how to increase my idle rpms

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gwmcgowa

New Member

Feb 23, 2010

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Mar 3, 2010

#1

• Mar 3, 2010

• #1

when i am idling in gear, my rpms are at about 700-800 and i can literally watch the battery voltage drop. if i keep one foot on the gas just a little and keep the rpms at a steady 800, the voltage is perfect. i have a cam which gives a rough idle already and i just installed a 140 amp alternator, so i know it should have plenty of juice. i am thinking if i just increase the idle rpms i should be alright, how would i do that? thanks

 

tannerc91gt

This last 25% is foreign territory at this point

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#2

• Mar 3, 2010

• #2

You can adjust it with the idle set screw
but I wouldn't recommend it. The 5.0s like to idle in the 650-750 range from my experience. It's up to you but, I'd say you have another issue. Did you use the stock wiring when you installed the new alt?

 

f8tlfiveo

My wife likes my spool and blow-off valve.

Aug 8, 2007

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Lancaster, PA

Mar 4, 2010

#3

• Mar 4, 2010

• #3

I have a upgraded alternator also... Don't believe the stock gauge.. It's junk.. Mine does the same thing.. But if you get the voltage checked under the hood it is pin fine..I did turn my idle up to about 800-850..it was around 650 before..now the gauge stays right at 14-15 volts..plus the idle is more steady now. It used to fluctuate about 200 rpms.

 

S

stangfanatic

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Oct 4, 2009

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Mar 4, 2010

#4

• Mar 4, 2010

• #4

As an alternative to screwing around with the idle if you are having charging issues, you can replace the alternator pulley with a slightly smaller one so the alternator spins faster at idle.

 

stykthyn

I want to measure mine. It doesn't look that tall.

15 Year Member

Jul 6, 2006

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Mar 4, 2010

#5

• Mar 4, 2010

• #5

change the pulley. you are idling exactly where you are supposed to.

 

Mustang5L5

That is…until I whipped out my Bissell

Mod Dude

Feb 18, 2001

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Mar 4, 2010

#6

• Mar 4, 2010

• #6

ASP makes overdrive alt pulleys for about 20 bucks summitu sells then. i have one on my car

 

tannerc91gt

This last 25% is foreign territory at this point

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Mar 4, 2010

#7

• Mar 4, 2010

• #7

Im putting a smaller pulley on as well, and removing the alt fan.

Still curious if you upgraded the alt wiring or just the alt?

 

G

gwmcgowa

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Feb 23, 2010

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Mar 4, 2010

#8

• Mar 4, 2010

• #8

thanks everyone for the replies this all sounds good, i will start with changing the pulley. When i changed the alternator, i bought a 140 amp 1 wire, so i guess you can say i did change the wiring because it no longer uses the factory harnesses/connections.

 

T

TorontoGT

Member

Dec 9, 2009

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Toronto, Ontario

Mar 4, 2010

#9

• Mar 4, 2010

• #9

My idle seems a bit low after I had my distributor off. I put it back right where it came from, but I feel the idle is lower now, but I can't recall 100% where it was prior to removal. The car also feels like it stumbles a bit when I blip the throttle...



Is timing my issue?

 

Gearbanger 101

Straight Outta Locash

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Mar 4, 2010

#10

• Mar 4, 2010

• #10

stangfanatic said:

As an alternative to screwing around with the idle if you are having charging issues, you can replace the alternator pulley with a slightly smaller one so the alternator spins faster at idle.

Click to expand...

Yup...good, inexpensive advice.