930 Running Rich
 

I HAVE A 77 930 THAT IS RUNNING SUPER RICH. WHEN I PUNCH DOWN ALOT OF BLACK SMOKE FROM THE EXHAUST. I WAS ADVISED THAT IT COULD POSIBLE BE THE WARM UP REG WHICH I HAVE CHANGED AND STILL NO HELP. I HAVE TRIED TO ADJUST THE CIS AND NOW THE ENGINES RPM IS HUNTING (FROM 950-1400) CAN ANYONE HELP ME SEE SOME LIGHT THRU THE BLACK SMOKE.

Welcome to the Board, now turn off the CAPS! :D

(I don't know how to help, I just couldn't stand the screaming.)

I see two rich symtoms. Black smoke and hunting idle.

ROBERT ANY SUGESTIONS ON CORRECTIONS

Better let some of these better qualified turbo heads help you there. But I think leaning it out a bit might help. I run my 83 sc without 02 sensor and bump the mixture up a touch. It hunts for about the first 30 seconds when i start it cold, but then it settles down. Not sure on the 77 though.

It's the same thing, although, if you "adjusted" the mixture and it started hunting that means you went even richer. It's normal for a turbocharged engine with cis ( i think ) to blow a slight black smoke under initial boost. I'm told that the system under initial boost goes very rich and leans out a bit progressively until you hit the rev limit. I might be wrong though. But if your going to be adjusting a cis on a turbo, with high risk of detonation, i would use a co machine to make sure of your mixture so there are no expensive mistakes.

I'm no turbo expert yet, but I think it is much better for a turbo to run rich than to run lean. Mine will puff a bit under hard acceleration, and then runs perfectly fine. It should idle smoothly.

Get some pressure gauges and diagnos the problem. Turbos are not supposed to blow black smoke. If it is running too rich fuel gets past the rings and dilutes the oil.

Check sensor plate rest position.

Doug
75 911S

thanks for all the advice i think my initial problem is at idle. it is almost imposible to stand by the exhaust because of it running so rich
any sugestions??????

doug,
by the way would you happen to know where the sensor plate is positioned at idle?

Lean out the mixture alittle

Everyone is "right on". Get a fuel pressure gauge (WUR check) on
the car and get access to a CO machine (mixture adj.).

Stop throwing "darts" to analyze the problem.

Good luck
Loren
Systemsc.com

1) Lean the mixture.

2) Install an Andial Fuel Enrichment system so your mixture is "richened" while under heavy boost - prevents running too lean and melting pistons.

My 930 used an andial enrichment system, but the controller pooped out a year or so ago so I went looking for replacements.

If you want a better way of enriching your fuel injection I recommend something like the following.

http://www.hksusa.com/products/?id=638

With CIS + AIC you have all the benefits of a mechanical injection system with a small piggybacked EFI system that allows you to tune the mix at different RPM and manifold pressure points.

Either a vacum/boost leak check all the connection to and from turbo to throttle body, check to see if your AIC is leaking. My SC turbo does the same thing when there's a leak in the pipe work.

You don't give any background info on how the car ran before the rich condition started and / or what condition the engine is in.
If you have not tinkered with the CIS fuel enrichment screw then that should not be the problem. You should check all of the vitals first - to see where you are BEFORE you start fiddling. The CO should be set at 3%, the A/F ratio can be as high as 15:1 at idle and as low as 12:1 under full throttle. Fuel pressure should be set as per factory specs for your engine. Check for any plumbing leaks first. Changing the settings to compensate for an undetected leak will only complicate things. Get ahold of a set of factory manuals if you can or try out the schematics here on the Pelican site.

I have an 88 930 that is doing exactly the same as your 77, I am very interested to see if you fix your problem