zguy95135 Posted February 8, 2004 Share Posted February 8, 2004 My dad's 78 280Z starts fine cold but after driving around for a while and turning it off it wont start. It'll crank over but it wont catch for a very long time, and when it does it barely runs. It will backfire and it is on the verge of stalling at idle. After running for about 45 seconds it will run fine, the car seems to be flooding like its not getting enough oxygen. When get bought the car it was running ok but it slowy started to get worse so now it barely starts. We need to get this fixed so he can get it smogged and back on the road. Any replies and suggestions would be appreciated. Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted February 12, 2004 Share Posted February 12, 2004 It could be a number of things (Doh!). If it's ignition related it could be your dist, cap, rotor, spark plugs, plug wires, coil, or your ignition module. Some of these items will need to be checked w/a V/O meter. Your fuel injectors may be malfunctioning. Do you have a Factory Service Manual(?), which will give you instructions on how to properly check the electrical items. It could be a fuel injection relay: check your relay's w/an V/O meter. Be sure and check the simple things like your air filter first. When you say it runs fine once it finally starts-does this mean that the engine has plenty of get up and go..or does it ever back fire after starting?...and any rpm?...under WOT? Describe how the engine turns over just before it starts: does the engine turn over sluggishly or does the engine turn over quickly? Sluggishly-I would check your battery cables, both the ground cable & the cable going to your starter. If it turns over quickly then your problem is not in the starting system...unless your Ignition Switch is defective. Kevin, (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
zguy95135 Posted February 12, 2004 Author Share Posted February 12, 2004 we came back from a trip near LA and we were moving pretty good on the way back (over 110mph ) so I dont know if it could be the injectors. When the car turns over it does it fast, and when it finally catches it barely keeps up the idle so he has to constantly adjust the throttle to keep rpms up, and it usually idles right on tjhe verge of stalling and backfires about 4 times while right after it catches. The car has no problem picking up rpms when he blips the throttle but if he lets completely off the throttle it will stall. Its strange because after keeping it running for a bit and drives it it is fine. Quote Link to comment Share on other sites More sharing options...
QWKDTSN Posted February 12, 2004 Share Posted February 12, 2004 Heat soak? Quote Link to comment Share on other sites More sharing options...
Phantom Posted February 12, 2004 Share Posted February 12, 2004 Yup - sounds like vapor lock to me. How long after shut down do you have the problem with the restart? If it's just a few minutes you shouldn't have a problem but if it's about 10-20 minutes and you're having the problem it's vapor lock. Fuel injector rails are being baked by the exhaust manifold and vaporizing the fuel in the rail. Is your heat shield in place between the exhaust manifold and the intake? If it's not - there's your culprit. Otherwise - you may need to install additional shielding of some kind for the rails. The 280Zx cured the problem with a blower that blew air across the rails for a certain amount of time after engine shut down. Quote Link to comment Share on other sites More sharing options...
zguy95135 Posted February 12, 2004 Author Share Posted February 12, 2004 i'll try putting on some extra shielding, hopefully that will help. thanks for the replies Quote Link to comment Share on other sites More sharing options...
zguy95135 Posted February 17, 2004 Author Share Posted February 17, 2004 We went for a drive in the Z and when we stopped after about 30 mins of driving (pretty fast) the car wouldnt start. The fuel lines didnt feel hot to the touch but the intake was extremely hot (im pretty sure thats normal). We tried spraying some water on the fuel lines bt it didnt do anything. When we were driving the temp guage didnt say it was hot . BTW he has a four core radiator on the car so could it be giving off more heat then usual? (dont think thats the problem because he's had it for a while). Also could the fan clutch be going out? edit: also, the car is backfiring through the airfilter (actually its more like "spitting" ) Quote Link to comment Share on other sites More sharing options...
Brad-ManQ45 Posted February 19, 2004 Share Posted February 19, 2004 If you wait about 20 minutes w/hood up, does it start/idle ok? Quote Link to comment Share on other sites More sharing options...
zguy95135 Posted February 19, 2004 Author Share Posted February 19, 2004 yea Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.