p0l1wrath 10 Posted April 14, 2016 Hello, Been having odd idle/start problems with the Corrado for a while now, and seems like I've changed nearly everything... Found a repeatable problem now which is: When car is first started blue ECU temp sensor is reading ~-20 degrees c. After ~5 mins and the temp sensor starts reading ~-10 degrees c. At which point ECU seems to stop reading value and defaults to the standard 77.7 degrees c If i turn the car off at this point and go to start it again the sensor is being read at the ~20 degrees c mark again, this is fine if the car is cold, but will profusely pump a cold start amount of fuel in to try and start the car even if warm, a fix for now is too unplug the ECU temp sensor to have the ECU default to 77.7 degrees c and the ECU start the car on a warm map. ECU part no. 021 906 258 AG 1993 VR6, coil pack, 6 pin MAF. Brand new blue temp sensor from VW (plus two others from euro car parts) Few questions: What does vagcom/VCDS read a blue temp sensor on ignition before the car is started? What voltage is supplied to the blue ECU temp sensor on a well running car? Is there anyway of checking these ECU's? or a company somewhere that can check them? Does anyone have a 021 906 258 AG i can borrow out of a working car? Will drive to you, closer the better, I'm Swindon based ( Hopefully I can get to the bottom of this this time!:bonk: Thanks Quote Share this post Link to post Share on other sites
tony_ack 0 Posted April 15, 2016 Sorry, don't have answers to your specific questions, but I'd be checking the earths if you haven't already done so Sent from my MotoG3 using Tapatalk Quote Share this post Link to post Share on other sites
p0l1wrath 10 Posted April 15, 2016 Have checked multiple earths, but I've always struggled to find a comprehensive list of earths to check and what they relate to? Sent from my iPad using Tapatalk Quote Share this post Link to post Share on other sites
Dox 22 Posted April 15, 2016 What condition are the CTS plug connections in? Are they making a good contact with the sensor? If you suspect an earth issue (broken wire?) for the CTS then you could make a new / extra one? Quote Share this post Link to post Share on other sites
p0l1wrath 10 Posted April 15, 2016 The connections are fine, and no don't think it's an earth problem, pretty sure it's connecting back up to the ECU fine, I think it's the ECU at fault, maybe providing the wrong voltage to the sensor in the first place Sent from my iPad using Tapatalk Quote Share this post Link to post Share on other sites
della_corrado 10 Posted April 15, 2016 fairly sure its 12v. if your dash guague reads fine then swap your blue plug with the black one in front of it and see how it runs. easy test on the sensor. ive seen brand new sensors fail instantly, they are crap. quick and easy test Quote Share this post Link to post Share on other sites
p0l1wrath 10 Posted April 18, 2016 My dash one is yellow and four pin, the black one is stage three fan, is anyone just able to go stick a voltmeter on the coolant temp sensor plug? I wanna know if mine is getting the correct voltage or not, don't want to spend much more money on this problem without getting it fixed... Sent from my iPad using Tapatalk Quote Share this post Link to post Share on other sites
Dox 22 Posted April 18, 2016 G60 ecu is similar to MK2 digifant but has lambda etc, if you're a member of CGTis forum I'm sure you'll get an answer from Rubjonny or others who'll know what voltage should be at the plug. Quote Share this post Link to post Share on other sites
Dox 22 Posted April 18, 2016 http://a2resource.com/electrical/management.html Quote Share this post Link to post Share on other sites
p0l1wrath 10 Posted April 18, 2016 I'm VR6 not G60 but thanks though Sent from my iPad using Tapatalk Quote Share this post Link to post Share on other sites
Dox 22 Posted April 18, 2016 I'm VR6 not G60 but thanks though Sent from my iPad using Tapatalk VR6 wiring is there too Quote Share this post Link to post Share on other sites
p0l1wrath 10 Posted April 18, 2016 Ah yeh sorry was referring to the forum you mentioned, been to that site a lot recently, it's only wiring colours for the VR6, unless I'm missing something? Sent from my iPad using Tapatalk Quote Share this post Link to post Share on other sites
Dox 22 Posted April 18, 2016 That was across the blue plug, similar with neg probe on the neg of the battery, battery terminals read 12.8v after idling for a min or so with engine off Sent from my iPhone using Tapatalk Quote Share this post Link to post Share on other sites
p0l1wrath 10 Posted April 18, 2016 Thanks, helps a lot! Do you know what your blue sensor is reading with engine cold on vagcom? I know I might be asking a lot... Sent from my iPad using Tapatalk Quote Share this post Link to post Share on other sites
Dox 22 Posted April 18, 2016 Thanks, helps a lot! Do you know what your blue sensor is reading with engine cold on vagcom? I know I might be asking a lot... Sent from my iPad using Tapatalk I have vagcom but don't know how to access what you want. I have a spare sensor I could measure the resistance cold? Quote Share this post Link to post Share on other sites
p0l1wrath 10 Posted April 18, 2016 If you can get to measuring block 1 on vagcom, there should be a value there which represents the temperature the sensor is reading Sent from my iPad using Tapatalk Quote Share this post Link to post Share on other sites
Dox 22 Posted April 18, 2016 (edited) Sent from my iPhone using Tapatalk Engine not running Edited April 18, 2016 by Dox Quote Share this post Link to post Share on other sites
Dox 22 Posted April 18, 2016 (edited) Sent from my iPhone using Tapatalk Engine running Edited April 18, 2016 by Dox Quote Share this post Link to post Share on other sites
p0l1wrath 10 Posted April 18, 2016 Thanks so much for your help Dox, definitely gives me some stuff to go on, will be back when I've done some more investigation Thanks again! Sent from my iPad using Tapatalk Quote Share this post Link to post Share on other sites
Dox 22 Posted April 18, 2016 Thanks so much for your help Dox, definitely gives me some stuff to go on, will be back when I've done some more investigation Thanks again! Sent from my iPad using Tapatalk You're welcome Quote Share this post Link to post Share on other sites
Dox 22 Posted April 18, 2016 Just to add, mine passed its MOT last week after a service, also replacing the CTS, fuel pump (noisy) and filter (ancient) after failing the week previous on emissions - the readings pointed towards CTS being the culprit, the other items were on my to do list. Quote Share this post Link to post Share on other sites
p0l1wrath 10 Posted April 18, 2016 Mine failed only on passenger door not being able to be opened from the outside Saturday just gone, passed emissions with decay installed, baring in mind mine is a '93 therefore emissions aren't as strict, something surround CTS seems to be at fault here, as I am getting the -49 degrees before starting the engine, but getting minus figures until the CTS is then ignored (i think) by the ECU about 5 mins in Sent from my iPad using Tapatalk Quote Share this post Link to post Share on other sites
p0l1wrath 10 Posted April 20, 2016 Did a few checks and just before i try to re-pin the sensor to the ECU, can someone confirm the resistance of the blue coolant temp sensor when cold? I found this online, but it is for a Golf VR6. 5500Ω at 0°c 2500Ω at 20°c 1250Ω at 40°c 600Ω at 60°c 325Ω at 80°c Thanks Quote Share this post Link to post Share on other sites
Dox 22 Posted April 20, 2016 From corrado bentley manual Sent from my iPhone using Tapatalk Quote Share this post Link to post Share on other sites
Dox 22 Posted April 20, 2016 Have you checked the ecu plug for corrosion? Quote Share this post Link to post Share on other sites
