Carbed 5.3 won’t start please help! - Page 2 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

geezer#99 · 11-11-2018, 02:14 PM

Quote:

Originally Posted by Rdwagoner

UPDATE***
The truck runs and sounds like a beast! I did have it wired wrong and I spliced into the pink ignition wire for the constant 12v, ran to my relay for the MSD box and she fired right up! Now I have the computer hooked to it and it gave me a cam sensor fault. One other thing is it’s idling about 1100rpm and I have the idle screw all the way out. It’s a summit 600 carb. I can press the throttle forward barley, just enough to get the idle down to about 850rpm or so. Any ideas on the idle? Thank you everyone for your help! I’m just glad to see and hear it run!

Is the secondaries adjustable on your carb?
Could be too far open.

Or high idle on choke needs adjusted.

**HO455** · 11-11-2018, 02:34 PM

Good to hear you have it running. Glad it was a simple fix. Now you can get into dialing in the timing and carburetor The fun stuff!

jjzepplin · 11-11-2018, 03:31 PM

Isn't a 600cfm a bit small?

Rdwagoner · 11-11-2018, 04:44 PM

Yes, dialing it in will be challenging but fun. I tried to research a good bit on a carb. I hope the 600 is enough. It’s pretty tunable.

**AussieinNC** · 11-11-2018, 08:05 PM

Try removing the accelerator cable from the carb lever, leave the return springs on...then start the engine...I have seen cables hold the throttle lever open...

Also look for vacuum leaks as these will cause high idle levels...

Cam sensor fault is most likely a bad sensor...

Great that you got it going...

Rdwagoner · 11-11-2018, 08:21 PM

I don’t have the cable hooked up, I’m reading up on the carb. I’ll have to mess with it some. I ran it about 15 minutes today and cranked it a few times. A couple times shutting it off it wanted to keep running with the key off, like it was running out of fuel. Never had a this happen before, another fault in the wiring somewhere? At least it’s running now thanks to everyone’s direction!

geezer#99 · 11-11-2018, 08:46 PM

It’s not in your wiring.
Running on is known as dieseling.
If your primary throttle is open enough to allow a bit too much air into the motor, a hot spot in your intake will ignite the air and a bit of fuel to make it run without the ignition on. It continues to try to run because the air going into the intake draws a little fuel from the carb.
Cure is to close the throttle almost completely.

There’s a section in this link which deals with the transfer slot on a Holley. Your carb is the same. If you get your transfer slot set you’ll likely cure your high idle and your run on.

http://www.crankshaftcoalition.com/w...EI_distributor

KQQL IT · 11-11-2018, 09:36 PM

Or the alternator is back feeding power thru the MSD box. Needs a diode in the charge wire.

Rdwagoner · 11-11-2018, 10:24 PM

You guys are very informative and I’m greatful for the help. I’ll look into the article and see what I can find out. Thank you and I’ll update soon.

68Stepbed · 11-12-2018, 10:13 AM

OK, I went through a similar issue with mine. If you're getting a cam fault code, you will have starting issues. Make sure you have genuine cam and crank sensors!! I honestly believe my issue was using aftermarket cam sensors. I finally went to a front timing cover and timing gear setup from a GTO, with GM sensors. No more starting issues.

As for the 600 cfm carb, it'll be fine for that 5.3. I have a +.010 5.7 with AFR heads making 531hp and it only pulled 580cfm at 6000rpm on the dyno.

Rdwagoner · 11-12-2018, 05:17 PM

I've tried to look but it seems the primaries are not adjustable on the Summit 600 to mu knowledge. The secondaries appear to be adjustable. Summit tech line told me not to mess with any transfer slot adjustment but I may have too much fuel pressure? I have an inline gauge that reads 4 1/2 when running but it could be off. it is also dieseling on occasion when i shut the key off. You guys seem to know much more than the Summit tech. I'll adjust primary and secondary if possible. Anyone else ever adjust this on a Summit carb?

Rdwagoner · 11-12-2018, 05:33 PM

Here are a few pics. Seems my transfer slot is way out of spec.

Rdwagoner · 11-12-2018, 05:36 PM

http://67-72chevytrucks.com/vboard/a...1&d=1542058490

http://67-72chevytrucks.com/vboard/a...1&d=1542058493

http://67-72chevytrucks.com/vboard/a...1&d=1542058493

geezer#99 · 11-12-2018, 05:37 PM

Quote:

Originally Posted by Rdwagoner

I've tried to look but it seems the primaries are not adjustable on the Summit 600 to mu knowledge. The secondaries appear to be adjustable. Summit tech line told me not to mess with any transfer slot adjustment but I may have too much fuel pressure? I have an inline gauge that reads 4 1/2 when running but it could be off. it is also dieseling on occasion when i shut the key off. You guys seem to know much more than the Summit tech. I'll adjust primary and secondary if possible. Anyone else ever adjust this on a Summit carb?

Of course you have a primary adjustment. It sets your idle speed.
Did you pull the carb off to find the secondary screw adjuster?

Give us a better pic of the complete bottom of the carb.

Rdwagoner · 11-12-2018, 05:38 PM

http://67-72chevytrucks.com/vboard/a...1&d=1542058702

Rdwagoner · 11-12-2018, 05:40 PM

I know my main idle adjustment on the throttle linkage but it’s already all the way out, not even touching. See how much gap is in the primaries at idle? Has to be a way to close that gap some.

geezer#99 · 11-12-2018, 05:46 PM

Check the high idle screw.
It’s on the passenger side. Under the choke.

Is your choke wide open?

Rdwagoner · 11-12-2018, 05:59 PM

I don’t think the choke is open but I’ll check. It look like it’s on the lowest notch. I see the 1/4 screw head under choke. That’s my high idle screw?

geezer#99 · 11-12-2018, 06:05 PM

Yup!
That’s likely it.

Exactly what carb do you have?

Rdwagoner · 11-12-2018, 06:27 PM

Summit 600 electric choke with vacuum secondary.

geezer#99 · 11-12-2018, 06:36 PM

Quote:

Originally Posted by Rdwagoner

Summit 600 electric choke with vacuum secondary.

Give us a link to it.
There are different styles.

Rdwagoner · 11-12-2018, 06:51 PM

https://www.summitracing.com/parts/sum-m08600vs

geezer#99 · 11-12-2018, 06:57 PM

It’s a 4010 style.
Your electric choke is adjustable by turning the black cap if you need to lean it out.

Rdwagoner · 11-12-2018, 07:20 PM

Roger that, I’ll try that and also adjust the gap on the primary. Thanks and I’ll update afterwards.

Rdwagoner · 11-13-2018, 11:57 AM

Adjusted the primaries and the choke a bit. I’ll hook up in a bit and update on how it runs. Does the transfer slot look correct now?

http://67-72chevytrucks.com/vboard/a...1&d=1542124593

http://67-72chevytrucks.com/vboard/a...1&d=1542124593

11-11-2018, 02:34 PM	#27
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 10,791	Re: Carbed 5.3 won’t start please help! Good to hear you have it running. Glad it was a simple fix. Now you can get into dialing in the timing and carburetor The fun stuff! __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban the WMB,1991 S(stink)-10 Blazer,1969 GTO, 1970 Javelin, 1952 F2 Ford 4X4, 29 Model A, 72 Firebird. 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377

11-11-2018, 03:31 PM	#28
jjzepplin Registered User Join Date: Feb 2012 Location: Ruskin Florida Posts: 4,544	Re: Carbed 5.3 won’t start please help! Isn't a 600cfm a bit small? __________________ 70 swb 4x4 406sbc 700r4 203/205 d60/14blt locker yadda yadda http://67-72chevytrucks.com/vboard/s...88#post6935688 Yeller 72 Blazer 2wd conversion project "No Daggum Money" http://67-72chevytrucks.com/vboard/s...d.php?t=550804 LS1-T56 3.73 LSD super budget build Blanco-2014 Sierra SWB https://67-72chevytrucks.com/vboard/...d.php?t=810350

11-11-2018, 04:44 PM	#29
Rdwagoner Registered User Join Date: Nov 2018 Location: Loganville Posts: 52	Re: Carbed 5.3 won’t start please help! Yes, dialing it in will be challenging but fun. I tried to research a good bit on a carb. I hope the 600 is enough. It’s pretty tunable.

11-11-2018, 08:05 PM	#30
AussieinNC Moderator Join Date: Jun 2017 Location: Cherryville, NC Posts: 2,153	Re: Carbed 5.3 won’t start please help! Try removing the accelerator cable from the carb lever, leave the return springs on...then start the engine...I have seen cables hold the throttle lever open... Also look for vacuum leaks as these will cause high idle levels... Cam sensor fault is most likely a bad sensor... Great that you got it going... __________________ Family and country before all others... 2006 Chevy Silverado (Daily Driver) 2012 Chevy Equinox

11-11-2018, 08:21 PM	#31
Rdwagoner Registered User Join Date: Nov 2018 Location: Loganville Posts: 52	Re: Carbed 5.3 won’t start please help! I don’t have the cable hooked up, I’m reading up on the carb. I’ll have to mess with it some. I ran it about 15 minutes today and cranked it a few times. A couple times shutting it off it wanted to keep running with the key off, like it was running out of fuel. Never had a this happen before, another fault in the wiring somewhere? At least it’s running now thanks to everyone’s direction!

11-11-2018, 08:46 PM	#32
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,510	Re: Carbed 5.3 won’t start please help! It’s not in your wiring. Running on is known as dieseling. If your primary throttle is open enough to allow a bit too much air into the motor, a hot spot in your intake will ignite the air and a bit of fuel to make it run without the ignition on. It continues to try to run because the air going into the intake draws a little fuel from the carb. Cure is to close the throttle almost completely. There’s a section in this link which deals with the transfer slot on a Holley. Your carb is the same. If you get your transfer slot set you’ll likely cure your high idle and your run on. http://www.crankshaftcoalition.com/w...EI_distributor Last edited by geezer#99; 11-11-2018 at 09:00 PM.

11-11-2018, 09:36 PM	#33
KQQL IT At the body shop. Join Date: Aug 2009 Location: Land of fruits and nuts. Posts: 5,128	Re: Carbed 5.3 won’t start please help! Or the alternator is back feeding power thru the MSD box. Needs a diode in the charge wire. __________________ " That didnt make it any newer " " Dont antique the equipment "

11-11-2018, 10:24 PM	#34
Rdwagoner Registered User Join Date: Nov 2018 Location: Loganville Posts: 52	Re: Carbed 5.3 won’t start please help! You guys are very informative and I’m greatful for the help. I’ll look into the article and see what I can find out. Thank you and I’ll update soon.

11-12-2018, 10:13 AM	#35
68Stepbed Registered User Join Date: Mar 2005 Location: 10-Uh-See Posts: 5,609	Re: Carbed 5.3 won’t start please help! OK, I went through a similar issue with mine. If you're getting a cam fault code, you will have starting issues. Make sure you have genuine cam and crank sensors!! I honestly believe my issue was using aftermarket cam sensors. I finally went to a front timing cover and timing gear setup from a GTO, with GM sensors. No more starting issues. As for the 600 cfm carb, it'll be fine for that 5.3. I have a +.010 5.7 with AFR heads making 531hp and it only pulled 580cfm at 6000rpm on the dyno. __________________ Matt 68 C10 stepside, LS1/700R4, TCI Engineering suspension system

11-12-2018, 05:17 PM	#36
Rdwagoner Registered User Join Date: Nov 2018 Location: Loganville Posts: 52	Re: Carbed 5.3 won’t start please help! I've tried to look but it seems the primaries are not adjustable on the Summit 600 to mu knowledge. The secondaries appear to be adjustable. Summit tech line told me not to mess with any transfer slot adjustment but I may have too much fuel pressure? I have an inline gauge that reads 4 1/2 when running but it could be off. it is also dieseling on occasion when i shut the key off. You guys seem to know much more than the Summit tech. I'll adjust primary and secondary if possible. Anyone else ever adjust this on a Summit carb?

11-12-2018, 05:33 PM	#37
Rdwagoner Registered User Join Date: Nov 2018 Location: Loganville Posts: 52	Re: Carbed 5.3 won’t start please help! Here are a few pics. Seems my transfer slot is way out of spec.

11-12-2018, 05:36 PM	#38
Rdwagoner Registered User Join Date: Nov 2018 Location: Loganville Posts: 52	Re: Carbed 5.3 won’t start please help! http://67-72chevytrucks.com/vboard/a...1&d=1542058490 http://67-72chevytrucks.com/vboard/a...1&d=1542058493 http://67-72chevytrucks.com/vboard/a...1&d=1542058493 Attached Images

11-12-2018, 05:38 PM	#40
Rdwagoner Registered User Join Date: Nov 2018 Location: Loganville Posts: 52	Re: Carbed 5.3 won’t start please help! http://67-72chevytrucks.com/vboard/a...1&d=1542058702 Attached Images

11-12-2018, 05:40 PM	#41
Rdwagoner Registered User Join Date: Nov 2018 Location: Loganville Posts: 52	Re: Carbed 5.3 won’t start please help! I know my main idle adjustment on the throttle linkage but it’s already all the way out, not even touching. See how much gap is in the primaries at idle? Has to be a way to close that gap some.

11-12-2018, 05:46 PM	#42
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,510	Re: Carbed 5.3 won’t start please help! Check the high idle screw. It’s on the passenger side. Under the choke. Is your choke wide open?



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11-12-2018, 05:59 PM	#43
Rdwagoner Registered User Join Date: Nov 2018 Location: Loganville Posts: 52	Re: Carbed 5.3 won’t start please help! I don’t think the choke is open but I’ll check. It look like it’s on the lowest notch. I see the 1/4 screw head under choke. That’s my high idle screw?

11-12-2018, 06:05 PM	#44
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,510	Re: Carbed 5.3 won’t start please help! Yup! That’s likely it. Exactly what carb do you have?

11-12-2018, 06:27 PM	#45
Rdwagoner Registered User Join Date: Nov 2018 Location: Loganville Posts: 52	Re: Carbed 5.3 won’t start please help! Summit 600 electric choke with vacuum secondary.

11-12-2018, 06:51 PM	#47
Rdwagoner Registered User Join Date: Nov 2018 Location: Loganville Posts: 52	Re: Carbed 5.3 won’t start please help! https://www.summitracing.com/parts/sum-m08600vs

11-12-2018, 06:57 PM	#48
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,510	Re: Carbed 5.3 won’t start please help! It’s a 4010 style. Your electric choke is adjustable by turning the black cap if you need to lean it out.

11-12-2018, 07:20 PM	#49
Rdwagoner Registered User Join Date: Nov 2018 Location: Loganville Posts: 52	Re: Carbed 5.3 won’t start please help! Roger that, I’ll try that and also adjust the gap on the primary. Thanks and I’ll update afterwards.

11-13-2018, 11:57 AM	#50
Rdwagoner Registered User Join Date: Nov 2018 Location: Loganville Posts: 52	Re: Carbed 5.3 won’t start please help! Adjusted the primaries and the choke a bit. I’ll hook up in a bit and update on how it runs. Does the transfer slot look correct now? http://67-72chevytrucks.com/vboard/a...1&d=1542124593 http://67-72chevytrucks.com/vboard/a...1&d=1542124593 Attached Images

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