My car smells .... rich

Smells perfect to me... if it's running okay better too rich than too lean... love the smell of petrol in the morning

just mind that it doesn't dilute your oil too much!

 

If the mixture is correct for all conditions, it won't smell "rich." The cats don't "fix" this issue, they just hide it as they kill themselves with the too-rich mixture. Once a car is warmed up, too-rich should not exist unless you have a non-stock camshaft. Hi lift, high overlap cams cannot generally burn cleanly at idle. But otherwise, the FI or carbs can be adjusted for the proper mixture that won't smell that way. Obviously improper ignition timing or other ignition issues (wires/plugs, etc) can cause the same problem.

 

I had the same problem, it was so bad I had to roll the car out of the garage before starting it. I, like you, was also concerned with those that pulled up behind me at stop lights.

The fix for me was to have the carbs rebuilt and to have the ignition sorted out. Its not perfect, however, significantly better and worth the investment getting it corrected.

 

My car runs a little on the stinky side.


Don't assume it's to rich by the smell, unless you have a lot of experience with these cars

Pull a few plugs and report back

 

I had the same problem when I first got the car. After I did the pertronix change I did the birdman carb tune up and it runs just a bit rich but not to noticeable from someone behind. I have only done the carb tune up once in 10 years and it still runs great. I am also running ngk 5's which are a little hotter plug. Oh unless you have a modified cal. car my 77 came without cats and is labeled as such on the door. Just do the tune up and it will lean out as much as you want .

 

rskdsk:

Your car smells....Rich....Because....it is a Ferrari.

Just my thoughts.

Cheers,
D

 

Try looking here and follow the process. http://www.birdmanferrari.com/service/sync/carb_synch_tutorial.htm

 

Unfortunately on a car of this vintage it's likely a bit of everything. Could be carbs, electrical, ignition and some vaccuum lines all getting weak. If carbs haven't been rebuilt in many years that is a good place to start.

The upside is that if many of these systems haven't been touched in years, cleaning each system will probably make the car run a little cleaner and a bit stronger.

 

I'm Stefan, from Hungary, with '79 GTS.
As I received my Car from Florida to Budapest, the first was sync the carbs, as Birdman says on her site. (Sorry my english is not so very good)
I have make the sync in 4 hours. When all so, how he says, its OK.
I had using for last step, for adjusting the idle mixture Colortunes.
For example this one:
http://cgi.ebay.com/ebaymotors/GUNSON-COLORTUNE-14MM-G4074-BRAND-NEW-RETAIL-BOXED-_W0QQcmdZViewItemQQhashZitem2a0cb764daQQitemZ180601971930QQptZMotorsQ5fAutomotiveQ5fTools
Step by step all zylinder by 1500 rpm.
You can see the color for all explosion in zylinder.
Colors :
Yellow-blue: to rich
Darkblue : to lean
And runs all eight zyl. wonderful.
I reccommend this Colortune for all carb cars, very good.

regards
Stefan from Budapest

 

if you can smell the gas odor in the car, then you have a problem. if it's an exhaust odor, then you may not have a problem. these cars tend not be smell-free. even a euro (cat-less) 328 will give exhaust odors.

 

When smells, is more different things :

1. The smell is blue, thats mean :
1.1. When everytime smells, too much oil going to upside the pistons (pistonrings and liners are wrong)
1.2. After long time running on idle rpm, and push throttle, smells 1 or 2 sec. and after there no smells, that means valveseals are to old and hard

2. The smell is darkblack, that mean :
2.1. On Idle rpm smells, on higher rpm not : the idle mixture is to rich.
2.2. On higher rpm smells and idle not : the float is too high, the mixture in higher as 2650 rpm is too rich, but to 2650 rpm working in mixture only the idle jet.

hello
Stefan

 

make sure your chokes system isnt engaged at the carb interfaces. they do sometimes stick here and will result in a rich condition.
i highly recommend a wideband O2 sensor in the exhaust stream with the associated gauge in the cockpit for carb cars - or any car for that matter. i have this on my 308 gts and it is a lifesaver for tuning purposes and provides very accurate feedback for ALL driving conditions, warmup, cruise, deceleration and acceleration. (i validated it against several dyno sniffers and it is spot on).

 

I have Crane X700, is absolutely recommended, and cheep.

 

One place to start might be to check your fuel pressure. Weber carbs do not need very much. I do not know what to set fuel pressure to on a 308 but on other engines with Webers it is around 3 1/2 lbs. Too much fuel pressure makes problems such as you describe.

 

Remember that the fuel on older cars was leaded fuel not the unleaded fuels chock full of additives. All of my old vintage gassers are the same running on unleaded premium octane or regular. Remember as kids that there was a air quality problem! Just a thought.

 

The front 4 cylinders that near the bulkhead is not easy accessible , may I know what method do you use when you use colortune ?

Thanks

 

If you are happy with the tune of your 308 otherwise, don't do anything radical. Don't mess up a good thing!

Before going down the slippery slope of changing jets, you might first try turning the idle mixture screws back in (clockwise) in small increments. I'd suggest going in one half of one flat (so 1/12 of a turn) on all cylinders and then seeing what you've got. If you aren't popping and backfiring on the overrun (too lean), and still too rich, try another 1/12 turn.
This technique is similar to what the Weber manual suggests, though the manual starts at lean and works back. (All this is assuming you don't have a way to check the CO on each cylinder.)

Another item from the Weber manual is to individually pull each spark plug wire one at a time at idle. If all the idle drops are all similar, the cylinders' mixtures are adjusted the same.

You'll need to find the longest and skinniest screwdriver you can buy. Found mine at NAPA and it stays with my tool kit now.

Hope this helps. Once the carbs are set right, wow, they'll really sing.

Merry Christmas. Jeff

 

thanks a lot for the info.

Ok I will use colortune at the front 4 cylinders with easy access, and monitor it. And just roughly adjust clockwise at the back 4 cylinder which is hard to use colortune.

1/2 turn or 1/12 turn ? 1/12 turn seems to be very small a turn .

 

Yes, I would recommend a very small turn on each.

If your 308 is running well, but just a bit rich, 1/2 turns shouldn't be necessary. You can make the adjustments in baby steps now. Half a flat (hex headed idle mixture screws) on ALL CYLINDERS AT A TIME, one twelfth of turn, will be noticeable when you are getting close to perfection. If you don't notice any improvement after a drive, try another 1/12 next time, and so on. (Now it could be that your carbs are not already uniformly set. If you turn in a particular cylinder a small turn and the cylinder starts dropping off line, then that cylinder is already far too lean, so make sure to listen carefully.)

This fine tuning is what worked for me, and is a hybrid approach based on the 308 factory manual and the Haynes Weber manual.

It sounds like you have a good running car, but just need to slightly lean it to cut down on noticeable exhaust smell. It shouldn't take too many 1/12 turns to fix your problem.

Best of luck with it. Jeff

 

Thank you Jeff, yes my car is running well just too rich and smell petrol. So I will follow your method as it make sense...
Thanks again!

 

One question- colortune is for one cylinder only and the carb has two air/fuel mixture. So shall I balance and adjust the two mixture concurrently ? Or I only adjust one moxture until I see the blue spark ?


Sent from my iPhone using Tapatalk