Two80z4me Posted July 13, 2009 Share Posted July 13, 2009 MY 1978 280z seems to be stumbling upon its share of problems, I would like help with the L28/P79 engine. The Throttle is sticking when you first put your foot on it, it is hard to push and "sticky" then it lets go and releases and its easy to push again? Also, it is recently having trouble starting in the 50degree range, It starts up quick when its 70-100, but it takes a few tries to start it in the colder weather, when it does start in the cold weather, it stutters horribly for the first 20minutes you drive it (in the 1000-2500rpm range, anything above it slows down its stuttering)? p.s. Im trying plugging it in tonight to see if that might help. And I tried searching but found nothing on the throttle and very little that I hadn't done already relating to the starting. Quote Link to comment Share on other sites More sharing options...
MJLamberson Posted July 13, 2009 Share Posted July 13, 2009 With the throttle thing try spraying some wd-40 on the linkage, or just convert to cable,its so much smoother. Quote Link to comment Share on other sites More sharing options...
Two80z4me Posted July 13, 2009 Author Share Posted July 13, 2009 With the throttle thing try spraying some wd-40 on the linkage, or just convert to cable,its so much smoother. thanks for the suggestion, Right now its just the stock bar linkage. The previous owner started to do the cable, I have the parts in a box. Is it very complicated? Quote Link to comment Share on other sites More sharing options...
rinn240z Posted July 13, 2009 Share Posted July 13, 2009 have you tried cleaning the throttle blade? this may also help with the cold start issue Quote Link to comment Share on other sites More sharing options...
Two80z4me Posted July 13, 2009 Author Share Posted July 13, 2009 have you tried cleaning the throttle blade? this may also help with the cold start issue Im new to Z cars actually, I have only ever owned saabs so im not sure were that is located, is it by the front of the engine were the linkage conects or closer to the clutch area. Quote Link to comment Share on other sites More sharing options...
m4xwellmurd3r Posted July 13, 2009 Share Posted July 13, 2009 I found out what caused my throttle to stick JUST like you describe. Look at your throttle linkage. The very rear bushing, near the firewall, is probably rotten, causing the shaft to have a lot of slack. it sticks because once it kinks over from hitting the throttle, it binds. I didn't really fix mine, I just soaked it in 3 in 1 oil and eventually it stopped sticking haha Also sounds like your cold start injector isn't going off when it's cold outside. Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted July 13, 2009 Share Posted July 13, 2009 As mentioned above. There is gunk betweent the throttle plate and the body causing it to stick. The side benefit to cleaning the throttle body is your idle air control system doesn't have to add as much air. Quote Link to comment Share on other sites More sharing options...
Two80z4me Posted July 14, 2009 Author Share Posted July 14, 2009 I fixed the throttle sticky, i soaked everything in wd-40 then oil, so somewhere along the line it got fixed. Now my main concern is the way its driving, its running very rough, it stutters and clugs thru 1500-3000rpms and then it sputters and skips from 2000-3000. I really haven't an idea on this, it has new spark plugs/wires, and the distributor is clean. Im testing all of the vacuum lines tommorow. And maybe its being cause by the gasket that burst between my header and exhaust, it leaks substantional exhaust thru the headers now, so if that might cause it please tell me? Quote Link to comment Share on other sites More sharing options...
Challenger Posted July 14, 2009 Share Posted July 14, 2009 I know you solved the throttle stick issue but figured Id mention another possible thing that can cause it. (for future members searching) If your throttle stop screw isnt screwed in far enough the throttle plate will close so far that it actually wedges itself into the throttle body opening. Way to fix it is obviously run the screw in alittle. Im not sure how this affects the idle air control since I removed all of that before I had that problem. Quote Link to comment Share on other sites More sharing options...
m4xwellmurd3r Posted July 14, 2009 Share Posted July 14, 2009 I fixed the throttle sticky, i soaked everything in wd-40 then oil, so somewhere along the line it got fixed. Now my main concern is the way its driving, its running very rough, it stutters and clugs thru 1500-3000rpms and then it sputters and skips from 2000-3000. I really haven't an idea on this, it has new spark plugs/wires, and the distributor is clean. Im testing all of the vacuum lines tommorow. And maybe its being cause by the gasket that burst between my header and exhaust, it leaks substantional exhaust thru the headers now, so if that might cause it please tell me? My Z stumbles at partial throttle because my throttle position switch is set a bit off, so it actually thinks the throttle is closed, and puts it into its idle enrichment mode or whatever you call it. Quote Link to comment Share on other sites More sharing options...
Two80z4me Posted July 14, 2009 Author Share Posted July 14, 2009 My Z stumbles at partial throttle because my throttle position switch is set a bit off, so it actually thinks the throttle is closed, and puts it into its idle enrichment mode or whatever you call it. Thats exactly what it does, it only does it when my foots into below a quarter of the way in, it stops doing it when I give it 1/2 or more (foot in the gas) or if im just driving normal it goes lug lug lug skip lug. thats my best impression of it. Quote Link to comment Share on other sites More sharing options...
Two80z4me Posted July 15, 2009 Author Share Posted July 15, 2009 Today, I diagnosed my problem, it went from a slight missfire to today it MISFIRES. Its very aparent and I will be diagnosing the problem on my lonesome from here on out, thank you for your assistance and if anymore problems re-open themselves I will post a new link after I Search. thank you, and Mods you may now destroy the thread. Quote Link to comment Share on other sites More sharing options...
m4xwellmurd3r Posted July 15, 2009 Share Posted July 15, 2009 Thats exactly what it does, it only does it when my foots into below a quarter of the way in, it stops doing it when I give it 1/2 or more (foot in the gas) or if im just driving normal it goes lug lug lug skip lug. thats my best impression of it. Maybe your TPS is causing the issue if it's only doing it at that much throttle, because that's exactly how mine reacts. actually, if I'm at speed and I slow down, giving it just enough throttle to open it up a bit, it'll start pouring in gas and will rumble like crazy. it'll backfire too at times. Though, that's pretty normal it seems. But from your last post, it seems the problem has gotten worse? Quote Link to comment Share on other sites More sharing options...
Two80z4me Posted July 15, 2009 Author Share Posted July 15, 2009 Maybe your TPS is causing the issue if it's only doing it at that much throttle, because that's exactly how mine reacts. actually, if I'm at speed and I slow down, giving it just enough throttle to open it up a bit, it'll start pouring in gas and will rumble like crazy. it'll backfire too at times. Though, that's pretty normal it seems. But from your last post, it seems the problem has gotten worse? yes, now it has turned into a misfire that is blatently clear, and its an electrical misfire. Also the hole that developed in my header isnt exactly helping. 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.