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Please Help. Sanity 99% Gone........

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I have a 140 Celica that just WILL NOT idle properly.

  • Yo-yo-ing short term fuel trim,
  • rough vibration through steering wheel/seat/floorpan,
  • rich smell of fuel form exhaust,
  • Rocking/vibrating engine block,
  • vibration in exhaust pipe
  • constantly changing exhaust note/tone at idle
  • incriminating hiss around intake manifold,
  • Severe hiss/suction noise as throttle is opened
  • timing chain rattle
  • Absolute throttle position at 11% ( - at idle)
  • No CEL.
  • good fuel economy (~ 38 mpg)
  • hesitancy for first second under acceleration.

I have been trying on & off for the past 12 months to solve it, with no success.

Tried all the usual culprits/common faults, with no luck what so ever.

Any and all help gladly appreciated right now.

I have precious little sanity remaining, and would like to retain what's left..............

I really, really don't want to have to admit defeat and unload the car.

Please please please help..........

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How about changing the Inlet manifold gasket & throttle body gasket. O2 sensors been changed?

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Inlet, throttle body & IACV gaskets all changed 6 months ago.

All mating surfaces were RTV sealant'd a belt&braces effort.

Pre & post-cat sensors removed, cleaned, checked, and replaced. No error codes.

Inlet manifold removed & examined in january. No *visible* evidence of cracks/fractures/splits anywhere. Looks to be a good, solid manifold.

Symptoms remain.

I'd like to accurately diagnose & confirm before i start disassembling/shelling out for spare parts again - too much potential for stuff to go wrong in the process.

Also, not enough skin left on the knuckles, and not enough in the bank account to fund replacing loads of parts (sadly).

Is there a recognised technique for testing the <intake> manifold whilst still on the car?

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Mmmm dont see fuel filter mentioned in list, I had this in another car changed filter problem gone.

worth a try maybe? Throttle position sensor clean? Mine was full of black soot.

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I had disregarded fuel filter, as once the engine is in gear and running (when it would be consuming more fuel) there is no evidence of anything ill.

Am i right in thinking the fuel filter for the 1zzfe celica is within the fuel tank???

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It is in the fuel tank.

They don't usually need changing as they are supposed to last the life of the vehicle.

Only usually change them if you've had a bad batch of fuel, sucked up any bits from the bottom of the tank and have blocked it or if the car has been sitting for a long time and the fuel has gone off.

I know you've said you've changed some bits, but without a full list I don't know what you've done. Any below you haven't checked? Just a few I can think of.

Coil pack

Spark plugs


Vacuum leak

Idle control valve.

Is the throttle body gunked up?

I don't think the cat being on the way out would affect the cars idle, plus you said fuel consumption is good, it usually affects the fuel consumption.

What about Oil control valve.

But out of all of them the vibrations, the hissing, different tone of the engine I would have said air/vacuum leak this would cause the idle problem which causes the engine to vibrate through the car.

Are you running standard air box or induction kit?

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ah damn it. I knew it'd be in the tank.............

I can't say i know of it having bad fuel/been left standing, but i also don't know how it was treated before i had it, so...........

To be honest, i've changed/checked so many parts i've lost count/track (hence title). In response to your list above though:

Coil packs: - all in tolerance.

Spark plugs:- changed@service (4K miles ago) with handbook recommended Denso plugs - torqued correctly.

MAF (& IAT sensor): electrically within tolerance. Cleaned with isopropanol spray for good measure.

Vacuum Leak - checked all (visible) pipework for damaged/correct connections. Pipework seems good. Still have incriminating hiss from intake manifold.

IAC: stripped down, cleaned out (isopropanol spray) & new gasket

Throttle body & plate: cleaned front& back, inside & out.

Oil control Valve: Taken out and flushed out (isopropanol spray). Minimal cloging on strainer.

- No improvement.

I addition i have since checked the TPS, Fuel trims, and each fuel injector.

TPS: Very close to acceptable tolerance, but just in.

Injectors: Readings between 14-17 ohms. Checked with a toyota technician. Says they are low (expects around 20 ohms) but deemed acceptable.

Reading around, lower resistances should produce 'safe' over fuelling, as the pintle puts up less electromechanical resistance - so is open for a slightly longer period per operation....apparently???

Short -Term fuel trim (@idle): fluctuates between -9% & +8%.

Long-Term fuel trim (@idle): holds around -3%

Wierdly the OBD2 tool says throttle position is at 11% at idle. Is this right???

Oh, and been round and cleaned & remounted each earthing point.

No noticeable change :( ...........

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Are you a member on celica club?

If not pop over and post this there, there are a few more members on there who may be able to help.

One has a username of AMS he is a car breaker and pretty good with diagnosing problems.

I have posted everything that I can currently think of.

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