My Runner left me dead on the road! Please help diagnose.

[JohnsD90]

I would say a spark issue was equally as possible as a clogged fuel filter.

It would misfire from a spark issue. Misfiring feels like the rear end is bouncing.

 

[004Gunner]

Great to hear you're back up and running! I cringed when I read the q-tipped MAF part though! I noticed that there were some thoughts that O2 sensors or bad plugs can not stall an engine, which is false. I have actually stalled my engine when a single plug was bad (bad=a massive failure). I have also had a JGC stall because of a bad O2 sensor. I'm not going to say it's likely or normal, just that it has happened. I don't like to rule things out before I rule things out :happens:

Edit: Can we change this title to My Runner Left Me Dead Because I Neglected MAF Maintenance! :jk:

 

[BTO]

Google K&N and MAF and see what you get.

 

[SkidPalace]

Ah well the saga continues...
I was putting around town all happy with my avoided catastrophe and wouldn't you know on the way to return the new MAF to Advance, the CEL came back on. She's still running great, just the CEL is now mocking me. Keep in mind the CEL never came on when the trouble started, just after my truck was already crippled.
Now, I am getting the light when the truck runs fine. Could it be that I did actually destroy the MAF with the Q-tip?
I cleared the computer by disconnecting the battery and holding the leads together for two or three minutes. The truck fired up real crisp and ran very well with no CEL... for about 10 minutes. Then I noticed just a bit of sluggishness. No big deal, the truck still ran well, just not as crisp as when I first fired it up. So I make a stop and when I hop back in the car, bingo... CEL. Fortunately I was stopped at Auto Zone. I have the guy scan the codes and it says P1130 and P0171 again(maybe it was too soon for the 0172?).
I just don't get it.
Tomorrow AM I will clear the computer and install the new MAF. We'll see where that takes us. After that it's back to square one I guess.
Well, I suppose beter than square one. I still think that the plugs and wires are fine since the truck ran like a raped ape after the computer cleared.
I can only guess tht it's either a bad MAF sending false signals to the computer resulting in a too lean mixture tripping the 1130 and 0170 codes reported by the a/f sensor. OR it could actually be a bad A/F sensor. It has gone before. Not to mention that I recall reading s/c'd engines without fuel upgrades can increase EGTs and toast these sensors.
I may also test my MAF with the following procedure from the service manual:
INSPECTION
1. INSPECT MAF METER RESISTANCE
Using an ohmmeter, measure the resistance between terminals
THA and E2.
Resistance Temperature
13.6 - 18.4 kW -20 °C (-4°F)
2.2 - 2.7 kW 20°C (68°F)
0.5 - 0.7 kW 60°C (140°F)
If the resistance is not as specified, replace the MAF meter.
2. INSPECT MAF METER OPERATION
(a) Connect the MAF meter connector.
(b) Using a voltmeter, connect the positive (+) tester probe to
terminal VG, and negative (-) tester probe to terminal
E2G.
(c) Turn the ignition switch ON.
(d) Blow air into the MAF meter, and check that the voltage
fluctuates.
If operation is not as specified, replace the MAF meter.
(e) Turn the ignition switch OFF.
(f) Disconnect the MAF meter connector.

 

[SkidPalace]

Both MAFs test good and both throw CELs shortly after the second start after resetting the computer.
At least the truck runs fairly well.
I'm open for options on the next step diagnosis. I went to my dealer to buy the SST for checking the fuel pressure at the rail and they said they do not sell them.
Can you use a universal gauge to do it?

 

[SkidPalace]

Anyone know if a fouled MAF could cause the ratio to go so far off that it would knock out a A/F ratio sensor?

 

[skorpion]

I had the same symptoms and the same codes. Here is what happened with mine. I did a tune up and had to loosen the ground wire that bolts to the intake on the driver side of the motor toward the front above the first plug. Now you didnt mention doing anything with the vehicle but if for some reason that cable is loose or damaged it would cause a frensy with your fuel delivery system. Thats why your vehicle keeps throwing both lean and rich codes, that cable has to do with your ground for injectors and iginition. Check that cable, I replaced a MAF and the A/F sensor before I had a mechanic look at it who fixed it in 5 minutes.

 

[SkidPalace]

I had the same symptoms and the same codes. Here is what happened with mine. I did a tune up and had to loosen the ground wire that bolts to the intake on the driver side of the motor toward the front above the first plug. Now you didnt mention doing anything with the vehicle but if for some reason that cable is loose or damaged it would cause a frensy with your fuel delivery system. Thats why your vehicle keeps throwing both lean and rich codes, that cable has to do with your ground for injectors and iginition. Check that cable, I replaced a MAF and the A/F sensor before I had a mechanic look at it who fixed it in 5 minutes.

I had been ****ing with my intake prior to the incident. But not on the drivers side, only the intake silencer and all parts upstrem of the throttle body. I did also drive error free for about 50 miles since last messing with anything though.
I will look for said ground wire first thing in the AM.

 

[nolo]

I had the same symptoms and the same codes. Here is what happened with mine. I did a tune up and had to loosen the ground wire that bolts to the intake on the driver side of the motor toward the front above the first plug. Now you didnt mention doing anything with the vehicle but if for some reason that cable is loose or damaged it would cause a frensy with your fuel delivery system. Thats why your vehicle keeps throwing both lean and rich codes, that cable has to do with your ground for injectors and iginition. Check that cable, I replaced a MAF and the A/F sensor before I had a mechanic look at it who fixed it in 5 minutes.

Let me add a +1 to this. On top of the engine, you will see a "DIAG" plug. Run that down, and you'll see a ground bolt screwed into the engine block. IF this is loose, it will mess up your driving. I paid toyota 228.86$ to diagnose a stalling 2000 4runner, and all it was was this grounding bolt had come loose. I tightened it up, my codes went away, and all is right in the world. I would suggest everyone check to make sure it's tight.

When it stalled the first time, did you hear a clicking underneath your dash on drivers side? if so, i would bet your ground is flaky on the engine block. check it.:fishing:

 

[004Gunner]

I'm open for options on the next step diagnosis. I went to my dealer to buy the SST for checking the fuel pressure at the rail and they said they do not sell them.
Can you use a universal gauge to do it?

A universal adapter doesn't have enough room to fit on the fuel rail. OTC-528768 and OTC-528766 are the fittings you need that should work with a universal gauge. The 1st part is the double banjo bolt and the 2nd is the adapter

 

[SkidPalace]

Closing out this issue

I just wanted to close out this issue for future readers.
Thanks to all who helped diagnose my stalling problem.
I just posted the resolution of my woes on another YotaTech thread here.
It turns out that it was actually a burnt Air/fuel sensor after all.

I switched it out with a new Denso unit from Amazon.com for only $124 (Gadget sells them for $167 at URDUSA.com) and she is up and running with no trouble codes and normal smelling exhaust.
Thanks again for the help.

 

[BTO]

I'm glad you posted back Skid but your story is real aggravating.

We had our A/F sensor go out and all it did was throw three codes and set the CEL. It still ran fine. How is it that it cause your 4r to be FORD (found on road dead)? Could it be the SC?

 

[SkidPalace]

I'm glad you posted back Skid but your story is real aggravating.

We had our A/F sensor go out and all it did was throw three codes and set the CEL. It still ran fine. How is it that it cause your 4r to be FORD (found on road dead)? Could it be the SC?

You know I really wish I knew. I also had it go out on me ~40K miles ago and I drove it with the CEL on for almost 6 months. Other than increased exhaust emissions (and probably lousy gas mileage, though I never bothered to check) there were no other symptoms of an ill engine.
What I think happened was my MAF sensor clogged and went berserk. That caused my engine to blow massive amounts of fuel through the system. This flood of fuel possibly burned out my A/F sensor by the time I could get it back to the house. Alternatively the fouled MAF possibly caused a too lean condition and the heat generated by the lean condition fried my A/F.
I know my engine is still not 100% healthy since when I restart after a computer clear it runs extremely well. Then it slowly settles back into a less neck snapping feel. This, however is probably due to the lack of fuel upgrades for my supercharger. I am betting that there is a bit of knock happening and being picked up by the knock sensor, thereby backing off the timing in the first few minutes after a computer clear. I would also bet a 7th injector would keep my engine running at its peak potential indefinitely. Unfortunately I don't have a spare grand lying around.
I also have purchased a set of NGK wires, a paper air filter and a new fuel filter. I would have had the new fuel filter in today if I could have got the damn rusty outlet fitting undone.

The inlet came off with a mighty effort.
I will keep spraying PB Blaster on the outlet fitting on a daily basis until I can wrench it off.
Next I need to purchase new plugs and I should have a fairly complete tune up in place.

 

[SkidPalace]

Let me add a +1 to this. On top of the engine, you will see a "DIAG" plug. Run that down, and you'll see a ground bolt screwed into the engine block. IF this is loose, it will mess up your driving. I paid toyota 228.86$ to diagnose a stalling 2000 4runner, and all it was was this grounding bolt had come loose. I tightened it up, my codes went away, and all is right in the world. I would suggest everyone check to make sure it's tight.

When it stalled the first time, did you hear a clicking underneath your dash on drivers side? if so, i would bet your ground is flaky on the engine block. check it.:fishing:

This is what the ground wire in question looks like on 1st gen supercharged engines, for the benefit of the thread readers. They are the terminated wires in the dead center of the picture, attached to the bracket attached to the supercharger. I did check mine and they were was tight as a drum. Thanks anyway.

 

[97fun4x4runner]

thanks and help~!

Skid, my 97 did the same thing last weekend...driving home 65mph, 25 degrees outside, hurrying home and old faithful bogged down, and then wouldn't start again..or would start, but not hold idle, and would effectively flood out.
Your posts have been very helpful. I tried cleaning my MAF sensor with CRC MAFS cleaner, put it back on, and no change. I did notice that I could only see ONE wire inside, and the whole assembly seems impossible to dismantle to get a closer look.
Here's a pic from Autozone of same item:
AutoZone.com | | Mass Air Flow Sensor | REM MASS AIRFLOW SENSOR from Autozone website..it looks just like that. Is it possible some MAF sensors only have one wire? If I special order that one, and install it..they won't refund it if that's not the problem. I don't have a code reader, and the 'helpful assistant' at Autozone suggested I have a mechanic come out, get it running and then they could do a code check for free ~! (greeat...fix it and then code.)
My runner has 225k miles on it, and I have all maint records from previous owner indicating that the MAF sensor has never been replaced, but then again, neither has the part that ended up being your problem either. Hate to gamble w/ a $200 part. What's a cheaper option?
Many thanks in advance..am stranded at the moment, so not going anywhere soon.

 

[SkidPalace]

Skid, my 97 did the same thing last weekend...driving home 65mph, 25 degrees outside, hurrying home and old faithful bogged down, and then wouldn't start again..or would start, but not hold idle, and would effectively flood out.
Your posts have been very helpful. I tried cleaning my MAF sensor with CRC MAFS cleaner, put it back on, and no change. I did notice that I could only see ONE wire inside, and the whole assembly seems impossible to dismantle to get a closer look.
Here's a pic from Autozone of same item:
AutoZone.com | | Mass Air Flow Sensor | REM MASS AIRFLOW SENSOR from Autozone website..it looks just like that. Is it possible some MAF sensors only have one wire? If I special order that one, and install it..they won't refund it if that's not the problem. I don't have a code reader, and the 'helpful assistant' at Autozone suggested I have a mechanic come out, get it running and then they could do a code check for free ~! (greeat...fix it and then code.)
My runner has 225k miles on it, and I have all maint records from previous owner indicating that the MAF sensor has never been replaced, but then again, neither has the part that ended up being your problem either. Hate to gamble w/ a $200 part. What's a cheaper option?
Many thanks in advance..am stranded at the moment, so not going anywhere soon.

Your 97 has a different mass air flow sensor than the 99+ runners. I don't know for sure how many wires are on it. It is a completely different animal and almost three times the price.
I have heard that you can remove (unplug) the MAF sensor and the truck will run at a reduced fuel flow, sort of a "limp mode" or something like that. Maybe you can try that out and it will run well enough tto get you to the parts store. Or, you could just order a $23 code reader from Amazon.
Sorry, man, I wish I was of more help. I feel your pain.
I was fortunate that Advance allowed me to return my MAF (of course I told them that I never installed it...).
Also, try to clear the computer by removing the batt cables or EFI fuse. That got me pretty far before the computer would adjust itself to death. OF course, my issue was a/f not MAF.
I'm surprised that they wouldn't loan you the code reader like they loan tools out. What's the difference between loaning a $35 spring compressor versus a $35 code reader. You break it you own it.

 

[97fun4x4runner]

will try the limp mode-thanks~!

I'll try unplugging that sensor, see if it runs at all.
I was incorrect..the 'helpful assistant' was at Advanced, not Autozone...I may also have to 'borrow' the unit if it doesn't solve the problem, especially since they won't loan the $30 code reader, as you said. I just can't swing paying $200 for a part, and then it not solving the problem...we'll see what happens.
Thanks for your input.

 

[rjaudi]

I'll try unplugging that sensor, see if it runs at all.
I was incorrect..the 'helpful assistant' was at Advanced, not Autozone...I may also have to 'borrow' the unit if it doesn't solve the problem, especially since they won't loan the $30 code reader, as you said. I just can't swing paying $200 for a part, and then it not solving the problem...we'll see what happens.
Thanks for your input.

If it is the MAF, you can install a 99 airbox from a junkyard and use the cheaper MAF. There is a write-up somewhere on how to change it. The 99 air fuel sensor is also different than the 98 and earlier one.

 

[97fun4x4runner]

junkyard/pullapart

thanks for the input..still no answers yet.
I tracked down two gen3 4runners at a "Pull-a-Part" in New Orleans, and had a buddy who was there for the weekend drive over and check em out..seems someone had already carved out the air intakes, boxes, mafs, and even the throttle body on one....so no luck.
I didn't realize I could swap out boxes on later models, thanks for that info...heck, if I can track one down, the new mass air flow sensor for gen 4 is about half the cost of gen 3..worth knowing, thanks. ~!
At this point, think I'll just bite the bullet and buy a new MAFS, try my luck, and roll the $200 dice--gotta get back on the road at some point, right?
EDIT: Found Scanner:
A friend happened to have a scanner, and ran scan:
first page:
IAT Sensor Circuit Malfunction
Mod $10
P0110
2nd page:
MAF or VAF
A circuit malfunction
P0100
So, did that help anything? sounds like it still could be original 2 issues, either a Mass Air Flow Sensor, or Air/Fuel sensor?
Any help w/ sensor data? Thanks.

 

[SkidPalace]

thanks for the input..still no answers yet.
I tracked down two gen3 4runners at a "Pull-a-Part" in New Orleans, and had a buddy who was there for the weekend drive over and check em out..seems someone had already carved out the air intakes, boxes, mafs, and even the throttle body on one....so no luck.
I didn't realize I could swap out boxes on later models, thanks for that info...heck, if I can track one down, the new mass air flow sensor for gen 4 is about half the cost of gen 3..worth knowing, thanks. ~!
At this point, think I'll just bite the bullet and buy a new MAFS, try my luck, and roll the $200 dice--gotta get back on the road at some point, right?
EDIT: Found Scanner:
A friend happened to have a scanner, and ran scan:
first page:
IAT Sensor Circuit Malfunction
Mod $10
P0110
2nd page:
MAF or VAF
A circuit malfunction
P0100
So, did that help anything? sounds like it still could be original 2 issues, either a Mass Air Flow Sensor, or Air/Fuel sensor?
Any help w/ sensor data? Thanks.

P0100 and P0110 are both MAF issues. I'd say it's a safe bet to grab a new MAF sensor. P0100 is a MAF circuit malfunction and the P0110 is an Intake air temp ssensor circuit malfunction (built into MAF sensor).