VR6 running problems (118 degrees running temp!!)

[swiftkid 1]

I know this starts off exactly the same as every other VR6 overheating question but I have done a search and found nothing relating to my issue, knowing my luck i'll get the first replay with exactly the right symptoms!

 

Basically I put on a 6 branch manifold, wrapped it to make sure it didn't get too hot, then a couple of days later converted it to obd2. I did have some problems with it but it all seems to be running fine now, my problem is that it seems to run a hell of a lot hotter than it used to, water temp is fine and doing the usual but the oil is a bit silly.

 

It used to run at about 94-102 around town and maybe up to 112 degrees on a motorway run on a hot day, now it seems to run at around 114-120 degrees constantly, which is quite concerning really. I have a hunch the auxillary water pump isn't working but that wouldn't cause the oil temp to spike that high would it? even though the water temp is fine.

 

Another thing I have noticed is the fan after run doesn't always kick in as it should, could this be temp switch related? All just seems a bit strange considering everything was fine before I did the conversion.

 

Any idea's as to what may be causing this?

 

 

 

EDIT: just tested the auxillary water pump and its not working, will be doing searches to try find out how to problem solve that one but again, could this cause oil temps to rise that high? also if anyone has off the top of their head a way of problem solving auxillary water pump it would be appreciated!

Edited June 21, 2011 by swiftkid

[swiftkid 1]

Firstly bump for any help.

 

Secondly I have just got 250 miles to £60 yet my mfa is reading 35-38mpg which has previously been quite accurate. It does smell very rich but vagcom isn't bringing up any error codes. Any idea's what to check for, symptoms etc? is does go onto a lumpy idle occasionally but after a couple of minutes goes back to normal

[Purple Tom 0]

When I did an OBD2 conversion on my old VR6 I had quite a bit of trouble with the engine earth connections giving little niggles. Have you double and triple checked these? If the engine is essentially the same other than OBD2 and a 6-branch then there is no logical reason for the oil temperature to go up by 10-odd degrees. I'd be checking all of the electrical connections if I were you, particularly the earths.

 

Regarding the MFA reading - this is normal. OBD2 uses much finer, more accurate fuel metering than OBD1 and as a result the ECU doesn't provide a very accurate MFA reading. I found mine consistently over-read by about 4mpg which would put your MPG down to about 31-35 mpg which is about right for a VR6 driven gently.

 

Hope that helps a bit.

 

Cheers

Tom

[swiftkid 1]

Well theres only 2 earths that i've put on and they are fine, double and triple checked them. Understand about the MPG reading but the fuel consumption has considerably dropped, driving sensibly I could easily get 300 miles before. I havn't changed the lambda sensor from the obd1 yet but I was told as mine was the latest of the late (CP ecu code) the lambda sensor is the same, i'm not beginning to doubt this so will change it over on the weekend and see if it makes a difference.

[swiftkid 1]

Right, need more help from knowledgeable people. Changed my lambda sensor and I think thats cured the low MPG, we shall see soon enough!

 

Now need help without overheating, it is quite strange. Basically

 

-I have bypassed the radiator switch and fan stage 1 comes on but not 2

-I have bypassed the yellow temp sender and neither the aux water pump or the fans come on.

-I have put a 12v feed into the aux water pump and it did nothing.

 

So I have come to the conclusion that the aux water pump is knackered so need a new one but when I put a voltmeter on the aux water pump wires it wasn't getting any power. Another thing is my fan doesn't kick in until near 110 degrees and by that thought would suggest I need a new radiator temp sensor.

 

Could anyone help out with how to fault find to rule out wiring and fan controller. My water temp doesn't run awfully hot, Sits at 84 usually but when i get town driving it does go up to 100-108 pretty quick, problem is the oil has started sitting at 114-120 which is my biggest concern. I was going to try sort out the aux water pump first to see if that could be related but i would have thought it would have taken water temps up with it and it doesn't. Strange thing is this has all happened since converting to obd2 and putting 6 branch on, but I can't understand why it would cause the oil temps to get that high.

Edited June 20, 2011 by swiftkid

[Kevin Bacon 5]

The Aux water pump doesn't affect oil / water temps. I haven't run an Aux pump at all on mine for 3 years and water is always in the mid 80s and the oil rarely goes over 98 in winter and 110 max during summer at 90 mph cruises.

 

Pins 1 & 4 of the yellow switch are for the fan after-run. On at 100 deg, off at 95. You should see 12V accross there with the ignition off and at that temp range. If you do, then the fault lies either with the fan controller itself, or the wiring between the yellow sender and the controller.

 

Sounds to me like it's running hot. As in, too much ignition retard or running lean. Have you VAG-COM'd it? Changing to the proper OBD2 lambda was a good idea as it's different to OBD1. Anything else from OBD1 that's still there and shouldn't be? :lol:

[swiftkid 1]

Have had it plugged in to vagcom but other than reading error codes i'm a bit lost with what it out of the norm. Yea well I got told the latest of the late VR6's have the same lambda sensor, obviously not! No, everything should be obd2 now, or everything in the list in the obd2 thread. When i changed the lambda sensor i reset the ecu as well to make sure it wasn't playing silly buggers.

 

What should I be looking for to tell if its running lean?

[swiftkid 1]

Just taken these readings, anything out of the norm?

[Kevin Bacon 5]

Nothing out of the ordinary there really. Lambda addition of 12% is a touch high, but that's probably to counter the 75 deg intake temp. That's just at idle though. Logging a 20 minute drive will tell you more.

[swiftkid 1]

Ok, will do that tonight. Is it normal to have minus figures in the lambda learnt values?!

[swiftkid 1]

Just taken these readings, looks like its in closed loop alright but I did notice that when i unplugged the maf it stuttered for a couple of seconds then ran fine and now when i unplug it nothing happens. Could this be the problem?

LOG-01-001-003-004.pdf

[swiftkid 1]

bump, anyone have any idea's? going to try the maf tomorrow but other than that im a bit stumped

[Kevin Bacon 5]

The Lambda regulation swings of -10 to +15% over such narrow time stamps says to me it's working hard to keep the fuelling in check, probably because the MAF is duff. Normally you'd see 0 or ~5% lambda regulation. I reckon it's the MAF. The stumble when you unplugged it was the ECU adapting to another sensor (throttle position).

[swiftkid 1]

Thanks as always Kev, appreciate your help oh knowledgeable one! I've swapped the MAF for my old obd1 one (ECU CP code) that I know was working. Temp climbed to 106 this morning on way to work but no higher so fingers crossed this will prove the MAF is at fault. Will give it a run this afternoon to see how it manages and take another reading but it gives me something to think about. If that helps it, ill buy a replacement obd2 one.

 

I Googled the MAF code (021 906 462) and it came up with golf vr6 91-97 so i'm hoping will do the job for now, the one i took off was 021 906 462 a.

[Kevin Bacon 5]

No worries!

 

I think you need the 'a' MAF mate, IIRC. And did you fit the proper OBD2 lambda in the end, from VW?

 

Luckily the OBD2 MAFs are pretty cheap, so worth a gamble imo.

[swiftkid 1]

Yea swapped over to the OBD2 lambda, got it with the rest of my obd2 parts, it was kicking up lambda codes with obd1. Thinking about it, if the MAF was giving incorrect readings that would make the lambda adapt more than 15% which is obd1's limit, therefore appearing to be faulty.

 

Anyway will give it a go with the obd1 and swap to an obd2 once I have one.