code 00089 Fuel Pressure Regulator 1 Performance

Post by **oragex** » 11 Nov 2018, 10:38

Replace it with a cold engine, and release the pressure as mentioned. On a warm engine the pressure keep building up and you'll have a surprise when removing the sensor. Upon removing the sensor about 1oz of gasoline will leak (can be caught with a small tray) so better not do this inside a garage. Always smear the seal with Vaseline before inserting the new sensor on the rail

Post by **abscate** » 11 Nov 2018, 17:42

adrian22 wrote: 11 Nov 2018, 08:19 I never used a fuel pressure gauge before and not sure if there is a Volvo specific kit or any universal kit will work
Also please indicate where to hook up the gauge hose in order to take the measurements ?
I saw this kit on the ebay -do you think will work for my xc70 2005?

https://www.ebay.com/i/142437148601?chn=ps

That seems perfect

You can also rent them for free from major auto shops like Advance and Pep Boys

EngineeringBloke · Post by **EngineeringBloke** » 12 Nov 2018, 16:13

Regulator

You reported a "P0089 is Fuel Pressure Regulator 1 Performance, indicating a problem in the fuel pressure regulator system."

Your pressure gauge may show a normal reading and miss the actual issue you are having. I think you need a new fuel pressure regulator.

The fuel pressure is changed by the fuel pump acting in response to the fuel pressure sensor's readings. This is a feed back system that acts quickly, but not quick enough! There is also a device called a fuel pressure regulator (AKA damper) that prevents surges in pressure, that has not been mentioned in this thread yet.

"The opening and closing of fuel injectors creates pressure pulses in the fuel rail which can lead to unstable fuel pressure. In order to achieve a safe and consistent rail pressure, a fuel pulse damper (FPD) is often necessary. The FPD's internal diaphragm will absorb oscillating pulses and stabilize fuel pressure."

As an injector fires, it allows fuel to flow from the fuel rail through the injector. This briefly lowers the fuel pressure in the rail. When the flow stops, the pressure will briefly increase as new fuel enters the rail. The regulator/damper acts as a local reservoir to smooth these changes. If it is not working then the pressure may briefly higher or lower than commanded when an injector fires so the wrong amount of fuel is being provided. It may not be off by much but if it is, then it may affect injector operation.

The fluctuations may be too quick to be seen on a gauge but will still be picked up by the pressure sensor and seen by the ECM computer to indicate that damping is not working as expected. This would set the check engine light. The code you report refers to pressure regulation and does not refer to actual pressure levels, so I do not think the pressure sensor is the problem.

There are pictures of this unit on this site - this appears to be suitable for your '05 XC70.
https://www.fcpeuro.com/products/volvo- ... vo-9186278

2005 Volvo XC70 Fuel Pressure Regulator
Engine range: To 2815192

In this PCV work article, the fuel rail is removed and inverted. You can see the fuel injectors and a domed unit. That domed unit is the pressure regulator. It is in the 8th picture here:
viewtopic.php?f=1&t=55413

So perhaps your issue is with an aged regulator diaphragm and not with the sensor.

Post by **jimmy57** » 12 Nov 2018, 19:39

There is no FPR used for regular pressure control on the cars that will report P0089. Well, there is one but it is for a 6.25-6.5 Bar pressure as a backup if the electronic regulator system fails.
The fuel pressure sensor supplies the info to ECM of the rail pressure. ECM sends a control signal to an amplifier called the PEM (pump electric module) and in some cases called the FPCM (fuel pump control module) to control current to pump. The pump is run to whatever speed needed to keep pressure in the target range. Most models will have initial fuel pressure of 400kPa gauge and then settle to 300kPa gauge. The ECM will on occasion run pump to max current and let the FPR "vent". The wear particles of pump can get into it since it is past pump and in front of filter so they effectively clean it by running pump and letting it open to dump excess fuel. If the signaling to PEM is out of anticipated and allowed range then 0089 sets. The sensors fail and the fuel pressure is greater than sensor reports so the ECM signal goes high. Another failure is PEM terminal corrosion or internal circuit failure so the current is low and again the ECM has to over signal. If the fuel pump is faulty, or filter plugged , or the fuel pressure reg has something in it making it leak, any of these can cause the issue. Any poor grounds or corroded connections in the system anywhere could cause it also as those also would make the ECM ramp up signal to try to get pressure to desired value.

adrian22 · Post by **adrian22** » 13 Nov 2018, 09:44

I really appreciate all your posts trying to solve the P0089 code problem
Again car running ok with no symptoms-so I assume it is an electronic minor issue not a real pressure problem--I ordered a fuel pressure gauge to measure it-will post results soon
There is no leak in the system since after a week of car being parked in the driveway the rail pressure is still high
Please confirm if this car xc70 -2005 do NOT have a pressure regulator at the rail as the older 850 model has and instead it is located as a separate unit next to fuel filter or is part of the pump ensemble and in order to replace it I have to change the pump unit

Post by **jimmy57** » 13 Nov 2018, 10:02

If you have that code then you HAVE to have the system with fuel pump speed control for pressure regulation. The pressure reg being on fuel rail ended in 97-98. There were FWD turbo models in 97 and 98 that had FPR in fuel pipe behind engine at firewall. Then the FPR was on the cap for fuel pump assembly. The next change was the electronic fuel pump speed control to regulate fuel pressure. There is no sensor for fuel pressure to report low pressure.

Often the 0089 code has no noticeable symptoms, it is just the ECM noting that the signal needed to PEM to get pressure in target is too high. If you clear the code how long before it returns?

adrian22 · Post by **adrian22** » 13 Nov 2018, 10:31

after the code is cleared it will return always at the second trip or second time I start the car after about 1 min
I replaced the pressure sensor at the end of rail but made no difference-mechanic said to ignore the code....not sure this will not destroy the pump after sone time

Post by **abscate** » 13 Nov 2018, 20:32

Take out the PEM and clean it. Good thread on it in this forum, search by part number

adrian22 · Post by **adrian22** » 14 Nov 2018, 09:13

2005 XC70-AWD--- VIN YV1SZ592051176610 Can anyone tell me where the PEM module on a 2005 XC70 is located, and from where to access it-what is involved in removing it. I've heard different stories..under the car or inside rear passenger seat..it's near the fuel tank, next to fuel filter or you have to lower the gas tank to get at it, under the right rear wheel liner, on top of the fuel tank, under the back seat?

adrian22 · Post by **adrian22** » 14 Nov 2018, 13:34

ok I located the PEM -it is next to fuel filter and easy accessible
I unplugged the connector but is clean -no corrosion
Also replaced 2nd time Fuel pressure sensor at the rail just to make sure it was not defective.
I measured the fuel pressure at the rail and got 20? steady /consistent pressure no matter if I accelerate or not
--same pressure measured at the fuel filter valve under the car--- please see picture not sure what that # means
I know the pressure should be around 58 not sure the units,,,please explain if the pressure is so low why the car runs ok with no issues except Check engine light with code 0089