2l 16v (9a) Idle problem ISV question

[marf497 0]

I have a problem with my car when i start my car it starts no problem then after about 10 seconds of driving my revs die down and there is no power i need to floor the accelerator to get it going then after about 1/4 mile it is ok no problems idles and drives no problem at first this was only when the car was warm maybe after being driven then left for an hour or so then it would happen when starting the car again. I've had a look through old posts for rough idle and i've checked the throttle body and the micro switch all ok i took of the ISV and filled it with carb cleaner left it for about 30 mins poured out the carb cleaner and it was clear. I seen on some posts that when you switch the ignition on the ISV should buzz I don't hear anything from mine with it of the car i put 12v directly on to the connector pins and nothing happened what should happen if anything also if my ISV was knackered would the idle not be playing up all the time??

 

Cheers for any advice.

[VR6 South 0]

I have had probs with the isv on my Golf. I know they should buzz when the ignition is on. I presume it would be the same for a Corrado.

[marf497 0]

replaced ISV with one from breakers gave it a clean but my cars still the same I also cleaned thecvontacts on my dizzy cap I cant hear anything from the ISV but when i took the pipe of my car stalled. Any ideas would be appreciated.

[easypops 8]

There seems to be loads of running/idiling issues with the 9A ........and plenty of reading to be done too :D

 

viewtopic.php?f=1&t=62564

viewtopic.php?f=1&t=47311

 

hope these help :shrug:

[Jim 1]

On the 2.0 16v there is a little box of electronics on the underside of the throttle body which controls the ISV. I found some threads to do with my current cars previous previous owner on Club GTI where he'd had problems with unpredictable idle, where replacing the ISV hadn't help and he found damage to the cabling to the bit on the underside of the throttle body. So it might be worth checking your ISV cabling all the way back to the throttle body is in tact - and possibly source a cheap / 2nd hand throttle body from a breakers. I picked up another one recently for £10.. god knows how much they'd cost new from VW!

[easypops 8]

On the 2.0 16v there is a little box of electronics on the underside of the throttle body which controls the ISV. I found some threads to do with my current cars previous previous owner on Club GTI where he'd had problems with unpredictable idle, where replacing the ISV hadn't help and he found damage to the cabling to the bit on the underside of the throttle body. So it might be worth checking your ISV cabling all the way back to the throttle body is in tact - and possibly source a cheap / 2nd hand throttle body from a breakers. I picked up another one recently for £10.. god knows how much they'd cost new from VW!

 

Thats where the problem was on mine Jim.........I found the wiring was broken inside the plastic sheathing..........got a new one from euro car parts for about £70 i think......which wasn't needed but i put it on anyway :D

 

edit.......it was a new throttle potentiometer i got.......not a throttle body

[marf497 0]

Had my vag-com on my car and the lambda control in the measuring blocks is reading 000 when my car starts idles ok then revs drop to near stalling after about half a minute to a minute revs return to normal and the reading is still the same even when revving my car any ideas what this should be reading this only happens when the engine is warm even 4hrs after last run but if srarted in the morning when engine is cold it starts and runs ok??

[Tim_R 0]

Hi mate, I'm guessing that is group 6 in vagcom?

When started from cold it should read 000 for about 30 seconds to a minute then start giving a reading as the lambda has heated up enough to work.

 

Below are a few lines from my own vagcom, In the 6th column there is a 0 as the car is running without lambda feedback the starts reading 254, 252 as it starts to control fueling.

 

136 21 38 227 222 0 130 0 5 157

136 30 39 227 222 254 130 0 5 154

135 28 35 226 222 252 129 0 5 148

135 36 37 226 223 250 129 0 5 150

 

It wouuld be worth looking at the first column as your engine warms up, its the engine coolant temperature and the numbers should drop steadily as the coolant warms up. If that is doing something strange, or reading 220 the ecu will think its freezing and fuel to compensate, then you'll need a new sensor, they are about 8 quid from GSF, a lot cheaper than a new lambda!

[marf497 0]

Cheers i'll have a look tomorrow i was going by column 8 from this link http://www.ross-tech.com/vag-com/m_blocks/000.html when you say that column 1 if the value is high then the ecu will think the engine is freezing i'm sure mine was reading about 80 with the engine still warm (started about 20mins after a run) i thought the reading was the actual temperature i see yours is about 135 do you know how to convert these readings into actual measurements. Also with your measurements what temperature was your engine??

 

Cheers.

[Tim_R 0]

That link seems to give some different info in the fields to what I have.

Volkswagen Scan Tool Companion, 1990-1995 from amazon will help with decoding it if you want the full book, this covers the 9a and many other engines.

 

According to that book 80 is about 68 degrees.

 

Drop me a pm with your email and I'll send over some of the relevant info you might need from it. :) It's all a bit chucked together at the moment and will need a bit of reading.

[marf497 0]

Eventually got round to having a good look at this if i disconnect the connector from the metering head the connector on the wing side then i have no problems only thing is when engine is hot i think it revs a little higher would this point to the coolant sensor or is it a metering head problem??

 

Cheers.

[davidwort 0]

you might have put the ECU into average settings mode where it ignores all inputs by disconnecting that sensor, that can somtimes help idling by excluding dodgy lambda readings from the inputs to the ECU,

that may explain why the revs rise as the engine gets warmer, the ECU is not adjusting for temp.

I thought you had to disconnect more than one ECU sensor to get it to operate like that, but I guess you may have another totally bust sensor already anyway.

[marf497 0]

I've got another metering head so i'm going to change it over and connect up the connector and see how it goes i noticed 1 of the wires on this connector goes to the coolant sensor so might be the coolant sensor but i'll change the metering head first.

 

Cheers.

[marf497 0]

Eventually got to the bottom of this problem I took my car to Bedrocks veedubs vw specialists in Motherwell it was my oxygen sensor causing over fuelling. At the end of last year i had a new cat and oxygen sensor fitted as i've found out these engines don't like aftermarket oxygen sensors so new VW oxygen sensor and mixture reset and my car is now running a dream.

[davidwort 0]

not the first time I've heard that on the 2L 16v.

The pattern/generic lambdas do seem to be a bit ropey.

I know this isn't much help after the event, but that does all add up now, I've seen a couple of other 2L cars that wouldn't idle at all unless you unplugged the sensors on the airbox, that does cause the ECU to run from internal values and ignore the lambda input.