Idle on a 68 250 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

whitesswj · 01-09-2004, 10:41 PM

Why wouldn't a 68 250 I6 Idle at less than 1400 RPM?
I've adjusted the air/fuel mix, adjusted the points, gave it a tune up. Thinking about replacing the airfilter. Anyone w/ experience shed some light on this situation?

Thanks

jef5150 · 01-09-2004, 11:20 PM

are you saying,,,,,, you are backing the idle screw all the way out ,and it "still"idles at 1400?,,,,,,,or if you adjust the idle down below 1400 it dies?............jeff

whitesswj · 01-09-2004, 11:27 PM

If you back the screw off anymore it will die! I got tired of Restartign it every time I shifted gears and stopped, so I raised it to an idling point. I Dies if the screw is backed off.

MOTHERTRUCKERS · 01-10-2004, 12:05 AM

You probably, maybe, could have a vaccumn leak or a cracked intake manifold

charlieo · 01-10-2004, 01:50 AM

On my 250 there is a solenoid looking thing with 2 vacuum hoses attached to it . I think it's an anti-dieseling devise you screw out & the idle comes down !

whitesswj · 01-10-2004, 08:54 PM

I've just recently checked for a cracked manifold and vacume. NONE. Points? And I don't have any thing resembling what charlieo has. anyone else??

**Palf70Step** · 01-10-2004, 10:11 PM

My 70 250 ran really weird like that when I first got it. Turned out if was worn bad were the thottle rod(think that's what it is called) goes into the carb. It allowed it to leak..sort of like a vacumn leak, but I couldn't ever get it to show up under normal country/backyard troubleshooting.

Only other thing that comes to mind is that your carb maybe gummed up in the internal passages and it won't pull enough fuel below that RPM level. I would either rebuiled the carb or, least get the gaskets, pull the top off the carb (6 screws), gently lift it and spray everything in the float and passage areas with carb cleaner. Because mine sits so much I have to do that occassionally to get it to start and run. Once it's has the new tank in and is on the road more, I'll rebuild the carb again and permanently clean out that mess.

69_hafton · 01-11-2004, 03:06 AM

Could be any of the things mentioned. First real thing I did
to mine was put an HEI distributor in. Big difference. I had
a high idle problem when I first bought the truck. Couldn't
find a vacuum leak. High idle cam on the carb isn't even connected - still
isn't. But when I put the dist. in, it was the first time I
could even time the engine!

I still haven't touched the carb,
but it no doubt needs attention. It's more than liveable now,
though, before I couldn't stand the mileage or sitting at a
stop light at 1500-2000+ rpms.

whitesswj · 01-11-2004, 05:49 PM

I've been hearing alot abou these HEI distributors, what are they? And how do I go about getting one of them?? Cost?

**67sss** · 01-11-2004, 06:03 PM

To find out if you have a leak, vacuum or otherwise, take a can of WD40 and start spraying at the base of the carb first then work your way up. If there's a leak the WD40 will get sucked in and cause the engine to run faster...then there's your leak. I allways run premium gas in my 6cyl seems to help, may cost more at the pump but alot less repairs...

PanelDeland · 01-11-2004, 06:33 PM

HEI distributor is a High Energy Distributor.They are Electronic(no points).I got one complete with.coil,cap,dist, and harness from a guy who was parting out a late 70's model.It cost me $25.00 and $8.00 shipping.I cleaned it up and it has worked well.I think 74 or 76 was the first year for them and they should be fairly easy to find.Also since so many people want small blocks they aren't in great demand.

BTW he shipped it by US Mail and it got here in 3 days from OK. It was cheap and fast for shipping.

Longhorn Man · 01-11-2004, 06:52 PM

I agree with the vacume leak idea. I never used WD40 for the testing, but carb cleaner.
Check all your vac lines, like the PVC and power brakes if equipped.
No need for high octain fuel. Run the least amount of octain needed to keep spark knock away. Octain is nothing but resistance to ignition formula and if you run more than needed, it'll not only carbon up your engine more, but may DECREASE MPG and performance.

69_hafton · 01-11-2004, 07:56 PM

To add to PanelDeland's post, GM made the HEI distibutor for the
6 until 79 or so (whenever they quit making the inline 6 pretty much)

I paid $65 for mine locally. Didn't come complete, I had to buy the
cap, wires, and coil for mine. The coil sit in the cap, so try to
get one that has everything. I think there's also an ignition module
that sits up there. Accel makes a kit for the coil and module if I
remember right. It improves spar voltage, but OEM will be a huge improvement
over points.

Watch Ebay, I've seen them go for $40 or so. Hit search on this site
and read up on HEI also. I've probably missed a few things.

MOTHERTRUCKERS · 01-11-2004, 08:34 PM

I have a few 6 cyl HEI's 40.00 each + shipping.

whitesswj · 01-12-2004, 12:55 AM

I just did a point job on it, cost 10 bucks and did it in less than 20 mins. the set i bought came w/ point, condenser, and <i>feeler guages<i>

Lowerd it to 1,000.

Mother - i'll have to think about it! pictures??
thanks!

Longhorn Man · 01-12-2004, 01:16 AM

ouch...65 bucks incomplete. I can get them all day long for 15 - 25 bucks...guranteed.
They ran the inline well into teh mid to late 80's. Look under the hood of work vans and pick ups. Those work trucks was the last run of the inline engines.

01-09-2004, 10:41 PM	#1
whitesswj Embrace the Redneck Join Date: Jan 2004 Location: Cabot, AR Posts: 1,334	Idle on a 68 250 Why wouldn't a 68 250 I6 Idle at less than 1400 RPM? I've adjusted the air/fuel mix, adjusted the points, gave it a tune up. Thinking about replacing the airfilter. Anyone w/ experience shed some light on this situation? Thanks __________________ '01 Camaro *Son, you just can't get there from here...*

01-09-2004, 11:27 PM	#3
whitesswj Embrace the Redneck Join Date: Jan 2004 Location: Cabot, AR Posts: 1,334	If you back the screw off anymore it will die! I got tired of Restartign it every time I shifted gears and stopped, so I raised it to an idling point. I Dies if the screw is backed off. __________________ '01 Camaro *Son, you just can't get there from here...*

01-10-2004, 12:05 AM	#4
MOTHERTRUCKERS Registered User Join Date: Dec 1999 Location: BRADENTON FLA Posts: 3,269	You probably, maybe, could have a vaccumn leak or a cracked intake manifold __________________ Rest in Peace Ed. Thanks for all the good times.

01-10-2004, 08:54 PM	#6
whitesswj Embrace the Redneck Join Date: Jan 2004 Location: Cabot, AR Posts: 1,334	I've just recently checked for a cracked manifold and vacume. NONE. Points? And I don't have any thing resembling what charlieo has. anyone else?? __________________ '01 Camaro *Son, you just can't get there from here...*

01-10-2004, 10:11 PM	#7
Palf70Step State of Confusion! Join Date: Jul 2002 Location: Gulfport, MS USA Posts: 47,216	My 70 250 ran really weird like that when I first got it. Turned out if was worn bad were the thottle rod(think that's what it is called) goes into the carb. It allowed it to leak..sort of like a vacumn leak, but I couldn't ever get it to show up under normal country/backyard troubleshooting. Only other thing that comes to mind is that your carb maybe gummed up in the internal passages and it won't pull enough fuel below that RPM level. I would either rebuiled the carb or, least get the gaskets, pull the top off the carb (6 screws), gently lift it and spray everything in the float and passage areas with carb cleaner. Because mine sits so much I have to do that occassionally to get it to start and run. Once it's has the new tank in and is on the road more, I'll rebuild the carb again and permanently clean out that mess. __________________ Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God! Last edited by Palf70Step; 01-10-2004 at 10:14 PM.

01-09-2004, 11:20 PM	#2
jef5150 Inline 69 Join Date: Apr 2003 Location: valleysprings,california Posts: 1,018	are you saying,,,,,, you are backing the idle screw all the way out ,and it "still"idles at 1400?,,,,,,,or if you adjust the idle down below 1400 it dies?............jeff

01-10-2004, 01:50 AM	#5
charlieo Registered User Join Date: Feb 2003 Location: sw Posts: 341	On my 250 there is a solenoid looking thing with 2 vacuum hoses attached to it . I think it's an anti-dieseling devise you screw out & the idle comes down !

01-11-2004, 03:06 AM	#8
69_hafton Sleep-Deprived Join Date: Sep 2002 Location: Tulsa, Oklahoma Posts: 445	Could be any of the things mentioned. First real thing I did to mine was put an HEI distributor in. Big difference. I had a high idle problem when I first bought the truck. Couldn't find a vacuum leak. High idle cam on the carb isn't even connected - still isn't. But when I put the dist. in, it was the first time I could even time the engine! I still haven't touched the carb, but it no doubt needs attention. It's more than liveable now, though, before I couldn't stand the mileage or sitting at a stop light at 1500-2000+ rpms. __________________ 1971 K/10 Long Fleetside 350/350 - 6" Lift 1969 C/10 SWB 292 - Sold It

01-11-2004, 05:49 PM	#9
whitesswj Embrace the Redneck Join Date: Jan 2004 Location: Cabot, AR Posts: 1,334	I've been hearing alot abou these HEI distributors, what are they? And how do I go about getting one of them?? Cost? __________________ '01 Camaro *Son, you just can't get there from here...*

01-11-2004, 06:03 PM	#10
67sss Registered User Join Date: Nov 2002 Location: Mt. Vernon, WA.. Posts: 2,325	To find out if you have a leak, vacuum or otherwise, take a can of WD40 and start spraying at the base of the carb first then work your way up. If there's a leak the WD40 will get sucked in and cause the engine to run faster...then there's your leak. I allways run premium gas in my 6cyl seems to help, may cost more at the pump but alot less repairs...

01-11-2004, 06:33 PM	#11
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,992	HEI distributor is a High Energy Distributor.They are Electronic(no points).I got one complete with.coil,cap,dist, and harness from a guy who was parting out a late 70's model.It cost me $25.00 and $8.00 shipping.I cleaned it up and it has worked well.I think 74 or 76 was the first year for them and they should be fairly easy to find.Also since so many people want small blocks they aren't in great demand. BTW he shipped it by US Mail and it got here in 3 days from OK. It was cheap and fast for shipping. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

01-11-2004, 06:52 PM	#12
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	I agree with the vacume leak idea. I never used WD40 for the testing, but carb cleaner. Check all your vac lines, like the PVC and power brakes if equipped. No need for high octain fuel. Run the least amount of octain needed to keep spark knock away. Octain is nothing but resistance to ignition formula and if you run more than needed, it'll not only carbon up your engine more, but may DECREASE MPG and performance.

01-11-2004, 07:56 PM	#13
69_hafton Sleep-Deprived Join Date: Sep 2002 Location: Tulsa, Oklahoma Posts: 445	To add to PanelDeland's post, GM made the HEI distibutor for the 6 until 79 or so (whenever they quit making the inline 6 pretty much) I paid $65 for mine locally. Didn't come complete, I had to buy the cap, wires, and coil for mine. The coil sit in the cap, so try to get one that has everything. I think there's also an ignition module that sits up there. Accel makes a kit for the coil and module if I remember right. It improves spar voltage, but OEM will be a huge improvement over points. Watch Ebay, I've seen them go for $40 or so. Hit search on this site and read up on HEI also. I've probably missed a few things. __________________ 1971 K/10 Long Fleetside 350/350 - 6" Lift 1969 C/10 SWB 292 - Sold It

01-11-2004, 08:34 PM	#14
MOTHERTRUCKERS Registered User Join Date: Dec 1999 Location: BRADENTON FLA Posts: 3,269	I have a few 6 cyl HEI's 40.00 each + shipping. __________________ Rest in Peace Ed. Thanks for all the good times.

01-12-2004, 12:55 AM	#15
whitesswj Embrace the Redneck Join Date: Jan 2004 Location: Cabot, AR Posts: 1,334	I just did a point job on it, cost 10 bucks and did it in less than 20 mins. the set i bought came w/ point, condenser, and <i>feeler guages<i> Lowerd it to 1,000. Mother - i'll have to think about it! pictures?? thanks! __________________ '01 Camaro *Son, you just can't get there from here...*



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01-12-2004, 01:16 AM	#16
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	ouch...65 bucks incomplete. I can get them all day long for 15 - 25 bucks...guranteed. They ran the inline well into teh mid to late 80's. Look under the hood of work vans and pick ups. Those work trucks was the last run of the inline engines.

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