1.6 gti wont idle at all

[mvh 0]

Hi to all,

 

This is my first post on 205GTIDrivers forum, so I hope I've posted in the correct place?!

 

We have two cars, a track car and a road car. The road car is a completely standard 1.6 GTI which at the moment will not idle at all. You can start the car and it will run as long as you keep the throttle open but the moment the throttle closes, it stalls. 

 

I've changed the plugs and rotor arm, I've also taken out the SAD which appears to be okay. I put the SAD in the fridge so it was nice and cold and it opened up, I let it warm up and it closed (although it doesn't close 100% there is still a very small hole about 3mm) I tested across the two pins on the heater which gave a reading of 47.2 so presume the heater is working.

 

If I keep the car above 2000revs it runs but as i back the throttle off the throttle closes at 2k and it stalls, it wont let me balance the throttle at lower revs, the throttle is closed.

 

I hope this makes sense, and someone can steer me in the right direction.

 

Thanks in advance.

 

Martin.

[Tom Fenton 1,524]

Clean out then set the throttle body up, Haynes covers what to do well enough as it’s too long winded to write it all out.

Remember that you cannot send air down a wire, it relies on mechanical adjustment.

[mvh 0]

Thanks Tom,

 

I have had the throttle body off and cleaned it, there didn't seem to be there to do but I will look again. Is it that you're think it's definitely air related? 

[jackherer 543]

When you cleaned the throttle body did you unscrew the idle adjustment screw? It needs to come out and be cleaned until it is shiny!

 

Then go through the set up process in the Haynes as Tom mentioned.

[mvh 0]

I did take the idle screw out but didn't polish it, I will do now though! I cleaned the body considerably but shall do it to a higher standard!

 

Thanks very much!

[mvh 0]

Is there a diagnostics tester that plugs into the ECU and are they available? They mention that there is in the Haynes manual.

[Tom Fenton 1,524]

49 minutes ago, mvh said:

Is there a diagnostics tester that plugs into the ECU and are they available? They mention that there is in the Haynes manual.

Yes, it’s a very rudimentary thing, will it solve your problem, no, and that’s from experience as I’ve got one. Clean the throttle body so the drillings are all spotless, then do the set up.

[jackherer 543]

It's not a digital ECU, there is no software running on it so the diagnostics tester does nothing you can't do with a multimeter as far as I know.

 

Assuming you have a Jetronic ECU that is, which you probably do if your 205 is UK spec.

[mvh 0]

Yes its a UK spec car, I think it's the LE2-Jetronic. Its an 89 car ph1.5

 

I've taken the throttle body off again and cleaned it, all the drillings are spotless, the idle screw is also polished everywhere internally is mint.

 

I reinstated it all and it's still the same.

 

There's a section in the manual titled 'Throttle initial position - LE2-jetronic system' in 4C.3 is this the set up you're referring to? It mentions using a vacuum gauge, which I don't have but am happy to get one then go through the process.

The only other section is on the next page titled 'throttle housing' , it just tells you how to remove and refit which basically is all i have done.

 

[DamirGTI 323]

Seems to be "starving" for air ... my assumption that the throttle butterfly is not adjusted properly thus just the bypass orifice in the TB is not enough to make it hold the idle .

 

There's an small screw at the back of the TB which pushes on the TB butterfly leaver , with this one you adjust the TB butterfly to have just an fraction of gap to let the air past the butterfly inside the engine .

 

Some basic setup for that screw is , unscrew out then back in whilst it barely touches the TB butterfly leaver (use feeler gauges to verify) then turn it 4 full turns inside .. and re adjust the TP sensor afterwards  .

Also , AFM mixture screw , turn fully in then out counting 7-8 turns then stop .

 

After that , fine tune the idle via big brass screw on the TB . (should be about 1/2or 2 turns out .. but that'll vary from one to another car , just have it opened at least 1/2 of a turn)

 

I'd try advancing the ignition too .. move the distributor a little bit on the advance side and see what happens .. (more ignition advance will make it run higher idle rpm.)

 

Also , there's literary tons of posts here about this the same issue over the years so , i'd also suggest doing some research/reading .. as it's very common problem .

Forum search function isn't so good so try instead via google : site:205gtidrivers.com

 

 

Edited January 19, 2020 by DamirGTI

[jackherer 543]

1 hour ago, mvh said:

There's a section in the manual titled 'Throttle initial position - LE2-jetronic system' in 4C.3 is this the set up you're referring to?

Yes!

 

I reposted it here too:

Try it without a vacuum gauge, I've never used one.

 

[mvh 0]

Excellent! Thanks very much everyone for your help I really appreciate it!

 

I shall go through the whole process the next chance I get.

 

I'm sure there are loads posts on here regarding this topic, but like fixing cars I was also hopeless at searching them! 

[Simes 248 2 Cars]

Bolt that holds the oil filler to the plenum.

Is it there?

[mvh 0]

Good morning,

 

Hi Simes, yes the bolt is there.

 

I followed the instructions in the haynes manual involving the the throttle adjuster and idle screw, the best i could manage to get it to idle at was about 1550 rpm then it would stall. So I think now I have to move on to setting up the TPS. 

 

When the throttle screw was wound down 4 turns from just touching and the idle screw fully wound in it was revving 2200 rpm, so I tried to balance the revs by adjusting the throttle screw and air screw, as I said before, best achieved was around 1550 rpm.

 

TPS next.

 

 

[mvh 0]

Ok, I've had a good go this weekend at trying to resolve the problem. Its impossible for me to follow the haynes manual exactly as it says about letting the car idle at 650 rpm which is the problem in the first place, Throttle open or closed the car wont idle below about 1550 rpm I've tried balancing the rpm by adjusting the throttle stop, air screw and dizzy. I've wound the airflow meter screw all the way in and out 7 complete turns too, tried to get a reading from the TPS (which is a mission on the car) and got a zero reading at closed throttle the car still responds the same. The fuel filter is old so I'm going to change that but wondered if the fuel regulator could be playing a part?

[jackherer 543]

If it's idling at 1550 rpm with the idle screw wound all the way in and the throttle totally closed it has an air leak somewhere. Check the hose that goes to the SAD from under the inlet manifold and the injector O rings. Also double check the bolt Simes asked about above is totally sealed, it goes directly into the inlet manifold. You can spray brake cleaner at an area you suspect may be leaking, if the idle changes when you spray it there is a leak.

[DamirGTI 323]

Have it idling @ 1550 , or where ever it can hold the idle , undo the top air hose which connects air box and AFM and with the palm of your hand close/block the AFM inlet ... if there's no air/vacuum leak it should stall immediately .

If it continues to run , even just barely , then you've got a problem .

 

 

D

[Tom Fenton 1,524]

On ‎1‎/‎24‎/‎2020 at 11:27 AM, mvh said:

Good morning,

 

Hi Simes, yes the bolt is there.

 

I followed the instructions in the haynes manual involving the the throttle adjuster and idle screw, the best i could manage to get it to idle at was about 1550 rpm then it would stall. So I think now I have to move on to setting up the TPS. 

 

When the throttle screw was wound down 4 turns from just touching and the idle screw fully wound in it was revving 2200 rpm, so I tried to balance the revs by adjusting the throttle screw and air screw, as I said before, best achieved was around 1550 rpm.

 

TPS next.

 

 

Set the throttle gap, adjust the TPS once you have done that so it makes the idle switch contacts when the throttle is shut and breaks them as soon as you move it open. Once you have done those steps do not touch the throttle gap again. Then adjust the idle on the bypass screw.

[DamirGTI 323]

1 hour ago, Tom Fenton said:

Once you have done those steps do not touch the throttle gap again.

 

Correct ! ... set TB butterfly adjustment screw @ 4 turns as described above and leave it .

 

D

[mvh 0]

Okay great thanks, plenty there for me to try. Probably wont get a chance now until the weekend.

It's really difficult to get the points of the ohms meter on the terminals of the TPS, I assume this is the only way to set up the TPS ?

[welshpug 1,621]

yes, all you need to know is that there is continuity from middle pin to one of the outer ones as the throttle comes to rest, you will hear a click as well, just ensure that the tps is not holding the throttle open.

 

once that is set also check from the middle pin to the opposing pin for wide open throttle, there is no click for W.o.t.

 

use the buzzer function as opposed to the ohms.

[DamirGTI 323]

It is a bit hard to reach the TPS contacts directly with multimeter probes ...

 

What i usually do is use an old spare 3pin connector with some length of it's original wiring ... and plug that on the TPS so that i can connect the multimeter on the wiring and do the adjustment like so without the hassle of reaching down below the inlet manifold and radiator with multimeter probes .

 

No spare spare 3pin connector with wiring around , no problem either - cut come wires (three of them , each different color) , fit 3mm female spade connectors on the each wire end and plug them one by one on the TPS contacts (make sure they're not touching each other) and write down which wire color you've connected on which TPS contact point .. and do the TPS measurement/adjusting via those wires .

 

D

[mvh 0]

Brilliant! That's a great idea! I can make that up as I don't have a spare block.

 

I know i haven't solved this yet but I really do feel I'm getting somewhere, learning a lot and gaining confidence thanks to everyone's help.

 

Much appreciated,

 

Martin.

[mvh 0]

Oh dear. 

In my excitement to set the TPS, I switched off my brain and instead of winding the throttle screw out and back in to set the four turns I just kept screwing down and wound the screw out the bottom! Not a major problem, first attempt at putting it back in, it fell out, luckily on the floor. Not so lucky the second time, it didn't sound like it fell far at all but I can't find it. I've taken loads out, TB, AFM, hoses to get a clear picture, I think I'm gonna need to take the front off rad etc. 

My biggest fear is, if the stud fell into the hole in the top of the bell housing! If so, is it likely to cause damage? And will it need to be a gearbox out job? Silly question really but sometimes you need to ask the obvious. 

[mvh 0]

Panic over, I found it stuck in 20 years of oil and grit under the starter motor.

The cars absolutely in pieces now so might be a while getting it back together. Gonna take the opportunity to change a few hoses etc.