Marco's 2003 V70 T5 journey Topic is solved

[Marcobrick]

HOWEVER, there’s a jolly great clunk taking up drive, and between selecting reverse and drive (and vice versa).
I think I will investigate the inner CV joints.

[Marcobrick]

The car was on a hoist today for it’s annual safety check which it passed with flying colours. I knew it had an aftermarket rear exhaust silencer, but now I can see it has a TME stainless cat-back system. No wonder it sounds so lush!

Before the safety I knew I had to fix the left turn signal which was very intermittent. I just pulled the stalk switch, and blasted some contact cleaner in there and put some more tension on the contact wipers. Good as new!

Also no issues with inner CV joints. I think the clunk is just diff backlash. It seems to have enough to make it clunk, but other than that, it’s not noisy so I will cease to worry about it.

Also I can confirm absolutely zero oil leaks! Nothing. A first for me and 5 cylinder Volvos.

[Marcobrick]

I have again removed the upper tailgate trim. Infuriatingly, it will not stay attached and rattles like mad within a few kilometres of fitting. All of the mounting lugs and clips are in pristine condition, and there are no cracks anywhere.

Any tips? I fear I shall go mad...

[Marcobrick]

Ok, so I was hoping the throttle body would be filthy, thereby easily explaining my erratic throttle behaviour. Nope.

Also cleaned the MAF, put it all back together and we’ll see where we go from here.

[precopster]

There's a replacement loom for those throttles sold by both XeModex and Volvo dealers. Perhaps try one?!

https://xemodex.com/us/product/repair-h ... -body-etb/

[Marcobrick]

There's a replacement loom for those throttles sold by both XeModex and Volvo dealers. Perhaps try one?!

https://xemodex.com/us/product/repair-h ... -body-etb/

Looks like a PITA to install. Thanks for the link.

[Marcobrick]

Today I disconnected the MAF to see what would happen. It has way more power and response and less jerkiness at low throttle. A bit hairy at high boost, but I kind of expected that with disconnected MAF. The untrained wouldn’t even notice a difference except for the CEL it’s about to throw... Funny, because my old 850R wouldn’t even idle properly with the MAF unplugged.

[Marcobrick]

Investigations have continued. My best mechanic friend was visiting and we set to trying to diagnose what’s going on. Much easier being able to concentrate on driving while a knowledgeable person studies the data. By disconnecting and blanking various hoses we managed to get a better idea of what is happening with boost, airflow, throttle position. Finally we disconnected the wastegate and carefully allowed it to free boost, which it really didn’t do, but we think we know why! What’s happening is boost is leaking (you can hear it) and we think we’ve narrowed it down to the compressor bypass valve. I’m pretty confident the erratic throttle behaviour is due to the ecu trying to iron out boost spikes and leaks. I have just received a new bypass valve rebuild kit from IPD, and hopefully I can install it this coming week. Wish me luck!

[Marcobrick]

New bypass valve fitted today. It’s the second time I’ve done that job on one of these, and man what a pain to get the bolts started when refitting!

Reconnected the battery, went for a drive and....nope. Still not enough boost, surging etc. Next I’ll go through all the vacuum lines AGAIN.

[abscate]

Those M6 bypass bolts are hell. What’s even worse is when you get them in, and then you look down and realize the rubber diaphragm fell out before you slipped the cap back on.