Gas gobbler?

Mikkels · Post by **Mikkels** » Tue Feb 17, 2004 8:07 pm

Hi List

Now the 1.8 in my 1990 conversion runs quite well except...

Uses a lot of petrol 20 mpg is all I obtained running around town. It
is rich at cold start which is I guess to be expected as there is no air
bleed on the 1.8 plenum. When it is hot and I boot it there is no
excessive soot out the back that I can see however it does pop on the
over rum between the gears. I thought that meant lean? Don at Autoway
looked at the car before Xmas and found the o2 sensor was US. He
replaced that and put hotter plugs in because the others were black.
Definitely reduced the smoky start up considerably however developed the
pop on over run. Performance has remained good.

Now I'm in Auckland I need help finding help.

Any ideas?

Don
1990 1.8

Rex Johnston · Post by **Rex Johnston** » Tue Feb 17, 2004 8:38 pm

On Tue, 2004-02-17 at 20:07, mikkels wrote:

Uses a lot of petrol 20 mpg is all I obtained running around town. It

<SNIP>

Now I'm in Auckland I need help finding help.

First, get yourself a mixture meter. Jaycar sell them as kits for about $20.
Solder it together. Wire it up with a switch so that you can lift the signal
from the O2 sensor to the computer, but the meter remains hooked up to the O2
sensor all the time. Now you can force the car into open loop mode by flicking
a switch, and you can see what effect this has.

Cut open the silicone around the door on the top of the flap air flow meter.

Warm the car up. Adjust the spring in the AFM (clockwise richens, anticlockwise
leans) so that, in open loop, the car is just lean when driving around at the
lightest of throttles, but richens up when you plant boot.

Restore closed loop.

As good as you'll get without a dyno...

Cheers, Rex

SLYDIT · Post by **SLYDIT** » Wed Feb 18, 2004 5:47 pm

water temp sensor??
OR maybe you need to tighten the spring up on your
airflow meter to account for the increased airflow
that the 1800 pulls through the 1600 air flow meter.It
could be opening up too much and telling the ecu to
increase fuel, but as you have 1800 injectors
installed, it may be getting too rich???

Milford Autoelectrical · Post by **Milford Autoelectrical** » Wed Feb 18, 2004 6:35 pm

Whatever you do DONT play with things you know nothing about, you are asking for trouble. Peeling the cap off the air flow meter and fiddling with the spring is not the thing to do, unless you have got all the diagnostic equipment eg. for start a 5 gas analyser. It was factory set by Mazda in Japan (I thing they know a little more than you + I put together). You have a mixture problem probably caused by a faulty part, get it checked by someone in the know, there are a lot of things that can give you that symptom: Coolant temp sensor, air flow meter, air leak, ECU fault, bad wiring install, TPS not set up can give you your backfire between gear changes etc,etc

Steve Driscoll

Milford Auto Electrical

Rex Johnston · Post by **Rex Johnston** » Wed Feb 18, 2004 6:57 pm

On Wed, 2004-02-18 at 18:35, Milford Autoelectrical wrote:

Whatever you do DONT play with things you know nothing about, you are
asking for trouble. Peeling the cap off the air flow meter and
fiddling with the spring is not the thing to do, unless you have got
all the diagnostic equipment eg. for start a 5 gas analyser. It was
factory set by Mazda in Japan (I thing they know a little more than
you + I put together). You have a mixture problem probably caused by

Don't lump me into your presumptions please.

a faulty part, get it checked by someone in the know, there are a lot

Actually, it's more likely caused by replacing the B6 motor with a BP
and not swapping all the control electronics along with it.

I've done it with a mazda 323 turbo too, and fiddling with the air flow
meter was the ONLY way i could get the air fuel ratios right. It was
not difficult and i had a friend with a gas analyser confirm that it was
just fine.

Hell, one of the upgrades for the MX-5 is an RX-7 AFM. How do you
expect to make that work WITHOUT adjusting the spring.

of things that can give you that symptom: Coolant temp sensor, air
flow meter, air leak, ECU fault, bad wiring install, TPS not set up
can give you your backfire between gear changes etc,etc

Thanks for the lesson in paranoia.

Rex

GrubbyMX · Post by **GrubbyMX** » Wed Feb 18, 2004 8:41 pm

Is this going to become a "I am the most paranoid" contest?

Ralph

Edney · Post by **Edney** » Wed Feb 18, 2004 8:49 pm

Hey Ralph - that is a very disturbing prospect!

Colin Francis · Post by **Colin Francis** » Wed Feb 18, 2004 9:14 pm

On Wed, 18 Feb 2004 20:41:37 +1300, you wrote:

Is this going to become a "I am the most paranoid" contest?

Nope. it is going to become a "Why don't you get a decent Email program "
contest . Please set your quoted text parameter properly. LOL]

--
Col

Col's law
* Thinly sliced cabbage *

Rex Johnston · Post by **Rex Johnston** » Wed Feb 18, 2004 9:15 pm

You guys are talking about me!!!

Rex

On Wed, 2004-02-18 at 20:49, Edney wrote:
[...]

Simon Lord · Post by **Simon Lord** » Wed Feb 18, 2004 10:20 pm

Just because I'm paranoid doesn't mean they're not out to get me...

End of topic? Please?
Simon

Nina · Post by **Nina** » Wed Feb 18, 2004 10:36 pm

Paranoid is somebody sitting on the first row of pews in a Norwegian church,
seriously thinking there's somebody behind them...
End of thread?

Nina

~~~~~~~~~~~~~~~~~~~

It's all fun and games until your rat explodes

Mikkels · Post by **Mikkels** » Fri Feb 20, 2004 7:54 am

Thanks Rex

Trust me I don't know what I am doing however I learn by experience.
Hell I did the engine swap with a little help from a mate (mini
enthusiast) and the net. I therefore believe I can take a look at the
AFM. The car is rich alright. Lots of black smoke out back and fuel
consumption proves that. It is likely to be the AFM setting but maybe
not exclusively.

The car will be open loop when cold right as the sensors take a minute
to come on line - not heated up. It is very rich on start up.

I may just go to a friendly dyno man. Will depend on my mood when I
decide to tackle the problem.

Cheers

Don

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