https://dev.z31library.com/index.php?action=history&feed=atom&title=Forums%2FZ31P%2Fz31-repairs-forums_engine-mechanical%2FInteresting_no_start_issueForums/Z31P/z31-repairs-forums engine-mechanical/Interesting no start issue - Revision history2026-08-15T15:45:26ZRevision history for this page on the wikiMediaWiki 1.43.8https://dev.z31library.com/index.php?title=Forums/Z31P/z31-repairs-forums_engine-mechanical/Interesting_no_start_issue&diff=6042&oldid=prevz31p_FrozenZ: Forum archive import (z31performance)2026-05-15T05:16:55Z<p>Forum archive import (z31performance)</p>
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|op_user=FrozenZ<br />
|op_date=2015-07-10 19:58:06<br />
|post_count=6<br />
|archive_url=/Z31performance_archive/forum/z31-repairs-forums/engine-mechanical/25192-interesting-no-start-issue.html<br />
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'''FrozenZ:''' <small>(2015-07-10 19:58:06)</small><br />
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So:<br />
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Car was having hard hot starts for about a month (but ran idled and fine after) and then decided not to start. 84NA2T running 87T ECU, auto transmission. No idle controls, no o2 sensor, but ran like a top for 2 years like that. Battery is brand new.<br />
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Car will fire once if you leave it for 10 minutes or so, otherwise it just cranks. It isn't sputtering or backfiring or anything.<br />
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In troubleshooting I have put on a new CAS, cap and rotor. I have spark, tested with a spark tester on the #1 wire.<br />
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Fuel pressure is 37PSI after the filter before the rail. Fuel pump primes when key is turned. Not smelling gas in the engine bay so I don't *think* it's flooding.<br />
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Injectors have +12VDC when ignition is ON. What I don't know is if the injectors are firing and I am not sure how to test that - tried the screwdriver trick and I don't *think* they were firing but I am not sure. If the EFI relay was toast would I be getting 12VDC there at all?<br />
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ECU is only throwing the fuel temp sensor code.<br />
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Tried unplugging MAF and CHTS. Neither made any difference.<br />
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Not sure what to try next. Help?<br />
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'''FrozenZ:''' <small>(2015-07-10 21:46:49)</small><br />
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Update:<br />
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Replaced EFI relay because why the fuck not. No difference.<br />
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Ran fuel pump directly off the battery. No difference.<br />
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'''FrozenZ:''' <small>(2015-07-10 22:31:30)</small><br />
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Well fuck me. Bad ECU, or at least bad injector drivers. Put in the car's original minty fresh 84NA ECU and it started right up. Now I need a turbo auto ECU :P<br />
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'''wbnethery3:''' <small>(2015-07-10 22:39:32)</small><br />
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{{Quote|user=FrozenZ|Car was having hard hot starts .................................................. .................................. Bad ECU}}<br />
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^Come in after work and see a time capsule of a guy talking to himself^<br />
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Seriously though, thanks for sharing what you did… this is why FORUM>>>>fb ---- all day, every day…<br />
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'''FrozenZ:''' <small>(2015-07-11 12:40:17)</small><br />
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It's never the ECU (except when it's the ECU).<br />
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Have since discovered that a MT ECU will run an auto car just fine if you have no idle controls.<br />
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Cautionary tale for future troubleshooters: it really is very rarely the ECU. I swapped ECUs only *after* dumping codes, testing fuel pressure, testing spark, and doing things to fix the codes the ECU was throwing.<br />
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'''Mike87:''' <small>(2015-12-01 06:12:47)</small><br />
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Oh man i just posted a thread with an identical issue. I think my issue is the ecu too</div>z31p_FrozenZ