Flawless at night - Feel like burning it during the day?

[pillapow]

In the cool night (9-10 degrees) the car performs superb, smooth, silky power and right throughout the rev range.

Daytime, (14 degrees +) jerky, flatspots, erratic boost, (20 degrees +) warrants burning the thing, loud and horrible with what feels like literally no boost, albeit the boost is there on the gauge but the power isn't.

Was thinking about selling it and buying an old A8 4.2 quattro but after a superb midnight run I want to cure the girl, lol.. ♥♥♥

Help me guys, please. :-) Gracias Amigo's.

PS. I have tried spare IAT sensor, MAP sensor & MAF sensor, makes no difference.

[M-R-P]

Hmmm I'm guessing you have all the original air system intact except the filter?

[jamesy12345]

Any more codes showing up? Are you using the air con daytime? Did you sort out that wiring to the IAT sensor?

[oblark]

Sounds like the air temperature sensor is faulty.

[Biff]

The maf you bought, was it genuine bosch?
Sounds like my V70r which I chased the same symptoms for nearly a month. £200 later on a genuine maf & normal service was resumed.
I know rudeboy18 had the same trouble as he bought my maf when I broke the car. He said it made a hell of a difference.
My car had a brand new budget maf on it when I bought it.
Straight in the bin, they don't like them.

[960kg]

The maf you bought, was it genuine bosch?
Sounds like my V70r which I chased the same symptoms for nearly a month. £200 later on a genuine maf & normal service was resumed.
I know rudeboy18 had the same trouble as he bought my maf when I broke the car. He said it made a hell of a difference.
My car had a brand new budget maf on it when I bought it.
Straight in the bin, they don't like them.


......and members slag me off when i say VOLVO ONLY when to do with the engine and NOT cheap aftermarket parts!

[M-R-P]

......and members slag me off when i say VOLVO ONLY when to do with the engine and NOT cheap aftermarket parts!

I think it's more because you can come across as a bit abrasive at times Keith, using oe when it comes to mafs etc is a done deal really.

[pillapow]

Hmmm I'm guessing you have all the original air system intact except the filter?

Yes, all intact and sealed, only mod is drilled airbox previous owner did.

[pillapow]

Any more codes showing up? Are you using the air con daytime? Did you sort out that wiring to the IAT sensor?

Obd2 reader gives no codes but if I clear the empty list of codes the car resets itself and idles terribly for a few mins then settles back to normal, strange.

Air con is always off.

The wiring I was concerned about was to the coolant temp sensor, I didn't manage to get in there tbqh, I had forgotten about that too.

[pillapow]

The maf you bought, was it genuine bosch?
Sounds like my V70r which I chased the same symptoms for nearly a month. £200 later on a genuine maf & normal service was resumed.
I know rudeboy18 had the same trouble as he bought my maf when I broke the car. He said it made a hell of a difference.
My car had a brand new budget maf on it when I bought it.
Straight in the bin, they don't like them.
It was a genuine bosch , same part numbers, from acidicdavey on the other forum, he seemed a genuine bloke and guaranteed it was a good maf, it actually ran worse with the donor maf.

[pillapow]

Sounds like the air temperature sensor is faulty.

I'll reswap the IAT sensor only and give it some time/miles to adapt.

Sorry for separate replays guys, on a tablet here, can't seem to do it.

Thanks all.

[LiamT4]

Any boost leaks? I know it sounds weird but my brother had a small crack in his intercooler and it drove fine on short to medium journeys at night, but in the day it drove like a pig.

[pillapow]

Any boost leaks? I know it sounds weird but my brother had a small crack in his intercooler and it drove fine on short to medium journeys at night, but in the day it drove like a pig.

All boost lines/pipes are sealed and VAC lines replaced with silicone.

I did try to get the intercooler off but realised I had to disconnect the aircon piping etc so left it, I can't see any visible oily residue at all.

[LiamT4]

Get the audi, V8's are just better :hidesbehi lol

[pillapow]

LOL, just been to Carr Mill Dam to watch the powerboats, damn car is back to its usual self, yes, the V8 is appealing, probably get better MPG also..

[stribo]

If it's only doing it a higher ambient temperatures, then it's got to be a sensor somewhere, unless the car's plugged into VIDA though, you could be chasing your tail.

[LeeT5]

All boost lines/pipes are sealed and VAC lines replaced with silicone.

I did try to get the intercooler off but realised I had to disconnect the aircon piping etc so left it, I can't see any visible oily residue at all.

The Intercooler can be removed with out draining A/C. You'll need to drop the Coolant thou.

The oe IC's normally crack on the right hand side, just where the BPS lives, on the crease. Check for any residue in that area.

[JamesT5]

My car loves cold, damp mornings, the moist air seems to help and cold air is denser than warm air so the denser the air the more the engine can breath. Glad I paid attention in Science at School! :D

[Biff]

......and members slag me off when i say VOLVO ONLY when to do with the engine and NOT cheap aftermarket parts!

Difference is I don't care, they can say what they want. I'm no expert but I'm willing to share my personal experience with the op in the hope he gets his car sorted.
I used non genuine parts on my volvo but I made sure that they were of an or quality first as recommended by merc85 (Gav) & Jamie from parts for volvo's.
The maf that was fitted to my v70r was of very poor quality as was the other fuel parts components I've had experience with on other cars. It didn't throw any fault codes up but we were able to see how slow it was reacting to throttle response.
I'm not sure of the software used but my symptoms were very similar.

[pillapow]

8-10 degrees near Southport coast tonight, some mist too, Car ran superb, nearly locked horns with an old, white 850 T5 at Tesco near Formby but he went the other way.. Can anybody diagnose without paying stupid money to have it plugged in. Thanks.

[LeeT5]

8-10 degrees near Southport coast tonight, some mist too, Car ran superb, nearly locked horns with an old, white 850 T5 at Tesco near Formby but he went the other way.. Can anybody diagnose without paying stupid money to have it plugged in. Thanks.

Your more than welcome to bring it up to me if you want. I'll plug in for free and see what codes are logged.
I'm available next Wednesday.

[Redbrick]

My car loves cold, damp mornings, the moist air seems to help and cold air is denser than warm air so the denser the air the more the engine can breath. Glad I paid attention in Science at School! :D

yes but.... water injection doesn't work because water beats flame. :slap:

[Redbrick]

It was a genuine bosch , same part numbers, from acidicdavey on the other forum, he seemed a genuine bloke and guaranteed it was a good maf, it actually ran worse with the donor maf.

Any second hand component should have an element of doubt applied to it.

I had a problem a few years back with the coil. At high revs, high torque the engine would stutter, tried everything and then turned out to be the coil when I replaced that, ironically the last thing to replace! I guarantee I could pass that removed coil off as working 100% to 99% of 850 owners out there and it would work spot on for them. Not suggesting in anyway you are victim of this but just making a point.

[pillapow]

Your more than welcome to bring it up to me if you want. I'll plug in for free and see what codes are logged.
I'm available next Wednesday.

Thanks for the offer but its a little far to drive is Kent, thanks though :)