High RPM at start up/then occilates
 

I recently bought a '90 honda accord. It 'had' a bad vibration at
idle, so replaced the dogbone in the front (torn rubber element) to no
avail. Then changed out the rear motor/xmission mount (what a bear)
as it was the most probable cause and found it was indeed damaged. Of
course to do this I removed the intake manifold, so had to refill the
coolant, replaced the gasket etc. Now the engine revs up to 3500 and
back down to around 800 and then goes through the cylce again. I've
triple checked vacuum runs to make sure I didn't swap something,
checked for cracked vac hoses. Can anyone suggest
something...please...I've about run out of patience.

High RPM at start up/then occilates
 

On 11/16/2011 03:43 PM, wrote:
> I recently bought a '90 honda accord. It 'had' a bad vibration at
> idle, so replaced the dogbone in the front (torn rubber element) to no
> avail. Then changed out the rear motor/xmission mount (what a bear)
> as it was the most probable cause and found it was indeed damaged. Of
> course to do this I removed the intake manifold, so had to refill the
> coolant, replaced the gasket etc. Now the engine revs up to 3500 and
> back down to around 800 and then goes through the cylce again. I've
> triple checked vacuum runs to make sure I didn't swap something,
> checked for cracked vac hoses. Can anyone suggest
> something...please...I've about run out of patience.

re-bleed the coolant. air bubbles affect the coolant sensor and thus
the fuel injection.


--
nomina rutrum rutrum

High RPM at start up/then occilates
 

On Nov 16, 5:43*pm, wrote:
> I recently bought a '90 honda accord. *It 'had' a bad vibration at
> idle, so replaced the dogbone in the front (torn rubber element) to no
> avail. *Then changed out the rear motor/xmission mount (what a bear)
> as it was the most probable cause and found it was indeed damaged. *Of
> course to do this I removed the intake manifold, so had to refill the
> coolant, replaced the gasket etc. *Now the engine revs up to 3500 and
> back down to around 800 and then goes through the cylce again. *I've
> triple checked vacuum runs to make sure I didn't swap something,
> checked for cracked vac hoses. *Can anyone suggest
> something...please...I've about run out of patience.

Sounds like a big vacuum leak. You can tru looking for internal leaks
by checking the egr and pcv systems. Also if everything is hooked up
properly again. if you need diagrams I can help.
lemme know
hondatech327