Cold Start Jerking
Guest
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Cold Start Jerking
Hi,
JUst recently purchased my first Z car, 81 non-turbo 280Z w/94K miles. Her is my problem. On cold start the engine jerks and bucks while driving until warm. When warm it has only a slight miss when accelerating. I have replaced the cap,rotor,wires (factory) and plugs. Also the rubber boot on the air flow meter (throttle body side) is cracked from age. Does this affect the performance ? Should I replace it?
All imput is very much appreciated.
Thanks
JUst recently purchased my first Z car, 81 non-turbo 280Z w/94K miles. Her is my problem. On cold start the engine jerks and bucks while driving until warm. When warm it has only a slight miss when accelerating. I have replaced the cap,rotor,wires (factory) and plugs. Also the rubber boot on the air flow meter (throttle body side) is cracked from age. Does this affect the performance ? Should I replace it?
All imput is very much appreciated.
Thanks
Guest
Posts: n/a
Re: Cold Start Jerking
yeah the crack in the boot after the meter sure does make a difference because its measuring air that that isnt getting to the motor or its getting more air than the afm is telling it... so try replace that first ....
Rusty Datsun x 3
Rusty Datsun x 3
Registered User
Joined: Feb 2002
Posts: 2,906
From: Saskatoon, SK
Re: Cold Start Jerking
ill check for that too but we had a discussion about this long time ago...like here in canada at -5 lets say i can barely get my car started it turns on and just shuts off right away...i hit the gas it just stalls it it doesnt revv up ....so i dunno before they said this is normal to all Z cars....i dunno
The Evil Twin
Joined: Mar 2001
Posts: 9,297
From: Seattle, WA
Re: Cold Start Jerking
Mine does that a bit too. I replaced my distributor after finding out tha my vaccume advance was stuck. It helped a lot!
The problem is still there, but not nearly as bad. I can at least drive a little when it is cold. I used to have to just set for a minute before I started out, and even then I would have to be really easy on the throttle. I think it might have something to do with my throttle body. I put on the Motorsport big throttle and ever since I've had a problem with cold starts. It progressivly got worse though untill I fixed the distributor.
The cold-start valve may also be a cause of this. My intake hose appears to be complete. Even when warm, the large throttle has a fraction of a second of hesitation where I remember my stock throttle was so responsive. That's what I loved about my Z when I first got it. I always talk about going back to the stock throttle because I hate everything about this large throttle body! I just never have the time to fix it!
The problem is still there, but not nearly as bad. I can at least drive a little when it is cold. I used to have to just set for a minute before I started out, and even then I would have to be really easy on the throttle. I think it might have something to do with my throttle body. I put on the Motorsport big throttle and ever since I've had a problem with cold starts. It progressivly got worse though untill I fixed the distributor.
The cold-start valve may also be a cause of this. My intake hose appears to be complete. Even when warm, the large throttle has a fraction of a second of hesitation where I remember my stock throttle was so responsive. That's what I loved about my Z when I first got it. I always talk about going back to the stock throttle because I hate everything about this large throttle body! I just never have the time to fix it!
Guest
Posts: n/a
Re: Cold Start Jerking
just get some rubber tube that is the same size you should be able to get an angled piece at an automotive store.
The bucking might have to do with your EGR valve, or your TVV (thermal vacuum valve) check if they are working properly.
The TVV opens and closes depending on the engine temp which activates you EGR valve, if either of them aren't working the engine will run as you have described.
The bucking might have to do with your EGR valve, or your TVV (thermal vacuum valve) check if they are working properly.
The TVV opens and closes depending on the engine temp which activates you EGR valve, if either of them aren't working the engine will run as you have described.
The Evil Twin
Joined: Mar 2001
Posts: 9,297
From: Seattle, WA
Re: Cold Start Jerking
If you have a solid rubber piece running from your throttle body to your air flow meter, how do you suggest someone hooks up the cold-start vaccume hoses to the TVV and the valve cover vent hose?
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