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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="Wyvern_64" data-source="post: 437065" data-attributes="member: 20769"><p>Hi all,</p><p></p><p>I have a '93 Wrangler YJ 4.0L (automatic transmission), and I'd like help diagnosing it. Here's what I've observed so far:</p><ul> <li data-xf-list-type="ul">I started it recently and drove it a short distance. About an hour later, it would turn over but not start.</li> <li data-xf-list-type="ul">It turns over just fine every time, so the starter system seems good. 12.5V at the battery</li> <li data-xf-list-type="ul">I think it has good spark - I disconnected the spark plug wires from 2 of the spark plugs and confirmed spark on both of them (they were the easiest to get to), and I also disconnected the spark plug wire from the ignition coil at the distributor and confirmed good spark there.</li> <li data-xf-list-type="ul">With a fuel pressure tester connected to the Schrader valve on the fuel rail, I measured about 40 psi while cranking. In my online research it seems like this is about right?</li> </ul><p>Any ideas for what to look into or try next? I'm at a loss, and in all of my online research people's issues have been one of those 3 things above. The only thing I suspect is the crankshaft position sensor (leading to bad spark timing), but I thought it wouldn't even spark at all if that was bad.</p><p></p><p>Thanks in advance!</p></blockquote><p></p>
[QUOTE="Wyvern_64, post: 437065, member: 20769"] Hi all, I have a '93 Wrangler YJ 4.0L (automatic transmission), and I'd like help diagnosing it. Here's what I've observed so far: [LIST] [*]I started it recently and drove it a short distance. About an hour later, it would turn over but not start. [*]It turns over just fine every time, so the starter system seems good. 12.5V at the battery [*]I think it has good spark - I disconnected the spark plug wires from 2 of the spark plugs and confirmed spark on both of them (they were the easiest to get to), and I also disconnected the spark plug wire from the ignition coil at the distributor and confirmed good spark there. [*]With a fuel pressure tester connected to the Schrader valve on the fuel rail, I measured about 40 psi while cranking. In my online research it seems like this is about right? [/LIST] Any ideas for what to look into or try next? I'm at a loss, and in all of my online research people's issues have been one of those 3 things above. The only thing I suspect is the crankshaft position sensor (leading to bad spark timing), but I thought it wouldn't even spark at all if that was bad. Thanks in advance! [/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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