1978-280z overheating issue - Nissan : Datsun ZCar forum :Nissan Z Forum: 240Z to 370Z
User Tag List

 1Likes
Reply
 
LinkBack Thread Tools
post #1 of 12 (permalink) Old 03-20-2017, 01:05 AM Thread Starter
Member
 
Join Date: Feb 2008
Posts: 36
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
(Thread Starter)
Question 1978-280z overheating issue

When I run the car for an extended amount of time (about 30+ minutes) and get to my destination, the car is turned off, it seems that the fuel rail gets extremely hot after about 15 min and then doesn't want to start. After several attempts and getting some cooler fuel into the rails, it will finally turn over and start. I've replace the fuel regulator, AAV, fuel filter, plugs, and a few other things..... Does anyone have any other suggestions?? It gets worse as the weather gets warmer.
montanagrl is offline  
Sponsored Links
Advertisement
 
post #2 of 12 (permalink) Old 03-20-2017, 09:59 AM
Senior Member
 
Join Date: Jun 2001
Location: Gainesville, GA
Posts: 2,325
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 53 Post(s)
Technically that's not overheating. That's heat soak.

Do you have a stock exhaust? I can't remember whether or not there is a heat shield. Other than that you could put some insulating material around the fuel lines/fuel rail like this:




To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- A great place to search for answers

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- the cheap source for FSMs

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- Look up S30 part numbers

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- My blog with some tech tips and pictures of my car-loving life

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- Pictures from various car shows
steve240Z73 is offline  
post #3 of 12 (permalink) Old 03-20-2017, 12:08 PM
Senior Member
 
pilgrim's Avatar
 
Join Date: Mar 2008
Posts: 507
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 64 Post(s)
Either insulate the fuel rail, or consider adding a fan like those on the turbos to blow air over the fuel rail. Insulation would be much the simpler option. Doing the wiring and figuring out a thermostatic or timer option to fun the fan would take some thought.
pilgrim is offline  
 
post #4 of 12 (permalink) Old 03-20-2017, 05:59 PM
Senior Member
 
sactojohn's Avatar
 
Join Date: May 2015
Location: Sacramento, CA
Posts: 205
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
It is common to run rough for a little while, but it should start. Not only the rail gets hot, but the injectors get even hotter so the fuel changes from liquid to vapor. The ZX had a cooling fan to try and remedy the problem. Adding alcohol to our gas has turned it from a slightly rough start to a really rough start since alcohol vaporizes at a lower temperature. I noticed that it gets worse in the winter and that is because winter fuel is designed to vaporize at a lower temperature than summer blends. That might be nice for our air, but it is bad for these cars which have no trouble at all vaporizing fuel. You also might have a fuel pressure leak that makes the problem worse. Try installing a pressure gauge or a push button going to the fuel pump relay so you can run the pump before starting. Of course, I'm also assuming that the fuel filter is fairly new, plugs, wires, cap, rotor, and timing, are fresh. You just give it some gas after starting until the idle starts to smooth out. Once it is in gear and traveling, everything is fine again. I'm currently assembling a simple cooling setup using a bilge blower in mine to avoid the hot start problem altogether. I will post it up once I get everything working properly. It should look clean and have a programmable timer so the fan comes on for X minutes after the engine is shut off. It only uses 2.5 amps.

Last edited by sactojohn; 03-20-2017 at 06:11 PM.
sactojohn is offline  
post #5 of 12 (permalink) Old 03-20-2017, 10:33 PM
Senior Member
 
Join Date: Mar 2010
Posts: 462
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 38 Post(s)
A cheap, crude "fix" is to just pop your hood when you stop and leave it slightly ajar (to the first 'catch' or even wider). This allows the heat to escape much faster - and therefore cool the fuel rail down quicker. Yes, it's a pain in the butt. But I got into the habit of doing it to my '75, especially in the summer when the hot engine would fart and pop like a cement mixer for 5 mins before smoothing out. It works great, but yes I did have fears someone would mess with the engine. Nobody ever did tho, even when the wind would blow the hood all the way open. LOL
Just to be sure - your '78 does have the original hood vents, yes? The story is that Datsun added them to the '77-78 Z cars specifically to help alleviate the heat soak probs in the '75-76s, which did not have hood vents.
6shutr is offline  
post #6 of 12 (permalink) Old 03-21-2017, 07:37 AM
Senior Member
 
Join Date: Jan 2002
Location: Phoenix, Az
Posts: 950
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 41 Post(s)
Here in the desert the hood popping works great. Also second the notion of being sure that you have the heat shields installed.

az240z
Taken from another: The more I touch the more I break!!!

1973 240z Long gone and then wrecked
1975 280z auto to manuel sold
1976 280z sold
1985 300zx sold
1986 300zx 78K miles wrecked
1978 280z Body done trying to rest Sold
1973 240z 3 liter Sold
Z less for now
az240zz is offline  
post #7 of 12 (permalink) Old 03-21-2017, 08:43 AM
Senior Member
 
Join Date: Sep 2015
Location: Central FL
Posts: 496
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 93 Post(s)
do you run ethanol free gas?
Dave M is offline  
post #8 of 12 (permalink) Old 03-21-2017, 08:45 AM
Senior Member
 
Join Date: Jun 2001
Location: Gainesville, GA
Posts: 2,325
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 53 Post(s)
Here's a site to find out if there is ethanol free gas near you: http://www.pure-gas.org


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- A great place to search for answers

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- the cheap source for FSMs

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- Look up S30 part numbers

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- My blog with some tech tips and pictures of my car-loving life

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
- Pictures from various car shows
steve240Z73 is offline  
post #9 of 12 (permalink) Old 03-23-2017, 03:40 PM
Member
 
Join Date: May 2016
Posts: 34
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
I have tried many things, popping the hood works well. But if I forget, I have to floor the pedal when starting and leave it floored till it starts and RPMs get to about 3K. Then it runs poorly till the gas bubbles are pushed out.
Greaser2 is offline  
post #10 of 12 (permalink) Old 03-24-2017, 10:56 PM
Senior Member
 
sactojohn's Avatar
 
Join Date: May 2015
Location: Sacramento, CA
Posts: 205
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Very few ethanol free stations in CA on that list. It is illegal to use in a motor vehicle here and it is $6.93 per gallon. On top of that, most of us have to drive for hours to get to these out of the way towns with empty gas cans and cart it back home. Cheaper to just figure out a solution to the problem or just live with it.
sactojohn is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Nissan : Datsun ZCar forum :Nissan Z Forum: 240Z to 370Z forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



  Similar Threads
Thread Thread Starter Forum Replies Last Post
Overheating Issue (1982 280zx) ford 70-83 Tech Discussion Forum 3 07-13-2015 05:03 PM
Overheating issue cured 4-EZT 90-96 Tech Discussion Forum 7 09-03-2008 10:38 PM
79 280ZX MILD Overheating Issue nny403 70-83 Tech Discussion Forum 14 09-29-2007 11:13 AM
Strange Overheating Issue Asharak7777 84-89 Tech Discussion Forum 2 08-06-2005 02:28 PM
Overheating Issue Asharak7777 84-89 Tech Discussion Forum 4 07-16-2005 02:17 AM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome
 


Content Relevant URLs by vBSEO 3.6.1