| FAQ |
| Members List |
| Social Groups |
| Calendar |
| Search |
| Today's Posts |
|
#1
11-29-2023, 12:37 AM
|
|||
|
|||
'65 Tri-Power Idle's Rich When Cold
Hello,
Recently restored '65 Tri-Power has begun running rich, 10-11:1 AFR at idle when cold. Sounds and idles horrible and can stall out unless I feather the throttle. After warming up and driving 3-4 miles the issue self-corrects and the idle AFR is 14-15:1 and the idle is smooth and good. I have a center carb rebuild kit and I am thinking of simply doing a basic rebuild and doing my best to clean the idle circuit. Any ideas on what causes a rich idle when cold, but self corrects when warm after a few miles? Thanks!
__________________
1965 Pontiac GTO 455/469 w/ #48 Heads, '65 Tri-Power 9.25:1 CR Stump Puller Cam Muncie M22W 1st-2.56 2nd-1.75 3rd-1.37 4th-1.00 3.55 Rear Differential Front: 225/60R15 Height: 25.6" Rear: 275/60R15 Height: 28" |
|
#2
11-29-2023, 04:22 AM
|
||||
|
||||
|
Choke settings?
|
|
#3
11-29-2023, 12:21 PM
|
||||
|
||||
|
Agree, choke setting
|
|
#4
11-29-2023, 12:51 PM
|
|||
|
|||
|
Choke operates normally, I have confirmed the choke plate is open.
Maybe the float is sticky and frees up after some heat and driving around?
__________________
1965 Pontiac GTO 455/469 w/ #48 Heads, '65 Tri-Power 9.25:1 CR Stump Puller Cam Muncie M22W 1st-2.56 2nd-1.75 3rd-1.37 4th-1.00 3.55 Rear Differential Front: 225/60R15 Height: 25.6" Rear: 275/60R15 Height: 28" |
|
#5
11-29-2023, 11:00 PM
|
||||
|
||||
|
What is normal?
Manifold heat to cross-over? Heat tubes to choke working properly? Correct choke spring for the Tri-Power? TV
__________________
"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
|
#6
11-29-2023, 11:10 PM
|
|||
|
|||
|
Choke, fast idle, etc. all set up and functioning properly. The vehicle cold starts fine, fast idle bumps it up to 1500 rpm, and choke opens with heat, etc... The carbs where restored by Mike W., so are set up as correct as can be in our hobby. Idle mixture tubes have been enlarged by Mike in accordance with my engine specs.
__________________
1965 Pontiac GTO 455/469 w/ #48 Heads, '65 Tri-Power 9.25:1 CR Stump Puller Cam Muncie M22W 1st-2.56 2nd-1.75 3rd-1.37 4th-1.00 3.55 Rear Differential Front: 225/60R15 Height: 25.6" Rear: 275/60R15 Height: 28" |
|
#7
11-30-2023, 07:04 AM
|
||||
|
||||
|
Vacuum leak?
Flooding condition/black exhaust? |
|
#8
11-30-2023, 01:04 PM
|
|||
|
|||
|
No, vacuum leak would result in a lean condition. I have an O2 gauge. This is a rich condition. It's not flooding either.
__________________
1965 Pontiac GTO 455/469 w/ #48 Heads, '65 Tri-Power 9.25:1 CR Stump Puller Cam Muncie M22W 1st-2.56 2nd-1.75 3rd-1.37 4th-1.00 3.55 Rear Differential Front: 225/60R15 Height: 25.6" Rear: 275/60R15 Height: 28" |
|
#9
11-30-2023, 04:06 PM
|
||||
|
||||
|
Ok, then i would check the choke rod adjustment.
For 1965 Tripower the measurement should be .055". If this still makes a too rich initial cold start mixture you may want to adjust to a slightly larger distance. HTH |
|
#10
11-30-2023, 05:18 PM
|
|||
|
|||
|
OK, but the condition persists when the choke is fully open (visually confirmed), then self corrects when fully warmed up, 180F, and I have driven 3-5 miles.
I'm going to clean out the idle circuit as best as I can and take it from there.
__________________
1965 Pontiac GTO 455/469 w/ #48 Heads, '65 Tri-Power 9.25:1 CR Stump Puller Cam Muncie M22W 1st-2.56 2nd-1.75 3rd-1.37 4th-1.00 3.55 Rear Differential Front: 225/60R15 Height: 25.6" Rear: 275/60R15 Height: 28" |
|
#11
11-30-2023, 10:56 PM
|
||||
|
||||
|
Have you spoken to Mike to review your engine/trans specs and his choice to increase idle tubes? What did he say? While end carb problems usually result in lean idle conditions, have you removed end carbs and installed blanks?
|
|
#12
12-01-2023, 09:46 PM
|
||||
|
||||
|
Mike's been doing Tripowers for a very long time. I'm sure if you call him, he'll walk you right through the steps and what to look at, or if he needs a carb back from you. He's a nice guy and very approachable....If it were me, I'd give him a text and a ring.
|
|
#13
12-11-2023, 07:18 PM
|
|||
|
|||
|
I did a full rebuild today.
The one issue I found was a damaged / torn accelerator pump rubber cup. See photo.  Car runs great now! Sent from my iPhone using Tapatalk
__________________
1965 Pontiac GTO 455/469 w/ #48 Heads, '65 Tri-Power 9.25:1 CR Stump Puller Cam Muncie M22W 1st-2.56 2nd-1.75 3rd-1.37 4th-1.00 3.55 Rear Differential Front: 225/60R15 Height: 25.6" Rear: 275/60R15 Height: 28" |
|
#14
12-11-2023, 07:44 PM
|
|||
|
|||
|
Problem solved
It did a complete rebuild and found a torn accelerator pump rubber cup See photo Car runs great now. Sent from my iPhone using Tapatalk
__________________
1965 Pontiac GTO 455/469 w/ #48 Heads, '65 Tri-Power 9.25:1 CR Stump Puller Cam Muncie M22W 1st-2.56 2nd-1.75 3rd-1.37 4th-1.00 3.55 Rear Differential Front: 225/60R15 Height: 25.6" Rear: 275/60R15 Height: 28" |
|
#15
12-11-2023, 07:45 PM
|
|||
|
|||
|
Problem solved
It did a complete rebuild and found a torn accelerator pump rubber cup See photo Car runs great now. Sent from my iPhone using Tapatalk
__________________
1965 Pontiac GTO 455/469 w/ #48 Heads, '65 Tri-Power 9.25:1 CR Stump Puller Cam Muncie M22W 1st-2.56 2nd-1.75 3rd-1.37 4th-1.00 3.55 Rear Differential Front: 225/60R15 Height: 25.6" Rear: 275/60R15 Height: 28" |
|
#16
12-11-2023, 09:25 PM
|
||||
|
||||
|
Ahhh! the simple things in life...that can drive a man to drinkin'!!!
Happy you found the culprit. |
|
#17
12-14-2023, 02:00 PM
|
||||
|
||||
|
Sorry, I don't understand how the torn pump cup could cause flooding.
__________________
BONESTOCK GOATS '64 GTO Tripower Hardtop (Wife's Car) '64 GTO Tripower Post Coupe (My Car) '99 Bonneville SE Sedan |
|
#18
12-14-2023, 03:59 PM
|
||||
|
||||
|
Quote:
|
|
#19
12-14-2023, 05:13 PM
|
||||
|
||||
|
I can't see how a torn pump cup causes a rich idle when cold, but self corrects when warm after a few miles?
|
| Reply |
|
|
The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.
Linear Mode
