Guest Guest_Chris_* Posted November 20, 2008 Report Share Posted November 20, 2008 Gas mileage significantly reduced following a number of engine tunes (see list below). I used to get 22mpg. Now getting 18mpg. Also may be running hot (see heater core change below). Hoping I can get some ideas on root cause and fixes...’99 XC70, 95K miles, Denver, CO (Purchased new in CT)Recent changes:• Air filter (drop in K&N)• VVT Solenoid – Had a CEL with a P1332 code, which is for the solenoid. Removed solenoid, and tested it to be bad (powered the terminals and it clicked but didn’t slide). Purchased new one and installed. Slightly different design, but same mounting footprint. Was told by Volvo it was the replacement for the original part. Have not had CEL since....Any chance I didn’t do the VVT solenoid replace correctly ( e.g. I reversed wiring) and it's not working, so I'm stuck in one of the two valve timing cycles and not benefiting from VVT? Any way this can happen without triggering a CEL?• Replaced heater core (was leaking into passenger compartment) I may be imagining this, but it seems to be running hotter since then. The temp needle is now exactly horizontal, @ 3 o'clock, when at operating temp and I had thought previously it normally ran more like at 4 o'clock...like is said, i could be imagining this, but thought I'd mention• Oil change (Valvoline high mileage synthetic blend)• New cabin air filter (aftermarket carbon impregnated) Link to comment Share on other sites More sharing options...
Dan A Posted November 21, 2008 Report Share Posted November 21, 2008 I'm thinking it's your cabin air filter. Always go OEM. Call Jamie or Don at Waltrip Volvo for a good price. The charcoal in the aftermarket filters is of known lesser quality and efficiency, which increases your overall drag coefficient.Just bullshitting you.I would think it would be more along the lines of basic maintenance items needing replacement like plugs, vacuum lines, or a number of things. Look at the stage 0 list pinned in the Performance forum and make sure you are at a good starting point. Link to comment Share on other sites More sharing options...
ozzimark Posted November 21, 2008 Report Share Posted November 21, 2008 • Replaced heater core (was leaking into passenger compartment) I may be imagining this, but it seems to be running hotter since then. The temp needle is now exactly horizontal, @ 3 o'clock, when at operating temp and I had thought previously it normally ran more like at 4 o'clock...like is said, i could be imagining this, but thought I'd mentionthat's pretty concerning. 4 o'clock is too hot, it should really never move away from the 3 o'clock position, because the ECU compensates for temp fluctuation and puts the needle there for a wide range of temps. perhaps take a look into the condition of your thermostat and egine coolant temp sensor?n Link to comment Share on other sites More sharing options...
Chilled man Posted November 21, 2008 Report Share Posted November 21, 2008 that's pretty concerning. 4 o'clock is too hot, it should really never move away from the 3 o'clock position, because the ECU compensates for temp fluctuation and puts the needle there for a wide range of temps. perhaps take a look into the condition of your thermostat and egine coolant temp sensor?nI agree 100% if the car is running hotter it will burn more fuel its amazing the stupid little things that will throw the car offI had a brake position sensor go bad in my old 2000 NA V70 wich cause the gas milage to drop to 15mpg Link to comment Share on other sites More sharing options...
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