'94 Burb timing question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Leftyarmstrong · 07-13-2011, 10:39 AM

Got this "free" 3/4 ton, 4wd Burb with a 454 (trans?). When I went to pick it up in the California desert, it started right up even though it's been sitting for years. Runs real strong. Hauls ass for a big heavy. Anyways, took it in for pre-smog and they said it needed an O2 sensor and cat. Did that. Failed smog for NO. Took it back to pre-smog guys and two days later they said the harmonic balancer slipped so it won't time. Brought it home and put on a new balancer. Made no difference and I don't think the old balancer had slipped. The timing mark was way advance of the tab by several inches. When I try to set the timing at 4 degrees, it barely runs. What is up with this thing? Would it run at all if the timing chain had slipped? Would a stretched chain do this? Engine is original and other than maintenance, nothing has been done to it I don't think. I've spent $720 paying the back registration and I now have more money into this "free" vehicle than its worth but I thought it would make a good donor for a re-body with a pre-smog Burb. Until I find that vehicle, want to register and drive this thing as it would make a very good tow vehicle. Thanks, Don in So Cal.

Leftyarmstrong · 07-15-2011, 12:38 AM

Hoping for this to be picked up by automotive technicians. There must be someone out there...hello. Is this thing turned on?

sntrym95 · 07-15-2011, 12:57 AM

Did you disconnect the timing connector in the cab to disable the electronic advance?

Leftyarmstrong · 07-15-2011, 01:07 AM

Aha! Someone is out there! Yes. Just under the glovebox. Brown with black stripe. It made absolutely no difference disconnecting that wire. Shouldn't it have made a difference?

**bwood** · 07-16-2011, 05:03 PM

I believe the timing is set at 0 with the timing wire unhooked. You are just setting a baseline of 0, then when the timing wire is reconnected the ECM knows where it is (it assumes 0). If you set it at 4 and the ECM thinks 0, it may run better on one end of the rpm and worse at the other. Some guys have been able to get by with this, but they usually have made a mod that needs it or possibly have another issue that doing this covers up. As far as the balancer goes, you should be able to put them together and see if the old one slipped.

Leftyarmstrong · 07-17-2011, 01:10 AM

Turns out the distributor was off by a tooth. Timed and passed smog.

07-13-2011, 10:39 AM	#1
Leftyarmstrong Registered User Join Date: Jul 2009 Location: Huntington Beach, Ca. Posts: 17	'94 Burb timing question Got this "free" 3/4 ton, 4wd Burb with a 454 (trans?). When I went to pick it up in the California desert, it started right up even though it's been sitting for years. Runs real strong. Hauls ass for a big heavy. Anyways, took it in for pre-smog and they said it needed an O2 sensor and cat. Did that. Failed smog for NO. Took it back to pre-smog guys and two days later they said the harmonic balancer slipped so it won't time. Brought it home and put on a new balancer. Made no difference and I don't think the old balancer had slipped. The timing mark was way advance of the tab by several inches. When I try to set the timing at 4 degrees, it barely runs. What is up with this thing? Would it run at all if the timing chain had slipped? Would a stretched chain do this? Engine is original and other than maintenance, nothing has been done to it I don't think. I've spent $720 paying the back registration and I now have more money into this "free" vehicle than its worth but I thought it would make a good donor for a re-body with a pre-smog Burb. Until I find that vehicle, want to register and drive this thing as it would make a very good tow vehicle. Thanks, Don in So Cal.

07-15-2011, 12:38 AM	#2
Leftyarmstrong Registered User Join Date: Jul 2009 Location: Huntington Beach, Ca. Posts: 17	Re: '94 Burb timing question Hoping for this to be picked up by automotive technicians. There must be someone out there...hello. Is this thing turned on? __________________ https://picasaweb.google.com/orchids...vyiKGThcblmQE#

07-15-2011, 12:57 AM	#3
sntrym95 Registered User Join Date: Jan 2006 Location: Big Pine Key, FL Posts: 745	Re: '94 Burb timing question Did you disconnect the timing connector in the cab to disable the electronic advance? __________________ Mike

07-15-2011, 01:07 AM	#4
Leftyarmstrong Registered User Join Date: Jul 2009 Location: Huntington Beach, Ca. Posts: 17	Re: '94 Burb timing question Aha! Someone is out there! Yes. Just under the glovebox. Brown with black stripe. It made absolutely no difference disconnecting that wire. Shouldn't it have made a difference? __________________ https://picasaweb.google.com/orchids...vyiKGThcblmQE#

07-16-2011, 05:03 PM	#5
bwood Registered User Join Date: Jan 2003 Location: Denison, Texas Posts: 1,919	Re: '94 Burb timing question I believe the timing is set at 0 with the timing wire unhooked. You are just setting a baseline of 0, then when the timing wire is reconnected the ECM knows where it is (it assumes 0). If you set it at 4 and the ECM thinks 0, it may run better on one end of the rpm and worse at the other. Some guys have been able to get by with this, but they usually have made a mod that needs it or possibly have another issue that doing this covers up. As far as the balancer goes, you should be able to put them together and see if the old one slipped. __________________ 1998 GMC Sierra SLE 1/2 ton 2WD 305 Vortec -Gibson Stainless Cat Back Swept Side -SS Wheels 2005 Honda CRF250R 2006 Honda CRF150F

07-17-2011, 01:10 AM	#6
Leftyarmstrong Registered User Join Date: Jul 2009 Location: Huntington Beach, Ca. Posts: 17	Re: '94 Burb timing question Turns out the distributor was off by a tooth. Timed and passed smog. __________________ https://picasaweb.google.com/orchids...vyiKGThcblmQE#



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