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Hey guys. I'm just about done with my restoration of my 72 240 Z and it looks amazing. I painted it LaManes Sunset (350z Orange) but here's the problem...

The car fill's with exaust. I've tried everything I can think of and nothing gets rid of it. I've replaced every gasket and weatherstriping that can be replaced. It seems to me that the problem is the engine is running to rich. I have tried to tune the SU's about a million times and only once has the car not smelled like exaust, and that only lasted about a day. I've adjusted the float bowles, changed out the needles, adjusted the mixture nuts. It seems like no matter what I do it smells like exaust. I'm going to be going turbo with my engine soon but i would like to be able to drive my Z with out smelling like i was sitting next to an exaust pipe. Any suggestions would be really Helpfull.


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Matt , you are sure it is exhaust fumes and not a stale gas smell right ? New vent hoses right ? You have replaced the tail light gaskets and all the hatch seals , right ? What shape were the hatch hinge seals in ? Check in the inner fender area by the antenna , down low where the drain hose from antenna exits . Another area could be a problem is where the vent hoses enter the cabin below the hatch sill . There is supposed to be rubber seals that fit around the hoses Seal this area with silicone . Do you have rubber plugs in the hatch that fill the holes along the bottom of the hatch ? Are you running stock air cleaner with the vent hose running to it from the valve cover , or are you using one of the little filters ? If you are smelling a too rich fuel mixture , have you checked the float levels . If they are set too high the carbs will could be dumping raw gas into the air stream also what needles are you using . I am running a ZX engine with SUs and a Cam and SMs or 27s were way too rich , as soon as I changed to 54s it was just right . When you painted the car did you also paint the engine bay with the engine out ? Are all the holes in the firewall plugged or have proper seals ? Choke cables and throttle linkage and around the wiring below the battery where the main harness enters the firewall ? This is all I can come up with , I hope this is of help . Gary

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Hi Gary, thank for the reply. I have replaced all of the weather striping and tail light gaskets along with the two plugs in the back of the hatch, the Hatch hinge rubber was in great shape. I'll check the drain hole for the anteni I don't remember if I pluged that one up. I know that it is an exaust leak and not fuel vapor If you stand in front of the tail pipe it smells the same as the inside of my car. I also have the N54 needles on my SU's, We have almost the same engine setup I have a ZX (flat top) with N42 head and cam (460 270) electric dizzy, 60 amp altinator, headers, 2.5 inch exaust. The valve cover vents into the stock air cleaner box just as it is suposed to. How do you check your float bowl level. I think the problem is caused by the SU's ... It just smells way to rich. It doesn't put out black smoke (or any smoke for that matter) but I can stink up a parking lot easily. I whish I could hook up an O2 sensor and see what my AFR really is.

Give me a tip on how you set your float bowls Gary and I'll try that and see if it changes anything.

Thanks for your help, Matt-

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As a quick experiment you could get some 2"wide masking tape and tape off the entire hatch area. (Autobody tape not other types) Get the tape off quickly so it doesn't bite into your new paint. If the hatch isn't it then try taping elsewhere. Is your hood to cowl seal in place?? The fresh air intake is under the grille. Check the exhaust system for leaks too. Is your flange gasket leaking? Are your air injection ports on the exhaust plugged correctly? I'm assuming that your car isn't using the smog pump anymore. You could also try using tape and carboard to create a division between the luggage compartment and the pass compartment. Clear the air in both and have someone start the car while you are in the luggage compartment then do the same for the pass cpmt.

Just a few things to try.



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