2001 V70XC - sharp mpg drop... 14.8 last night

Post by **xHeart** » 18 Feb 2015, 07:54

There is sharp drop in mpg. Last night the average dropped to 14.8. It use to city average above 18.
It runs on 93 Octane.

Recently replaced both HO2s, MAF, Brake Pedal Sensor, vacuum cleaned airbox and filter.
Fuel filter was replaced a year ago.
Did I not install the fresh air hose from airbox to turbo correctly?
No CEL at this time.

draser · Post by **draser** » 18 Feb 2015, 17:13

Mine dropped to 20, I run 22 in summer. I attribute that to cold weather. You're kinda low, could you run a set of live data and post? Do you feel a change in car driveability?

Post by **xHeart** » 25 Feb 2015, 07:28

draser wrote:Mine dropped to 20, I run 22 in summer. I attribute that to cold weather. You're kinda low, could you run a set of live data and post? Do you feel a change in car driveability?

I can't feel the difference -- consistent drive since replacing ETM a year ago.
It averages 28-29mpg over a 300-900 miles trip.

I often fill up when it is at halfway mark, this time noticed the average was 14.3 mpg.
I will run live data this coming weekend.

Thank you.

Post by **abscate** » 25 Feb 2015, 09:24

Intercooler might have iced up and seriously messed with induction.

Post by **xHeart** » 25 Feb 2015, 10:19

abscate wrote:Intercooler might have iced up and seriously messed with induction.

Where is that notorious passage at intercooler that needs draining - rooting?

Post by **abscate** » 25 Feb 2015, 11:04

On my 1999 it is a weep hole at the bottom of the intercooler - I think you have to drop the panel to see it (?)

Post by **xHeart** » 07 Mar 2015, 12:54

...branching off from the ECM-4801 thread https://www.matthewsvolvosite.com/forums/viewtopic.php?f=9&t=66635

Connected gauge at schrader valve at fuel rail:
- turn the key to ON position, no reading
- started the engine, no reading at idle

Took a drive, warmed up engine
- reconnected fuel pressure gauge
- turn key to ignition ON position, no reading
- started the engine, no reading at idle

The fuel is visible in the pressure release tube, disconnecting at schrader valve discharges fuel.
Is this gauge bad?

The average mpg is now at 14.2.
2001 V70XC did not come with fuel pressure sensor.

Post by **kahl** » 07 Mar 2015, 15:26

I would say your intake manifold bearing need grease or you have a bad tester gauge yea bad gauge.

Post by **abscate** » 08 Mar 2015, 05:09

Probably not the right connector at the Schraeder, or not depressing the pin enough to allow pressure to gauge.

Post by **xHeart** » 08 Mar 2015, 06:40

So I decided to determine the health of gauge using our 97 850. There isn't enough space to screw on the gauge hose once the adapter is placed over the schrader valve.

So now, not sure about the gauge.
The gauge manual refers to procedures for Ford and GM cars. It also highlights removing vacuum hose at FPR to check the vitals.

I had removed the cover over the rail to locate FPR. After a 360º at FPR, I did not find a port or a vacuum hose.

I will return this gauge, and pick up one from a different outfit... start again.

V70XC runs normal but low mpg, two questions:
- what are symptoms of failed FPR?
- is there a vacuum hose for FPR, where?