t4 problems over fueling to the max.??

[DVR68U]

once again guys thanks for replying to these posts, i will cut the new earth into the ecu plug 2morro if i get the chance and see how that goes.
i suppose the bad earth (where ever it is) could be heating up with the current flow through it, increasing the resistance the longer the motor is running. The resistance would become greater as it heats up and then becomes too much for ecu to function.
it would make sense to me that it is a bad contact somewhere as it all happened after a few days of rain. which could have gotten into the wiring somewhere. also this van isnt a baby by anymeans, its got 370,000kms on its wiring lol.

cheers brenton

[DVR68U]

hey guys i checked the resistance on the major earth on the ecu plug, my mulit meter was showing less than 0 ohms, so it seems to be well earthed. there was a smaller about 1mm brown and yellow i think wire that i assume is another earth wire and it showed .3 ohms on the 10x setting so around 3 ohms i think.
i pulled out the o2 sensor but i have no other like it, so i couldnt swap it to try. i cleaned off the blackness lol and put it back in. i tryed to start with it unplugged and plugged in no difference.
how or where can i get this damn thing fixed
cheers brenton

[DVR68U]

hey guys another update , i fooled around again did so stuff cant really remeber now lol my brain is sore from staring at the motor. but i ended up splicing in a new 2nd hand o2 sensor from a 2.5l van and checked the sensor etc to make sure they where changing resistance for temp increase. got the van running and i ran for prob 30mins still seems abit rich , stumble from coasting to accel. but it didnt stall like it was before. ill have to wait untill the morning to see if it will start cold. here's hoping

will the ecu relearn new values and settle down abit ?

cheers brenton

[Jmac]

o2 sensors can cause big enrichening problems for sure, only thing is on cold start the system is in open loop till warm then closed loop, thats when the sensors are important. Just refresh me again mate , does it happen warm or cold???? im like you my brain is hurting large day mate
Cheers

[h100vw]

Jimmy, did you evre work on any G60s. When they started over fuelling, you could tape the wide open throttle switch in so the ECU ignored the lambda probe and ran off stored maps. Basically putting it into open loop.

Just wondering if it would be possible to do the same with this van.

Brenton can you see the output of the probe using VAG-COM? Or stick your multimeter across the probe on volts. From cold the voltage will increase from 0 up towards a volt, once warmed up the voltage will hunt about a bit due to the slow sampling rate of the meter, but it will be indicating somewhere around 0.8 volts on average, showing that it is cycling up and down.

Revving the engine will make the voltage go high and stick there briefly, a rich mixture to make the motor accelerate. When you come off the throttle, the output will drop to 0, over run cutoff, until the revs drop to 1500 or so then, the hunting up and down will start again.

If you don't see what I have described above, you need to work out why.

You could also check the throttle pot and switches with VAG-COM and make sure they are behaving properly, you can also see the water temp output too.

Gavin

[DVR68U]

ill have a look at the readouts via multimeter 2moro gavin, the motor was warm when i changed the o2 sensor. and it seems to have leaned the fueling out a fair bit. ill have to see if i can start the van cold to see if the orginal problem is gone. i think the upgraded earths that i have placed around the engine has helped fix some of the problems.
also which sensor tells the motor when to change to closed loop ?
cheers brenton

[DVR68U]

hey guys it looks like i have fixed the van, lets hope it works cause im taking it down to canberra at 6 lol. so i reearthed the ecu, changed the 02sensor, changed the 2 and 4 pin sensors, cleaned air temp sensor, cleaned isv,
if i break down ill just put a for sale sign on the van and walk home hahah
thanks again guys for all the help ( gavin and jimmy ) lets hope this thread can help someone else in the future aswell. lots of good info one of the more indepth threads on the forum i think.
have a good weekend guys
cheers brenton

[Jmac]

Gavin , yes i did heaps on the G60 mate right in ma prime then buddy!!!!! hehehe yeah Golf with the digifant did this too - you are right if the computer read wide open throttle then you go into open loop like you say as i has no need to be regulating at wide open. Yeah very good point mate. Only one other thing apart from the stuff we discussed is a blocked return line???? this will also make a system rich. But me thinks the earths and then a proper reset of the ecu would make 100% difference to the Van.
CHeers mate
Jimmymac

[DVR68U]

hey guys i made it down to summernats pulled into the parking lot and stalled lol rolled into a spot then, stayed there till this sarvo. drained the oil and changed the plugs, pull started it and drove home with out stopping lol. so i have some more things to look for hey. blocked return line, ill check 2morro. with the ecu being reset , you do that with a 1551 ? i have used matts but he's not really sure on how to do all the things. i did see a menu that said some thing like reutrn to basic settings. is this what your talking about jimmy ? and can i just choose that menu and it will reset them for me ?
cheers brenton

[Jmac]

Yeah you can with 1551 mate no worries, use address word 01 for engine , then there is some bits and bobs you have to do before initiating the basic settings as follows -

‒ Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address word" 01. When doing this the engine must be running at idling speed.
(Connecting fault reader and selecting engine electronics control unit => Page 01-2.)
‒ → Pull crankcase breather hose off pressure regulating valve ( the pipe that fits onto the breather on the rocker cover and route so that only fresh air can be drawn in.
‒ Operate fault reader taking into account the information on the display:
‒ Input 04 for "Initiate basic setting" and confirm with Q.
Note:

If the engine stalls, after restarting it can take for up to 4 minutes at an increased idling speed. In this case do not continue, until the idling speed has decreased.


→ Indicated on display: Basic setting HELP
Input display group number XXX

‒ Press keys 0, 0 and 1 for "Display group number 1" and confirm entry with Q key.


→ Indicated on display:
(1...4 = Display zones) System in basic setting 1 ⇒
1 2 3 4

‒ Terminate engine basic setting by pressing the ⇒ key. When doing this the radiator fan must not run.
‒ Input 06 for "End output" function and confirm with Q.
Hope this helps ya mate the computer imo does need to be reset after you have fitted the new earths.
Cheers