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Rich at idle! Help! #2754716
03/22/20 06:24 PM
03/22/20 06:24 PM
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junction city oregon
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viperblue72 Offline OP
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I have a 440 in my ramcharger with a 4150/1050 proform. No matter what I do it runs rich at idle.
I set the throttle blades to show the transfer slots just as I should, set the idle mixture screws 1.5 turns.
Checked the power valve, opened up the idle bleeds from 73 to 76.
It has around 8” vacuum currently. It has 10” if I turn the idle up a little.
But no matter what I do it has little to no effect on a/f ratio of 10.8-11.2.
I’m at a loss.
It cruises around 12.5 and is around 12.5 at full throttle.

Last edited by viperblue72; 03/22/20 06:25 PM.
Re: Rich at idle! Help! [Re: viperblue72] #2754732
03/22/20 06:52 PM
03/22/20 06:52 PM
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AndyF Offline
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If the idle screws don't make much difference then you need to reduce the size of the idle restriction in the metering block. Depending on which carb you have the IFR might be a drilled hole or it might be a jet.

Re: Rich at idle! Help! [Re: AndyF] #2754744
03/22/20 07:23 PM
03/22/20 07:23 PM
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in the middle
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dodger mope Offline
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after shut down for 5 or 10 minutes,does it restart with long crank or blubber- it could be a internal leak like a power valve

Re: Rich at idle! Help! [Re: viperblue72] #2754746
03/22/20 07:26 PM
03/22/20 07:26 PM
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So. Burlington, Vt.
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No matter what you do??

Can you stall the motor by turning the mixture screws all the way in?

If so, I’d say the circuits are functioning properly...... and probably need a different calibration.

If it won’t shut off by turning the screws all the way in....... then figure out where it’s getting fuel from when the screws are all the way in.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: Rich at idle! Help! [Re: fast68plymouth] #2754756
03/22/20 07:43 PM
03/22/20 07:43 PM
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viperblue72 Offline OP
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It does die if I turn the mixture screws too far. But to the point it doesn’t like it, doesn’t change the a/f much at all.
When I took the idle bleeds out of the primary completely it went to 12.2 but then the accelerator pump didn’t work the way it should. I put a 4.5 pv just now and it made no difference.

Re: Rich at idle! Help! [Re: dodger mope] #2754757
03/22/20 07:45 PM
03/22/20 07:45 PM
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viperblue72 Offline OP
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Originally Posted by dodger mope
after shut down for 5 or 10 minutes,does it restart with long crank or blubber- it could be a internal leak like a power valve


It starts and drives no problem at all even after sitting. And it does run just fine. I just can’t get the idle to stop running rich.

Re: Rich at idle! Help! [Re: AndyF] #2754758
03/22/20 07:47 PM
03/22/20 07:47 PM
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viperblue72 Offline OP
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Originally Posted by AndyF
If the idle screws don't make much difference then you need to reduce the size of the idle restriction in the metering block. Depending on which carb you have the IFR might be a drilled hole or it might be a jet.


It does have jets inside on the metering block on both sides of the power valve, along with holes that appear to be for jets. I bought the carburetor new so those are whatever came on the carb. And I don’t know what those do.

Re: Rich at idle! Help! [Re: viperblue72] #2754759
03/22/20 07:50 PM
03/22/20 07:50 PM
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viperblue72 Offline OP
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For what it is worth it didn’t seem the idle mixture screws made any difference for vacuum either. When I opened them past 1.5 the vacuum didn’t go up.

Re: Rich at idle! Help! [Re: viperblue72] #2754764
03/22/20 08:07 PM
03/22/20 08:07 PM
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viperblue72 Offline OP
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Ok now that I have made other adjustments I’m not sure what caused this but now the screws are leaning the mixture. What is the most you want to turn these in? I’m at 12.2 now and the screws are about one full turn out. But now it stumbles really bad when I try to take off.

Last edited by viperblue72; 03/22/20 08:12 PM.
Re: Rich at idle! Help! [Re: viperblue72] #2754768
03/22/20 08:24 PM
03/22/20 08:24 PM
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Romeo MI
MR_P_BODY Offline
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Lean it down a 1/4 turn and open the blade to get the rpm back
wave

Re: Rich at idle! Help! [Re: viperblue72] #2754776
03/22/20 08:45 PM
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The carb should idle on the idle circuits, if it is 4 corner idle adjust both throttle shafts, so the throttle plate DO NOT expose the transfer slots tskscope wrench If they are exposed at all it is not idling on the idle circuits only like it should twocents
Years ago some one on here started the misinformation about exposing the transfer slots to make THEIR carb idle instead of fixing their real issues with that carb rant down


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Rich at idle! Help! [Re: MR_P_BODY] #2754786
03/22/20 09:03 PM
03/22/20 09:03 PM
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viperblue72 Offline OP
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I’ll give that a try next but now it’ll have to wait until tomorrow.

Re: Rich at idle! Help! [Re: viperblue72] #2754804
03/22/20 09:52 PM
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Originally Posted by viperblue72
Originally Posted by AndyF
If the idle screws don't make much difference then you need to reduce the size of the idle restriction in the metering block. Depending on which carb you have the IFR might be a drilled hole or it might be a jet.


It does have jets inside on the metering block on both sides of the power valve, along with holes that appear to be for jets. I bought the carburetor new so those are whatever came on the carb. And I don’t know what those do.


Those are probably the emulsion jets. The idle feed restrictions will be in the upper corners. Maybe post a picture of your metering block and someone will show you what is what.

Re: Rich at idle! Help! [Re: MR_P_BODY] #2754831
03/22/20 11:28 PM
03/22/20 11:28 PM
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crackedback Offline
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Smaller IFR or larger IAB would be a start.

Try dropping the float level slightly. That will help sometimes to clean up idle.

You should have more control over the idle setting, my guess is a smaller IFR so the mixture screw is less sensitive to movement, requires more movement to alter A/F ratio.

Make sure you have initial timing in the correct spot too.

Re: Rich at idle! Help! [Re: crackedback] #2754833
03/22/20 11:32 PM
03/22/20 11:32 PM
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Yes, timing with a big cam should be at least 20 or 25 degrees. Smaller IFRs usually solve the idle tuning problem but sometimes it just takes a little more timing.

Re: Rich at idle! Help! [Re: AndyF] #2755014
03/23/20 12:14 PM
03/23/20 12:14 PM
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junction city oregon
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viperblue72 Offline OP
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Cam is only 230@050 and 112lsa. 050. 9.8 compression rpm intake. Motor made 490hp/553tq.
I did open up the idle air bleeds to 76 from 73. It’s more responsive to adjusting the idle screws.
I got it to 12.2 by closing them up to 3/4 or 1 turn out I can’t remeber exactly. But now it stumbles and dies when I try to take off.
Next idle try to open up the butterflies some to see if it helps, but doesn’t that uncover too much of the slot?
Timing is 18initial 36 total.

Re: Rich at idle! Help! [Re: viperblue72] #2755026
03/23/20 12:33 PM
03/23/20 12:33 PM
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Originally Posted by viperblue72
Cam is only 230@050 and 112lsa. 050. 9.8 compression rpm intake. Motor made 490hp/553tq.
I did open up the idle air bleeds to 76 from 73. It’s more responsive to adjusting the idle screws.
I got it to 12.2 by closing them up to 3/4 or 1 turn out I can’t remeber exactly. But now it stumbles and dies when I try to take off.
Next idle try to open up the butterflies some to see if it helps, but doesn’t that uncover too much of the slot?
Timing is 18initial 36 total.


Maybe re calibrate your Gauge


1968 Charger COLD A/C Hilborn EFI
512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim
2020 T/A 392 Stock 11.79 @ 114.5

Re: Rich at idle! Help! [Re: CSK] #2755044
03/23/20 01:21 PM
03/23/20 01:21 PM
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junction city oregon
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viperblue72 Offline OP
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I believe the gauge is pretty accurate, being what I saw on the dyno through the rpm range
Was consistent with that I seen on this gauge when I put it in the truck.
FWIW the idle wasn’t this rich when I first installed the engine. Which leads me to believe it is something I am doing wrong.
I installed this on my cuda and had to make adjustments then put it back on the truck.
It doesn’t seem to run rich at idle on that motor which is a 410” with big Indy single plane and much bigger cam.

Re: Rich at idle! Help! [Re: viperblue72] #2755046
03/23/20 01:29 PM
03/23/20 01:29 PM
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Romeo MI
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It sounds like one(or more) of the bleed are plugged with trash or something
wave

Re: Rich at idle! Help! [Re: viperblue72] #2755047
03/23/20 01:32 PM
03/23/20 01:32 PM
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Check your exhaust system for air leaks, they will really mislead the O2 sensor and gauge scope


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