on cruise-control
VP Commodore / No Thermo without aircon - ECU Reading temp fine...
Hey guys I've been searching around for a couple of days now but I can't find any info on what I'm experiencing here... Any help would be hugely appreciated!
Ok we have a 92 VP Commodore, Automatic V6 Executive (with factory cruise control for what it's worth).
The other night I noticed my car idling up and down quite erratically, 800-1500/2000rpm pulses in neutral, a lot more calm when I had it in a gear.
I've also noticed that now my thermo fan doesn't engage when it warms up either, I have to either drive or switch the a/c on to get it to cool back down.
My first thought was to check the coolant temp sensor, so I plugged in a borrowed scantech diagnostic computer and brang up the vitals... Coolant temp would rise to over 94c (apparently where the thermo should cut in), and still no sign of the fan spinning.
At this point I noticed something funny, as temps climbed over 96c, every few updates it'd read out something like '36...96...38...97...' I'm assuming this could be the scan tool fudging up the readings, so moving on...
Anyway, today just as I got ahold of the scan tool the thing decided to idle perfectly again (this car always makes a liar out of me), so with that out of the way, I only have the fan to worry about.
Where do I go from here? I'm assuming if the fan circuit was faulty, then the a/c override wouldn't be able to engage it either... all the sensors have been replaced under the bonnet of this thing by the way(I'm kinda obsessive about this stuff)... The only original engine-related electrical component left is the ecu.
Thanks in advance to anyone who can help me out here.
on holiday
i fixed a vn a while ago with the same sort of thing would run rough cutting in and out had the same issue with the coolant temp would jump down to 30 ish degrees then back to normal over and over on my laptop if it stayed low to long it would die with no throttle changed sensor still there put new plug onto wires still there replaced ecu all good still going strong
on cruise-control
Thanks delcowizzid, I'm hopefully getting hold of an ecu to try tomorrow, fingers crossed! Keep the words of wisdom coming people.
on holiday
could be the same reason for no fan as well all linked to the coolant sensor circuits in the ecu
on cruise-control
Yeah I was aware that was the case, hopefully I'll kill two birds with one stone. Found recon Delcos mega cheap today too so if the loaner ecu fixes it I'll be set.
-semi related-
My car has always hunted to some degree though, not sure how common it is but for example, idling into a carpark it would hunt a little as I lost speed, sometimes causing a little "clunka clunka" on my driveline as the revs rose and dropped. Hmmm...
on holiday
can be the swing of the o2 sensor my vp did it to and it matched up too the swing of the o2 sensor volts when in closed loop only did it when nearly stopped rolling up too the lights and stuff
on cruise-control
gotcha, does it help that my erratic idle problem is non-existant just after start-up in open loop mode? It only starts to hunt when it goes to closed loop.
on holiday
how old is the o2 sensor.mine was more tune oreintated as i fixed it with a few changes to the ve table in the tune .
on cruise-control
It's a 1.5yr/25000km ish old sensor, bosch from memory...
on holiday
it could also be due to the same coolant issue jumping below the closed loop temp enable threshold and cold engine fuel and stuff the vn i fixed with this issue would drown in fuel when the temp dropped from going to cold start mixtures
on cruise-control
Unfortunately I can't tell, because whenever I plug the scantech tool in, it runs in open loop mode for some reason. Makes diagnosing problems like this fun.
Assuming "Fuelling mode: OPEN" means open loop anyway.
on holiday
yip wont go closed loop till after 44 degrees coolant temp and wont be in closed loop at idle not moving
on holiday
and jumping from 98 to 34 degrees adds about 200rpm to idle too
on cruise-control
You sure know a lot about these computers! Glad you came along.
on holiday
any idea what memcal you are running should have a little silver sticker on it.or the code maywell still be visiable on the out side sticker on the ecu will be four letters like BAAM its the broadcast code for the memcal
on cruise-control
I couldn't tell you right now, I can tell you when I've got mine out after work tomorrow to swap them over though, all things going to plan. Can I ask why you ask?
on holiday
so i can see if it is a vp tune in there not a vn one by mistake or it could be an aftermerket one. when you put the other ecu in swap your memcal into it if its a different code to what you have allready .you never know whats in there could be v8 or v6 vn or vp allways pays to check unless you know exactly what it came out of.and before you drive somewhere to get an ecu to borrow and give back make sure the metal security panel covering the ecu has been removed before they are a hassle to remove especially if you are in a hurry they are rivited in with solid rivits if its been taken out before it may be screwed back in which is easy.
on cruise-control
Alright cool, I'm off to bed now, but when I've got them both in front of me (hopefully tomorrow night) I'll post back, thanks once again for all your help.
on holiday
on cruise-control
Nah, test one from Holden is already in a car, and a mate who has one in a wreck is uncontactable. Can't win. In other news my 11 month old worked transmission doesn't engine brake anymore as of this afternoon... All this car trouble is getting old!
on cruise-control
*maybe* getting my hands on a proven ECU tonight, fingers crossed.
on cruise-control
Still no ECU... this is getting frustrating! Anyone got a VP Auto ECU they want to sell me cheap or lend to me for a week or so?
on cruise-control
So, I put some music on, cracked open a beer, and set to cleaning every electrical contact I could find in the car. Funnily enough most plugs were in decent repair and didn't seem as though they needed cleaning (I filed and contact-cleaner-sprayed them all anyway). I put it all back together and went for a drive, still no fan... bugger. Much later that night on the way home, it came on sitting at the lights! This is a huge wtf moment for me. Does anyone have the wiring diagram (wire colours, locations etc) for a Vp V6 engine loom? I'd love to be able to trace back the thermo-on signal wire from the ecu.
on holiday
on cruise-control
Don't happen to know which path it follows to the relay box? I'm still keen to try another ECU... My idle is still kinda rough.
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