Running rich and fuel consumption ..

[grinder]

Right then ,

lets see if we can all get to the bottom of this

my car is a standard 1988 2nd gen N/A on a 1988

its got a janspeed exhaust , k&n panel filter and air pump removal mod

the car once warm ticks over at about 900 rpm

car runs 100% , no missing or back firing etc..

BUT

its running very rich , i was backing it up the drive way last night and the girlfriend complained that is smelt horrible out of the exhausts and it stunk of petrol - now i dont know as i was driving ! ha ha ha

and its a bit heavy on the fuel ( i think ) not actually done a full check on the miles to petrol ratio - but driven hard i can get 25 miles to quarter of a tank

SO

can some one point me in the right direction here

will altering the timing make it run better ( i assume that it would make it burn all the fuel rather than dumping out of the exhaust ?? )

after read the service manual - found at : http://www.iluvmyrx7.com/1988_factory_service_manual.htm

it says that i can adjust the timing by use of a strobe lights etc..

now it says that you can adjust the crank case sensor which effects the timing - now where is shows it - mine has a dizzy cap and loads of wire - is this normal and the diagram shows with the dizzy cap off ??

and the fact that it keeps mentioning trailing wires etc.. its all a bit confusing - not like a normal engine

would this solve the problem - or could this make it worse or kill the engine - i know that if you get pinking then its game over

is there anything else anyone can suggest ..PLEASE

and also ( sorry about this guys and gals ) ... i took it up to about 115 in 4th gear , but when i changed to 5th the car didtn seem to like it at all - could this be down to it running rich and therefore getting toooo much fuel ( or too little ?? )

thanks

stu

[bnaellis]

If the car is running fine, then don\'t touch the timing.` Whats the state of your spark plugs and air filter ?? That would be the best diagnosis of it\'s running rich or not.

rgds

Brian

[grinder]

i took the air filter out a few weeks ago and gave it a good clean - it looked dirty but not that bad !

and the plugs ... hummm not had a look at them yet ( im scared ! )

if it is running rich , what colour should i expect them to come out

[Glenn Butcher]

Hi Grinder!

If it is running rich then they will be black!  ever had any problems starting it?

A general tune-up would be:

1. Replace spark plugs
2. Air filter
3. Possibly Fuel filter
4. Check the timing with a timing light
5. Oil and Oil Filter change


Do you know if the injectors have ever been cleaned?
Do you know if the leads have been replaced?


With a high flow exhaust, you may be able to Advance the timing a little (but do this with a timing light).

Finally - has it had a compression check done recently?  if compression is low, the fuel is not burnt as efficiently as it should be.  If it is low, then don\'t despair as a non-turbo engine will run for quite some time on low compression.

[grinder]

the air filter is a K&N thingy - so i thought the idea was just to clean and replace !

it had the plugs done about 5K ago - and yes i know i should have changed them by now !

Fuel Filter - is that the canister one - or is it an inline one ?

the oil change - it uses a lot of oil so therefore its getting a constant change !

but the oil filter was done before i bought it - but not 100% sure when

im really scared about doing the timing !!

ive not had it compression checked yet - again i dont want a bad result - so no result is a good one !!  ( but as i said , its using oil ,maybe this is a sign of low compression and therefore this could make it run rich ? )

**edit **

usually always starts first time every time - only had 2 occurances where it wouldnt start

1 - it flooded as the better half tried to start it !
2 - i started the car and drove about 10 feet and stopped it - came to it 3 days later and had a nightmare of a time trying to start it !

[Paul-Tll]

Are sure its not just rich on idle (no cats and no air pump)
25mpg prob. about right?
my turbo only returns about 18 ish mpg.
Paul...

[MikeLMR]

changing the plugs made a big difference on my car, as did changing the fuel filter !

give it a good service and see how it runs afterwards, rotaries are picky about ignition parts   (new dizzy cap and rotor arm on my car made a night and day difference in the way it drove !)

[grinder]

paul - not 25 mpg - 25 to a quarter of a TANK !!

its had a new dizzy and plug leads - will throw some plugs in it over the next few weeks !

this fuel filter that you talk about - is it a little inline filter or the charcoal canister thingy ??

it could just be rich on idle - but how can you tell if it runs rich when you are driving round

[Grizzly]

Theres Loads of things it could be but start with the Simple stuff first (give it a service Plugs,Filter,Oil etc) then get the Mixture and Timing etc done Properly.

If there is a Fault they wont be able to set the Mixture up, but if the car runs ok and it has good power etc its going to be somthing simple.

But the Comp test is a Must! I am the other way about knowing my Engines condition, Id rather fix it before there is any big damage done.

Chris

P.s. the Plugs alone can be temprimental due to there design, you find they dont do to many miles before needing Changing.