Author Topic: idle rpm  (Read 1826 times)

Offline 351c4v71

  • Jr. Member
  • **
  • Posts: 244
idle rpm
« on: May 12, 2016 - 09:01:25 PM »
Hi guys,
Just got back my 71 cuda with 440-6 from the local speed shop.
They re-installed the choke which disengages when engine is hot. Car starts well when cold but rpm is 2200, isn't this high??
I have an A833, power steering (not power breaks), 270H comp cam (mild), headers, rest is stock.
It takes about 8minutes driving for the choke to disengage then rpm falls to about 900 (is this too high?).
Very hard to start engine when hot ?!!!?? :clueless:

Still have some bakfires on hard acceleration and when I slow down quickly (downshifting) the car somtimes stalls...  :pullinghair:

Any ideas, suggestions are appreciated. :1zhelp:

Thanks as always.

JS
Montreal, Canada




Offline CUDA JAS

  • Resident
  • *****
  • Posts: 2292
  • vroooooom!
Re: idle rpm
« Reply #1 on: May 12, 2016 - 09:10:17 PM »
It does not sound right...do you have any info on the timing???

Jason
74 'cuda 360/727



Gearhead: car nut, automotive enthusiast, one who loves hot rods, muscle cars, hot trucks, burnin' rubber and neck snapping performance. 

Just call me a gearhead!

Offline cudabob496

  • Sr. Resident
  • ******
  • Posts: 8024
Re: idle rpm
« Reply #2 on: May 12, 2016 - 09:19:35 PM »
that kinda idle rpm is common when have vacuum leak.
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000

Offline Chryco Psycho

  • Administrator
  • C-C.com Guru
  • *****
  • Posts: 36620
  • 70 Challenger R/T SE 70 tube Chassis Cuda now sold
Re: idle rpm
« Reply #3 on: May 12, 2016 - 11:28:47 PM »
there is a small tab that hooks into the fast idle cam , it can be ebnt with a small screwdriver drop it to around 1400 cold
 hot idle can be 800 or so  had starting cold is partially the heat crossover in the intake , a 1215 intake gasket wil solve this but then you need to go to an electric  choke system or the choke will never come off

Challenger - You`ll wish You Hadn`t

Offline 351c4v71

  • Jr. Member
  • **
  • Posts: 244
Re: idle rpm
« Reply #4 on: May 13, 2016 - 08:50:09 AM »
I don't have info on timing.

Thanks for the info guys.

Offline HP_Cuda

  • Hit the skinny little pedal on the right!
  • Sr. Resident
  • ******
  • Posts: 5268
  • Mopar or No Car!
Re: idle rpm
« Reply #5 on: May 13, 2016 - 02:47:41 PM »

Chokes are always more pain then they are worth.

I must have pulled about 10+ in my days.
1970 Cuda Clone 440 4 speed - sublime green
1970 Cuda 383 4 speed - yellow - SOLD

Offline cudabob496

  • Sr. Resident
  • ******
  • Posts: 8024
Re: idle rpm
« Reply #6 on: May 13, 2016 - 09:08:31 PM »
Chokes are always more pain then they are worth.

I must have pulled about 10+ in my days.

ya, got a single plane and 850DP. Cut off the choke tower. You can learn to start your car without it.
I pump twice, wait a minute for the gas fumes to move throughout the engine, then hit starter, and starts
right up without choke. Just have to keep rpms up around 1500 for a little with with your foot, just like the choke
does.
« Last Edit: May 13, 2016 - 09:55:02 PM by cudabob496 »
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000

Offline moper

  • Resident
  • *****
  • Posts: 2368
Re: idle rpm
« Reply #7 on: May 19, 2016 - 12:19:56 PM »
Your engine should idle hot around 700-750 and cold on high idle around 1300. With the popping and other issues I'd say you need to find someone who is familiar with the sixpacs to tune yours. Everyone seems to think you need a high idle. they should idle cleanly and at the factory rpm unless you've really modified the engine.

Offline AMXguy

  • Sr. Member
  • ****
  • Posts: 1035
Re: idle rpm
« Reply #8 on: May 22, 2016 - 11:42:33 AM »
I have the blocked off heat passage on my six pack and I set the choke to come on VERY  LIGHTLY and it works  pretty good.   set it like you're supposed to and I'm sure  it wouldn't come off.   

1970 R/T SE Challenger
 1970 Superbee
 1969 S code Mach 1
 1967  GTO