Reasons For Running Rich.

[Samhyland]

Details

Car: 1995 s1 r33 gtst rb25

Mods: exhaust and pod filter

Recently brought and have been putting bp ultimate premium 98 in it and have been told its spitting fuel out the exhaust and I constantly back fire and split flames. I get approximetly 300-350kms from a tank im not sure whats normal.

Does anyone know any reasons it would be running rich?

Maybe its not tuned to ultimate premium 98? If so should I put 98 or 95before through it to see which runs better? Thanks in advance for help

[Moodles2]

Standard stuff, check spark plugs, replace if old. Check cam timing. Change oxygen sensor.

Don't put anything put 98 in, unless you want it to run like crap.

[Plattsy]

how do you check the cam timing?

not being funny, genuinely want to know! timing light? remove the timing belt cover?

[DVS JEZ]

Have to remove the top timing belt cover. Align the crank pulley with TDC and then check cams are aligned with there corresponding marks.

Be aware that to remove the top timing cover u need to remove the crank sensor, this is in a certain position and is very inportant. Either mark its current position before removing. Or better yet check with a timing light before removing (engine at operating temp) then reset to the same after refitting

[Plattsy]

nice one. gotta check the condition of my timing belt this weekend so might as well check that too! (consult is showing my timing bouncing around a little bit.its got me worried)

[mad082]

your timing will bounce around a little bit. that is normal. the raw fuel and flames may be caused by the timing being physically out (such as a jumped tooth on the timing belt), but it may just be that there is a more simple reason. i'm guessing that your catalytic converter is probably hollow (as that allows flames a lot more), but it may also just be that you have a fuel supply issue, caused by a fouled injector, AFM reading wrong, or an intake leak. or possibly even something like the thermostat not closing properly (causing the car to run too cold) can affect the fuel economy. if the car takes more than about 5 mins of driving for the temp needle to start to get to around the middle of the gauge (or it never does and only stays around the bottom of the gauge) then start by replacing the thermostat and you will find that the car runs better and uses less fuel.

how many litres are you classing as "a tank" as that will give a better indication of your fuel economy and just how rich it is running. your driving style will play a big part.

i used to only get about 17L/100kms out of my r33 gts-t, but i had a bit of a lead foot. regular boosting, etc.

[Plattsy]

nice one, i dont get any flames or anything, just that timing jump around! thanks for easing my mind!

[blind_elk]

Is the trans manual or auto?

It could just be that it is burning more fuel, but not necessarily running rich. eg, maybe you have a binding brake.