V8_DatZun Posted January 16, 2007 Share Posted January 16, 2007 i just installed a sbc 383 into my 280zx a week or so ago.. the past 3 days i've fired it up a few times for a few seconds just to hear it etc. now i have the radiator and im ready to break it in (it is a newly built engine) i didnt have the vacuum distribution fitting on the back of my intake (so it idled very high) so i got that and installed it (had to take off my carb to do it... also had the carb upside down as i put permatex on the gasket to be sure it sealed yeah i know i know.. wont do it again) i got everything connected back and now the engine doesnt want to fire back up.. it spits and sputters blows smoke out the headers and i got it to start up 1 time for a few seconds.. then it cut back off soon as i left off the throttle.. i was going to break it in but i cant get it to fire up now... could it be flooded, a float stuck or something from turning it upside down? also i have the Fuel pump wired to turn on when the ign is on the on position not the cranking posititon... this probably also led to the flooding... maybe i need to get new plugs and try it? any suggestions? Quote Link to comment Share on other sites More sharing options...
jnjdragracing Posted January 16, 2007 Share Posted January 16, 2007 My first thoughts are that since the vacum port was open then it was getting plenty of air, now since you have sealed it you are not. You need to turn out ( counter clockwise ) your air / fuel mixture screws to allow more air. I would go about a full turn and a half on both sides and give it a try. Plugs could be gas fouled but his only happens if it was running awhile and the float was stuck. You said it just tried to fire up. Foulded plugs will cause it to misfire and such. I take it that it is a holley carb, if so just tap the float adjuster with a wrench a couple of times on the primary and secondary. This should free the float. You can also have a friend turn on the fuel pump while you look at the carb and see if there is fuel coming out. Hope this helps. John Quote Link to comment Share on other sites More sharing options...
V8_DatZun Posted January 17, 2007 Author Share Posted January 17, 2007 one other thing i thought of... i didnt have the pulleys on and my engine builder had torqued the balancer bolt on.. when i tried to loosen it the engine rotated backwards about a half a turn.. the distributor was still in but could this cause the problem? when it DID fire up today gas shot out of the top of the carb in a mist.. kinda heavy though. thats why i believe it is flooded... if it is that flooded then my plugs are probably fouled. it would fire right up no problem.. now it just sputters and tries to start sometimes.. mostly just turns over though. Quote Link to comment Share on other sites More sharing options...
jnjdragracing Posted January 17, 2007 Share Posted January 17, 2007 As long as the dist. was still in, then rotating the engine back would not cause an issue. You need to fix the fuel issue 1st. You still have not stated what kind of carb. you have. I would change the way you have the fuel pump wired, have it on a seperate switch, this way you can turn it on, then off to crank the engine. If fuel is spraying out then you probably have fouled plugs. A lot of raw fuel is ot good for a new engine, will wash out the cylinders and go past the un seated rings. Needs to be resolved soon. John Quote Link to comment Share on other sites More sharing options...
iaconsultants Posted January 17, 2007 Share Posted January 17, 2007 Also depending on which make and model of carb you have you could have plugged air bleed holes or pocket that is on the bottom surface of the carb. Generally they do not have them but I have seen a few that do. I believe rochester is one of them. Next time just use a gasket and do not use permatex to seal any carb to an intake manifold. Also depending on which carb you have most have a sealed float but there are a few out there that have open top floats and if you turned it over then you filled it up. There is little that anyone can give you on advice until they know what carb you are using. Good luck Quote Link to comment Share on other sites More sharing options...
V8_DatZun Posted January 17, 2007 Author Share Posted January 17, 2007 ah... sorry.. holley 750 DP and im pretty sure that it was the fact that i left the fuel pump on for like a minute w/o firing it... so do i need new plugs if they are fouled? Quote Link to comment Share on other sites More sharing options...
jnjdragracing Posted January 17, 2007 Share Posted January 17, 2007 Yep, it is the easy way to go. I would make sure the fuel issue is corrected before installing new plugs. Quote Link to comment Share on other sites More sharing options...
V8_DatZun Posted January 17, 2007 Author Share Posted January 17, 2007 thanks... so you suggest a switch that i manually flip when i want to start the car? say i have power to the switch when the ign is to the on position... then i flip the manual switch it powers off.. that way if i forget to hit the manual switch atleast the ign kills the fuel pump... i can add a "Fuel Pump On" red light on a gauge with an LED also... if this is what you meant by a switch. thanks for the help. Quote Link to comment Share on other sites More sharing options...
sweetleaf Posted January 18, 2007 Share Posted January 18, 2007 If you did flood it , I would also change the oil. It probably went past the rings and into the crankcase/oilpan. Quote Link to comment Share on other sites More sharing options...
Paz8 Posted January 18, 2007 Share Posted January 18, 2007 Run the fuel pump circuit through an oil presure switch so it shuts down if the engine stalls,(like the JTR manual shows) once the carb has fuel in it there is plenty fuel to give it a shot of gas to start the engine. Unless your car is for racing only a toggle switch only to shut off the pump is not a good idea, what if something happens were the engine stalls and the car is one it's side or upside down, you will have gas running until you think about turning it off, if you are able to. Quote Link to comment Share on other sites More sharing options...
V8_DatZun Posted January 18, 2007 Author Share Posted January 18, 2007 i have the jtr manual but somehow overlooked that part... ill have to search for that part of it... thanks. *Ok i see now how it works... i knew there had to be a way w/o manually doing it thanks for the info... Quote Link to comment Share on other sites More sharing options...
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