Low Boost, TCV Adaptation 2000 V70R

[bmdubya1198]

I've been troubleshooting a low boost issue on my 2000 V70R, and I finally discovered that the evap purge valve could have been causing a vacuum leak. Now it seems every time I get into boost, the gauge goes up to 8 or so PSI and backs off slightly. I have a Hilton stage 1 tune, I know this car should be making probably double that!

I've done some logging in VIDA to see how all of the sensors and whatnot are performing and everything looks good. Only codes I have are related to the MIL and ETS light signal wires shorting to ground, which I don't think would cause low boost. I'm going to take care of that issue, but I can't figure it out and I'd like to get the car boosting properly first. Before I replaced the purge valve, the TCV was going to 100% duty cycle so the ECU isn't trying to dial back boost. The only things I can think are that either the TCV has yet to adapt (I've driven over 60 miles so far) or there is a problem with the tune. I've contacted Hilton, but he has not yet responded, so that's why I wanted to post here in the meantime.

So would I be experiencing this low boost while the TCV is still adapting? The TCV is new, the Porsche Pierburg upgraded unit. I've also replaced all vacuum hoses and checked for tightness on all intercooler hoses. I replaced the CBV with the iPd HD parts. When I pulled the wastegate line, the turbo had no problem boosting to 20 PSI and beyond (don't worry I'm not stupid, I'm not going to try to spin my gauge around a second time!), so the turbo is not the problem. Anyway, it's not right that I'm making more boost in my light pressure turbo car! What's going on here?

[scot850]

I had a problem with the IPD TCV which I have mentioned many times. Not sure about the Porches Pierberg version. The IPD version is finicky to install as you can't crank the the plastic legs in tight as the middle one crushed a small wire mesh and jambs the valve from opening or opening fully.

The Volvo unit is only rated to 12 psi, but if you still have it try swapping it back in and at least eliminate the TCV from the issue.

Neil.

[bmdubya1198]

The Porsche TCV is sold by ARD and several other parts suppliers. I got mine on eBay, but it’s a genuine Pierburg part. http://www.ardideas.com/Turbo-Control-V ... _2180.html

I’ll try swapping back the original though and see what happens. I did that already, but it was before replacing the purge valve.

[wizechatmgr]

I have the Pierburg part working on my 99. So far ~2 years on it.

[bmdubya1198]

I have the Pierburg part working on my 99. So far ~2 years on it.

Yeah, my cousin has the same one on his '99 T5. He's had it for at least a year.

[Sommerfeldt]

Hang on a sec. if your TCV is going to 100% duty cycle, it’s reducing boost, not building it, right? IIRC, the lower the number in the tables, the more danger...

Also, the stock Volvo TCV can’t be rated at 12 PSI. The T5R and R 850s run 14 psi, and the iPD tune for a 2000 R will jack it to 20.

- S

[bmdubya1198]

Hang on a sec. if your TCV is going to 100% duty cycle, it’s reducing boost, not building it, right? IIRC, the lower the number in the tables, the more danger...

Also, the stock Volvo TCV can’t be rated at 12 PSI. The T5R and R 850s run 14 psi, and the iPD tune for a 2000 R will jack it to 20.

- S

I’m not sure, someone on Swedespeed told me that it should be going to 100%. Anything less and the ECU may be dialing back boost.

That’s what I was thinking as well, I don’t have an exact boost number for my Hilton tune, but stock boost on a 2000 R should be at least 14 PSI. I haven’t actually found any info saying what stock boost is on this car unfortunately.

[Sommerfeldt]

The 2000 V70R should run 12 psi from factory, with 257 HP. With a tune of any kind, I'd expect you should see a higher number, so your estimation of about double your current 8 isn't far off, I guess.

Thinking about it, someone on Swedespeed is likely right - higher percentage is closing it, which means you should be starting out at 100% (99.6), then it should reduce and then ramp back up to 99.6 as load request increases and you reach WOT. Sorry about that - I was confused.

So if you reach 99.6, then that initially narrows it down to the TCV. Swap in the stock unit if you know it's good, and see what happens. It should have no problem handling the pressures.

- S

[bmdubya1198]

The 2000 V70R should run 12 psi from factory, with 257 HP. With a tune of any kind, I'd expect you should see a higher number, so your estimation of about double your current 8 isn't far off, I guess.

Thinking about it, someone on Swedespeed is likely right - higher percentage is closing it, which means you should be starting out at 100% (99.6), then it should reduce and then ramp back up to 99.6 as load request increases and you reach WOT. Sorry about that - I was confused.

So if you reach 99.6, then that initially narrows it down to the TCV. Swap in the stock unit if you know it's good, and see what happens. It should have no problem handling the pressures.

- S

Yeah, I did a quick search after my last post about the duty cycle.

I’m going to swap back the stock TCV tomorrow just to see what happens. Before that I’ll need to fix my shifter... I think I broke the white plastic piece around the bottom while removing the shift knob.
The good news is that I actually got the knob out. Now I’ll finally have a V70 shift boot instead of the 850 boot that didn’t fit.

[ndphotonl]

The Porsche TCV is sold by ARD and several other parts suppliers. I got mine on eBay, but it’s a genuine Pierburg part. http://www.ardideas.com/Turbo-Control-V ... _2180.html

I’ll try swapping back the original though and see what happens. I did that already, but it was before replacing the purge valve.

Do you have the OEM part number for this?