Bad idle - N/A. (videos included)

[FlrSupra]

Also give your ICV a clean (idle control valve)

 

ICV valve is cleaned. Was dirty but no help

[nevins]

Pm sent should explain a few things for you.

[David P]

From the configuration of the components, it looks as if you could have an auto that has had a manual conversion, if so, the throttle position sensors are a different part number and give different voltages at different throttle positions.

 

The position they are set to is different too.

 

The part no. for the TPS for a manual is 59452-35010.

 

If that is the case, which ECU do you have?

[FlrSupra]

From the configuration of the components, it looks as if you could have an auto that has had a manual conversion, if so, the throttle position sensors are a different part number and give different voltages at different throttle positions.

 

The position they are set to is different too.

 

The part no. for the TPS for a manual is 59452-35010.

 

If that is the case, which ECU do you have?

 

 

What makes you think that my car could have had an manual conversion? Now I`m truly interested

 

I`ll check the ecu part number in next free day from work. thanks for the tip again!

[David P]

Because there is a clutch master cylinder, but the manifold Y branch you have is for an auto, the manuals have a 'dogs leg' in the pipe as it leaves the manifold on route to the rocker breather, the auto's have a straight pipe, like the one you have.

 

Check the number on the TPS, and the setting, will look it up in the manual for you.

Edited July 16, 2010 by David P (see edit history)

[David P]

I was wrong about the TPS settings being different for manual and auto, but correct re. different TPS part no.

 

For a J spec N/A, both auto and manual settings are;

[Guest Snaps]

This is also the exact same thing that's happening to my car, I've tried cleaning the MAF sensor, IACV and resetting the ECU, with none of these working. I think it may be my fuel filter getting clogged. When was yours last changed? I'm going to change mine next week, I can get back to you if it fixes it!

 

Check this out: http://www.ehow.com/facts_5183619_bad-fuel-filter-symptoms.html

 

Edit: Oh, mine's a factory auto, so it's got nothing to do with a manual conversion.

[Shane]

For a while I had really rubbish idle on my NA and couldnt get to the bottom of it with no fault codes being stored either to give me a clue. Then one day it got really bad on me and cut out at some lights, but this time it did store a code, cant remember which one though...maybe 43...but when I looked it up it was something like "TPS signal lost for more than 1 second", dont quote me on the exact wording or time but it was along those lines. Anyhow, cleaned and re-tensioned the connections to the TPS and it not only cured the fault code but also the idle issue. In your case if the intermittant signal from the TPS is below whatever the preset time is required to store a code, this could explain things. Have a good look around that area.

[FlrSupra]

I was wrong about the TPS settings being different for manual and auto, but correct re. different TPS part no.

 

For a J spec N/A, both auto and manual settings are;

 

Hey. You`re tip got me working and taking pictures with cost of spending my lunch hour on work for this

 

Anything spectacular showing on these pictures?

 

--------------------

 

#1 Picture

 

http://gto.kuvat.fi/kuvat/ecu1.jpg/full

 

Ecu label

 

#2 Picture

 

http://gto.kuvat.fi/kuvat/ecu2.jpg/full

 

Ecu connections. Black box on the left is control unit for Clifford alarm.

 

#3 my current TPS

 

http://gto.kuvat.fi/kuvat/tps.jpg/full

 

----------------

 

 

Is everything looking normal on outside?

Edited July 17, 2010 by FlrSupra (see edit history)

[FlrSupra]

This is also the exact same thing that's happening to my car, I've tried cleaning the MAF sensor, IACV and resetting the ECU, with none of these working. I think it may be my fuel filter getting clogged. When was yours last changed? I'm going to change mine next week, I can get back to you if it fixes it!

 

Check this out: http://www.ehow.com/facts_5183619_bad-fuel-filter-symptoms.html

 

Edit: Oh, mine's a factory auto, so it's got nothing to do with a manual conversion.

 

Hi. I also do have new OEM fuel filter on the bag and was going to change it also in next few days.

 

Please let me know if it cured your idle problem. Atleast one happy supraman would be nice to be heard of

[David P]

That's definitely the TPS for a manual, it looks as though it has been 'dicked' with though.

 

Have you tried setting it to the correct position?

 

I would think M/T is for Manual Transmission.

Edited July 17, 2010 by David P (see edit history)

[David P]

If setting the TPS to the spec I posted yesterday does not fix it, run these checks to see if the sensor is functioning correctly.

[Guest Snaps]

Right, done the fuel filter and spark plugs over yesterday and today, and it seems to have fixed the problem, I went for a 1/4 of an hour town drive and the 'hiccupping' didn't happen any of the times I stopped, so it looks like it's fixed! The spark plugs were normal coppers, which I have replaced with NGK iridiums, the coppers were pretty black, so there's every chance they had something to do with it. The fuel filter also looked pretty dirty inside, as far as I could tell.

[FlrSupra]

..and the troubleshoot continues..

 

Bought "feeler gauge" and "multimeter" today to diagnose my problem better.

 

But.. since I`m newbie on these my TPS testing was no success. I have red tons of instructions how to check and adjust TPS, but I`m not even 100% sure where to put my feeler gauge.

 

I measured the pins IDL and E2 from TPS and everytime got 0.01 reading with "2K Ohm"-setting on multimeter. No matter where I stuck my feeler gauge the reading from pins was always the same.. maybe I`m doing something wrong here... hmm.

 

Didn`t have enough courage to remove the actual sensor since the car is my daily driver

 

...

 

and for the problem #2 I diagnosed. Now when I had multimeter on hand I checked the reading of Oxygen sensors as well from diagnostic port. Instructions were simple enough for me

 

OX2 pin showed steady 0.84 V at warm idle

OX1 pin showed steady 1.22 V at warm idle

 

This surely tells that something wrong is going on on my engine. Oxygen sensors are brand new OEM from Toyota.

 

h-e-l-p ?????

Edited July 20, 2010 by FlrSupra (see edit history)

[Ian C]

Those voltages would say it's running too rich and can't compensate any further by reducing duty cycle. Generally that's either your fuel pressure is too high, or you have a bad sensor telling the ECU lies. Overfuelling suits all your symptoms as well.

 

The TPS is at an extreme of adjustment. I suspect the IDL switch isn't being engaged so the ECU never goes into idle mode, hence the dodgy running. For testings' sake, move it to the other extreme. That'll ensure the IDL switch is engaged when the throttle is closed, even if it's a bit off on the throttle position readings. See if that clears up the idle.

 

Be warned - the screws holding the TPS in place are awful as the heads strip really easily. Make sure your screwdriver fits perfectly and press really hard into the screw before trying to turn it

 

Also, just thinking about this, it might be the TPS sending the wrong signal to the ECU - if it thinks it's at 100% throttle all the time, it'll never go into closed loop and control anything. But try the adjustment first.

 

-Ian

[FlrSupra]

Those voltages would say it's running too rich and can't compensate any further by reducing duty cycle. Generally that's either your fuel pressure is too high, or you have a bad sensor telling the ECU lies. Overfuelling suits all your symptoms as well.

 

The TPS is at an extreme of adjustment. I suspect the IDL switch isn't being engaged so the ECU never goes into idle mode, hence the dodgy running. For testings' sake, move it to the other extreme. That'll ensure the IDL switch is engaged when the throttle is closed, even if it's a bit off on the throttle position readings. See if that clears up the idle.

 

Be warned - the screws holding the TPS in place are awful as the heads strip really easily. Make sure your screwdriver fits perfectly and press really hard into the screw before trying to turn it

 

Also, just thinking about this, it might be the TPS sending the wrong signal to the ECU - if it thinks it's at 100% throttle all the time, it'll never go into closed loop and control anything. But try the adjustment first.

 

-Ian

 

Thanks for participating Ian.

 

Good thing you pointed out that the TPS is in another extreme position so I got courage to change it position by hand. I tried several positions (another extreme as well), but the original position it was brings best result on idle.

 

I didn`t reset the ecu when changed TPS position. If it matters on quickie tests.

 

Running rich and overfuelling are terms that definetly put my cars problem on words. But the big question is... why?

 

Tomorrow I decided to take a visit to Toyota to adjust TPS and I will have new fuel filter on 26th of this month. If the idleproblem still is present after those... then... then... then..

[Guest Snaps]

Changed out your fuel filter yet? That was the problem with mine, I haven't had the problem again yet!

[msupra]

This happens to me also.

 

Sometimes my idle will be like at 500/600 and my car shakes... normally when it's at 900 it's very quite.

 

Don't know why this happens.

[FlrSupra]

Next steps I will do are:

 

- Fuel filter change and proper TPS adjustment. Next monday by mechanic

- MAP-sensor change. Next monday I get one on loan by local Supra-club member.

 

 

I`m really hoping this will solve the problem finally. :/

[Ian C]

Measure the voltage you are seeing from the MAP sensor (pin 62 I believe), and post it up here

[FlrSupra]

Ok so...

 

Fuel filter is now changed. No cure.

 

TPS adjustment didn`t worked `cause when I put multimeters red&black wires to IDL and E2 pin on TPS and measure in Ohm I could only get 0.00 figure. No matter how I positioned the TPS.

 

Am I doing something wrong on TPS adjustment???

 

there is definetly some change if I put the TPS to another extreme position so it`s doing atleast something...

 

Emissions was way high and idle was hiccupping like before.

 

 

God damn..

/vbb/images/smilies/bbcode_angry.gif

[FlrSupra]

Measure the voltage you are seeing from the MAP sensor (pin 62 I believe), and post it up here

 

Thanks for the tip. I try to get the reading out.. my multimeterskills are pure rookie-level

[Guest 93supra]

I`m making new thread of my idle problem and try to tell as much information of my car that more experienced Suprapeople here could help.

 

My car is -94 N/A manual J-spec.

 

There is no other problem on the car. Accelerates smooth etc.

 

This problem is when I`m on stationary and it`s not constant. Sometimes it happens less and sometimes more.

 

---------------------

 

#1 Video

 

 

- When the revs make a drop it can be felt as shake on the car. (that one over 1000rpm rev is made by me)

 

#2 Video

 

 

- There is also this sound from exhaust everytime with the rev drop. Also when I recorded this I noticed there is strong petrol smell behind the car.

 

------------------------

 

I`ve been searching info here on the forum and I tried following to cure this problem:

 

- New spark plugs. NGK BKR5EYA-11

- New spark plug wires

- New OEM distributor cap

- New OEM rotor arm

- New K&N panel filter in stock airbox

- 2 new OEM Oxygen sensors

 

- Checked for error codes. *There was 1 code which was cured by changing Oxygen sensors (Code 25: running lean)*

- Checked for vacuum leaks.

- Cleaned ICV valve

- Resetted ecu

 

*= That error code 25 hasn`t come back after driving 40miles with new oxygen sensors. Now there is no codes stored.

 

Nothing of above have not made any change to that idle problem.

 

 

What to do next? I`m so frustrated.

 

Prize for the correct answer would be amazingly good finnish beer posted to your front door

 

i have 93 na and not all the time but sometimes my car does the same thing runs fine cant notice any other problems but sometimes it idles like that also alittle vibration with first rev up sitting still

[David P]

If you get no readings in any position, it sounds as though your TPS is not functioning, and needs replacing.

[FlrSupra]

Today I really focused to get TPS right myself.

 

I connected to TPS through Ecu harness so I got to move TPS really accurately and finally managed to get some readings.

 

 

BUT!

 

Ohm-readings stay on 0.01 when moving TPS from right to left. When the sensor position reaches about halfwaymark the Ohm-reading climbs up really fast and quickly over the scale so multimeter can`t read it.

 

There is no any stable readings between.. only 0 Ohm or over the scale. (using every step on Ohm scale , 2K, 20K, 200K, 2M.. no matter.)

 

Does this sound like faulty TPS-sensor?