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Rebuilt Engine wants to die

1K views 2 replies 2 participants last post by  BrokenCrank 
#1 ·
I recently finished rebuilding the motor on my 1992 Miata and started it this Saturday. However it will start and then immediately die. But when I disconnect the connector to the IAC Valve it allows the engine to idle albeit very rough and not even close to 850 rpm that is recommended. But in order to get the car to idle at even 1100 rpm smoothly, the timing has to be set way before BTDC like the mark is perpendicular to the ground (the CAS is turned all the way down) and the idle adjust screw doesn't seem to be really doing much of anything to help it. And the car still idles very rough. But when you give it gas it seems to do fine above 2000 rpm.

FYI I did jump the TEN and GND on the Diagnostic and when I installed the timing belt I double checked that all marks were lined up (and I also checked yesterday with photographic evidence), and I have double checked that my spark plug wires are going to correct coil pack.

I have posted this problem on two other forums and haven't got much response as of yet so I was wondering if anyone here could help me figure out my issue.

I haven't yet checked for any vacuum leaks with carb cleaner but on visual inspection I haven't found anything to suspect of a leak. Does the IAC Valve need to be replaced or is the fact that it will idle without it plugged in mean that the TPS is not properly adjusted or telling the ECU that it is closed?

Thanks,

Micah
 
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#2 ·
I haven't yet checked for any vacuum leaks with carb cleaner but on visual inspection I haven't found anything to suspect of a leak. Does the IAC Valve need to be replaced or is the fact that it will idle without it plugged in mean that the TPS is not properly adjusted or telling the ECU that it is closed?

Thanks,

Micah

This is why you haven't gotten responses. Do this first and report back. Most likely the problem, or an unplugged connector (not as likely).

Make sure all random vac ports on IM are capped, or the caps aren't broken. Yes it is very obvious, and yes you will completely miss it while sticking your eyeball on every section of vaccum line looking for pinhole leaks.
 
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