930 fueling problems - Page 1 - Porsche General - PistonHeads UK

Post on the 930 board on rennlist.com, or ask the guys at g-force-motorsport, they cut their teeth on 930's....

If your mileage is over 100k miles I bet you it is worn injectors.

Hi Injectors have also been checked and 2 were replaced. To qualify the over fueling problem. We're talking 10 mpg ! (used to get 16-18mpg). It's OK on long runs - ie when it's running at over 3000 rpms at a constant as opposed to on/off driving. The CO mixture on idle is about 6000% vol - a little high but at 3000 rpm + the mixture sorts itself out. You don't need a meter to measure it - you can smell the h/carbons !

Mate i'm lucky to get 5-8 mpg in town driving, what % CO do you get at idle? I should run 3% but it has been up at 8%....

It's off the scale on idle ! I think it should be vol h2 reading of around 300% - mine od idle is 7000 % Also I'm getting alot of fuel (well too much) in the mixing with the engine oil. So getting a bore washing problem as well. Mind you it goes pretty well at the moment - and the fuel dump into the exhaust system sounds pretty impressive. I'nm sure the tail pipe flames would be impressive if the box was taken off ! >> Edited by woof on Wednesday 11th June 10:45

Hmmm, odd one. Maybe ninemeister can comment. I had suspected injectors as worn ones can 'dribble' at idle, but behave faultlessly in terms of flow rate at high rpm. What did you find wrong with the two you replaced? If the others are playing up now, they may be the cause of the symptoms. It would explain why you have major problems at idle and overrun, when they should be shutting down a great deal. Also, does the car stall?

Hi Yep - it's booked in at Ninemeister for some TLC in July. Going to have a few more bits done to it - though not sure how I'm going to cope being seperated from my sweetheart ! The two injectors were dribbling - can't say it made any difference replacing them anyway ! The car doesn't stall - starts a little odd sometimes - like it goes to start has a think then starts fine. Here's my Ninemeister shopping basket ! Paintwork : Bonnet needs to be matched Both rear wheel arches are a little pebble dashed Front spoiler needs a little repair and spray. Engine: Overfuels on idle Needs a good tune Any extra power enhancements can be discussed ! Existing tweaks are a Turbo 2 intercooler, 1 bar spring, K&N cone air intake. Exhaust System Would like to put on a "sports system" - improved performance/boost and a nice engine note is what I'd like from it. If we can get a good flaming overun that would be good !! Steering Rods Sounds like a good idea? Brake bias: Just needs to be sorted out - the fronts lock up too easily. Already had the big red caliper upgrade. Heating: All the motors are now buggered. I might have all the bits from prestige salvage so JM AUtos may fit these prior to it coming up to you. Misc Needs a flat floor and corner weight setup >> Edited by woof on Wednesday 11th June 11:50

Here we go..... There is no point looking at anything until you have set the idle c.o. to around 1-2% (with the air pump disconnected) with the hydrocarbons around 300-400. You can adjust the mixture with a 3mm allen key in the plunger on the metering head, push down, engage the plunger and turn in tiny amounts until the mixture is where you want it. Once you have the c.o. around 2%, if it still guzzles fuel come and see me, the possibilities are nigh on endless but simple to test for with the right equipment.

Been there done that - THe metering head has been back and forth the KMI several times. And stil can't get the hydro carbons done below 7000 (yes really on idle) at revs it drops right down to 200 - 300. I needs someone that knows these engines - since James left the knowledge level isn't the same for the older models. I'll give you a call anyway to confirm when it's coming up JM

Since we used to be called 930 Motorsport, we MAY be able to help.

Not James as in UV? His knowledge level of older models is surely confined to the Bridget Bardot variety only

James Oconnor sadly departed - well now resident in Oz !

Which part of SE are you in? The Techie guy I use does a lot with these on Surrey borders.

Hi Might be a bit specialist but hopefully someone might point me in the right direction ! I've had an overfueling problem on my 1987 930 turbo for the last 6 months - Metering head, warm up reg have been replaced countless times and we're still no closer to finding out why it's overfueling on idle and lift off (on gear changes). There does seem something odd with the auxillary air supply from the right hand side of the intercooler. Basically there doesn't seem to be any air flow from this side at all. You can cut the air supply off from that side (expecting the engine to stall) and it does nothing ? Anyone got any ideas - or point me to somewhere else ?