P80 late Return lacking fuel system RLFS 9470755 8627005 - fitment for 98 99 00 cars

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It’s looks like they used numbers for the 850 then went to letters for the v70 in the North American market

The Volvo for chart picks those up but are amibiguous

I put in a -775 purge into Shagg. 22 ohm . It’s the Pierburg 04 suffix

I took a quick roll underneath to check the integrity of the canister hoses and found the little guy teeing off the evap line to the fuel pressure regulator was broken, so did a quick fix with silicone hose. 4.2 mm is the listed size

Volvo part 946958 for purists

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With my New fresh repair on my purge valve to FPR hose, EVAP and OXS monitors went ready in 30 miles. CAT monitor still not ready but I can inspect with two monitors Incomplete in NY

[FireFox31]

What symptoms showed you that the purge valve failed and/or that the vacuum line cracked? Did you have a DTC code? This is a part I haven't thought about and, knowing old Geronimo, it's probably failed.

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What symptoms showed you that the purge valve failed and/or that the vacuum line cracked? Did you have a DTC code? This is a part I haven't thought about and, knowing old Geronimo, it's probably failed.

P440 for purge valve fault would occasionally show, on about 6 month intervals, often pend with no light. Classic case of the code pointing to wrong component.

New found knowledge. If the evap monitor doesn’t set, the CAt and OXS monitors take a long time to set, like the 500 miles we see people report. Get the Evap to go, and things cascade to ready much quicker

I managed to get three cars inspected through emissions in on afternoon yesterday, thanks Munch auto in Stony Brook!

Kat, Evita, and Shagg


*********be careful pulling hose off thst nylon nipple. Do not break me… major pain to bond a T into the purge vac yum line

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Mystery solved!!

From a 2010 post, source unknown, but makes total sense.

My conjecture is with ME7 the dynamic range of the injection was sufficient to cover the turbo models, too

Well, you're right; that's the "three way unit with pressure regulator". I was looking at info for the turbo model. Sorry!

The Motronic 4.4 changes to the NA included a new "tailored return lacking fuel system". Here is the description:

Last year the Return Lacking Fuel System
(RLFS) was introduced on the B5254S with
Motronic 4.4. The fuel pressure regulator is
connected so that fuel pressure is retained at a
constant level (300 kPa (43.5 psi)) above the
pressure in the EVAP line to the fuel tank (≈
atmospheric pressure).

This gives an accurate enough control with
today's fast processors in the engine control
module (ECM) of a naturally aspirated engine.
On a turbocharged engine on the other hand
with larger pressure variations the intake
manifold, this does not provide enough
accuracy.

The advantage with not having a fuel return
line from the fuel rail is that the engine does
not heat the fuel, the temperature in the fuel
tank remains low and the amount of
evaporated fuel is reduced.

”Three way unit”
The fuel flow is controlled as before via a three
way unit which is integrated with the fuel
pressure regulator. The following are
connected to the three way unit:
The fuel line from the fuel tank.
The fuel line to the fuel rail.
The return line to the fuel tank.