Need help w/cruise control problem - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**ScottH** · 08-16-2005, 01:28 PM

1976 C10 with 454/400 has a problem maintaining the speed consistantly. If set at 60 it drops to 55 or less than surges back up to speed, drops back down, then accelerates back up, and repeats the cycle.

Can anyone tell me what might be causing this (calibration perhaps)?

Any info is greatly appreciated.

Thanks!

Russell · 08-16-2005, 09:49 PM

I found that those cruise systems were just like like. Mine did that all the time till I upgraded to an electronic one.

*Zilverado* · 08-16-2005, 11:27 PM

Quote:

Originally Posted by Russell

I found that those cruise systems were just like like. Mine did that all the time till I upgraded to an electronic one.

My '86 does something similar, but not that dramatic. I can't notice a speed change on the speedo, but I can still feel a slight surging - - just enough to be annoying.

Russell, could you explain the electronic cruise upgrade, or is my '86 already electronic. Never really looked at it, that's why I'm asking.

Thanks,

Russell · 08-17-2005, 12:56 AM

I installed a cruise system from an 89 chevy truck. It wouldn't work too well going to a carb, as I have the cable for it running to a spot that just happens to fit good on my TPI throttle body. I am sure that a guy could make a bracket to mount the cable, but it may be a bit challenging. Hookup consisted of a normally open brake switch (I bought a combo one, both normally open for the cruise, and normally closed for the brakes) a VSS signal, power, and ground, along with all of the stalk hookups, of course

The system I've got is a Delphi Electro-matic cruise system.

piecesparts · 08-17-2005, 09:32 PM

My son's truck was doiong this and I found that the speedo was causing it. His speedo head was failing and of course the cruise takes it;s input from the back of the speedometer itself, so it caused the cruise to go nutty. I went to the local Pick-a-Part and got another speedo head, worked like a charm.

**ScottH** · 08-17-2005, 11:13 PM

Thanks to everyone for the info. Piecesparts, do you mean you replaced the entire speedometer? or just part of it?

piecesparts · 08-18-2005, 11:34 AM

If you take the dash bezel off of your truck the instrument clusters are actually two different pieces. One piece is the speedo and the other is the fuel gauge. Either piece can be replaced in theplastic housing with another instrument. Take the speedo cable off and disconnect the screws that hold it into the housing. I bought a used one at a salvage yard for approximately $40.00 and got lucky the first time with a good one. Your odometer will change with the new unit, so take that thought and consider it, also. The one I got was relatively close to what was on the truck originally, but I didn't care.

Russell · 08-18-2005, 01:37 PM

His 76 won't have a VSS on the back of the speedo, his is an entirely vaccum controlled system. The newer systems with the VSS on the back typically worked a fair bit better

piecesparts · 08-19-2005, 12:05 PM

Sorry I thought i read an 86.

08-16-2005, 01:28 PM	#1
ScottH Senior Member Join Date: Sep 2002 Location: Hampstead, NC Posts: 8,190	Need help w/cruise control problem 1976 C10 with 454/400 has a problem maintaining the speed consistantly. If set at 60 it drops to 55 or less than surges back up to speed, drops back down, then accelerates back up, and repeats the cycle. Can anyone tell me what might be causing this (calibration perhaps)? Any info is greatly appreciated. Thanks!

08-16-2005, 09:49 PM	#2
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	I found that those cruise systems were just like like. Mine did that all the time till I upgraded to an electronic one. __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)

08-17-2005, 12:56 AM	#4
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	I installed a cruise system from an 89 chevy truck. It wouldn't work too well going to a carb, as I have the cable for it running to a spot that just happens to fit good on my TPI throttle body. I am sure that a guy could make a bracket to mount the cable, but it may be a bit challenging. Hookup consisted of a normally open brake switch (I bought a combo one, both normally open for the cruise, and normally closed for the brakes) a VSS signal, power, and ground, along with all of the stalk hookups, of course The system I've got is a Delphi Electro-matic cruise system. __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)

08-18-2005, 01:37 PM	#8
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	His 76 won't have a VSS on the back of the speedo, his is an entirely vaccum controlled system. The newer systems with the VSS on the back typically worked a fair bit better __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)

08-17-2005, 09:32 PM	#5
piecesparts Parts and more parts Join Date: Nov 2003 Location: Lebo, Kansas (middle of nowhere Posts: 6,821	My son's truck was doiong this and I found that the speedo was causing it. His speedo head was failing and of course the cruise takes it;s input from the back of the speedometer itself, so it caused the cruise to go nutty. I went to the local Pick-a-Part and got another speedo head, worked like a charm.

08-17-2005, 11:13 PM	#6
ScottH Senior Member Join Date: Sep 2002 Location: Hampstead, NC Posts: 8,190	Thanks to everyone for the info. Piecesparts, do you mean you replaced the entire speedometer? or just part of it?

08-18-2005, 11:34 AM	#7
piecesparts Parts and more parts Join Date: Nov 2003 Location: Lebo, Kansas (middle of nowhere Posts: 6,821	If you take the dash bezel off of your truck the instrument clusters are actually two different pieces. One piece is the speedo and the other is the fuel gauge. Either piece can be replaced in theplastic housing with another instrument. Take the speedo cable off and disconnect the screws that hold it into the housing. I bought a used one at a salvage yard for approximately $40.00 and got lucky the first time with a good one. Your odometer will change with the new unit, so take that thought and consider it, also. The one I got was relatively close to what was on the truck originally, but I didn't care.

08-19-2005, 12:05 PM	#9
piecesparts Parts and more parts Join Date: Nov 2003 Location: Lebo, Kansas (middle of nowhere Posts: 6,821	Sorry I thought i read an 86.



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