C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

delayed pulsing idle / recent slp runner install

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Old Jul 14, 2008 | 11:26 PM
  #1  
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Default delayed pulsing idle / recent slp runner install

Ok, straightened out the cold start valve tab and it sealed properly. This eliminated the vacuum leak and the car idled fine. Buttoned it up and at first ran great. However after about 15 min. developed a pulsing while idling around a parking lot. Put in in neutral and it pulsed to the point it almost died. Let it idle some more, revved it up a bit and the pulsing went away. Idled and drove fine then about 5 min later started pulsing at a stoplight. Took off started running fine again. ran fine for a while than stopped at a light and it died. started right up but pulsing again. then drove fine for about 5 min. and started pulsing again.

I don't understand why it would run fine then pulse (idle poorly) kind of a bllllllll bllllllll, then run fine. Please any advice would be greatly appreciated.

Going to the homecoming in Bowling Green this weekend and still haven't shined for the show. I've got to get this right fast!

Thank you as always,
Jeremy
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Old Jul 14, 2008 | 11:30 PM
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Pulsing? You mean loping idle?

Vacuum leak. Motors with vacuum leak rev beautiful - every time. Idle? No.
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Old Jul 14, 2008 | 11:35 PM
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Originally Posted by blue85z51
Ok, straightened out the cold start valve tab and it sealed properly. This eliminated the vacuum leak and the car idled fine. Buttoned it up and at first ran great. However after about 15 min. developed a pulsing while idling around a parking lot. Put in in neutral and it pulsed to the point it almost died. Let it idle some more, revved it up a bit and the pulsing went away. Idled and drove fine then about 5 min later started pulsing at a stoplight. Took off started running fine again. ran fine for a while than stopped at a light and it died. started right up but pulsing again. then drove fine for about 5 min. and started pulsing again.

I don't understand why it would run fine then pulse (idle poorly) kind of a bllllllll bllllllll, then run fine. Please any advice would be greatly appreciated.

Going to the homecoming in Bowling Green this weekend and still haven't shined for the show. I've got to get this right fast!

Thank you as always,
Jeremy
jeremy
you said you reinstalled the CSI and sealed it properly. How did you seal it? and with what?
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Old Jul 14, 2008 | 11:49 PM
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Just meant it seated properly with the O-ring.
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Old Jul 14, 2008 | 11:51 PM
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not a lope more of a steady beat................... ............. .................. ................. .............. all the way from 450-650 rpm at worst; but then will stop and idle around 620 rpm for 10 minutes plus.
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Old Jul 14, 2008 | 11:59 PM
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Originally Posted by blue85z51
Just meant it seated properly with the O-ring.
i would check that again, they are notorious for vac leaks.. put a bead of silicone on the o ring, then reinstall and do not start it till the silicone dries.. good job for tonight.
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