2008 xc90 starts but then dies. Runs most of the time

[lancelyons]

so it seems like the car has settled in on P0087 Low Fuel Pressure and P0172. It recently shutdown while driving when she accelerated. She is Getting impatient with dad trying to find the exact cause so looking like im taking it to the shop today.

[chitownV]

Did you change the fuel pressure sensor for a new Bosch one? Also, going back to the fuel pump and if it’s leaking, could be another source (the fuel smell). The fuel pump works off of a duty cycle to maintain pressure, but leaking fuel could also reduce pressure. When the car needs more volume and/or pressure, like accelerating, there might not be enough to supply the engine.

Maybe it is too much for dad to tackle especially with removing the back seat to check the pump, but do tell the shop what you have found and possible fuel pump related due to the fuel smell. At least the rich running codes are gone.

[FREEBUSINESSES]

Just for your interest if you have a Volvo xc90 which runs and randomly dies off and on. I went crazy with this issue for months and no one could figure it out after going through all the usual issues.

It was throwing the fuel pressure code, but not instantly, only after about 20 miles and engine would die. So I changed fuel pressure sensor, same problem. I changed filter, same problem, but I did notice black graphite like sludge in filter, so I thought for sure that was problem, but it wasn't. So in the end I changed fuel pump, same exact issue. But I did notice again a graphite like sludge on take up screen. Same problem, so I came to conclusion the tank was contaminated with this graphite like sludge in tank, and what was strange is this is a plastic tank. I tried to clean out tank from fuel pump as it was a real hassle to drop tank and replace or flush it out.

In the end, I got an instant read out live OBD app which showed how the fuel pressure would slowly drop from 40lbs. to about 15lbs. over the 20 mile range. It was consistent to the mile, crazy. So here was my conclusion, the fuel pump mesh filter was clogging up over the 20 miles, and as you may know, this sits at bottom of tank. Given it was a plastic tank, I was thinking about putting a heavy duty magnet to pick up the metal sludge, but it was useless on a plastic tank. But there are fuel tank straps, and one ran directly under fuel pump area. So the magnet stuck great, and low and behold, my problem went away. I drove for years after with no issues of dropping fuel pressure.

Wanting to figure out why and how this sludge of metal particles got into my tank, I figured it had to be from a gas station I frequented. Turns out many gas stations remove the pump filters to save costs as they are quite expensive. I had a friend who tipped me off on this money saving scam by many stations. If you look at the fuel pump hose at most gas stations, you will see a filter on the gas hose. Most gas station tanks are metal, and that is where the rust comes from and as a station empties the tank, it pulls up this sludge which is then pumped into customers tanks with no knowledge. As I thought back just before this problem came up, I can relate to it happening after I got a full tank of gas and even thought it was a water issue, also common. I used DEET to remove water in the past, so if water was in these tanks, so too was rust as the water sinks to the bottom of tanks.

Bottom line, if you are having these strange engine dying issues on a regular basis after 20 miles or so and have changed everything wasting money like I did, then consider this as the issue. Never mind those who rely on mechanics who will charge you hundreds with no answer, go buy a heavy-duty magnet at Harbor Freight or online and stick it to the fuel tank strap that runs directly under your fuel pump location on passenger side of tank. It is impossible to know what rust and sludge you may have in your tank and this is why gas stations have filters as this is common problem to have rust at bottom of their tanks. Saving money drives them to not install new filters, so BEWARE, hope this helps a few people with same symptoms.

[volvolugnut]

FREEBUS,
This is an excellent suggestion and a very logical problem diagnosis.
volvolugnut

[lilduke]

Hello FREEBUSINESSES,

Do you have the link to the magnets so I can purchase them? Also, do you have a picture showing where the magnets were placed?

[BoomerFT]

Bottom line, if you are having these strange engine dying issues on a regular basis after 20 miles or so and have changed everything wasting money like I did, then consider this as the issue. Never mind those who rely on mechanics who will charge you hundreds with no answer, go buy a heavy-duty magnet at Harbor Freight or online and stick it to the fuel tank strap that runs directly under your fuel pump location on passenger side of tank. It is impossible to know what rust and sludge you may have in your tank and this is why gas stations have filters as this is common problem to have rust at bottom of their tanks. Saving money drives them to not install new filters, so BEWARE, hope this helps a few people with same symptoms.

Please provide the part name and elaborate on the location underneath for placing the magnet. I suspected water in the gas.