924Board.org

[924turbo_sout_africa]

Ok i've been searching like crazy but just cant find what i'm looking for ...my 931 is running way to rich so i will need to check the settings.I know it is here somewhere as i read it when i got on the board but i cant find it now??

please can someone show me where it is or how to do it i want to check everything well the timing is right so all i need to do is set the air scrue that is in the tb and the idle screw and the mixture on the fuel distributor so that i can finally have it right ......
_________________
Porsche ...where dreams are a reality
'79 924 turbo canada spec
'98 Formula Vee (M3 eater)

Time in the 931 is a dream come true !!

[924turbo_sout_africa]

ok found some intresting info in a thread from what i assume the throttle stop was being use to set the idle and the scrue that turns into the tb (air bypass) is actually to be use to set the idle and the air fuel mix is set in the fuel distributor with a 3mm hex key or somehting like that...? please tell me i have it right now ?
_________________
Porsche ...where dreams are a reality
'79 924 turbo canada spec
'98 Formula Vee (M3 eater)

Time in the 931 is a dream come true !!

[RC]

Yes.
Dont touch the throttle stop screw. Adjust idle speed by the air bypass screw. Out, CCW, is more, faster.

AFR is adjusted with the 3mm allan key through the hole in AFM. Be slow and only adjust within about 1/2 turn, noting start position. CCW is leaner. Back off till engine stumbles (lean) then slowly turn CW. Rough setting is about halfway between lean and rich and max reading on vacuum gauge.

[924turbo_sout_africa]

thanks....well did about 4 hours of reading and found that message by smoothie as well ...i will note the position it is in the A/F and then do as you say turn until it stumble's to lean and then rich and then set it about in the middle of those 2.....

i just want to find out will it be possible to just give it a 1/4 turn to lean and drive it and check on plug 3 to see if she is running to lean or still very rich ..cause i read i think vaughan said to do that ? cause mine is running quite rich
_________________
Porsche ...where dreams are a reality
'79 924 turbo canada spec
'98 Formula Vee (M3 eater)

Time in the 931 is a dream come true !!

[RC]

How do you know its rich? Smell? Black plugs or smoke?

Any adjustment at the "mixture screw" will only change at idle. It will make virtually no change at WOT or even part throttle. To read the plugs satisfactorily you need to do a drive at the same conditions (speed & load) for at least a few minutes then kill the engine quickly and coast to a stop. Then pull the plugs. Best thing is a WB AFR gauge.

If you are rich at anything but idle it is time to check system and control pressures. You WONT correct it by the idle mix adjustment. Check air filter and vacuum leaks etc too.

[924turbo_sout_africa]

well i get black smoke on start up and i can smell fuel when driving hard and the exaust is very black and you can smell the fuel in it.....

as farr as i understood if you set the air fuel mix at the plug that you use the 3mm hex it will change the mix this was the case on my golf 2 gti that used the same system ,so as far as i know this is where it should be tune'd on the porsche ?

all the 924 racers i talk to told me as well it needs to be set there and told me they can see it is running very rich ..o yes the plugs are very black check it is not oil it's fuel
_________________
Porsche ...where dreams are a reality
'79 924 turbo canada spec
'98 Formula Vee (M3 eater)

Time in the 931 is a dream come true !!

[Smoothie]

Yes, actually the mixture setting at the AFM unit affects the mix over the entire range from idle-part-full throttle. There are other things that affect it as well - such as the WUR (CPR), lambda (o2 sensor) system, etc.
You might also have an imbalance between cylinders due to clogged injectors. If you can't get it leaned out enough to stop the black smoke and still keep it running, I'd check the injector spray patterns and flow volumes.
The WUR is checked with a CIS fuel pressure tester.
_________________
"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[924turbo_sout_africa]

thanks for the info smoothie ...well i actually know it is set too rich as the mechanic who built the motor last year when he set it he told me he set it a bit rich to make sure it will not run lean but i found a couple of vacuum leaks and since repairing those is when it whent from being a bit rich to i think a little too rich so i just want to lean it out by a very small amount but i will do the test tomorrow and check the plugs after a drive just to make sure it is not too lean.i will come and let you all kno once i've done this ...i also picked it up in the gas milleage as it is giving me about 8kilometers to a litre which is a bit heavy on the gas hehe

but thanks for the info again
_________________
Porsche ...where dreams are a reality
'79 924 turbo canada spec
'98 Formula Vee (M3 eater)

Time in the 931 is a dream come true !!

[924turbo_sout_africa]

ok so i gave her a 1/4 turn to the lean side and can you believe it is better know no more smell of fuel the hole time and when starting up no more balck smoke she feels like she is pulling a lot better as well,check the plugs it now has a brown like caramel colour same as on my race car that gets dyno's every month so according to me she is now running perfect on thi mix ??? any comments will be helpfull
_________________
Porsche ...where dreams are a reality
'79 924 turbo canada spec
'98 Formula Vee (M3 eater)

Time in the 931 is a dream come true !!

[Paul]

Change your oil.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

[924turbo_sout_africa]

well it was not running that rich so there is no fuel in the oil checked it as well...car is due for a service in 3 months so will have it all done then as i'm not driving her daily anymore so it's ok
_________________
Porsche ...where dreams are a reality
'79 924 turbo canada spec
'98 Formula Vee (M3 eater)

Time in the 931 is a dream come true !!

[JayZzzz4]

I think I'm running a little rich too. I have a chrome muffler and i clean the inside just about half of an inch about every 2-3 drives, and it's always full of black powdered. I recall a post saying about this, and i think it said it's because of the engine running rich. But even if I went leaner, I don't think I'll fix the powder problem since my catalytic converter is coated in powder I'm guessing.. But when I accelerate hard, I do smell a bit of gas. Any ideas what I should do? Just run a little leaner?
_________________
White 1987 Porsche 924S manual

[Paul]

How's your gas mileage?
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

[JayZzzz4]

Well, I can't tell for sure since I keep filling it up at half way or so. But it seems like I'm not getting that good of mpg. But thats because I get up on it once it's warmed up ..... I guess I'll have to calculate it out in the spring when I use up my full tank... I thought I'll be saving money by filling it all the way up, saying to myself," the price of gas is only going to go up in the spring", so i feel like kicking myself buying it at $4.00/gal now thats it's around $2.30 or so
_________________
White 1987 Porsche 924S manual

[924turbo_sout_africa]

well if you smell gas in the cabin well then you are maybe running a bit rich i brought mine down by about a 1/4 turn and still smel a b it of gas but i dont want to run lean u know....but i dont have that black dust or what eve coming out of the exaust
_________________
Porsche ...where dreams are a reality
'79 924 turbo canada spec
'98 Formula Vee (M3 eater)

Time in the 931 is a dream come true !!