I swear my car hates me!

[stig]

Hi people! Hope you can help me out here:

Had this problem a while ago but not for ages now, I thought I had maybe cured it but alas no.....

Ok basically your driving along and the car looses almost all power to the point of theres just enough left to keep you going on the flat (no chance uphill etc) When your trying to accelerate the car sort of comes back to life/dies randomly almost bunny hopping but sporadicly.
Last time I had this I checked the usual stuff first, plugs, leads, cap etc etc then moved on to having diag vans out and going to 'specialists' who were little help. Eventually someone suggested a new map sensor so I got another from a jap car breakers and it was the same, but a helpful taxi driver turned up and told me to unplug the throttle position sensor while car was ticking over to reset something... so anyway I tried it and it 'seemed' to fix it. Been doing this trick whenever I have this problem now and it seems to stop it for a while, although whenever I go the car wash or we have heavy rain it seems to trigger it off a lot more.

(your saints if you made it this far)
So has anyone any ideas for a cure? All I can think of now is a faulty TPS, please someone help me..... [-o<

[PW@Woodsport]

have you pulled the fault codes out first? thats the first step

[stig]

Thanks for replying:

Yes checked the codes and theres none showing, just a constant flash which I understand as no error codes.

Dunno if that helps?

[stig]

Ok bit more info:

From what I can tell it seems to do this more/maybe only - from cold, so ie trying to get work and home is a nightmare of power/no power mid acceleration.
By the time I get home (app 15-20 mins of driving) and it seems to clear up or at least be drivable again.

Also tickover sometimes drops below the 750rpm to like 4 or 500 to the point of stalling (left without a pedal prod it will stall)
Tried my previous trick of unplugging and replugging the TPS plug in and this doesnt seem to help any, also tried a diff map sensor but still the same.

On my previous fun with this I checked codes, plugs, leads, had someone check the ecu was ok, all sorts and NOTHING helped......

Please someone throw some ideas at me as just about ready to sell the stupid thing!

[THE DUKE]

TPS's are tricky little buggers when the go wrong, normally requires a multimeter to get the correct position, have you tried a new one yet?

Also have you checked your throttle body butterfly is opening closing correctly, check for play in turbo shaft, no air leaks.. you know the usual stuff.

[JOHNM400]

Deffo sounds like a faulty TPS. Sounds like the tracks inside are burnt and the voltages leaving the sensor are all over the place. Wouldnt always show up as a fault on the dash unless the TPS voltage goes completly out of range.

[stig]

Ok thanks for the input guys

Rang Toyota earlier just to get a price on a new TPS - £84.88 ugh, but worth it IF it fixes it!
Is it just a case of swap it over and cross my fingers it works, or does there need to be some sort of calibration/setting up done? If so what kind?

Checked turbo shaft quite recently and seems the same as when checked it 12+ months ago, plus no leaks or cracks in pipes that I can see. Although because the problem isnt a constant one, that suggests to me more electrical than mechanical perhaps? Like a sensor of some kind.

Really hope its this TPS as pretty much checked everything else I can (as a mere mortal when it comes to this sort of thing)

Thanks for the input guys but keep the ideas coming!

[stig]

Ok update:
Cars still having a jibber, but seems to settle down after 20 mins or so of driving - does this still sound like a throttle position sensor problem?

Hope so as just ordered one (here for sat hopefully so can have a mess)

Q: Do I just straight swap the old sensor for new one or do I need to have the new one set up or calibrated in some way?

Any help much appreciated!

[johnnymr2]

maybe be of no help but mine used to hesitate like a beatch when cold (not that i boot it tho) i changed my ignition components and it has cleared it up. it could be either mechanical or electrical tho as mechanically it could be something freeing up when it gets warm

[Martha Foker]

Stig I had the same problem as you for quite a while and replaced all the ignition components with no result. Then a mechanic friend of mine suggested cleaning the throttle body out and i also changed the fuel filter. Now she runs like a dream!
HTH

Mark

[stig]

Ok guys thanks for that.

Did swap my fuel filter about 6 months ago as part of my trial and error when I had this problem last time.

Will try a new TPS and see if that helps any - btw does anyone know if I just plug a new TPS sensor on or do I need to follow a certain procedure?
ie: swap while cars running/up to temperature or have something calibrated etc etc...

Will try to look into the throttle body idea next when I get chance.

Still noticing though how it mainly seems to be a problem while warming up - started from cold today when finished work and left on tickover without moving, after 2 mins the revs dropped and it started to hunt a bit. After I made it most of the way home it seemed to improve a lot. It's like its ok for the first min from cold then from 1 min to 20 mins in it plays up, then clears up.

Could it be something to do with the automatic choke/cold start system or similar playing up and causing the problem? Like flooding the engine or similar until the chokes all the way off hence it clearing up?

Sorry not very car techinical, hope you see what I'm getting at lol

[stig]

Ok got a new throttle position sensor today, not fitted yet as been busy, plus constant rains not helped!

So can anyone can tell me before I attempt to fit it (tommorow weather permitting) if I need to do anything specific with this or just bung it on?

Thanking you

[BenF]

I don't have the BGB any longer - but I do seem to recall that they do have to be aligned. Does yours have some yellow paint on the screw holding one part of the TPS in and then on its body?

Before you take it off though, I'd check it with a Multimeter - you can get one for under a tenner from Halfords.

As you open and close the throttle (engine off ) you should see the resistance increase and decrease smoothly with no jumps.

The other thing that it could be is the Airflow meter if you have a Rev1 or 2 car - again, check the resistance rises/falls smoothly as you open the flap inside. If you're going to check the AFM - DON'T UNSCREW the two screws on its side - you release the metal retaining clip and unplug it ..

[stig]

Thanks ben.

Ok update again:

fitted new TPS sensor today, no probs (so far lol) and seems we fitted it ok.
BUT...
Thinking it was ok on leaving friends house (car had cooled down a bit by then) I started up the car and after 20 secs- chug chug, revs dropping and car hunting again...... Damnit!

So thats £85 down the swanny and tested everything else I can think of, really fed up with this now

All I can think of now (as it seems to be temp related) is its something to do with cold starting as its mainly from cold and slightly cold - like a 10 to 15 mins stop then start when it does it.
So obv it doesnt have a choke but the injection system 'equivalent'.

so my Q is what does this involve and what could it be?
Please help, beginning to feel like I will never get to the bottom of this

[Adam J]

Try spraying some easy start type stuff into the intake when its doing it, If the car picks up you know its not getting enough fuel.

The choke is the cold start injector, located underneath the throttle body, has a pipe running from the fuel rail up to it.

[JOHNM400]

Hi Stig,sorry to hear your still having problems after buying a new TPS.Unfortunately thats one of the problems of trying to gain help over the net in that its very hard to pinpoint a fault with having the car infront of you.

Seeing as you seem to think its a temperature problem you may want to look at the temperature sensor. Ive had those be corroded away in the past causing hard starting and poor running when cold but once warm the car runs ok. You could also try to unplug the cold start injector when the car is first started from cold and see if it makes any difference.

[stig]

Hi John,
Oddly enough the cars been fine today (kiss of death lol) but then its been a warmer day so perhaps that had something to do with it?

Btw hope it didnt seem like I was having a go at you in one of my previous posts, just fed up with the car as it could be several things, intermittant faults are the worst to have!

I was going to go along the lines of what Adam and yourself have suggested with the cold start injector, I'm 99% certain which it is - looks like it has white plastic on/around it and a few larger sized screws holding it in (can see it best from drivers side)
Next time it starts to play up I'll try and unplug it, see if it does anything.

Thanks chaps, to be continued......

[Adam J]

Im pretty sure the cold start connector is black, from the passenger side of the throttle body, hard to get to without taking the inlet pipes off. Here is a picture of the cold start pipe from the fuel rail, its the small 'L' shaped pipe in the center, going from the fuel rail up to the throttle body. I would check if it is a fuel problem before replacing it.

[stig]

Think I see which one you mean on your pic, doesnt look like the one I was thinking of then lol.

I was looking at one that looks like another unit similar in size to the TPS maybe bigger, with another similar electrical plug type connector.
Not sure what that is then, its right under the short rubber pipe that goes into the throttle body I think.
If it starts playing up I'll get a picture of what I mean.

Cheers again.