850 Turbocharger Install Tips

You can get the CBV diaphragm from lots of places, but I would make sure it is made by Mitsubishi. I have seen posts recently about people getting new CBVs that leak immediately or soon. I have bought them on eBay in the past but it is getting tougher and tougher to buy there and not end up with junk.

1999 V70 T5 – Reflections On Servicing Turbo CBV

I’m in the middle of PCV service and replacing the last hoses on my 1999 before it goes to college.

Working behind the motor is tough and it’s tough to get your hands down into the area. Many operations require two hands …more to come.

Approaching the beast…turbo pipe, cooling hoses removed

Here is the winter of your disconnect….

Bolt number one, 10mm wrenches off easy..you are 1/3 done and sitting pretty.

Bolt number 2, at the bottom, you go underneath since your hand won’t fit from top. Note the shiny part of the turbo coolant return pipe. You guessed it…the bolt will not clear the pipe with it installed, so plan on replacing that hose for this job. From below, left hand to start the threads, it is tough moving cover to align but it must be done. Tension bolt number one so that the cover moves but stays in place.

How MAF Affects Idle, mpg and More

MVS Forums contributor and Volvo wizard jimmy57 explains how the mass airflow sensor affects the air/fuel ratio, idle, mpg and more and various Volvo models. On Bosch systems that is not really a MAP. It is used for boost pressure monitoring. The earlier extrapolation algorithm where MAF vs engine speed was used for boost level […]

What Makes a PTC Valve Work?

I always wondered what was inside the PTC valve and how it worked electrically, so I decided to take apart one of the ones I harvested from the junkyard a few months ago.

I removed the rubber bushing by prying it up and off. Then I used a hacksaw to slice down one side of the main PTC tube. While I was sawing the last bit of the side, when the blade dug into the bottom piece it popped off. The bottom piece is also copper and was soldered onto the copper tube.

S70 DIY Boost Gauge Install Complete Guide

MVS Volvo Forums Contributor mecheng crushes the ball out of the park with a guide on installing a boost gauge in an S70. This will be identical to V70 and XC70 Volvos, 1998-2000 model years, and very close to 850s. Here’s my 850 headliner boost gauge install. Remember, it’s always the pink wire. Ok, I […]

Vacuum Lines on Turbo 1993-2000 850/S70/V70/XC70

MVS Forums Contributor and enthusiast CN90 turns the volume up to maximum and cranks out a beautiful post about a particular Pre-2001 850/S70/V70/XC70 failure point: vacuum lines. [Looking for non-turbo vacuum line routing?] I just want to dedicate a thread strictly to photographing the vacuum lines in these aging Volvos. As the car gets older, […]

Vacuum Lines on Non-Turbo 1993-2000 850/S70/V70/XC70

MVS forums user Erik goes “full auto” and documents the vacuum lines on non-turbo Volvos in the P80 family: As a companion to a similar thread for turbo cars [vacuum line diagrams for turbo Volvo 850 and Gen. 1 S70/V70/C70/XC70], here is a thread dedicated to documenting the vacuum lines in the non-turbo (NA) 850 […]

1998 vs. 1999 Changes & Differences

Well, what are they? MVS Forums member (hey, it’s free, why not register?) j-dawg and the rest of the crew answer this important bit of Volvo trivia. This is actually one of the more interesting bits of P80 lore, to me. No idea why. 98- cars don’t have the electronic throttle, VVT, solid lifters, as […]

S90 Intermittent Hesitation At Low Rpms

MVS Forums member bloodrootfc asks, then answers, a question about diagnosing intermittent hesitation on his Volvo S90 sedan: After getting fed up with “try this” from 4 mechanics, I started doing my own diagnostics with a Torque app and scan tool, and calling the shots. My mechanic works faster than I do, and he does […]

Turbo S80 TCV & Vacuum Line Routing

The pressure from the outlet of the turbo presses on the wastegate diaphragm to keep it closed. When the ECU decides there is enough boost, it stops allowing the air from the turbo outlet from going to the wastegate actuator and allows it to go to the compressor inlet tube. The system is a pulse width modulated system meaning it is never “always on”, but instead cycled on for longer periods of time to increase boost, and shorter to decrease boost. When the TCV is off, air from the compressor is dumped to the compressor inlet, and the spring pressure in the wastegate is what regulates compressor outlet pressure.