Car jerking intermittently

[mansoof]

hi guys im from south Africa I have a Daewoo lanos 1.6sx 2000 model

so my problem is the car jerks , sometimes I would drive to work with no jerk , but on my way back in the afternoon it would jerk like crazy like it has no power .

these are the things I changed recently :

new plug leads
new fuel filter
new TPS sensor (Really thought it was this )
new spark plugs ngk
fuel pump is about 3 years old sounds fine

I think it has some thing to do with the throttle I don't know , can someone please advise me I can take pictures of my vacuum , it only jerks when pressing throttle

also I noticed when it is not jerking and I come to a robot the idle stays on on 1000 rpm

but when it jerks and I come to a robot the revs jump below 1000 and to 1500 like on its own

I don't know anymore please help , I don't want to give up

[mansoof]

actually I changed the IAC not the tps

[Daniel]

First try by cleaning the throttle intake and butterfly (both faces) with rag/brush/petrol.

But TPS could be the problem.
With a voltmeter check the voltage on the dark blue wire (you may use a needle into the wire to make contact, but cover the hole with some glue after work) while you slowly move the throttle from closed to wide open. Voltage must follow smoothly.
You may gently move the wires to detect some bad contacts.

[mansoof]

hi thanks for that I will try it in the afternoon

this morning when I was driving to work it comes and goes , but once I am cruising at 120km no problem , like it is not there , it is when I am moving between 20km to 100km but like I say it comes and goes , I am going to go pass a spare shop today and see if there is a tps sensor which is not to expensive .

I will take a picture of my vacuum wires today and see what you guys think of the setup if it is correct ,

this morning while I was driving I thought it was the intake manifold leak , but I was cruising at 120km fine , if there is amn intake manifold leak would it not sputter and jerk all the time ?

[Daniel]

Why change parts without checking them? May end costly.

[mansoof]

yeah I do get the economic side of it , but I think the sensors are not to expensive and im so irritated with it right now id do anything , I cant get it to a mech right now due to a car accident theres only one car in the family , still looking for a new one . I will clean as much as I can this afternoon and try and get the tps .

I am the type to put new things my dad isn't , I inherited this car from him .

[mansoof]

okay so I bought the tps sensor I fitted it , while fitting I noticed the blue wire was exposed so I opened it further and the blue wire was cute before and now joined via solder , anyways I changed the sensor none the less , at the moment its starting on high idle and engine management light is on all the time I just dis connected the battery and going to have supper

any ideas ,

when I left from work to the spare shop it was jerking like crazy and than I got to spare shop the guy wanted to see the pins so I unplugged the plug showed him and put it back m, when I was driving home it drove like a dream .......so surely it is sumthing to do with a connection or a bad sensor

cos howcome it jerks when it wants to ?

[Daniel]

So seems good now?

When battery is disconnected idle learn procedure is asked.

[mansoof]

okay so connected the new TPS sensor and when I started it the idle rev went high and the engine management light came on and stayed on

so I took it for a drive , the car drives fine no jerking , but idle is high and management light is on ? do you think it is a faulty sensor ? im going to put the old one back and see if the light goes off ?

I did the idle learn process is there anyway for the TPS learn process ?

thanks
mansoof

[mansoof]

how do I post pictures

[Daniel]

okay so connected the new TPS sensor and when I started it the idle rev went high and the engine management light came on and stayed on

so I took it for a drive , the car drives fine no jerking , but idle is high and management light is on ? do you think it is a faulty sensor ? im going to put the old one back and see if the light goes off ?

I did the idle learn process is there anyway for the TPS learn process ?

thanks
mansoof

Since the high idle occured after changing of TPS, its maybe not the good one. Revert to old and/or measure the blue wire voltage as suggested above.

I don't know of TPS learning process.

[Daniel]

how do I post pictures

I don't know if this still work http://www.daewootech.com/forum/viewtop ... =19&t=4608

Or you may try "Upload attachment" in options below while you compose your post.

Or use a image hosting service like http://postimage.org/ .

Good luck

[mansoof]

I am going to check the voltage in the morning at idle.and full throttle, I read somewhere you can adjust the tps if it is not sitting at 0.45 at idle by loosening the screws and slight movement clockwise , going to try in the morning

I have read a lot of articles where people installed new tps and jumps to high idle

[Trey05Woo]

You may have installed the TPS wrong. It has a recessed ear inside where the throttle valve shaft fits into. This is how the throttle valve actuates the sensor. If you install it wrong, the TPS sensor can be giving an open throttle signal, when the throttle plate is actually closed. This can be the cause of the idle spike.

I would also pay attention to the wiring issue you are having. You should always address all wiring issues BEFORE replacing any components.

You should also get some type of a scan tool connected. This will tell you what the trouble code is, and you can confirm the TPS signal.

Finally, you should also run the idle relearn after replacing the TPS or IAC. I can post instructions on how to do this if needed.

[mansoof]

Hi thanks for the reply, when I took out the old sensor I took it out gently not touching the shafts and when I put the new one I aligned it with the bolts and I slide it in, is there a way I should redo it?

I did the 5 second and ten second thing but didn't work I'm going to start it up now and let it isle till the fans come on and see what happens if not back to the sensor to check voltage when closed and when open and adjust I don't really know how to adjust people have been saying few mm adjustments