FV-QR

That's a lot of good troubleshooting, but what does it "feel" like? Do you feel a lurch, like a misfire, then limp mode? If so, you might be getting boost spikes which throw the engine into limp mode. 1.3 bar doesn't sound like a huge spike, but maybe there's something else going on.

 

Re: FV-QR (Evos_R)

Thanx 4 the reply. No jerking nothing. I pull off in 1st, take it to just over 6000rpm and then 2nd. it will start to boost or boost 1.3 for a while then suddenly theres loss of power and when I look at the boost guage its at 0.5 bar. this happens in 2nd or 3rd gear.

isnt limp mode suppose to show orange or reg light in dash? I have bought a cheap ELM327 code scanner etc and its almost TOO clean (error wise). I pulled several sensors like MAF, boost pressure, cam posistion sensor (each at a time) too see if my scanner picks it up and it does, and MIL light comes on.

Previous owner is Volvo repair centre and is quite goog. He took the turbo apart when he had the car a year or two ago and noticed a crack on the wastegate seat. But then, why does it run 100% at highway speeds for long periods (5 hours drive the other day)?

 

Re: turbo boost drops on WOT fast pull away (dlourens)

Has your wastegate been adjusted? If yes was it done properly using a pump and gauge to ensure it starts opening at around 7.5 psi?

I had a similar problem with the car going into limp mode after installing an Autotech tune that was was being caused by the wastgate being set to start opening @ 10 PSI.

I adjusted the WG to start to open @ 7.5 psi and solved the problem

 

Re: turbo boost drops on WOT fast pull away (jstro)

interesting, so yours opened later and boosted more. Mine hsa been mapped to boost to 1.3 bar so that should be fine but I will have it checked out.

 

Re: turbo boost drops on WOT fast pull away (dlourens)

Your wastgate should start to open @ .52 bar (7.5 psi)

If you have a boost gauge you can just disconnect the electrical connection from the TCV which will will take you ECU out of the boost equation and your max boost will be limited to whatever you WG opens at

If it is above .52 bar I would adjust your WG to see if that fixes your problem.

1.3 bar = ~ 18.9 PSI which should not cause limp mode on a tuned car. BTW whose tune are you running?

 

Re: turbo boost drops on WOT fast pull away (jstro)

I did more or less the same. I connected my vacuum line from the turbo directly to the WG actuator. I had the boost guage also in that line to monitor.

I got .5 bar (its a needle type so can't see decimals). So its not the WG. the previous oak tunes it at some local guy. They ran octane boosters and stuff so it might be tuned for higher octane than what I am currently using? I still would like to know why doesn't it show any error codes, MIL light or anything? surely if the ECU corrects the boost it should show a problem?

Could they somehow with the new mapping overide the ECU to throw a MIL or similiar?

 

Woah, I thought our wastegates were 7psi springs ?!

If you have the vacuum line connected directly to the wastegate, you should NOT be seeing 1.3bar whether the ECU is remapped or not. You are bypassing the ECU at this point and should only be seeing wastegate pressure. With that much wastegate boost, someone could have adjusted the wastegate way out of range, or there is a mechanical problem.

 

Re: (phuz)

Thats exactly what I say, I dont get 1.3bar with turbo vacuum connected to WG. I only get .5 bar which means WG is operating fine.