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

lancelyons · Post by **lancelyons** » 28 Mar 2022, 19:31

Hi, lately my daughters xc90 has occasionally had times where it starts and then dies but other times it runs with no problems. The engine code was p089.

Recently in past 6 months she has smelled gas in her garage coming somewhere from her car but I have looked for this an couldn’t find anything.

does this sound like fuel pump starting to go out? Any suggestions?

Post by **ggleavitt** » 28 Mar 2022, 21:51

Could you indicate the motor? This model year could be 3.2 I6 FWD/AWD or 4.4 V8 AWD (assuming you're North America), might make a difference in the answer.

In the meantime, have you ever changed the fuel filter ? Always an easy enough answer to start with..

Thanks

chitownV · Post by **chitownV** » 29 Mar 2022, 00:29

If you couldn't find a fuel leak underneath the vehicle, it might not be the fuel filter leaking, which is located and accessed under the rear passenger side.

If you smell it inside the cabin, it could be the fuel pump and/or its connections. The connections can break, the seal on the locking ring can leak, etc. Unfortunately, the only way to get a good look is to remove the rear seat and remove the cover to the fuel pump.

Here is a video where you can see what is involved to get to the fuel pump and when the person finally does get to the pump, you can see the fuel sitting on top.

lancelyons · Post by **lancelyons** » 03 Apr 2022, 16:15

Hi, I have been out of town until yesterday and had no time to look at this. The gas smell is always smelled outside. She says only after filling up so maybe its a false alarm.

I have seem engine codes P0172, P0175 and P087

Again her issue was it would start and then immediately die. At the moment I have the car and I am not experiencing any problems other than the 172, 175.

what should I look into

lancelyons · Post by **lancelyons** » 04 Apr 2022, 07:02

It looks like I should be looking for air leaks, MAF issues, fuel pressure regulator, etc. So excess air in the system is causing the fuel to essentially be turned down as far as possible maybe putting this into a low low fuel pressure scenario where it wont start.

does that sound possible?

chitownV · Post by **chitownV** » 04 Apr 2022, 13:32

It sounds like her XC90 has two issues, but first, fix the fuel smell. That is not normal and that could potentially be more dangerous than a stranded vehicle. Again, she smells it after filling the tank up. That could be the fuel pump seal leaking, I say this because you couldn't see any fuel leaking underneath the vehicle, like if it was the filler neck.

Second, it could indeed be the fuel pressure sensor causing another issue. This is normal for age and mileage on all XC90s (1st gen). If it was never changed, it could be a good idea to change it at least preventatively. In someone else's XC90, I encountered the rich codes, but low fuel pressure readings before. It too had rough start-ups (especially when left overnight) and at random times, it would run rough. We changed the fuel pressure sensor to ensure it wasn't the cause and as preventative, but the codes persisted. It turned out to be sticking or leaking fuel injector(s). We ran Liqui Moly's Jectron in 1/2 a tank (label says good for between 7-20 gallons). Used up 1/4 a tank within a day of driving and the problem started to improve. To this day (already a few months later) the codes and problem have not returned.

Age, mileage, sitting gas, bad gas at a gas station, etc., can all contribute to sticking or clogged fuel injectors. I recommend to use a modern fuel injection cleaner instead of the old Seafoam. The newer fuel system cleaners are better suited for fuel injection with the ethanol gas we have today.

Trying a fuel system cleaner might be an easy thing to do for you or your daughter to see if it improves the issues. Worth a try since, for a low fuel pressure code, you will need to look into the fuel pressure sensor, then after that for the rich codes, as you said may need to look into air/vacuum leaks.

lancelyons · Post by **lancelyons** » 04 Apr 2022, 18:17

Thanks for the response. I will certainly look at throwing some fuel injector cleaner in the tank to get that going at a minimum today.

So I finally took it out for a drive after it started with no problem and ran several times over the past week. Ran up to Albertsons (5 miles) and was in the store for 15 min. When I came out the problem my daughter experienced showed up. It would start but would not stay running. At one point it did barely run for 5 seconds like it was starved of oxygen or fuel. I tried several more times to start over the next 10 min. I had a scanning tool so I cleared the codes 172, 175 and then turned the car off and let it sit for a minute and turned it back on. It actually started and ran and i drove it home.

Sounds like something computer related that might be triggered with heat. Still trying to formulate my plan

I dont smell any gas currently. My daughter seems to think its related to right after she filled the car up with gas.

chitownV · Post by **chitownV** » 04 Apr 2022, 18:32

You have the exact symptoms the XC90 I worked on was experiencing. We were worried it might be the fuel pump or fuel module/power train module related. Even trying to think outside the box if it was ignition coil related. We replaced the spark plugs with 30k miles on them so we could inspect the condition of the plugs. It showed that several of the plugs were dark from running rich.

A leaky fuel injector(s) will create a rich condition upon start-up (throwing rich code) making it difficult to start (extra fuel has to burn off) and since it is leaking, will reduce fuel pressure, especially at start-up. It will still run rich after. The computer will make adjustments and clearing the codes will reset those short-term adjustments for the running rich codes. The owner of the other XC90 cleared the codes continuously to get from point A to B.

After the fuel pressure sensor and spark plugs change, it was a cheap attempt to see if the fuel injectors were indeed an issue by dumping some fuel system cleaner in and see what happens. Lo and behold, it was the issue. Again, we decided to use the bottle of Jectron fuel system cleaner in 1/2 a tank so the detergent concentration was higher.

lancelyons · Post by **lancelyons** » 10 Apr 2022, 16:49

we just finished up running a half tank through the system with the jectron. We are still getting some different trouble codes.

currently we have p0087 fuel pressure low and p0191 Fuel pressure sensor. Early last weak it was p0172 and p0175.

Havent yet decided what I should look into next. The fuel pressure sensor was replaced about 2 years ago with a $30 inexpensive one. Seems like the car runs for the most part. there seems to be a few hiccups while driving where it seems like the car either misses or slighly hesitates while going 50-70mph.

chitownV · Post by **chitownV** » 10 Apr 2022, 19:58

That is progress. It could be multiple issues. The injectors could have been sticking. Not getting the too-rich condition codes is good. If you are getting 2 codes now with the fuel pressure sensor, and it was changed with a cheap one two years ago, try a quality Bosch part replacement. Again, mileage, age, or bad gas could affect both the injectors and fuel pressure sensor. However, you wouldn’t be the first to have a cheap fuel pressure sensor go bad prematurely.