Ronnyboy

Hey 4Runner buddies!

I'm new to the world of 4Runners, and I'm doing it in style. I have a 93 4Runner, V6, 4WD, 5 speed, 295k miles. Thing is a beast, and is pretty well taken care of. New sheet metal, new exhaust, A/C works and all the electrics are good inside.

I am having a problem, and it seems strange to me. When I start the 4Runner, give it full revs, it runs and sounds fine and doesn't give me any headaches, no CEL either. However, when I go to drive it will drive fine for about 15 seconds, throw a CEL and then it starts to chug. It feels like it wants to go, and it does, but it seems like it's choking out, kind of like putting your hand over a carb.

Thought the ignition system was crapping out, replaced all the plugs with NGK's, did the cap and rotor, and all new wires as well. Idled better, but still having the issue. The previous owner said it was probably the VAFM, but research I've seen doesn't seem to show that it would cause this, right?

The real issue is that I'm not use to Pre-OBDII computers, so can I check the code without it being shown on start up? Sorry for the dumb questions, like I said, I'm new to this! I've included some bonus pics to show her off!

scope103

Welcome to Yotatech.

You only need key-on to check the codes.
http://personal.utulsa.edu/~nathan-b...85diagnosi.pdf
As you can see, you'll need special service tool SST 09843–18020 (but we all use one of these: http://www.staples.com/Staples-reg-J...product_525923)

Next time you upload pictures (and, thanks!), shrink them first. You uploaded 5312x2988 (nice camera!) but even though the page has to load all those megabytes it's only displayed at 1024x576. (And that's much more than big enough; smaller is even faster)

Ronnyboy

Huh, seems strange to me that it wouldn't show the code at idle though... Go figure though. And sorry about that, Galaxy S6 will do that, I'll resize them

scope103

Look through the FSM section. You'll see some of the codes only appear after certain conditions, like engine above a certain rpm for a certain time. The code will be stored, though, and you can retrieve it the usual way.

I know nothing about your rig, but from your description I fear you may find code 52. Keep your fingers crossed.

Ronnyboy

Damn, I hope it's not either! Luckily I've got some time until the snow falls to get this rig perfect. I'll test and report back to see what's happening

Ronnyboy

So, checked the codes and I got 24, 31, and... 52. So it looks like I need a new VAFM, any suggestions on where to buy one? And if I get one, can I try clearing the codes to see if it resets the knock sensor?

scope103

Aren't these "modern" trucks just the cat's meow? You get the code, it tells you exactly what part you need to buy, and you just snap it in like some big Lego!

Except, obviously, it doesn't work like that. The codes point to which circuit has the problem, but they don't tell you EXACTLY what the problem is. In your case, it might be as simple as a loose connector to the VAF. So you just need to get your $6 multimeter and run the diagnostics. http://personal.utulsa.edu/~nathan-b...92volumeai.pdf

And since you sound like you're new to this, here's a hint:




You can reset the codes by removing the EFI fuse (or just disconnect a battery cable, but then you'll trash your radio presets, the learned fuel trim, etc.) But there isn't much hope that your code 52 will just decide to leave. The MOST likely cause of code 52 is a bad "pigtail." The part is less than $10, but you have to remove the intake manifold to get to it.

Good luck!

Ronnyboy

I tested it and the resistance is all sorts of screwed up, I'll have to order a new one it seems! When it comes to the Knock Sensor, I read on a few random threads that you can relocate it? Doesn't seem necessary, as I can take off a manifold no problem and replace it, but just thought I'd ask.

Thanks for all the help!

RJR

Before I ordered a new VAFM (they're quite expensive), I think I would at least take a look inside the old one. As scope said, you do not get inside by removing the screws. Instead, take an xacto knife or razor blade and carefully slit the RTV seal around the flat top cover. Inside you'll find a wiper arm that slides on a circular track. Get some circuit/pot cleaner from your local electronics store and a cue tip and gently clean the track and wiper arm (don't dis-assemble anything). Put the cover back on. You can duct tape it good to seal it temporarily, but if it fixes your problem reseal it with RTV as soon as you can.

The VAFM is tightly sealed to keep dirt out, but it's not hermetic or anything, so there's no problem opening it as long as you do it in a clean environment and don't get dirt inside. You can take it off and work on it on your kitchen table if you want to be sure.

Ronnyboy

Huh, so today I took my truck over to my buddy's shop so we could clean up the VAFM. It tested fine afterwards, and we all got excited. However, when we put it on, we got a bad misfire. Now it seems after some testing that the #2 fuel injector is dead, so now I am going to order a new one. Would that throw the Air codes since it's not getting a god fuel/air mix?

Sorry I seem so dumb, but I'm just really confused now.

scope103

Not the codes you got, but a dead injector can certainly lead to code 25. Just think it through: You start with three perfectly balanced cylinders, and one that's squeezing out nothing but air and unburned fuel. The O2 sensor senses ... the O2, and the ECU tries to compensate by dumping in more fuel. The other three cylinders are now running really rich, but the air from cylinder 4 is still there! Eventually, the ECU "throws up its hands" and you get code 25.

You gotta take things one step at a time. You know a dead injector is bad, so you have to replace it (OR -- you could just clean the old one http://www.witchhunter.com/ new injectors aren't cheap). I doubt that will affect your code 52, but now you have a path.

Ronnyboy

Yeah, I figured that is what was causing my issues. Luckily I have a good source for a new injector, $30 delivered! So I'll be pulling the throttle body assembly this weekend to get to the fuel rail and replacing the injector. Will also make sure I don't have any wiring issues while I'm in there, since I assume that would also cause the injector pulse to be dead. Hopefully it'll clear everything up, will let you all know. Thanks for all the help scope

scope103

Uh, Ronnyboy, this is Yotatech. What are you supposed to do? (Hint: you already gave the price, we need the source and part number!)

It's good to share.

Ronnyboy

Haha, my source is a buddy of mine who used to be a Toyota tech. I called him up and he says "Yeah, I got some in box. $30 and some beer next time you come over". Showed up with $30 and some PBR, he handed me one and said "3.0? Good luck buddy"

This should be a good time

mrsboone

I'm getting a code 24 and 22. I have a 1994 t4r, 3.slow 4x4, automatic. Have been replacing sensors, found out the cold start temp switch might be our problem, also called start injector time switch--haven't been able to locate one, dealer wants $201. Gotta be a cheaper one? Doesn't there???

scope103

89462-20040 $152 http://www.toyotapartsoverstock.com/...rimLevel=18292

But before you go off and replace still MORE sensors, could you share with us how the Start Injector Time Switch could possibly have anything to do with code 22 or 24?

mrsboone

That's what code, book & dealer says. Process of elimination... Have already replaced other things that were throwing codes, there are 2 other codes that are also coming up, hubby doesn't have the list handy right now.

scope103

Here's the actual manual with the codes. http://web.archive.org/web/201211190...85diagnosi.pdf I don't see anything in there about the Start Injector Time Switch. (except a deep reference in code 26, is that one of your "other" codes"?). Unless I missed it.

Do you have a reference to your "code, book & dealer"?

Even if you have code 26, it's easy to eliminate the Start Injector Time Switch as a possible cause; you just disconnect it and see if that clears up the problem.

Why don't you give us the other codes, the other sensors you've replaced, and how you got there by the process of elimination. I'd hate to see you waste $201 or even $152

Terrys87

iTrader: (1)

I have fixed several Timing Switch sensors just by removing them and cleaning the hard water build up off of the sensor with a brass toothbrush. You can run a resistance check on it and if it passes, the sensor is probably good. Once I clean one and it passes the test, I have never had one to fail. A Haynes of Factory Service Manual has a good test for them.

If you are from the Northwest or North Central there are a few salvage yards that have them or you could post a wanted ad.

mrsboone

22 Engine Coolant Temp Sensor, 24 Intake Air Temp Sensor, 32 Volume Airflow Meter (replaced--still throwing same code), 41 Throttle Positioning Sensor (replaced--still throwing same code).

Chilton manual. Magness Toyota Dealer, (where I bought my Taco).