24v Engine running rough

[Dutch24V 0]

Just posted this on vortex and signed up to the uikmkiv forums to ask there, but thought I'd ask here too as I'm a little stuck :(

 

When cold the engine is very smooth and runs fine, but after the coolant temp. reaches 70+ and after a bit of hard acceleration it runs really rough and lumpy. Power is down significantly too and the car is almost un-drivable.

 

After limping home (

 

18057 - Powertrain Data Bus: Missing Message from ABS Controller

P1649 - 008 - Implausible Signal

17528 - Oxygen (Lambda) Sensor Heating; B2 S1: Open Circuit

P1120 - 004 - No Signal/Communication - MIL ON

 

The first one is explainable by the fact that the engine is in my Corrado and hence not connected to the mkiv ABS unit.

 

The second one is obviously a problem, but which lambda sensor is this error for?

 

Apart from these there are no more errors, so how can I go about solving the rough running issue further? If I reset the ecu with the engine still warm it idles and revs fine again. I have not risked driving her again when warm so not sure if the problem returns after a hard run again or not at temperature. If I wait a day and try again, the same symptoms return with the same errors as above. Not sure if it

[dr_mat 0]

If you know the pin-outs on the lambdas, you just need to check which lambda has an open circuit on it's "heater" pins..

[Dutch24V 0]

Good idea, why didn't I think of that?

 

I have the wiring diagrams so will test the heater circuit on the sensors tomorrow.

I've just figured out it's one of sensors in front of the cat. so shouldn't be to hard to find :)

 

I doubt that's causing the problems I have though unfortunately

 

 

Dutch

[Jim 2]

To be honest, rough running once warm is classic bad lambda symptoms. I've only ever seen a G60 running with a dead lambda once but the effect was so serious you'd think the engine had serious mechanical issues. I guess from cold it uses preprogrammed values in the ECU but then as it warms up starts to expect values from sensors such as the lambda?

 

The G60 would idle at first then after about 5-10 minutes start to bounce up and down revs, nearly cutting out, be belching out black smoke and was pretty much undrivable...

[bigpants baby 0]

Just posted this on vortex and signed up to the uikmkiv forums to ask there, but thought I'd ask here too as I'm a little stuck :(

 

When cold the engine is very smooth and runs fine, but after the coolant temp. reaches 70+ and after a bit of hard acceleration it runs really rough and lumpy. Power is down significantly too and the car is almost un-drivable.

 

After limping home (

 

18057 - Powertrain Data Bus: Missing Message from ABS Controller

P1649 - 008 - Implausible Signal

17528 - Oxygen (Lambda) Sensor Heating; B2 S1: Open Circuit

P1120 - 004 - No Signal/Communication - MIL ON

 

The first one is explainable by the fact that the engine is in my Corrado and hence not connected to the mkiv ABS unit.

 

The second one is obviously a problem, but which lambda sensor is this error for?

 

Apart from these there are no more errors, so how can I go about solving the rough running issue further? If I reset the ecu with the engine still warm it idles and revs fine again. I have not risked driving her again when warm so not sure if the problem returns after a hard run again or not at temperature. If I wait a day and try again, the same symptoms return with the same errors as above. Not sure if it

[Dutch24V 0]

Hmmm, maybe it is the lambda then, but the fault is for the heating element only?

 

I'm using the air pump relay only. When the ecu was remapped I had the air pump deleted along with the 2 after-cat lambdas. I ditched the air pump relay too at first, but kept getting the following error:

 

17841 - Secondary Air Pump Relay (J299): Open Circuit

P1433 - 004 - No Signal/Communication - MIL ON

 

I have the relay connected now, but only to the 2 ecu wires. Seems to make the ecu happier as this error has gone.

 

I can rev over 3000 too, so like you say must just be with the us cars.

 

Dutch

[dr_mat 0]

Hmmm, maybe it is the lambda then, but the fault is for the heating element only?

 

The heater element is critical to the function of the lambda. It reads fuck all if the heater element isn't working.

[bigpants baby 0]

I dont think it would harm to sort out the clutch & brake switch if you havent got them connected?

[Dutch24V 0]

The heater element is critical to the function of the lambda. It reads **** all if the heater element isn't working.

 

Ah, OK, didn't know that.

 

I have the Clutch switch connected as it holds the revs a little whilst changing gear. Not sure the brake switch does anything worthwhile other than cutting the dbw or cruise control (not wired up) though tbh, and it only cuts the dbw after 3 seconds of braking. Even I can react quicker than that :)

 

Dutch

[Toad 0]

The heater element is critical to the function of the lambda. It reads **** all if the heater element isn't working.

 

Ah, OK, didn't know that.

 

It think that's why it didn't play up til the engine was hot, as has been touched on upon by Jim. The lambda has to get to a certain temperature before it will give readings, until this point the ecu uses set values, and whilst the engine was cold it hadn't reached that temperature. It's like driving at WOT, the ecu stops using the lambda readings (I think...) I thought that the lambda was heated within 20 seconds of startup though...

[Dutch24V 0]

It think that's why it didn't play up til the engine was hot, as has been touched on upon by Jim. The lambda has to get to a certain temperature before it will give readings, until this point the ecu uses set values, and whilst the engine was cold it hadn't reached that temperature. It's like driving at WOT, the ecu stops using the lambda readings (I think...) I thought that the lambda was heated within 20 seconds of startup though...

 

Do you know if the ecu uses pre-set values when the lambda is cold or when the engine is cold, as like you say the lambda heating element should be up to temp. within 10-20 seconds?

 

Anyhow, I may have found the problem. Paste from my reply on ukmkiv:

 

"I think I have just found the problem though, but have to go for a drive to confirm. I think I had plugged one of the pre-cat o2 sensors into one of the post cat holes! I had the ecu re-flashed a few weeks ago and had the 2 post-cat o2 sensors deleted from the programming along with the secondary air pump. I then removed the 2 post-cat sensors and the air pump & valve and plugged the corresponding holes accordingly.

 

Having just looked through the wiring diagrams though I'm fairly sure I had the B2 S2 sensor in the B2 S1 position. As far as I can tell the 2 pre-cat sensors should have 6-pin connectors and the 2 post-cat ones only 4-pins? I have swapped the removed 6-pin sensor into the B2 S1 hole and disconnected the 4-pin sensor that was there. I don't get anymore o2 sensor errors after clearing the error codes and revving the engine whilst cold. I will go for a drive shortly to confirm if the problem remains fixed when the engine is warm."

 

Dutch

[Toad 0]

Not a clue I'm afraid. I'd guess at a bit of both, until the engine reaches a certain temperature the emissions are going to be pretty cack, so the lambda would start affecting the mixture.

 

Glad you've found the issue...

[Dutch24V 0]

Thanks, me too, but I haven't driven her yet as I need to confirm which lambda goes where.

 

I have the 2 pre-cat sensors, one with a brown 6-pin connector and one with a black 6-pin connector. I'm not sure what side of the dp each one goes?

 

Bigpants, any clues?

 

Dutch

[dr_mat 0]

Do you know if the ecu uses pre-set values when the lambda is cold or when the engine is cold, as like you say the lambda heating element should be up to temp. within 10-20 seconds?

 

Pre-set stuff happens during the first thirty seconds or so on a cold engine and it relies on the lambda from then on. It doesn't know that the lambda hasn't reached correct temperature, either, just that the readings it is returning are stupid and wrong, hence the crap running, poor MPG and so on.

 

Later engines (i.e. post-Corrado) use the lambda for WOT too, there's not really any good reason not to, assuming all the sensors are working well.

[Dutch24V 0]

Popped to my local VW garage this morning and now have the info. I need:

 

- o2 sensor 079 906 262 F (with the brown 6-pin) goes on the drivers side (LHD)

- o2 sensor 022 906 262 Q (with the black 6-pin) goes on the passenger side (LHD)

 

Hopefully that will be the end of my problems and I can start enjoying her again after almost 18 months of the road!

 

How do I change my login name to Dutch24v ? :)

 

Dutch

[Jim 2]

You ask one of the mods nicely :) Drop me a PM to remind me to do it :)

[Dutch24V 0]

Thanks mate. PM sent :)

[Dutch24V 0]

Excellent, thanks Jim :)

[Jim 2]

No worries :)

[Dutch24V 0]

The problem is fixed and she now runs like a dream. So good in fact I took her for an APK (M.O.T) and she passed with zero problems, and the emissions are spot on too now I've sorted the lambda sensors out! :D

 

Just went for a little spin with her up to temp. and all I can say is f**k me, a LOT quicker from 2500 rpm than I imagined she would be. She has been remapped to 228 pk and it feels so much more responsive in the lower rev range than the old 2.9 12v it's almost night and day :)

 

I'm off or another little spin, but will get some more pictures and update my member

[CoxyLaad 0]

yey!!!!

 

glad you got it all sorted mate :)

 

happy 24 valving, that engine is a peach.

[dr_mat 0]

Nice, imho this is the way to go when your 12v dies. Glad to hear it doesn't require giving Vince £10k to sort it all out .. ! :)

[Dutch24V 0]

Thanks mate. She sure is a peach from what I can tell so far. The oil is still crystal clear after all the f**king about I've been up to so must be very clean on the inside. How many miles did it have again when you got it?

 

Basically it's a fairly easy swap to do, just loads of little fiddly things that take time, especially if you buy a RHD engine and loom and then fit it into a LHD car :) Also depends on how factory you want it to look and how much of the ancillaries you want to replace with new items (which then depends on how much spare cash you have at the time) etc.

 

If anyone fancies it themselves I'd recommend doing it yourself. I've learnt shed loads and am confident I can now fix pretty much anything that goes wrong with it from now on. One bit of advice though - if you don't have a garage, rent one, otherwise you'll be at the mercy of the weather, which is why I took so long.

[CoxyLaad 0]

somwhere in the region of 6000 - 7000 miles mate ;)

so basically brand new.

[Dutch24V 0]

So just about run in. Excellent, she should hopefully last for at least another 200,000 Km's or so then :D

 

Dutch