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-   -   new motor won't idle (https://www.miataturbo.net/engine-performance-56/new-motor-wont-idle-47786/)

DrewLGT May 25, 2010 07:03 PM

new motor won't idle
 
let me preface this by saying my experience working on cars is mediocre at best...


last summer i inherited a BP from a local who had spun a bearing. He had torn the motor down, but decided a junk yard motor would be cheaper and easier than rebuilding this one.

I bought new m tuned rods, and had the short block assembled at a reputable machine shop. The rest of the assembly was done by me.

I started pulling the old 1.6 last december, and seeing as this is a hobby i took my time. I started the new motor for the first time last weekend. the first time it fired, the throttle cable was too tight, and the revs started climbing, so i shut it down. I adjusted the throttle cable and tried again. Now it will fire, the revs go up to about 1600, then sometimes the RPM will immediately slow to a stop. sometimes it will idle high for 30 seconds or so, then die. if i goose the throttle while it's dieing it will go back to a high idle for a second, then die.



any ideas?

jacob300zx May 25, 2010 07:20 PM

maf unplugged

DrewLGT May 25, 2010 07:33 PM

^^ nope, double and triple checked. nothing is unplugged as far as i can tell...

Braineack May 25, 2010 07:45 PM

flapper door on afm is closing and then shutting off fuel pump.

DrewLGT May 25, 2010 07:46 PM


Originally Posted by Braineack (Post 578330)
flapper door on afm is closing and then shutting off fuel pump.

how would i check that?

Braineack May 25, 2010 07:47 PM

jump the fuel pump in the diagnostics box and see if it continues to run.

DrewLGT May 25, 2010 07:48 PM


Originally Posted by Braineack (Post 578333)
jump the fuel pump in the diagnostics box and see if it continues to run.

ground to fp?

DrewLGT May 25, 2010 07:58 PM


Originally Posted by Braineack (Post 578330)
flapper door on afm is closing and then shutting off fuel pump.



no dice...

DrewLGT May 26, 2010 06:51 AM

anybody else? i really dont know where to go from here

Braineack May 26, 2010 07:01 PM

hmmmmmm.

DrewLGT May 26, 2010 07:56 PM

i had a friend come by today, who is alot more experienced at spinning wrenches than i am. he also has a turbo protege...


he looked everything over and didnt see anything wrong. he had me start it up, and worked the throttle on the motor to keep it running. after it warmed up it idled pretty well. he said the idle valve is probably bad, and he has a few extra throttle bodies laying around. i'm going to swap it out and hope that fixes it.


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