Yorgee Posted May 20, 2007 Share Posted May 20, 2007 Well, it all started when I let my dad take my car to work in the morning because I needed a more fuel efficient car to drive to corona. When I get back, my dad tells me that my car died on him and gave him hell on the way back home. He basically had to hotwire the ignition straight to the coil to start the car and constantly use the choke to keep it running. So we were under the impression that the engine wasn't getting enough spark with the stock alternator. Luckily, we had picked up an alternator from a 280zx at a junk yard a while back and we were able to find some information online on how to intall it with the 240z harness. Using a diode and bridging some wires from the voltage regulator, it turned out great, the car starts instantly (even when cold). But about my engine. Its a l28, f54 block from an 81 280zx with dual downdraft 32/36 Webers. I was disapointed with how late the secondaries kicked in on the carbs so I had an idea of modifying the linkage a little bit. I wish I had my camera so I could take a picture of what I did... But basically, the little lever on the throttle that comes in contact with the secondary valve, I elongated it. I made it bigger to come into contact faster to open up the secondaries at a lower RPM. It turned out pretty insane, a definate power increase. The car drove fine after the modification. Which has me stumped now... I cleaned the sparkplugs, new points on the distributor, new more powerful alternator but still, somethings wrong. When I went to drive it, as soon as i hit the secondarys, the engine just completely chokes, struggles to stay running and when I engage the clutch, the car shuts off and can't stay on under its own power. Now I'm worried that my modification might be throwing in to much air?(but it was working fine before) Because I've tried tunning the carbs, moving the idle and mixture screw all sorts of directions to get a perfect throttle response, but still have the same problem. The distributor is advancing properly, I'm not sure what else it could be. So if anyone has any idea what the problem could be, I'm in dire need of some assistance. My car is just not drivable...and summer school starts on monday haha. I'm not taking no bus. Quote Link to comment Share on other sites More sharing options...
e_racer1999 Posted May 20, 2007 Share Posted May 20, 2007 maybe too rich? that's what would cause it to bog. any smells from the exhaust? Quote Link to comment Share on other sites More sharing options...
Yorgee Posted May 20, 2007 Author Share Posted May 20, 2007 Not sure, I'm going to open the carbs up today to make sure there is nothing going on inside, then try messing with the idle and mixture screw some more. Quote Link to comment Share on other sites More sharing options...
gjc5500 Posted May 20, 2007 Share Posted May 20, 2007 If u have to use the choke constantly, its prolly not too rich. maybe too lean. my engine used to bogg wen it was wya lean. fuel pump maybe? turn the mix screw all the way in, back them out 1.5 turns. thats a good starting point with those carbs, also check fuel pressure, 3psi is the right pressure i think, if ur high or low with those carbs, it wont wanna run right. Quote Link to comment Share on other sites More sharing options...
clsatt Posted June 3, 2007 Share Posted June 3, 2007 that sounds like what was going on with my car before I got the tank cleaned. check your fuel filter. if its dirty I'll bet thats your problem. something else to check is the rubber fuel line, if its cracked it could be creating those same issues. look for little splits around the clamps and if you have a clear filter look for tiny bubbles. as for the starting issue, I've had trouble with the plug on the column wiggling loose. don't know if any of these are going to help but it's cheaper to check them before you start replacing stuff. good luck, chris Quote Link to comment Share on other sites More sharing options...
z_cars_rule Posted June 4, 2007 Share Posted June 4, 2007 fuel pump could be on the way out, so now when the 2ndries open and the car demands more fuel and air, the pump cant keep up. Quote Link to comment Share on other sites More sharing options...
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