up and down idle, cat and lambda... ##SOLVED## explanations

Audi Nut Joined: Nov 11, 2004 Posts: 55

The idle of my car , when hot (more than 80º) is sometimes at 1100rpm and sometimes up and down between 800 and 1200 (very rythmical). I clean (more or less) the idle valve, but the problem changes only a little but it still there.

The catalist is broken right now. And may be the lambda is broken too. But I did not get any error from it.

The only error I get from the diagnostic led is 2232, that seems to be "air flow meter" have got this the KE3 Jetronic?.

I have a new cat and a new lambda but I don´t want to install them in the car and have to chage them 1 month later by a problem on too much rich mixture...

¿Could any body help me?

Posted: Thu Dec 09, 2004 8:28 pm

I would change the lambda certainly and clean the airflow meter too.

You may also want to check for cracked/split/leaking air hoses and breahter pipes. All can cause erratic idling too.

Audi Nut Joined: Nov 11, 2004 Posts: 55

Where is the airflow meter in the KE3 jetronic. I thouigh that this was only mecanical and have no electronic sensor for that ¿?.

Will I clean the plate and the body (all mecanical) or some potentioemter or something?

Sorry I am not very familiar with mecanical injections, I use to work with the Motronic 1.5 on my other car

Posted: Thu Dec 09, 2004 8:40 pm

Hmm, I thought the Jetronic would have one for sure - would be close to the airbox and between the box and the throttle body. Didn't this system have the famous "electic hedgehog" arrangement for monitoring airflow ?

Audi Nut Joined: Nov 11, 2004 Posts: 55

ok, so your talking aboiut cleaning the variable resistor (potentiometer) that will tell the injection how much air is going into the engine.... will search for something like that...

Posted: Thu Dec 09, 2004 8:59 pm

Rather than a pot it usually looks like some sort of wire that stretches across the unit in the path of the air. The wire is heated so the more air that crosses it, the more current it draws and hence it can measure the airflow.

Posted: Thu Dec 09, 2004 10:39 pm

I'm probably wrong here, but I thought the KE3 system fitted to the NG engines had a potentiometer fitted to the airflow metering head that measured the angle the plate was lifted through.

This would be on the side of the electric hedgehog next to the wing.

I'd be surprised if it had it's own fault code though.

Ian.

Posted: Fri Dec 10, 2004 7:28 am

ismasl

NG fault codes ,KE111 jetronic FEI

4444 no fault
1111 ECU
2121 throttle valve switch 1
2122 speed signal from FEI
2123 throttle valve switch 2
2141 knock control at limit
2142 knock sensor
2223 altitude sensor [ if you have one ]
2232 airflow meter potentiometer [ or load signal from ECU ]
2233 reference voltage from ECU for load and altitude sensors
2312 coolant temperature sensor
4431 idle stabilising valve
0000 end of fault list

don't forget this ECU has only flash memory , so test before you stop the engine after you have given it a drive a toda marcha , which generally shows up everything ;I have had just a bad connection on the air flow meter , so remember that before you start out for the cementario to find one if I doen't clean up .

after that , test your lambda , which is probably the main reason for the erratic idle , despite the test [ might even be the reason for the air flow fault]
on the input side of the cylinder head you will find a small bracket with 2 ellectrical connectors fitted ; normally one round and one square ;if you look you will see it is the connections to the lambda ; the square one is the heater circuit , so doesn't need to be touched ; open the other connector which is a push fit , and contact a very fine piece of multicore wire in before reconnecting ,so that you can have a contact at the other end of the wire ; this wire is just for convenience , so that you can stand at the front of the car and test ; I have made a small insulated end on mine which I can open , and leave the wire permanently connected .

with a cold engine , switch on the ignition , and measure the voltage with your DIGITAL multimeter between this connector and earth[ not on the battery, cylinder head perhaps , strangely I find the clamp on the top water hose is good even though it is on rubber !!!] ; it must be approx 280mV , which is outputted by the ECU .
if this is OK , start the engine ; after about 30 seconds the voltage should start to fluctuate , and you can see the effect of open and closing the throttle .

readings should be
amplitude minimum 600 [200-800mV?]
median 500
average 450
frequency 0.5 seconds

if you have that , it doesn't need changing ; but it is still a good idea to check regularly as you don't know how old it is I presume , and 100K is a good average life.

if you find the lambda is faulty , change it immediately ;this will correct the mixture ; and then get your emissions checked before changing the CAT , you will probably find that it is still OK , the lambda was causing the problem.

can I go back to bed now please ?

LB

Audi Nut Joined: Nov 11, 2004 Posts: 55

This is very interesting for me, maybe that is the same problem as I have, its very difficult that this part was broken (it have nothing to be broken...). So the problem must be a wire or a connection. Where did you find the bad conection? what was your problem about this? maybe is in an old post?

thank you very much guys. I am really happy to found you.

Posted: Fri Dec 10, 2004 8:14 am

The pot is on the fuel metring head itself, if you havn't found it already! Should be on the side nearest the wing I think...

Audi Nut Joined: Nov 11, 2004 Posts: 55

Yes I found it but it didn´t seems to be posible to remove it for cleaning or check. Did any one remove it?

Posted: Fri Dec 10, 2004 1:12 pm

inversors work 24 hour days ismasl !
with regard to the bad connection , my cars are quattro's with a second radiator ; one started to leak and the antifreeze got to the multiplug on the airflow meter , and caused a bad connection

but you cannot do anything without a good lambda !it won't come to any harm if you change it first [ as long as you don't use con plomo]

LB

Audi Nut Joined: Nov 11, 2004 Posts: 55

I have changed the lambda and the cat. Now it sounds better, no coins in the exaust sistem (jeje). I have change the gas filter too. Now the car is more powerfull. But... the idle still very hi about 1200 and goes from 800 to 1400 sometimes... the error code 2232 still there.

I will buy a complit part (all of that is in air filter) and see what has happen in the one I have. No other idea of what to do...

Posted: Sat Dec 11, 2004 11:35 pm

You could try clearing the fault codes by pulling the fuse for the ecu for a few minutes. Otherwise any corrected faults will clear after 99 engine starts I believe.

However, if you are still getting an erratic idle, you may still have a problem of course in which case the code will reappear.

UltraUser Joined: Jan 21, 2003 Posts: 4230

I looked up on my data and 92 2.3 NG code 2232 = VAF (volume air sensor) sensor or wiring faulty Evil or Very Mad

Posted: Sun Dec 12, 2004 8:21 am

on an NG you clear the fault codes by turning off the ignition , only 20v and S2 seem to have memories because they have MPI ecu's .

sounds like your idle control valve could be dirty as well ismasl , it's the device in the air intake hose and the throttle body ; just disconnect the wire , pull it out of the rubber hose , and clean the rotating interior with carburettor cleaner or WD40 or switch cleaner or something ; when you put it back , if the idle still oscillates but is steady but high with the wire disconnected , it is faulty or needs more cleaning

LB

Posted: Mon Dec 13, 2004 1:16 pm

just realised I was thinking about my 20v , on an NG the idle control valve is under the inlet manifold , beside the oilf filler cap ; normally you can just pull the whole thing out
LB

Audi Nut Joined: Nov 11, 2004 Posts: 55

the idle valve was not the problem. I buy used one clean every one with carburator cleaner spray hardly, but the problem still exactly the same (with any of them).

I thought that I must solve the 2232 error.... the car is doing 10 L/100km on highway at 130 km/h at max. I think this is too much.

UltraUser Joined: Jan 21, 2003 Posts: 4230

Lambda probe (oxygen sensor) controls the fueling via the cars ECU. Have it tested Evil or Very Mad

Audi Nut Joined: Nov 11, 2004 Posts: 55

I have change it from a new one 2 days ago, also the cat was changed for new one

Posted: Wed Dec 15, 2004 8:54 am

Have you tried testing/replacing this yet?? It'd be cheaper than throwing new cats & lambda at it! Razz

. If the air metre is throwing the mixrure out and making the revs drop the ECU will bump up the revs to compensate (probably via the ISV)...

Posted: Wed Dec 15, 2004 9:07 am

ismasl , 10 litres is not very bad ; when mine is perfect it uses about 9 litres like this .....my 20v is about 11
but you must fix this fault code problem

LB

Audi Nut Joined: Nov 11, 2004 Posts: 55

OK, now I am taken this very serious...(ejem)

Temp engine sensor
I take a multmeter and go to the bonnet. Warm up the engine. Look the termo sensor 400ohm (litle down 300 it good for 80º) any way swich the two terminals any way to be in closed loop mode. Nothing hapen idle very hi 1100 up and down...

Lambda
Take values (volt.) from the lambda betwin 0.0 and 0.4 seems like the lambda didnçt be able to change the mixture from riche to lean. It send the signal but nothing happens.... this is not going fine. The heater of the lamda has 12v. so its right. The lambda is new 1000km only.

Sencondary preasure regulator
I check the amount of Intesity runing through the preassure regulator and found somethig realy rare. Intensity fluctuate (like the idle, at same time) between +10 and -10 mAmp. These means the engine is going from reach to lean all the time and it is not estable. I have read that with fine idle at warm I will get 0mAmp if every thing is going fine.

So now I am thing about a bad secondary preasure regulator or a bad ECU. ¿What do you think? I promisse a good box fo Spanish wine for that who give me the right way to go...jejej... (serius)

Other hand I have check the idle swich (fine) and some of the cables but didn`t know how to check the airmass sensor... Didn´t know the right values for that (anyone with elsa, I am downlading it right now 1.9Gb)

excuse the large post... but I think it is iteresting and we can learn about this engines.

Posted: Wed Dec 15, 2004 10:36 am

ismasl , don't worry !make the posts as long s you like when you have something to say like this ; we can learn form you , as well as you from us !the mixture is clearly wrong as you say , I think I posted the lambda readings before ; your field is electronics ....why didn't you do this before !

next test .....separate the ECU from the lambda at the round connector beside the cylindre head ; switch on the ignition [ not start engine ] and measure the voltage on the wire that goes to the ECU ; is it 280mV [mas o minus ] . we had a case earlier in the year where the insulation had failed on the cable inside the ECU ; short circuit , wrong default voltage ; cut wire back a little , AOK

LB

Audi Nut Joined: Nov 11, 2004 Posts: 55

I have read 540mV.

Just as you say turn the ignition on (not start) take the male terminal going from the ECU and read 540mV from this to engne ground.

uhm, that is the most unexpected value. jeje

I have use two diferent multimeters to read this, with the same resault

Posted: Wed Dec 15, 2004 11:12 am

ismasl , I am not using my NG at the moment , so I will go and put a fresh battery on it and check again in case I am confusing the reading with my 20v , which has a Hitachi ECU

LB

Audi Nut Joined: Nov 11, 2004 Posts: 55

ok , thankyou

I will still searching for any other thing.

Posted: Wed Dec 15, 2004 11:44 am

ismasl , good news , yours is correct ; mine reads 550mV also ; the 280 must be the 20v !
so I hope the ECU is correct , and that means the air flow meter is the probable culprit as it says ; have you taken the airflow meter off to look ?

let us know what you find when you have your download of this as I have no default figures .

LB

Audi Nut Joined: Nov 11, 2004 Posts: 55

I have gone to the bonnet again with my multimeter. I take voltages and reistences on the airflow meter, and found something.

There are 3 cables on this sensor

pin 1 red/brown that seems to be ground
pin 2 green/grey that seems to be the signal
pin 3 red /blue +5v

So this is usally electronic for a potentiometer That is a veriable resistor with 0v (pin1) on one side and 5 (pin3) on the other side. The other ping (pin2) moves along the resistor ( by the arir flowiing on the intake) and send a signal by volt deppending on it is near to 0 (no air at all) or near to 5 (all the air in the word).

Other hand if we take the resistor fron pin 1 to pin2 we found that mine was given values from 20kohm to 100kohm... without sense (I thught) when the resistor between pìn 1 and 3 is allways 4kohm (more or less, dont remember).

So I am thinking that this resstor is bad or dirty, like the raido volume when it "scrachs and worf profff..."

¿Did anybody understand anything?..... jejej

Posted: Wed Dec 15, 2004 3:53 pm

estupendo !!! can you probe the output wire while you vary the revolutions of the engine in order to find out how the voltage varies with the speed ; the only problem is I don't know if the output should be linear !

but if you post your findings I will test my 20v tomorrow morning to compare ...unfortunately my NG is not running ....under repair at the moment ; but I expect the airflow meter will be the same output .or maybe someone else with a 5 cyl could do it this evening , an NG would be perfect of course

hasta luego!

LB