Help 1996 4Runner 3.4 Engine hesitation, no power over 2000 rpm

[werminghausen]

FSM says P0110 = intake airtemp circuit malfunction.

Possible causes: 1) open or short in intake airtemp sensor 2) airtemp sensor (built into mass airflow meter) or 3) ECM.

Page 202 and on in the FSM instructs on how to test. https://drive.google.com/open?id=0B20d86M4DqTrVU5wUHhyUVN4OWM

:cowboy:

Thanks so much for this information about the IAT.
I guess I'll need to wait until I get the ELM327 OBDII dongle and the iphone app to read the temperatures according the FSM p202 for testing.

It is stated: " If the ECM detects the DTC P0110, it operates the fail safe function in which the intake air temperature is assumed to be 20°C (68°F)."
This means that the difference in injection during normal weather cannot be substantial...
probably not even very noticeable?

I am not saying I don't care about this P0110 failure... however- unless you tell me differently- it is hard to believe that this code is resulting in severe engine trouble.

Second Code # P 0420: Catalyst Efficiency below threshold (bank 1) is described in FSM p 246-248 (great to have the manual).

Problems mentioned could be
1) Gas leakage on exhaust system
2) bad A/F sensor (bank 1 sensor 1)
3) Heated oxygen sensor (bank 1 sensor 2)
4) Three-way catalytic converter

I guess none of the issues would trigger severe engine problems except for #4 if the exhaust is badly clogged? So we are back inspecting and removing the catalyst.

What is your take here?

Martin

 

[jgue467]

I think based on your original post mentioning 'suddenly happened', 'occurs in gear driving or idling' and the 'puddles of water' tell me something shorted out with the water. I believe a cat would clog up slowly building up over time yet could still be an issue, one thing at a time.

I had an '82 Z that did the same thing (only ran up to 2000rpm), except i tried hosing the engine down and that caused a short in an electrical part which also kept the engine at or below 2000rpms in gear or not. Mechanic swapped part and away it went. It was near the intake so probably a MAF or similar part, bottom line was the lack of that part operating causing the ECU to not know throttle was being applied so it limited the rpms as a default safety feature. Maybe similar thing here, i really feel this is a limitation caused by electronics not mechanics.

So the proper thing would be to test the IAT/MAF and also test the A/F sensor (front one). If by chance both are out or going out combined they could cause some significant driveability problems, though i lean towards the water and underhood sensor. Perhaps disconnect the sensor and clean the contacts with some electrical contact cleaner. I'd start with simple things like that, verifying the electrical contacts to the sensors, the connections to the ECU are probably fine since inside the vehicle.

Let us know what you find. :cowboy:

 

[werminghausen]

Thanks jgue467

You convinced me... the IAT sensor might be a big deal, maybe also the front O2 sensor causing the sputtering/no power?

Anyhow I bought a new MAF and a new front O2 sensor.
I'll install as soon as the parts are here and report back.
If this works I'd be very happy,
If not...well then I need to dig deeper.

I got the OBSII dongle (GEMWON- label on it) need to find the app and then try out...curious what I can see.

With the bluetooth Scanner can I do scans during the engine running?
So far with my limited old scanner I could do readings with engine off only, ignition on.

Martin

 

[jgue467]

A '96 should have all the same readings available as other later years except trans temps. I use Torque (for android), they have a free version or the $5 version lets you configure/save a multitude of different types of electronic guages for the various readouts you want to see.

And yes it will show you live data for everything it displays including short and long term trims. :cowboy:

 

[werminghausen]

I bought a new MAF and a new front O2 sensor.
I'll install as soon as the parts are here and report back.
If this works I'd be very happy,
If not...well then I need to dig deeper.

I got the OBSII dongle (GEMWON- label on it) need to find the app and then try out...curious what I can see.

With the bluetooth Scanner can I do scans during the engine running?
So far with my limited old scanner I could do readings with engine off only, ignition on.

Martin

 

[heat]

Yes, live readings, engine running.

 

[BamaDrewski]

All of a sudden my 4runner was bogged down as soon as I get over 2000rpm... no power to get beyond second gear. With the car parked I cannot get the engine rev beyond 2500 and it is starting to shut off, then come back at lower speeds.
I cleaned the airflow sensor and throttle body but it was clean and nothing changed.

I guess it can be a lack of fuel that is causing starvation (computer?, fuel filter, fuel pump, throttle position sensor) or maybe spark (spark plugs and wires)?
It stared to happen this morning when there was so much rain and I had to go through puddles of water. But now with less water the same thing happens.

Any ideas... I need help

Martin

How long has it been since you replaced BOTH 02 sensors? Have they ever been replaced?

For the non-Cali T4R, I buy mine on Amazon. Denso #234-4162 (Both the same). I learned the hard way to change both sensors out at the same time.

You might try this (disconnect the battery while doing so) and then fire her up and see if that helps.

02 Sensors are finicky things. They rarely throw codes even when they fail.....I keep my sensors fresh and make their change out part of regular maintenance.

Others mentioned the TPS (Throttle Position Sensor) this can also create the symptoms you have described.

EFI relay. Could not hurt to change out the EFI relay..

Good luck man...

 

[werminghausen]

How long has it been since you replaced BOTH 02 sensors? Have they ever been replaced?

For the non-Cali T4R, I buy mine on Amazon. Denso #234-4162 (Both the same). I learned the hard way to change both sensors out at the same time.

You might try this (disconnect the battery while doing so) and then fire her up and see if that helps.

02 Sensors are finicky things. They rarely throw codes even when they fail.....I keep my sensors fresh and make their change out part of regular maintenance.

Others mentioned the TPS (Throttle Position Sensor) this can also create the symptoms you have described.

EFI relay. Could not hurt to change out the EFI relay..

Good luck man...

Thanks... Good Points
I replaced the downstream O2 Sensor 2 years ago.
I ordered now a new front one...because of the failure code
I ordered a new downstream one now...so I'll get 2 new oxygen sensors


TPS might be an issue even if it doesn't throw a code?
I can replace it just out of despair.

EFI relay: I already exchanged with tail light relay and no change. relay is good.

I'll put the 4runner now on the lift and will inspect the underside, Catalyst etc.
I'll see if find something.

thanks for everyone's help

Martin

 

[werminghausen]

Question: should I order and replace the catalytic converter the same time i am working down there?
What is your thought ? What aftermarket brand can be trusted?

 

[werminghausen]

I have the 4 runner on the lift and remove the catalyst. Wasn't as bad as I expected. To my surprise the bolts were not seized (very unusual!)
I guess the cat is open and not crumbled inside but I have a clear view only to one side.
The Cat itself is not in great shape but also not too bad. It is not a Toyota part but aftermarket . on the heat shield it says Made in USA.
The upstream O2 sensor (front, in the Cat part ) looks older and the plate broke off when I wanted to remove. So this part is sketchy.
Question is...as the parts are out now... I'd better get a new cat and get over with?
This depends on cost obviously.
What is a decent quality aftermarket Cat product? What brand and where to buy?
As I said I ordered 2 new O2 sensors already.

Attached a few pictures, Cat removed

 

[werminghausen]

I heard that Eastern Catalytic converter might be okay.
'Catalytic Converter-Direct Fit Eastern Mfg fits 96-00 Toyota 4Runner 3.4L-V6
Part# 40258'

What do people think?

Then I borrowed a OBDII scanner from my friend
It is a Innova 3040 with all the 16 pins.
Do you think that thing does the job ....live data for the 97 4 runner?

Martin

 

[heat]

No idea on the new cat.

Did you search on the scanner?

 

[19963.4lsr5]

It says the Innova 3040 has live data.

I have their 3130 model and love it.


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[werminghausen]

I think I will bite the bullet and order the cat converter from Eastern. They seem to have some quality and reputation. I think the old one might still work but it is very much rusted and not original, the o2 sensor port rusted out.
It might be not very old because the bolts were not rusted away as I know this from an original part.

So in a way I am throwing parts at this problem also because I am running out of time.

Martin

 

[werminghausen]

I bought the new CAT..throwing more parts at this problem.

I will replace

1) Catalytic Converter (Eastern)
2) 2 New O2 Sensors (Denso)
3) New Throttle sensor (Toyota I believe)
4) New Used Toyota MAP sensor

I'll report back as soon as the parts are installed.

Martin

 

[werminghausen]

It says the Innova 3040 has live data.

I have their 3130 model and love it.


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Yes the manual said Live data! YES !

 

[werminghausen]

I installed to night


1 new catalytic converter
1 new front O2 sensor (did not receive the second O2 sensor yet but the rear one was exchanged about 2 years ago)
1 new used MAP sensor
1 new TPS

The engine runs better but still it is hesitant to rev beyond 3500. Engine sputters at 3500rpm
At least I can drive, need this car
What are the next steps: Cancel the codes and drive and see what the scanner says?

Do people have any ideas and recommendations?

Martin

 

[19963.4lsr5]

Do you still have the code for intake air temp?

Whats your code reader say the engine and I take air temps are after sitting overnight or 8 hours?

Fuel filter? Or fuel pressure? Water in the gas? Run some good injector cleaner through it.

Are you using antifreeze? This will cause the 420 code.


Sent from my iPhone using Tapatalk

 

[werminghausen]

Do you still have the code for intake air temp?

Whats your code reader say the engine and I take air temps are after sitting overnight or 8 hours?

Fuel filter? Or fuel pressure? Water in the gas? Run some good injector cleaner through it.

Are you using antifreeze? This will cause the 420 code.


Sent from my iPhone using Tapatalk

Thanks,i‘ll Do the testing.

1) Engine and intake air temp after 8hrs
2) change fuel filter( is this a mess changing that filter?)
3) water in gas? Maybe... lines from filler to tank are super rusty
4) fuel pressure : where to put the gauge and test procedure.
5) injectors: how to clean? Just use cleaner in tank? Or take them out and flush?
6) makes sense to change spark plugs and wires?

Martin

 

[werminghausen]

You said Antifreeze does trigger code 420, but how? ( of course I use antifreeze in the radiator)
Martin