Fuel system running rich?

[Rednaz]

Hi Guys!

I haven't posted in while but I've been keeping tabs on some topics on here. I'm unashamed to have taken this long to turn to my fellow brethen about this issue that I've been dealing with for the past 2 years which comes and goes.

The car died late year mysteriously on my way to work and wouldn't crank even and an auto electrician troubleshooted it and was adamant that it was the fuel pump solenoid (which my gut highly disagrees with but he wouldn't listen to reason) and he CLEANED ALL THE SENSORS IN THE ENGINE BAY (which I feel is a warm lead to the issue).

After he returned the car it was driving normal for about 2 weeks and then the problems started to slowly return to where it is again as bad as below described.

My car (2NZ engine) has the following symptoms again like 2 years ago:

- Loss of power under acceleration randomly and the car will jerk with exhaust pops and smells of fuel
- Sometimes total loss of power in first gear. When putting it in neutral and revving it has a burbling noise that stays under 2000 rpms (like the engine is flooded with fuel) (I've got a video of this, if someone can show me how to upload it to show you guys, please do share how)
- shifting between gears has a jerky feeling and feels like you've hit "an invisible wall" as you start accelerating in the next gear.

So far the following has been checked:
- Fuel injectors tested - 100% okay
- Fuel sending unit replaced
- Fuel pump solenoid replaced twice (once by myself and once by an auto electrician)

My gut is screaming the following: A something is falsely signaling the car that more air is needed and the car compensates with the fuel.

Please help guys, I don't want this dying on me again randomly.

Apologies in advance if this topic has been covered in a different thread : )

TIA:bow:

[Rednaz]

UPDATE: I've been reading some of the other threads and ruling out some of the factors. I decided to take my car to an exhaust shop.

I explained the above and showed the video and they confirmed that my cat converter is clogged.

So we decat the car and on the drive home the random total loss of power was solved but proved that there's another issue with the car since it's still:

- Felt like it's lagging power and holding back when shifting in a new gear
- Accelerator seems to take a second to kick in 1st gear very evidently

Update of every checked so far:

- Decat exhaust
- Fuel injectors working
- Fuel pump replaced
- Air filter cleaned (K&N)
- Throttle body cleaned
- No check engine light
- No error codes

So I'm thinking should I be turning to the actual engine next to check any vacuum leaks of some sort?

[ex-x-fire]

Dirty MAF sensor, K&N filters can cause issues with maf sensor.

[Rednaz]

Hi ex-x-fire,

Should I go buy a normal replaceable filter to see if it helps perhaps? Would a dirty MAF sensor go undetected on when doing diagnostics?

Just a further update,the decat didn't help and I'm still have:
- the car can really struggles to drive up a 5 meter inclined ramp from my basement parking at work.
- the random power loss with ''burbling/drowning" sound when trying to rev.
- right through every gear you can feel a loss of power to the usual 2NZ engine.

I'm really stumped to what else it could be (vacuum leak on the engine block somewhere?) I read on another thread a guy with similar issues had to end up having Toyota check his wiring harness and $700 later the issue was solved.

Thank you for the input and any feedback is welcomed guys.

[ex-x-fire]

You can clean the maf sensor and try a regular air filter.

[bairjo]

You can clean the maf sensor and try a regular air filter.

I was thinking the same thing. I clean my MAS every oil change PM.


https://youtu.be/dFKSEisixfU

[Rednaz]

I got the normal filter today and even cleaned the throttle body and MAF sensor but no dice : (

[WeeYari]

Have you disconnected the battery in order for ECU to reset and relearn changes to fuel trim that may be necessary due to changes/cleaning you've done?

[Rednaz]

Yes I have, WeeYari. No change yet.

I took note that power loss and 'flooded' revs happens between 1000 and 2000 rpms.

Perhaps my ECU is doing it's own thing between that range?

[praivo]

You said you cleaned the MAF sensor... But did you clean the MAF sensor wire, or just the thermometer (IAT sensor) bulb? What did you use to clean it?

And yes, a faulty MAF sensor can be detected. A typical symptom is running normal to rich at idle/low load and leaning out at higher loads/WOT (as the sensor starts to under-report the airflow). This can be seen through the oxygen sensor annd/or the fuel trims.

https://www.autoserviceprofessional.com/article/95975/failure-in-spec-what-happens-when-a-mass-airflow-sensor-lies

[Rednaz]

Hi Praivo,

I cleaned both the hot wire and inside of it as well using Wynn's Throttle & Air Intake Cleaner.

[Rednaz]

UPDATE: Myself and a work colleague (that's more clued up on cars and makes a living from it as a side hustle) had a chat about all things that's been tested on my car and what it could be that's the issue.

He suggested unplugging the camshaft timing sensor and testing if it'll make any difference when driving the car coz he's theory was:

'' Maybe the sensor is constantly staying on an open-circuit (instead of closed-circuit on lower rev range) overflooding the engine on the lower rev range and being a bit more 'driveable' on the higher rev range. ''

Full disclosure: I have replaced this sensor once since owning the car in the past 5 years (the last one fell out in pieces when I took it out) and haven't looked back since.

This morning I unplugged the camshaft timing sensor and reset the battery for 1 hour. Thereafter I drove to a local supermarket about 3kms away (this did give me a check engine light) but there's a major difference in acceleration response and there's less lack of power feeling also.

I forgot my wallet when I got to supermarket, so I did this drive twice today and no issues. (I even pushed it a bit through the rev range of 2nd,3rd,4th gear to see if there's any a moment that it feel it's holding back (like when the MAF sensor is unplugged but limits you on higher speeds) but it was all good still.



Would the next step be to take this sensor out and clean it, then test again or replace it?

Right now if I have to replace it, it'll have to wait for the next month or so. But driving around with CEL with way better engine response I really don't mind but it won't harm the engine right?

Thank you for everyone's input so far guys..