My 73 mod 3,0SI Wont start when hot.

Jan-Arve Enoksen

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Hi
Hope to get some suggestions from you guys. My 3,0 Si starts fine and runs fine. BUT if i stop it after running for 20 min or more ,it wont start until it has cooled down for a while. I havent checked fuel and ignition at that stage yet. Any suggestians will be appreciated. Where do i start to look?
Thanks
 

teahead

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starter solenoid getting too hot? Check for bad grounds on that starter. May need a new solenoid.
 

duct-tape

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Explain the symptoms, does it turn over?

I'm not familiar enough with djet to know if it has a hot/cold start feature.

If it turns over, pull a spark plugs and see if it's wet.
 

Jan-Arve Enoksen

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Engine turns over.I have not checked spark plugs or fuel yet. But if i wait for 20-30 minutes ,it starts like normal again. As long as it runs , there are no problems. Only if i turn it of when it has normal cooling temp .
 

sfdon

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When it won’t start-

Crank the car when hot and listen for injectors clicking at each injector using a screwdriver held to your ear.

Key on - operate throttle linkage at throttle body. Listen for injectors clicking.


Crank the car with a spark plug on your valve cover inserted into the coil wire end
 

Jan-Arve Enoksen

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When it won’t start-

Crank the car when hot and listen for injectors clicking at each injector using a screwdriver held to your ear.

Key on - operate throttle linkage at throttle body. Listen for injectors clicking.


Crank the car with a spark plug on your valve cover inserted into the coil wire end
Thanks
Will try these suggestions. What is the solution if it is these thing(s)?
 

duct-tape

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okay, it's not spark or your starter.
The Si system relies on fuel pressure but when the car gets hot, the rail gets hot and you get a version of vapor lock. 99% of the time, you can replace the fuel pressure regulator, and it wouldn't hurt to be a 5psi higher. otherwise, your fuel pump is getting tired and can't re-pressurize the line with the hot fuel vapors at the engine. Modern gas tends to vaporize at less than 35psi when it's over 120*f
 

sfdon

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Just test for them.
No reason to write a book of solutions if neither is the problem.
 

Jan-Arve Enoksen

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okay, it's not spark or your starter.
The Si system relies on fuel pressure but when the car gets hot, the rail gets hot and you get a version of vapor lock. 99% of the time, you can replace the fuel pressure regulator, and it wouldn't hurt to be a 5psi higher. otherwise, your fuel pump is getting tired and can't re-pressurize the line with the hot fuel vapors at the engine. Modern gas tends to vaporize at less than 35psi when it's over 120*f
Thanks. I will look at that too. I already suspect fuel pump or pressure ,but would check here first for possible solutions.
I will report back when i have solved it.
 
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