87Stallion

My car idiling smells to high heaven. It smells like raw gas coming out the exhaust.

Carb has been professionally adjusted. Fuel pressure is @ 6 PSI

My question is can a failing ignition system cause this if all else has been checked.

I am running a 85 GT dizzy and a Duraspark II box. The plugs look good but man this thing stinks when idiling.

I am currently running 14 degrees of timing. Any ideas would be appreciated.......

mjr46

the idle circuit needs more tunning/attention, what carb??

87Stallion

Its a Holley 600 Double Pumper

Any help would be appreciated

mjr46

the throttle stop screw on the side of the carb is crucial you don't use that to set idle , otherwise you open the transfer slots at the base of the throttle plates and bypass the idle circuit, hence it runs rich, idle adjust should be done with the idle air bleed screws, is yours 2 or 4 corner idle adjust screws???

87Stallion

It is 2 corner. I readjusted it base on max vacuum with a guage and it still burns the **** outta my eyes

87Stallion

So what do you set the idle @ with the idle speed screw? Mine idles @ about 900 when warmed up.

mjr46

I take the throttle stop screw and back it all the way off then srew it in until it lightly just starts to open throttle plates from there 1.5 turns, then I use timing to achieve proper idle speed and I have base set around 19-20 degrees, remember this is a performance engine with coressponding camshaft the BS of 10-13 max goes out the window, total advance is what is key 34-36 total, the duraspark dizzy won't allow you to lock total out, what I have done with a duraspark dizzy is not use the vac advance and set base high and mech advance covers the rest and it falls in around 36 often with no vac advance, my 85 gt I use a msd billet which is fully adjustable.....anyway once throttle screw is properly set , what happens when you advance timing?? Idle goes up!!! so back off throttle stop screw until idle desired is achieved.....it burns your eyes cause you are wasting fuel/ unburnt fuel cause the timing/spark delivery is to late in the cycle, advancing timing will start the delivery earlier and by the time the change over occurs all burning should be done and it shouldn't burn your eyes as bad if set accordingly, to fine tune the idle circuit lastly go to the idle adjusting screws on the distribution block of the carb.........don't worry if base timing is at 18-20 degrees, worry about total advance which by 3500 total should all be in

87Stallion

I will give this a try and I'll let you know. Thanks for your help.

87Stallion

Thanks MRJ46 I did as you instructed and that made a hell of a difference. I set base timing to 20 degrees and that let me back off the idle screw and that reduced the exhaust smell big time. I didnt drive the car but it should be better. I'll probably go ahead and change my plugs now.

mjr46

now once you do that , you need to go back and reset the idle bleed screws to max manifold vaccum reading to further dial it in, also you need to check total advance and make sure it's not now through the roof, the Duraspark dizzy isn't very adjustable in stock form, rev car up to around 3500 and see what total advance reads on balancer.....reason it is better is you probably had turned the throttle stop screw in to far , hence opening venturis to far and uncovering the idle transfer slots down on the throttle plates and no longer using the idle circuit to govern such