ECU's OBD and all that junk - The 1947 - Present Chevrolet & GMC Truck Message Board Network

k72516 · 06-05-2005, 06:14 PM

Can anyone school me on the computers in 73-87 Chevy trucks? I just started thinking about that today. In 87 they started TBI, so I guess pre 86 would be the best bet at not dealing with computers too much? I just always assumed that pre 86 didn't have any computers or sensors or anything anywhere.

beaterC10 · 06-05-2005, 09:12 PM

The carbed trucks really don't have much of a "computer". All the box does is retard the timing if the knock sensor detects detonation. The box is under the dash near the steering column. The knock sensor is low on the engine near the freeze plugs. Trucks with lockup converts will have a vacuum switch to switch the 12v needed for the converter solenoid.

k72516 · 06-05-2005, 09:20 PM

awesome

Russell · 06-06-2005, 12:15 AM

Feedback carbed engines did have an ECM of sorts, along with a check engine light. It mostly controlled emissions systems on the carb, and acted as a bit of an early TBI by controlling the idle speed and such a little bit. They work awesome when everything is working properly, but can be more of a pain than a system with injectors if something gets messed up in the carb or whatever.

06-05-2005, 06:14 PM	#1
k72516 Registered User Join Date: May 2005 Location: Easthampton, MA Posts: 74	ECU's OBD and all that junk Can anyone school me on the computers in 73-87 Chevy trucks? I just started thinking about that today. In 87 they started TBI, so I guess pre 86 would be the best bet at not dealing with computers too much? I just always assumed that pre 86 didn't have any computers or sensors or anything anywhere. __________________ Go Fast - Be Loud

06-05-2005, 09:20 PM	#3
k72516 Registered User Join Date: May 2005 Location: Easthampton, MA Posts: 74	awesome __________________ Go Fast - Be Loud

06-06-2005, 12:15 AM	#4
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	Feedback carbed engines did have an ECM of sorts, along with a check engine light. It mostly controlled emissions systems on the carb, and acted as a bit of an early TBI by controlling the idle speed and such a little bit. They work awesome when everything is working properly, but can be more of a pain than a system with injectors if something gets messed up in the carb or whatever. __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)

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06-05-2005, 09:12 PM	#2
beaterC10 Senior Member Join Date: Jul 2003 Location: Indianapolis, IN Posts: 1,277	The carbed trucks really don't have much of a "computer". All the box does is retard the timing if the knock sensor detects detonation. The box is under the dash near the steering column. The knock sensor is low on the engine near the freeze plugs. Trucks with lockup converts will have a vacuum switch to switch the 12v needed for the converter solenoid.



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