My 18is is consuming way to much fuel...

Collapse
X
 
  • Time
  • Show
Clear All
new posts

  • 5Toes
    replied
    MTD pull off the intake boot and check it for cracks! once the intake boot is off the throttle body internals will be visible and DER E30's post will make alot more sense lol. I could try to explain it better but I think once you see it yourself you'll completely understand. but if your driving habits have not changed then this is certainly not the problem.

    My top 3 things to check would be:
    1. fuel pressure, get a gauge on there and observe what it does while underway. 43psi at idle and under wide open throttle it should bet closer to 50-53. If the pressure is too high that would cause the bad fuel economy

    2. coolant temp sensor. located under the intake manifold (usually blue in color). Get a digital multimeter and open the glovebox up. Pull off the ceiling panel and take the harness connector off the DME. You can find the pinout online at e30zone (http://www.e30zone.net/e30zonewiki/i...s#Motronic_1.7). test the resistance between pin 78 and 34 (ground). should be 1-3000 ohms stone cold and much lower after a good drive with the engine warmed up. If this sensor is broken the engine will run rich all the time because it thinks it is stone cold even when warmed up

    3. oxygen sensor. if your car has one its probably really old. if your fuel economy were down a couple mpgs it could be the o2 sensor but since its a considerable change your problem probably isnt from this. they arent too expensive to change and it would be a good idea to change it anyways.

    good luck!!

    2.

    Leave a comment:


  • MTD
    replied
    Originally posted by DER E30
    Maybe the Air flow meter? O2 sensor good start though. I'm not sure how to check it though.

    When you cruise do you use only the little throttle body or do you go fast enough to use the big one? If you feel the pedal there's a spot where it gets a tiny bit stiffer. I almost always sit on the max opening of the little one without cracking the bigger under cruise...

    I drive mine fairly hard when in the mood once its warm and I've never gotten less than 24mpg on a tank, I've gotten 32mpg on runs to school on the highway ~65-70mph with 4.10 rear so something is wrong with yours for sure. I'd say 27 average is normal for my driving habits
    I never noticed what you are talking about on the pedal. I'm gonna check it later tonight. Anyways, if i only press the pedal to a certain point, ill get better mpg?

    Leave a comment:


  • DER E30
    replied
    Maybe the Air flow meter? O2 sensor good start though. I'm not sure how to check it though.

    When you cruise do you use only the little throttle body or do you go fast enough to use the big one? If you feel the pedal there's a spot where it gets a tiny bit stiffer. I almost always sit on the max opening of the little one without cracking the bigger under cruise...

    I drive mine fairly hard when in the mood once its warm and I've never gotten less than 24mpg on a tank, I've gotten 32mpg on runs to school on the highway ~65-70mph with 4.10 rear so something is wrong with yours for sure. I'd say 27 average is normal for my driving habits

    Leave a comment:


  • MTD
    replied
    thank you guys, i will try to check that. 5Toes, what am i supposed to check on the o2 sensor if i find it?

    Any other tips?

    Leave a comment:


  • uturn
    replied
    Check all your fuel lines. Pull the rear seat and remove the fuel pump access cover to see if it's leaking there. The driver's side in front of the rear tire at the fuel filter. The two lines below the brake booster up to the fuel rail.

    Leave a comment:


  • 5Toes
    replied
    look at the exhaust piping for a plug coming off of it with some wires. its visible from the passenger side of the engine bay (if vehicle is LHD)

    Leave a comment:


  • MTD
    replied
    Originally posted by 5Toes
    only 1 or 2 aggressive starts? lol I cant say the same :)

    start with getting injectors rebuilt. does your car have a o2 sensor?
    How do i check that?

    Leave a comment:


  • 5Toes
    replied
    only 1 or 2 aggressive starts? lol I cant say the same :)

    start with getting injectors rebuilt. does your car have a o2 sensor?

    Leave a comment:


  • MTD
    started a topic My 18is is consuming way to much fuel...

    My 18is is consuming way to much fuel...

    Hey guys, my 18is is consuming way too much, I do not know what's going on ... Lately I will always get 11 l/100 (Or 21.5mpg for the US folks). For the type of driving I do, and the engine that it is, it's way too much. 70% of my driving is in the freeway, in 5th gear at 2200/2500rpm. little traffic. Shifting at 3000rpm. Etcetc. I may do 1 or 2 agressive starts each tank of fuel, but thats it.

    Given my type of driving, i should be getting much less fuel comsumption. I have no idea what it may be, since the car was revised and changed filters 1 month ago. Do you think?
Working...