Initial Throttle Position On Motronic 1.3

[mhyphenl 10 1 Cars]

Luckily I have marked the position on the AFM so I can put it back. I'll check tonight what the number is on the AFM, didn't get chance yesterday. Just another check, which ECU should I have? 0 261 200 160 or 0 261 200 162. I'm just going to make sure I have everything in line now and get to the bottom of this!

[MikeC 10]

I would be inclined to agree with Pug ham, the first thing i thought was had you the correct afm.

109 is standard Jetronic

Bosch LU2 Jetronic 0 280 000 345 (LE2 non cat is 340 for 1.6, 359 for 1.9)

[MikeC 10]

Just putting the afm part numbers for Jetronic so he can verify he hasn't a Jetronic afm

[pug_ham 241 3 Cars]

0 261 200 160 imo, the 0 261 200 162 is for the BX GTI which was a slightly different engine afaik.

 

I would be inclined to agree with Pug ham, the first thing i thought was had you the correct afm.

109 is standard Jetronic

Bosch LU2 Jetronic 0 280 000 345 (LE2 non cat is 340 for 1.6, 359 for 1.9)

This is for a motronic m1.3 cat equipped 205 GTI 1.9, not your normal Jetronic equipped version.

 

g

[DamirGTI 327]

Motronic AFM ends with 202 .. also , it's clearly different just by the looks both from the outside and particularly inside (internals underneath the cap) .

 

D

[mhyphenl 10 1 Cars]

Afternoon all! Ok, I've definately got a 202 AFM, I've attached a piccy to show the inside of the AFM, if anyone knows what the internal differences are can they confirm this is right. Just a quick note, the lid isn't glued on and wasn't when I got it from a remanufaturer, is this a possible air leak?

 

[DamirGTI 327]

Yes that's the right one for Motronic ..

 

Top cover must be sealed for internals protection against moisture (moisture can damage potentiometer track) , no air leak issues there just the moisture .

 

D

[mhyphenl 10 1 Cars]

Ok, so Water temp sensor tested and fitted, AFM confirmed and reset to original position, Throttle initial position set, injectors cleaned! Now I need to check the number on the ECU to make sure it's not the BX ending in 162!

 

In the time line of an ECU what could cause the revs to increase by 200 or so after about a minute. Pulsing the throttle brings them back down but then they slowly increase again. What does the ECU bring in after a while that would change the fueling and increase revs? Could it be Lambda? Ignores it until a certain point then when it kicks in it's altering the mixture to cause an increase in revs!

Also now I've put the AFM back and it again dies when coming off the throttle. I loosened the spring, (cog anticlockwise) which if I remember richens the mixture by making the ECU think more air is coming through, is this right? There was a noteable increase in revs which I then adjusted down with the air screw and the running was much more reliable. I'm assuming here that the AFM was correctly set when I got it, is there any way of telling? Any test that defines the correct setting?

[jackherer 543]

what could cause the revs to increase by 200 or so after about a minute. Pulsing the throttle brings them back down but then they slowly increase again. What does the ECU bring in after a while that would change the fueling and increase revs?

 

A dodgy throttle position switch can do that on a motronic Mi16, I imagine the same is true for an 8v on motronic too. Have you checked it with a multimeter?

[Anthony 1,000]

Now I need to check the number on the ECU to make sure it's not the BX ending in 162!

As far as I'm aware, both the 160 and 162 ECU's are correct for 205's - both are Motronic 1.3 for the 122hp XU9JAZ engine.

 

I suspect the difference is just minor mapping and software changes depending on age, in the same way as there was multiple ECU's for the same engine and management in 1.9 Mi16's for example - four different ones for M4.1 for example but all interchangeable and all "correct"

 

The worst I know of is 306 HDi's - there's something daft like 7 or 8 different ECU's for the same engine in just a 3 year window!

[mhyphenl 10 1 Cars]

Do you know what, I haven't! I assumed as I'd set it so it clicks just on close that it was working! I'll be so pissed off with myself if that's it now! I'll check and report tomorrow!

 

Good news on the ECU's though, shouldn't matter which it is then!

Edited March 25, 2014 by mhyphenl

[welshpug 1,626]

definitely check that TPS with a multimeter, they'll click when they are totally dead.

[mhyphenl 10 1 Cars]

definitely check that TPS with a multimeter, they'll click when they are totally dead.

 

Ok, checks out and is fine! Put the AFM back to normal. Here's what happens at the moment.

 

1. Start engine from cold, engine idles well and ECU light is off,

2. As engine warms up the revs drop but it starts to get lumpy.

3. After a minute or so the revs suddenly (over about 5 seconds or so) increase by a couple of hundred and smooth out.

4. If I pulse the throttle the revs drop and almost stalls but then they steadily increase again.

 

I've noticed that the exhaust sounds quite spluttery towards the front end. It's brand new with a newish lambda but could it be badly fitted and could that cause this?

The other thought I had was can the TP switch break down with heat??

[jackherer 543]

The throttle switches can definitely break down intermittently. If you're testing it with a digital multimeter it can be hard to see if it is cutting in and out when it shouldn't be. My multimeter has a continuity beep mode that is good for testing them, otherwise you need an analogue meter or just the classic bulb and wire test.

[MikeC 10]

You could test it under load (using a test lamp dependant on output voltage), the contacts may not be in great shape internally

[mhyphenl 10 1 Cars]

How do I wire that up? Pin 2 and 3 have 12v to them, pin 18 is the ground to the ECU, I'm guessing the ECU knows the throttle is closed by the connection being made across pins 2 and 18, do I put a bulb in series with one of the connections or parallel, my limited knowledge of circuits says series!?