Hot Starting?

[albert_ey]

Hey I've been having this problem with my Zed. When I start up my car in the morning when the Z is cold it will fire right up without a problem. After I drive it around and gets to normal operating temperature I park and turn it off, and if I Turn it on within five minutes it starts right up. If I Leave it for about 10 minutes, then come back and try starting it, it wont start unless I give it some gas. If I don't give it some gas it will just sputter and then turn off. Any ideas on what causes this, and how I can fix this. I own a 73' 240Z and the carbs were replaced with 72' 240Z carbs.

[zeiss150]

you don't have to give it gas when you start it cold in the morning? I always have to give my Z a little shot from the peddle when I start it. If I just start it with my foot on the break It wont get enough fuel into the engine to start, it'll just sort of sputter and die. Now keep in mind I don't have to pump it (unless its cold in the morning, below 70 F) just a tap on the peddle and vrrrooooooom.

if you have to pump it mabe your float bowls are draining ... but then that wouldn't explain the easy cold start.

Are you using the heat sheild? It could be getting the fuel lines to hot and causing problems?

I hope this helped.

Matt-

[albert_ey]

You know, I think it does have the a heat shield on some of the hoses the car was originally from Oregon and I think they had those on for the cold weather. I'll remove them and see what happens. Thanks, I don't know why I didn't think of that.

[Zs-ondabrain]

Also check your fuel lines for leaks. I know that sounds dumb cause you'd be able to smell or see it. BUT... If the fuel is allowed to sit for a bit longer it flows backwards and away from the float bowls.

Roughly it's a lack of fuel in the float bowls or the float bowl tube that goes to the carbs throttle needle. It's not a big deal and pretty typical of most carbed Z's.

Dave.

[beandip]

you don't have to give it gas when you start it cold in the morning? I always have to give my Z a little shot from the peddle when I start it. If I just start it with my foot on the break It wont get enough fuel into the engine to start, it'll just sort of sputter and die. Now keep in mind I don't have to pump it (unless its cold in the morning, below 70 F) just a tap on the peddle and vrrrooooooom.

if you have to pump it mabe your float bowls are draining ... but then that wouldn't explain the easy cold start.

Are you using the heat sheild? It could be getting the fuel lines to hot and causing problems?

I hope this helped.

Matt-

If you are running SUs there is no benefit to pumping on the throttle. SUs do not have any accelerator pump . Depressing the throttle only opens the butterflies and that is all . Adding choke is what is needed on a cold engine. Albert, are you in an area that has summer heat ? sounds like hot fuel lines . Are you running an electric fuel pump? These were added to the Zs in '73 to alleviate the peculating of the gas in the fuel rail. Just a thought. If you add choke will the engine fire up ? Gary

[Surfsup]

you don't have to give it gas when you start it cold in the morning? I always have to give my Z a little shot from the peddle when I start it. If I just start it with my foot on the break It wont get enough fuel into the engine to start, it'll just sort of sputter and die. Now keep in mind I don't have to pump it (unless its cold in the morning, below 70 F) just a tap on the peddle and vrrrooooooom.

if you have to pump it mabe your float bowls are draining ... but then that wouldn't explain the easy cold start.

Are you using the heat sheild? It could be getting the fuel lines to hot and causing problems?

I hope this helped.

Matt-

yeah same here i always have to press the gas pedal, i dont even have choke amazingly it works LMAO.

[zeiss150]

I know there is no accelerator pump so pumping the peddle alone doesn't do anything to add gas but the pumping action gives it a big gulp of air which will suck more fuel through the carbs than at idol alone. At least thats my theoryLOL my Z wont start unless I do the pumping thing if its in the 50's (thats cold for us in southern california). I stoped using the choke cause it caused more problems than it fixed, and I just didn't feel like fixing the choke problem.

Matt-

[albert_ey]

In the morning when I start it, I just open the choke and it starts right up. I removed the heat shield from some of the fuel lines. That seems to have fixed the problem. Yeah and there is also a leak which I will be taking car of that today. I went to put gas in my tank and I decided to fill it to the top, It wouldn't fill, then I saw there was a leak at the fuel pressure sending unit, the gasket is worn out. Any ideas where I can buy that gasket and what it is called? Will I have to buy a new unit?

[Arne]

Pumping it won't help. But depending on how your carbs are adjusted, holding the throttle open slightly may be necessary of helpful. But not pumping it.

[New-to-240z]

I just started noticing this same problem. Today i was at the Z show @ Little Oak canyon and after letting it sit out in the sun for about 1 hour (after driving for about 20 min) the car wouldn't start up at all!!!I opened the hood and let it sit for about 15 min. Some really nice guys in a grey 240z saw i was having trouble and helped me out. I had to literally push the gas pedal all the way down to the floor and start her up. after about 5 turns she started up, but if i were to just let her sit with my foot off the gas she would drop to 500 rpms start to stutter bad and then die. I had to keep putting her into nutral at every stop light to make sure it wouldn't die on me. (she's an A/T) Anyone have any clues? I'm gonig to replace the fuel filter and fule line from the top of the fuel filter tomorrow. Hopefully that solves the problem. I think my carbs arejust really poorly tuned.

Also, the heat shield you guys are talking about, is it in the engine bay, or under the car? Because i have no heat shields at all in the engine bay. Only under the front of the car, and that i believe is for keeping rocks and stuff from hitting things inside the engine bay.

[albert_ey]

The heat shields that I removed were on the fuel lines leading to the carbs, it looks almost like cotton covered in aluminum and wrapped around the lines. Man I wish I would have taken some pictures.