RPM: How to increase?

edward

Original poster
Member
Jan 17, 2012
7
Hi there !!!

I want to increase my Envoy I6 2004 from about 610 to 650. At 650 it feels much better, less vibration. How exactly i do that? What i need to buy if something? Any step by step? (sometimes, only sometimes, i miss the simplicity of the old cars )

Thanks a lot, Ed
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Me007gold said:
Give it some more gas, the rpms will go up.
:no: :frown: :hissyfit:

To permanently adjust the idle RPM, you need tuning software to edit a parameter table inside the PCM. Can cost $100+. A revised tuning table for instance from our vendor PCMFORLESS.COM can fix a whole raft of other issues and it's considered the best bang for the buck modification you can do.

But let's discuss why you think that's a useful thing to do. If you have a vibration at exactly 10 Hz, rotational that you can see on the intake manifold side of the engine, you may just have bad motor mounts. If the vibration is worse in DRIVE with the brakes on than it is in PARK or NEUTRAL, it's almost certainly motor mounts.

Tell us more.
 

edward

Original poster
Member
Jan 17, 2012
7
Thanks Roadie, good to see you are around!!!

Well, i did replace the motor mounts with genuine ones (only 2, did not replace the trany one). It feels better now but still some vibration (neutral and drive) that i notice almost go way, if the idle RPM are slightly higher. There is no vibration after 10 MPH or so while driving, nor when i brake. In fact, i spent (or invest?) around $1000 on maintenance recently (motor mounts, thermostat, water pump, trany filer/oil, all 4 brakes, gas filter, air filter, spark plug and one coil that failed due to water corrosion [know problem on these vehicles i believe]). Some of the spark plugs were corroded and some had oil when i changed them (know problem too i believe). I am doing now about 73K mi and i have to admit that in general, this Envoy feels like new. The slight vibration is annoying though, specially after replacing the mounts... should i replace the trany mount?

Hope you can provide further assistance. Your help is always truly appreciated.

Ed
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Wherever the community is, that's where you'll find me. :wink:

I neglected to ask for a maintenance history earlier - thanks for listing it. Were the plugs Delco 41-103?

I didn't change my tranny mount, and I might so it some day for fun. My vibration went down to 10-20% of what it was, so I gave up changing stuff. So I can't advise if the tranny mount will help at all. To adjust your idle will require a tune (a computer electronic modification) - so look into PCMFORLESS.COM
 

edward

Original poster
Member
Jan 17, 2012
7
Roadie
Yes, 41-103. Well, if you gave up, i will join the team !!! Next time that i go for a tune, i will ask for increased RPMs. Since probably it won't help, i will not replace the trany mount, though i might ask for it to be tested, if there is a way to do it. If you change yours, please let us know if that helped.
Thanks, for the help.

Ed
 

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