MPG Not too good

[Josh Waddi 0]

Hi

 

as you can tell from my recent posts, ive recently purchsed a 18. 16v with a whole cluster of problems.

 

the next one is the MPG, i travell approx 40 miles per day in the C and get approximatly 20mpg and if the road is clear i can sometimes can get 25-28 MPG, from what i have read on the parkers guide i should be getting a lot more.

 

any ideas on how to solve this issue?

 

The other enquiry was can this be re-mapped? or superchipped?

[The_Dude 0]

Have you got access to VAG-COM? Might be the best thing for you to do as poor mpg can be caused by loadsa stuff! (in my case it was a duff lambda probe)

[Josh Waddi 0]

Cheers for that,

 

im new to this so i dont know what VAG-COM is??? Also i was having issues with the damn thing starting when its cold, someone mentioned this Lambda probe, is it an expensive thing to change?

[davidwort 0]

vag com isn't of any use on a 1.8 KR, and there's no lambda etc.

The main things that affect fuel economy on the 1.8 are poor spray pattern from the injectors and the cold weather!

The warm up control tends to run them very rich until warmed up.

Check all the basic stuff like plugs leads, rotor arm, dizzy cap, air filter etc and then get the Idle CO checked, should be around 0.5-1.5% some run a little better set to 2%

Check the base timing is correct: 6deg BTDC +/- 1 deg

Check engine timing, i.e. make sure the timing marks all ine up, so the belt hasn't jumped a tooth or something.

Then as long as you haven't got wheel alignment out or a binding caliper or something, next job is to get al lthe fuel system pressures checked and finally get it rolling road tuned.

 

Few things to be going on there with. :)

[The_Dude 0]

oops, didn't see he had a valver. ignore me, listen to david! really must stop writing quick answers at work without thinkag and reading properly first :lol:

[Josh Waddi 0]

Cheers Dave, this will keep me busy for a while, ive done sparks, leads upto now which has helped slightly, think the next step is the dizzy and rotor arm. Just has a new timing belt which helped again, i was getting 10 - 15 MPG to start with, which was nightmare going to work costing £10 per day.

[craigowl 0]

Yes, get this fixed Josh Waddi and you will get much better consumption.

I just checked our VR6 today after filling up and it is 28 mpg. Even this is poor for the VR6. In warmer conditions and longer runs you can get 30-34mpg or even more.

 

Dont put up with 28mpg at best from your valver.

Good luck in sorting it.

[VR6 0]

Moving to Engine Bay ...... not all threads belong in drivetrain ;)

[Josh Waddi 0]

Hi Guys

 

ive done the sparks,leads, dizzy cap, rotor arm. i have checked the timing and it was out by a tooth or 2 but has been corrected now and also the idle has been changed so is doing better, i got upto 31.7mpg this morning, thats about 10mpg more than usual.

 

Next step is for the fuel system pressue, how can i check this?

[The_Dude 0]

Do you sit in traffic a lot? As your mpg will go down - no miles travelled but still burning fuel.

[Josh Waddi 0]

yeah, it takes me 45 mins to get to work and a good 30-35 mins sat in traffic, it possibly did better due to the lack of traffic this morning.

[davidwort 0]

Hi Guys

 

ive done the sparks,leads, dizzy cap, rotor arm. i have checked the timing and it was out by a tooth or 2 but has been corrected now and also the idle has been changed so is doing better, i got upto 31.7mpg this morning, thats about 10mpg more than usual.

 

Next step is for the fuel system pressue, how can i check this?

 

wish I had a quid for every valver I've come across with the belt out a tooth, they don't jump, it's just poor checking when the belts are changed usually.

 

I think you need to do a tank to tank fill and work out the MPG yourself, the 1.8's MFA is not the most accurate of things.

 

If you find you are getting close to 30mpg in the winter, average, with a variety of driving then that's not at all bad.

 

A haynes manual (for Passat or mk2 golf) describes how to check the injector spray pattern, but to check the fuel pressures requires a fuel pressure gauge and the right adapters for the K-jet system, kit which is very expensive generally.

Far better to take it to a Bosch injection specialist or somewhere like Stealth who have the kit and know how to test and set it up.