Re: Fuel Consumption

pol · Post by **pol** » Sat Apr 19, 2003 3:21 pm

I know the fuel consumption is never going to be good on a 1.7 turbo, but i'm sure it has got worse on my car..??? My car had a FSE powerboost valve fitted, which i dont really know how to set up properly other than just guessing when it feels better. Picked up a second hand standard pressure regulator today and the computer still shows a pretty poor reading, when i wasn't driving particulary hard today, with an average of maybe 17mpg... What is a good figure for these cars and is there anything i can do / check to make this better as i seem to be forever putting fuel in it! Its recently had new spark plugs (bosch super 4's) an oil change and i keep the air filter clean... What else is there???? Paul

volvofox · Post by **volvofox** » Sat Apr 19, 2003 5:42 pm

Hi, Yes, when you start altering the car this can happen....., but maybe some thing else. I am not a star in engine/ecu technology, this might be the case But is it realy this much ? Did you calculate the fuel usage your selves ?(check the driven milage at the pump and note the gallons there) Do this first. If the infocenter lies to you about the usage, fool it to make it believe the fueltank contens is bigger (of less) This can be done by turning the car totally off. Then push the right hand knob beneath the infocenterturnswitch, keep it in and than ignition on. The contens can then be seen and adjusted. This might not be your solution, but its always good to "calculate" the tank, and usage gauge. Luck JPF

David Thornber · Post by **David Thornber** » Sun Apr 20, 2003 9:06 am

Mine shows 26mpg on the computer, used normally (with a heavy right foot), and calculating the fuel used shows within 1mpg of the computer reading. It's a standard turbo with a bleed valve fitted between the turbo and wastegate. Consumption shows about 35mpg during motorway cruising.

pol · Post by **pol** » Sun Apr 20, 2003 12:33 pm

I have a bleed valve also... Out of interest, how high have you set your boost?? Do you know of a safe place to leave it.. I have mine turned off at the moment until i get a few things worked out. Dont want to break anything... whats the worst harm i can do by using a bleed valve?? Anyone ever killed their car with too much boost on a pretty standard engine.?? I would be happy with 26mpg, that seems about right to me or even 20... averages of 11mpg arent nice too see and i'm sure i'm not always that bad a driver! So volvofox, do you mean adjusting the variable resistor on the info centre control knob for the petrol tank contents? I think mine is out but on the rare occasions when i fill up completely, i forget to adjust and even then, i'm not too sure how to set it accurately. Paul

dan · Post by **dan** » Sun Apr 20, 2003 7:28 pm

I lost about 5+mpg due to a worn distributor. (God knows how much unburnt fuel l must have chucked down the exhaust, good job l had the forsight to remove my CAT)

pol · Post by **pol** » Mon Apr 21, 2003 9:23 am

Hmmm... I'll look into that... that might make sense... think my distributor cap was a bit messy... worth a try. Thanks.

volvofox · Post by **volvofox** » Mon Apr 21, 2003 12:06 pm

Hi, I think you have to set it to the real contens of the tank. There are several tanks. Luck, JPF

David Thornber · Post by **David Thornber** » Tue Apr 22, 2003 7:05 pm

I have it set so the maximum pressure shown on the gauge is just a fraction between the top of the yellow section of the gauge. If I set it higher the engine starts misfiring, which I assume is the overboost protection cutting the ignition circuit.

dan · Post by **dan** » Tue Apr 22, 2003 8:14 pm

I'm not so sure. I think the overboost protection is well into the red. When l had my distributor problem, it would misfire under load (i.e. coming on boost) when l turned the boost down it was less obvious (less load). I replaced the dizzycap and rotor arm, and now run boost that spikes nearly to the end of the gauge without ANY misfire. It holds red region boost no problem.

CHESH740R · Post by **CHESH740R** » Wed Apr 23, 2003 3:47 am

R U guys missifiring or getting something that sounds like pinking on the engine simular sort of think. Because if you turn up the boost to much with one of those bleed valve gadgets you can end up sending to much air in and not enough fuel and ending up with the fabulous and very expensive detonation. Which basically destroys pistons and basically totals the entire engine. Best thing to do safety sake is plumb in an Air Fuel guage and if it the readings start to lean off on full boost then restrict your boost until at a safe level. Otherwise go down the route of getting more fuel into the mixture by either bigger injectors and the like

dan · Post by **dan** » Wed Apr 23, 2003 5:47 am

CHESH740R, Please read the fuel boosting thread in the tuning section. Personally I'm more than aware of the risks, and make frequent power runs with wide band oxygen sensor to avoid such situations. In any case, l think the overboost cut out would come in way before the fuelling map would lean-out as there wouldn't be much point to it otherwise! Cheers, dan

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