2000 V70XC Poor MPG and hard start- Fuel pressure?

Post by **Kara503** » 29 Jan 2018, 12:49

Currently troubleshooting a few issues on my newest find, a 2000 V70XC. Picked it up for a $900 with only 130k miles, with a recently rebuilt Angle gear and turbo. Was puking oil- found the intake front cam seal was completely missing! Good times.

Anyway- It stumbles on start and gets a paltry 17 MPG. Fuel delivery is next on my list of possibilities. Priming the system several times before starting helps, but doesn't completely eliminate the hard/ stumble start. No CEL. At the valve on the rail, here is what I am getting-

On prime- Immediate 50 or 60 PSI. Priming several times brings it up to 60.
Running- rapidly jumps through range of 40-60, occasionally holds steady at 55-60, then returns to erratic pressures that fluctuate so fast there is no single reading, just a range.
On shutdown, pressure steadily drops to 40 PSI over the course of 10-15 minutes. After that, it goes down very slowly- haven't let it sit more than 30 minutes, and in that time it only went down another 2 PSI.

My guess is I have a fuel pump that is starting to go out. I'm in the process of replacing the fuel filter to see if that helps. Next I will be checking the regulator and check valve before...... choosing between cutting the floor of my car or dropping the whole rear to access the pump.

Any suggestions? Am I jumping too far ahead? Thanks!

wlkstout · Post by **wlkstout** » 29 Jan 2018, 13:27

I would check the pressure regulator before cutting a hole. Not sure where yours is but on my 98 v70na it is at the fuel filter area just in front of the fuel tank. It has a diaphragm and is vacuum controlled. It could have failed or have a vacuum leak. With the erratic values maybe a possibility.

Post by **RickHaleParker** » 29 Jan 2018, 14:09

Take a lot of the guesswork out, get Vida 2014D + DiCE. It will pay for itself in time saved alone.

Post by **Kara503** » 29 Jan 2018, 14:47

Good idea wlk. Rick- What kind of setup do you have/ where did you get it? I have done some looking at VIDA/DICE but am unsure what to buy.

Post by **oragex** » 29 Jan 2018, 15:19

That fuel pressure is pretty spot on for a turbo

Low mpg can be quite a long list of things. Even just a clogged PCV (thin k blown cam seal) can bring it down. I'd rather take the time and test everything before replacing parts, or at least replace with used parts so it doesn't get too expensive.

Post by **misha** » 29 Jan 2018, 16:10

How do you drive the car for that long to calculate mpg without front cam seal???

Post by **Kara503** » 29 Jan 2018, 16:53

I bought the car 2 months ago. Drove it to my house in that condition, and the parked it until I had time to replace the PCV system, clean the throttle body, replace all of the cam seals, and replaced the timing belt.

oragex- I've already replaced the plugs, tried a known good set of coils, and done an upper intake seafoam treatment as well as a few injector cleaners into the tank. I checked the timing after I did the belt, and checked it about 2 weeks ago and all the marks line up too so it isn't that. I feel I did a pretty thorough job on the PCV too- Cleaned all the block passages and replaced all of the piping. I'm unsure where to turn if it is not fuel related, but then again I have only been trying honestly to fix cars for about 6 months now

Post by **oragex** » 29 Jan 2018, 17:24

Removing and sending the injectors for an ultrasonic bath cleaning is a good idea at high miles - Ebay or even nearby shops who deal with truck diesel engines which need injector cleaning on a regular basis.

Other areas would be the fuel filter, thermostat stuck wide open, non binding brakes, no vacuum leaks, good engine sensors, not too old front O2 sensor, not clogged catalytic converter, no loss of compression, etc. On top of what others have already mentioned above.