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Jeep Wrangler YJ
YJ General Discussion
'93 Wrangler YJ 4.0 doesn't start: turns over, good spark, 40 psi at fuel rail
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<blockquote data-quote="machoheadgames" data-source="post: 437083" data-attributes="member: 18789"><p>Yup, IAC would be what I’d look into. If your spark and fuel are good, only thing left is air. If the IAC is stuck and not retracting to give the motor air, then it won’t start. Holding the throttle open by pressing the pedal while cranking would narrow it down. If it starts while holding pedal, then you need a new IAC. If that doesn’t fix it, then you have a spark or fuel issue which was incorrectly diagnosed when deciding that spark and fuel were good.</p><p></p><p>Definitely check out the IAC.</p><p></p><p>Fuel pressure should be 31 psi at idle with the fuel pressure regulator hose connected and 39 psi with it disconnected (simulates high load conditions - regulator is vacuum operated and ups the pressure when you’re on the gas hard).</p></blockquote><p></p>
[QUOTE="machoheadgames, post: 437083, member: 18789"] Yup, IAC would be what I’d look into. If your spark and fuel are good, only thing left is air. If the IAC is stuck and not retracting to give the motor air, then it won’t start. Holding the throttle open by pressing the pedal while cranking would narrow it down. If it starts while holding pedal, then you need a new IAC. If that doesn’t fix it, then you have a spark or fuel issue which was incorrectly diagnosed when deciding that spark and fuel were good. Definitely check out the IAC. Fuel pressure should be 31 psi at idle with the fuel pressure regulator hose connected and 39 psi with it disconnected (simulates high load conditions - regulator is vacuum operated and ups the pressure when you’re on the gas hard). [/QUOTE]
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Jeep Wrangler YJ
YJ General Discussion
'93 Wrangler YJ 4.0 doesn't start: turns over, good spark, 40 psi at fuel rail
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