High Rpm help 94 Ls

[ThunderTegg]

Hey Guys i just installed the intake manifold on my 94 Ls and when i turned it over the rpm went to 6, then i adjusted the wire thats for the gas pedal, and know its going from 4 to 2 repeatedly?? Is it a Vacuum leak? it has New IACV and New Gaskets?? Please Help

 

[Bianchi Fran]

hey guys, my 94 ls made this crazy bad grind sound in third gear at 5500 rpms. it sounded almost like i grinded a gear but i hadn't put my foot on the clutch or shifted yet. it scared the crap out of me, it seeems to run fine now.

 

[lsvtec1243]

Hey Guys i just installed the intake manifold on my 94 Ls and when i turned it over the rpm went to 6, then i adjusted the wire thats for the gas pedal, and know its going from 4 to 2 repeatedly?? Is it a Vacuum leak? it has New IACV and New Gaskets?? Please Help

vacuum leak. put your hand over the throttle body while the car is running and see if the car shuts off or if it stays running. be careful because their is a lot of suction on your hand from the engine.

 

[ThunderTegg]

I just installed a new PCV Valve and know its on 2 rpm, isnt that still a little high? 1 should be perfect but i cant seem to find the problem?? please help i really want to get my car up and running..

 

[BrianZ]

Hey Guys i just installed the intake manifold on my 94 Ls and when i turned it over the rpm went to 6, then i adjusted the wire thats for the gas pedal, and know its going from 4 to 2 repeatedly?? Is it a Vacuum leak? it has New IACV and New Gaskets?? Please Help

Definitely sounds like a vac leak. After adjusting the throttle pedal cable do you have slack, it need some slack. What intake manifold did you put on? Are you sure you have all the vacuum ports used or capped off?. how well did you clean the old gasket off the cyl head?

Did you change the throttle body? I have seen the high idle valve get stuck open a bit and give the same symptoms.

One trick you can used to locate the leak is to use some brake parts cleaner/carb clean and with the car running spray down any place there could be a vac leak (I recommend doing this when the car is colder).

 

[Merlins Beard]

I just installed a new PCV Valve and know its on 2 rpm, isnt that still a little high? 1 should be perfect but i cant seem to find the problem?? please help i really want to get my car up and running..

Is the 2000 rpm idle when the car is warm or cold? The cold engines will idle quite a bit higher than a warm engine. Normal warm idle is around 750 rpm, cold idle about 1500 rpm if I remember correctly. My Miata will idle around 1750-2000 rpm when its turned on in the cold weather, but once the engine warms up it will drop down to around 800-1000.

Did you replace or do anything with the throttle body? Your TPS might need to be recalibrated, mine came unplugged once and my idle sat around 2000 and the car was preforming pretty bad. Also double check to make sure the MAP and TPS connectors are not switched, they are located close to each other and both the connectors are the same and fit both of the sensors.