sure you'll peeked under the dash to check the area out.

Do you have a tilt steering wheel? If you do, try adjusting it up and down, just like you did for the key thing, see if that changes anything. It could still be the "ignition" thing I'm thinking of, but now that we've ruled out the cylinder switch (your key), let's look at the very next connection, the flat molex plug at the bottom of the dash area that the cylinder key wires connect to.

I'm thinking that whatever wire(s) are bad, are near the clutch pedal, and they're moving just enough with the pedal to cause a break.

Not trying to detract from the other posters remedies to try, but these are free, and if the engine is continuing to run, it surely can't be the igniter.

It's not throwing any codes. Igniter seems to be fine. (At least thats what the shop says)

I can't tell if the engine is actually off is because this only happens when I'm driving, anywhere from 20-90 mph (cant find any correlation between speed and this happening) and my tires and everything are too loud. Although the one way I think I know that the engine is not turning off is the fact that ONLY the check engine light comes on, nothing else. Then the check engine light goes away after either waiting a few seconds (letting myself decelerate) or instantly as I press the clutch.

I'm a tall, finicky guy and I adjust the steering wheel a lot and that has affected nothing.

Also, I just learning a little something new about it. The issue doesn't happen at all if I turn my cruise control on. This is seriously so weird.

 

[santanvalleydirt]

I recorded a video of it happening, so you can take a look here:

https://www.youtube.com/watch?v=kXBn28Jjzps&feature=youtu.be

 

[flyinhawaiian01]

Watched the video, but couldn't tell if you let off the throttle when it happened or the engine is actually shut down and decelerating on its own.

When it does this, hit the throttle to the floor and see if it accelerates. That will tell me if its losing spark or not.

If it does accelerate, you have an electrical issue with either power being cut to the ignition's ON circuit. This could even be a fuse that's corroded or loose, a connector that is corroded or not making solid contact, or a wire that's partially broken.

If it does NOT accelerate, then its time to check the ignitor again.

 

[santanvalleydirt]

Watched the video, but couldn't tell if you let off the throttle when it happened or the engine is actually shut down and decelerating on its own.

When it does this, hit the throttle to the floor and see if it accelerates. That will tell me if its losing spark or not.

If it does accelerate, you have an electrical issue with either power being cut to the ignition's ON circuit. This could even be a fuse that's corroded or loose, a connector that is corroded or not making solid contact, or a wire that's partially broken.

If it does NOT accelerate, then its time to check the ignitor again.

It does NOT accelerate, my foot was completely on the gas that whole time. As soon as the rpms drop, the gas pedal becomes dead weight. I can stomp it up and down all I want, engine doesn't do anything, doesn't move, doesn't rev, it does nothing. Soon as I press down the clutch or wait for a while, then I can use the gas to control the vehicle again.

 

[flyinhawaiian01]

Ahh, then you're back to square one with the ignitor. Power is being cut to the plugs, which means only one thing, ignitor is not getting power. Why it comes back on when you depress the clutch is beyond me though, and I still think its some sort of short, but it is a possibility that when you do depress the clutch, the engine stops rotating, and maybe that's what is allowing something to "reset".

And having typed that out, perhaps its something with the distributor. Try checking the plug that goes into it (I think its a green round plug, maybe its yellow). IIRC, there's two wires running out of it, red and white, check those and around the base to see if anything's weird about it. move 'em around and see if the issue changes.

 

[santanvalleydirt]

Ahh, then you're back to square one with the ignitor. Power is being cut to the plugs, which means only one thing, ignitor is not getting power. Why it comes back on when you depress the clutch is beyond me though, and I still think its some sort of short, but it is a possibility that when you do depress the clutch, the engine stops rotating, and maybe that's what is allowing something to "reset".

And having typed that out, perhaps its something with the distributor. Try checking the plug that goes into it (I think its a green round plug, maybe its yellow). IIRC, there's two wires running out of it, red and white, check those and around the base to see if anything's weird about it. move 'em around and see if the issue changes.

The distributor is new, but I'll go take a look at it. Thanks though. This has been a nightmare.

 

[santanvalleydirt]

Ahh, then you're back to square one with the ignitor. Power is being cut to the plugs, which means only one thing, ignitor is not getting power. Why it comes back on when you depress the clutch is beyond me though, and I still think its some sort of short, but it is a possibility that when you do depress the clutch, the engine stops rotating, and maybe that's what is allowing something to "reset".

And having typed that out, perhaps its something with the distributor. Try checking the plug that goes into it (I think its a green round plug, maybe its yellow). IIRC, there's two wires running out of it, red and white, check those and around the base to see if anything's weird about it. move 'em around and see if the issue changes.

But I mean, if it's the ignitor, why wouldn't it still happen even in cruise control?

 

[santanvalleydirt]

Ahh, then you're back to square one with the ignitor. Power is being cut to the plugs, which means only one thing, ignitor is not getting power. Why it comes back on when you depress the clutch is beyond me though, and I still think its some sort of short, but it is a possibility that when you do depress the clutch, the engine stops rotating, and maybe that's what is allowing something to "reset".

And having typed that out, perhaps its something with the distributor. Try checking the plug that goes into it (I think its a green round plug, maybe its yellow). IIRC, there's two wires running out of it, red and white, check those and around the base to see if anything's weird about it. move 'em around and see if the issue changes.

So I was poking around and found a tube that wasn't plugged in at all. Do you know what this is at all? I took a video of it:

https://www.youtube.com/watch?v=yx_mSVFY4iE&feature=youtu.be

 

[89FourRunner]

So I was poking around and found a tube that wasn't plugged in at all. Do you know what this is at all? I took a video of it:

https://www.youtube.com/watch?v=yx_mSVFY4iE&feature=youtu.be

I wouldn't think so. That vacuum line could create a bouncing idle, but I don't think it would create this problem you are having, especially if cruise control stops it.

Seems like some sort of short. The cruise control resolving the problem is mind boggling.

 

[santanvalleydirt]

I wouldn't think so. That vacuum line could create a bouncing idle, but I don't think it would create this problem you are having, especially if cruise control stops it.

Seems like some sort of short. The cruise control resolving the problem is mind boggling.

Yea I tested it, the line didn't fix anything. I have no idea what it was for. But I'm still having the problem. I'm at a loss here.

 

[Wazukie]

So, do you drive it for a little bit, like warm it up then it happens, or does it not matter if cold or warm? The reason I ask is because on my 4r, the ignitor was over heating and causing pretty much the same kinda thing. It would actually die, then I'd have to start it back up. It took a long time and a lot of research with other Toyota mechanics to figure this one out.

 

[4Reak Show]

There's a harness ground on the back of the engine on the passenger side, a little 10mm bolt holds it on. It's buried under the intake, not the easy one right on top. I believe it needs to be taken off when replacing valve cover gaskets and if it gets left loose it'll cause a very similar problem. Probably a shot in the dark unless you recently had that job done...(requires upper plenum removal.) It's a very important ground for the ECM. You could let it idle and wiggle the harness back there with long pliers, see what happens. And again, it's buried under the intake

 

[santanvalleydirt]

So, do you drive it for a little bit, like warm it up then it happens, or does it not matter if cold or warm? The reason I ask is because on my 4r, the ignitor was over heating and causing pretty much the same kinda thing. It would actually die, then I'd have to start it back up. It took a long time and a lot of research with other Toyota mechanics to figure this one out.

I've only really had it happen after it's warmed up a little.