I am not sure if this is the correct forum for this question, but here goes. My z has a very smelly exhaust. i have read all the forums about the exhaust smells. It does not have exhaust leaks The car has been totaly rebuilt right down to bare steel new seals gaskets etc. I get the smell in the car with the windows down at slow speeds and at a stop light, I understand the aero issues. I have a fairly warmed up 2.8 with round tops. I have tuned the carbs to what i consider a good tune. My question is do the early injection cars have the traditional smell or is it just the carb cars that have the smell. It smells when you stand next to the car as well when you drive it? I really love the car, but if i cannot do something about the smell I may have to give up and sell her. i have had many cars from the 60's and 70's. i have even considered building an aftermarket injection system and installing a high flow cat.

Thanks in advance

Bob

Ps sorry to be so long winded

A car without a catalytic converter will have some exhaust smell that may be what you call a "traditional smell." My '78 280Z has no catalytic converter (not a California model), and so it has a mild "traditional smell," even though it's fuel injected. It smells very much like my Edelbrock-carbureted '66 289 Mustang did. Any car with a catalytic converter will smell much cleaner.

There's no reason you can't install a generic catalytic converter on your 260 if the smell bothers you that badly.

What does this "very smelly exhaust" smell like?

Can you see the exhaust?

Are you loosing any fluids? Oil or water to be specific.

What's you gas mileage?

If antifreeze is getting into the cylinder chamber it will stink to no end.

If it's burning a bit of oil it will smell.

- Fresh engines will burn a bit of oil until the rings seat in.

- Engines that have been sitting a long while will get stuck rings. This will usually go away with regular driving.

If it's running rich it will smell more like a traditional old carburetted car or worse. Ha. Every car I own has a carburettor.

Running rich will make quite a stink. My 76 with EFI stank bad until I fixed the fuel pressure regulator. Maybe you just need a little more tuning at the idle and low rpm end.

Well I've never heard of anyone having to get rid of their car because of how bad it smells before.

I'd try walking your carb a few steps lean and see if that clears up your stinkies.

Wind up the windows when you stop.

They all stink.

Hi everyone

The engine is almost new it has about 1,200 miles on it. It smells like rich exhaust. I have tried leaning it out but then it misses at higher speed and surges at steady cruising. There is no fuel (black) smoke coming out of the back the inside of the tail pipes look fairly clean. I'm not sure what needles are in my 4 screw round tops as they have no markings. I have tried adjusted my fuel pressure, my float level and the mixture nut. I can change the amount of smell but not get it to go away completely. Maybe I am being to fussy but I do not remember my chevelles and mustangs smelling that bad. maybe the fuel smelled sweeter back then without all the crap they put in it nowadays. I think I am going to install an O2 sensor in the exhaust to find out excatly what is happening.

I am not sure what "smelly" really means, but I know my new motor smells on startup and when warm, but it smells like a new motor. I am assuming you mean exhaust smell? Is it the type that burns your eyes, just smells like rich exhaust, or burning surface oil and paint? You might give it a couple of really hard drives, get everything that will ever get hot, hot, and then see what you have. It may just need to break in, and your nose just may need to adjust. Hard to tell from Idaho.......

What do your plugs look like? Can you post some pictures of the bottoms of your plugs?

What do your plugs look like? Can you post some pictures of the bottoms of your plugs?

Yes, what do the plugs look like?

If you have carbs jetted for a 2.4 L on a 2.8L motor, it must run rich at low R's to feed the car at high R's. Sounds like you need to go up a size or two on the jets which will lean the car out at low R's (because you can adjust the car properly now) and still feed the motor at hammer down hold on tight time.

I will take some pic's and post them. can you get a larger jet or would it be different needles that I would need?

I will take some pic's and post them. can you get a larger jet or would it be different needles that I would need?

I never shopped jets for round tops, as I have a 2.4 L. I'm not sure about needles either, maby a call to ZTherapy is in order. But if the 2.8 is fresh, it will definetly want more gas at speed than a stock 2.4 L. I don't pretend to be a Z motor guru, but I have built ALOT of hot rods in the past using Kein side drafts, which are similar, and I always installed the DynaJet kits before installing the carbs.