Idle Mix vs. Idle Speed Vs. Timing For AIR INjection - The 1947 - Present Chevrolet & GMC Truck Message Board Network

bluec10 · 08-02-2015, 02:47 PM

Doing a tune up on my '69 with a 250 L6. Having trouble getting a smoothe idle. The dwell is in spec and timing set at 4 degrees BTDC. The truck came with AIR Injection but I took it off. The manual says that the timing should be a 0 degrees BTDC if the truck has AIR injection. I thought that since I took off the AIR injection system I should use the non-AIR recommendation of 4 BTDC. Is my logic sound or do engines with AIR injection have a different cam or something?

Also, does anyone have any advice for setting IDLE MIX VS. IDLE SPEED?
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bluec10 · 08-05-2015, 12:28 PM

ttt

swamp rat · 08-05-2015, 07:31 PM

Maybe the mods can move this thread to the engine and drivetrain folder??

08-02-2015, 02:47 PM	#1
bluec10 Registered User Join Date: Apr 2002 Location: Manitoba, Canada Posts: 663	Idle Mix vs. Idle Speed Vs. Timing For AIR INjection Doing a tune up on my '69 with a 250 L6. Having trouble getting a smoothe idle. The dwell is in spec and timing set at 4 degrees BTDC. The truck came with AIR Injection but I took it off. The manual says that the timing should be a 0 degrees BTDC if the truck has AIR injection. I thought that since I took off the AIR injection system I should use the non-AIR recommendation of 4 BTDC. Is my logic sound or do engines with AIR injection have a different cam or something? Also, does anyone have any advice for setting IDLE MIX VS. IDLE SPEED? Posted via Mobile Device

08-05-2015, 12:28 PM	#2
bluec10 Registered User Join Date: Apr 2002 Location: Manitoba, Canada Posts: 663	Re: Idle Mix vs. Idle Speed Vs. Timing For AIR INjection ttt __________________ Present: 2015 Tacoma. Yeah, not a GM, but I love it. 1969 GMC 32,000 - fix, drive, relax, fix... 2019 BMW R1250 GSA - Yahoooooooo 1979 Honda GL 1000 - retro touring at its best. Past: '05 Sierra 4x4 - Had 270,000 KM and running well when it was written-off by a stop sign runner. '94 F-150 from the "F word" company. I'll admit it...good truck. Sold what was left of it for $800 to a guy who came to pick it up at 11:00 PM with cash in hand. Hmm. '79 Sierra Grande (Black) organ donor - perfect rebuildable 4-bolt 350 and a good TH350. '76 Sierra Grande (Orange) - hate isn't too strong a word. Kid who bought it turned it into a hot rod. '68 C-10 R.I.P. - Dad's old truck...too far gone to resurrect. '59 C-50 - with hoist. Truck is gone, wife isn't. Nuff said.

08-05-2015, 07:31 PM	#3
swamp rat Registered User Join Date: Oct 2007 Location: Spanaway Posts: 8,451	Re: Idle Mix vs. Idle Speed Vs. Timing For AIR INjection Maybe the mods can move this thread to the engine and drivetrain folder?? __________________ Mike. Swamp Rat build thread : http://67-72chevytrucks.com/vboard/s...d.php?t=595019 72 3/4T 4X4 4" BDS Lift 33" BFG's



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