Volvo S60 won't go past 45km/hr

S20 · Post by **S20** » 28 Jul 2024, 12:56

Hello everybody

I have a manual 2003 Volvo S60 which has always been reliable and in near perfect form. Three weeks ago I was driving on the highway when it started to do hiccups and speed gradually lowered to 45 km/hr (30 miles) It has stayed like this ever since.
The check engine light is on and a message is saying slow down and change to lower gear.

I press the pedal RPM goes up but the speed does not increase. I can drive as much as I want, but only at max 45 km/hr!

I took the car to the mechanics the first guy changed the mass air sensor and checked and cleaned spark plugs. Nothing changed.

I took it to another mechanic and after a lot of tests they said old fuel in the tank had gummed up and gave me an estimation of 2800 dollars to clean the tank and fuel lines and change the injectors and spark plugs.

I was travelling abroad and for 4 years the car was sitting, but I came back 1.5 years ago and the car drove without the slightest problem.

Another garage (Volvo garage) told me it can not be the fuel because although the car was sitting for 4 years, it has been driving with no problem for a year and half after that.

So I am quite puzzled. What could this be?

Thanks in advance

Post by **volvolugnut** » 28 Jul 2024, 13:47

I have revived several vehicles and engines after they have sat unused for several years. They can sometimes start OK initially and then choke on the old fuel. Old fuel (especially with ethanol blends) can evaporate and leave a sticky sludge. This sludge can get in the fuel pump, fuel filter, lines and injectors. There may be a full or partial blockage. I think a partial blockage is what you are experiencing.

The 18 month delay may be result of gunk in the tank breaking free from the walls and getting in the rest of the system.
The repair may include removing the tank and cleaning with solvents or a radiator shop boil out. Fuel pump and filter may not be possible to clean. Fuel lines can actually get blocked (It happened on Ford truck). They can be cleaned with a wire and solvents like carb cleaner.
Fuel injectors can get gunked and may be cleaned or replaced with remanufactured injectors.

Try a fuel filter change and see if there is improvement. Then check the fuel pressure and flow at the engine. Then check spray pattern from the injectors.
Can you do any repairs yourself? If not, try to find a general mechanic that will do this work at a reasonable cost.

volvolugnut

S20 · Post by **S20** » 28 Jul 2024, 16:10

Thanks for the reply. My car does not seem to have a fuel filter. I saw some youtube videos and bought a filter to change it myself. I went under the car and saw nothing where it should have been. I must have a steel tank with filter in it. Also, I have been to different mechanics. Each says a different thing. What tests do you suggest shoukd be done to determine exactly what the problem is>

Post by **volvolugnut** » 28 Jul 2024, 17:48

I suggested this:
Try a fuel filter change and see if there is improvement. Then check the fuel pressure and flow at the engine. Then check spray pattern from the injectors.
Can you do any repairs yourself? If not, try to find a general mechanic that will do this work at a reasonable cost.

I think many mechanics do not want to troubleshoot to determine a problem. It can be time consuming and they may not get paid for their time. They want an obvious problem and then just change known parts.
volvolugnut

S20 · Post by **S20** » 28 Jul 2024, 20:08

You are right about the mechanics. I was charged over 320 for changing the mass air sensor which did no good at all. Some intelligent testing and diagnostic work has to be done before spending 3000 dollars on cleaning the tank which might not even be the problem. The car looks great and drove just like a new car, but it is not worth 3k after 20 years. So question is should I try to fix it or look for another winter car? If i knew what tests to do and how to interpret the results I could decide on that. Which is my immediate problem.

Post by **jonesg** » 29 Jul 2024, 01:40

a pressure test done at the rail will tell you almost everything.
autozone will loan you their gauge if you leave a deposit.
Low pressure suggests the in tank filter, confirm by pulling the pump, run the tank low on fuel before going in.
If the filter is not clogged then the pump might just be worn.

Keep in mind before removing the pump,
Disconnect the battery or you'll get an SRS code you cannot clear without a decent scanner.
Do not connect the battery to test the pump with the rear seat out or same SRS code will set.
I suggest watching some youtube on how to access the fuel pump, its not as straightfwd as just removing the seat.

I believe the gunked up tank condemns the car because book time is 7 hours (using a lift and professional tools)and I don't know how the tank can be cleaned even when removed. If you change the filter it will soon foul again.
If you run without a filter the injectors will clog so you can't do that as your car lacks an inline secondary filter.

heres a case study, volvo with a dirty tank, its a 5 part video but the final conclusion video says it all and demonstrates what you are looking for. This is part 5. He already installed a new pump and it didn't go 10 miles. the owner cleaned the tank several times himself, the video does not say how or if it worked, you shouldf look at tank cleaning videos and decide.

Post by **cn90** » 29 Jul 2024, 06:55

Add a few bottles of Lubro Moly FI cleaner for one month and hopefully it frees up the the gummy stuff.

Post by **volvolugnut** » 29 Jul 2024, 14:12

That is an interesting video. The mechanic has a great attitude even when dealing with a difficult customer.
volvolugnut

Post by **volvolugnut** » 29 Jul 2024, 14:15

S20,
Start with a fuel pressure test at the engine fuel rail. Do you need instructions?
volvolugnut

S20 · Post by **S20** » 29 Jul 2024, 15:07

Thanks volvolugnut. If it need any tools or expensive equipment I wouldn't need any instructions since the mechanics who would be doing it probably knows how to do it (although one can never be sure these days). Please give a list of tests that has to be done and I will check them on youtube and other places to see if I can do them myself. I prefer to do the tests myself, but if it doesn't need expensive investments on things that would be used only once. At this point I have practically written off the car, which is a shame since it drove like a champ just an hour before the problem started.
CN90, I am in Canada and we can't get that product you suggest here. So probably I will use Seafoam fuel injector.
Thanks for the detailed answer jonesg.