240Z, 260Z, 280Z Performance / Technical Discussions related to performance motor enhancements, upgrades.

AFM problems

Old 07-12-2018, 06:05 PM
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AFM problems

Ok guys, i have a 78 280z. The engine will randomly die while driving. I'll pull over, struggle to crank it, pull the boot from the afm, spray some starting fluid staight to the tb and she cranks. Recently I figured out I don't even need starter fluid. I just pull off the boot then she starts. She dies soon after. Sometimes ill crank her like this and put the boot on and she immediately dies. Sometimes when I put the boot back on she idles at about 1.8k. Any suggestions?
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Old 07-15-2018, 09:07 PM
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Welcome to ZDriver!
An engine needs 3 things to start (if it's mechanically working properly):
-Proper air delivery
-Proper fuel delivery
-Proper spark delivery

So when it won't start, does it have fuel (fuel pump works? fuel injectors spraying? fuel pressure?)
Does it have spark at all 6 plugs?

When you can start an engine with starter fluid, that means it's not getting proper fuel delivery... either fuel pump isn't working, or injectors aren't spraying.
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Old 07-16-2018, 07:07 PM
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Ok so I might have it narrowed, but I want to take time to troubleshoot methodically. However, in the early morning and late evening/ night... aka when the sun isn't up and its not hot out, it doesn't do it. It does it whenever everything heats up. I'm thinking vapor lock...
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Old 07-24-2018, 09:07 AM
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Originally Posted by Juffins
I'm thinking vapor lock...
Vapor lock is a carb issue, not fuel injection issue. Check your fuel pressure... should be ~30psi and should not leak down when it's turned off.
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