AFRs of the scale rich on tick over!

[UnstableCable]

Spent the day fitting a AFR gauge as the cars not been running so well so thought it would help with seeing whats going on with the car! Bought the AEM one from Scoff, real simple to to plumb up!

Anyway started the motor up and let it tick over till was warm but was reading of the scale rich and couldnt get it to lean out at all with the mixture screw. Havent taken it for a drive yet as its in the garage getting sills painted up so was wondering what else i could adjust to bring down the richness on tick over? Carb is a unknown but will have a look over the next couple of days with the micro drill bits into whats what!

[djinuk]

take the mixture screw out completely to check the end hasnt snapped off.

[UnstableCable]

take the mixture screw out completely to check the end hasnt snapped off.

Ah thats a good plan! Took me about 20 mins to dig through the crap they had bunged in ontop of the mixture screw so I could get in and to be able to adjust it but will take it out tomorrow and have a ganders!

[SCHWARTZ]

Also check the idle jet as some how wen igot my car the end was missing off that:confused:

[djinuk]

you may struggle to get the mixture screw out if its got crap around the threads.. if so whip the carb off, and it will make life easier having access to the bottom, be warned though when you flip it upside down it will dump lots of fuel out.

[UnstableCable]

Drove it home today so had a chance to see what the afr's was like on the run home. Still idleing of the scale but cruising on the motorway at about 3000rpm was reading 15.5-16 ish and on wot was about 14 on the gauge.

Again the carb is still unkown jets as I havent had a chance to look into it!

Any advice greatly appreciated!

[SCHWARTZ]

Bit lean matey at wot you want it in the 12s

[UnstableCable]

Sorry chaps just read the AFR part in the article section again and Im to lean rather than rich :ashamed:! Its 18 + on tick over which explains why its idling like a bag of sh$t!

[UnstableCable]

Bit lean matey at wot you want it in the 12s

Think Im a bit lean all round! will get the mixture screw out and see whats the deal!

[SCHWARTZ]

Give it a couple of turns out and see what that does at idle. What boost you running? When was the last time the fuel filter all ways a good idea;)

[UnstableCable]

Give it a couple of turns out and see what that does at idle. What boost you running? When was the last time the fuel filter all ways a good idea;)


Will do, gonna take it out make sure its still in one piece first :agree:

running 14psi on a vnt and belive the carb to be std but havent checked it yet!

[James5]

If your running a Vnt matey aim for 11.9 afrs so you have a little safety zone sounds like you need to increase the 2nd stage for wot driving as 14 is way to lean you may find you need to decrease the ac jet also. Little bit of advice from a fellow Vnt user would be a good idea to knock the tdc sensor to give some retard.

Your next step really is to find out what jet's are in your carb:agree:

[UnstableCable]

If your running a Vnt matey aim for 11.9 afrs so you have a little safety zone sounds like you need to increase the 2nd stage for wot driving as 14 is way to lean you may find you need to decrease the ac jet also. Little bit of advice from a fellow Vnt user would be a good idea to knock the tdc sensor to give some retard.

Your next step really is to find out what jet's are in your carb:agree:


Ok thanks for the advice mate, will get onto the carb tomorrow and report back :agree:

Im glad you bought up the timing actually as I have been wondering if I need some retard!
So for retarding the timing what would say is the best way? Will swapping the wires around retard the timing or will it need more than that and be worth me making a adjustable timing sensor as in the articles section?

[James5]

Ok thanks for the advice mate, will get onto the carb tomorrow and report back :agree:

Im glad you bought up the timing actually as I have been wondering if I need some retard!
So for retarding the timing what would say is the best way? Will swapping the wires around retard the timing or will it need more than that and be worth me making a adjustable timing sensor as in the articles section?


Merely swapping the TDC wires over will only give you a few deg's of advance to which you do not want with a VNT.

What you want to do is make you TDC sensor adjustable so that you can then move the sensor up and down the TDC shaft. moving the sensor to the front of the engine is retading the ignition and towards the bulkhead is advanceing it.

http://www.rtoc.org/boards/showthread.php?t=4757

I have mine full retard if I run OE position @ 20psi of boost on my setup my little GTT det's it's nut's off:crap: as many will confirm from a recent RTOC surrey meet:ashamed:

[SCHWARTZ]

:Dhavnt seen something that good in ages:wasntme:

[UnstableCable]

Merely swapping the TDC wires over will only give you a few deg's of advance to which you do not want with a VNT.

What you want to do is make you TCD sensor adjustable so that you can then move the sensor up and down the TDC shaft. moving the sensor to the front of the engine is retading the ignition and towards the bulkehad is advanceing it.

http://www.rtoc.org/boards/showthread.php?t=4757

I have mine full retard if I run OE position @ 20psi of boost on my setup my little GTT det's it's nut's off:crap: a many will confirm from a recent RTOC surrey meet:ashamed:


Haha Im getting everything back to front at the mo!

Sounds like im gonna have a busy day tomorrow! Thanks chaps youve been a great help! :agree:

[UnstableCable]

Hi All

Made some progress on this, got the timing gun out and gave it a check and it was runnning at nearly 10 degrees advance :eek: with the sensor in the standard postion, which was a bit concerning as I belive it should be 8 degrees? so made the sensor adjustable (great info in the articles section :agree:) and now backed it down to 6 degrees adavance to be safe with the vnt!

Also swapped the carb over as I rebuilt my good one and now the readings are 10 on wot as i has a 1.3mm main jet which I will be later swapping for a 1.2mm jet and indling around 16 on the afr's.

So thanks for the advice chaps, shes running great now and just leaves me to tinker with the jets etc to get the afr right :D