Fuel Economy Ranges

[Space Panda]

I am an Insight owner of just a couple of months and like all Insight drivers I have become obsessive with my MPG.

I'm chuffed that I can easily manage an average of 78mpg (65 US mpg) on a +50 mile motorway or dual carriage way journey and impressed that I normally get 64mpg (54 US mpg) around (a very hilly) town.

After recently refuelling and resetting trip a last week I was returning 51mpg (43 US mpg) however well I drove it. Even when cruising downhill in 5th the display was showing just 75mpg. Strangely, after racing an Audi A4 off the lights yesterday the car seems to be performing better than ever and I can see my average mpg rising again.

Simple question; what factors could effect the fuel economy that can be solved by some hard, foot to the floor acceleration? I have only recently (within the last 1000 miles) had the car serviced, although I'm wondering if it's a filter or intake problem.

Please keep any suggestions straight forward as I am a little simple when it comes to auto mechanics

[retepsnikrep]

I do my own servicing for a number of reasons now, one being when I took my car to have it serviced by a Honda dealer the mechanics insisted on tightening the back brakes so they dragged, but not enough to get hot. I even warned them about this before they started

The Insight when cruising needs very little power to maintain speed on the flat, so engine power is very low, especially if you are in hyper mpg lean burn mode. If the rear brakes are dragging in the slightest it will affect mpg. I noticed it as soon as I left the garage

How far does the hand brake lever come up now? Is it tighter since the service? If it is, I suggest get them to ease off the rear brakes a few clicks, looser is better IMHO. Unfortunately the wheels and drums have to come off to ease the rear brakes.

Obviously the handbrake still needs to work, but the wheels must rotate freely with the handbrake off without the slightest hint of brake binding.

Could be something else though

Peter

[Insightful Trekker]

Good idea Peter
(and I'll not tighten mine so snugly in the future)

But with such a steep decline I'd suspect it couldn't be "overtightened" rear shoes alone.

The more common errors of deflating the tires with a possible addition of 10W-30 vs. 0W-20 engine oil could also be part of the equation.

Still dosen't explain why it wasn't "found" immediately after the service visit though. I suspect something else is afoot.

HTH!

[retepsnikrep]

Originally Posted by Insightful Trekker

The more common errors of deflating the tires with a possible addition of 10W-30 vs. 0W-20 engine oil could also be part of the equation.

I agree could easily be these, I run my oem tyres at 50psi, hard but very good for mpg

[Space Panda]

Thanks for your responses.

My tires are always slightly over inflated (thats what the dealer says anyway).

I've looked at the rear brakes and that doesn't seem to the problem, but will be sure to look for that in future.

Normally when I drive at around 40mph on the flat and switch to neutral the mpg goes completely off the scale - over 150mpg. When it was under performing, even in neutral at 40mph it was sticking at around 100mpg. It wasn't revving any higher than normal and didn't appear to be performing any less.

I think it's just that every now and again the Insight likes to beat an Audi off the lights to boost iit's ego a little!

Thanks again!