Anyone know what the computer in an 85 does? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

87Bob · 08-12-2009, 06:28 PM

I am trying to figure what the computer in an 85 does and how to dump off the truck? When I make my engine swap I want to get rid of the Q Jet and go with something more tune able.

tylerg. · 08-12-2009, 06:57 PM

1985 c-10's have computers?

Driveway Dreams · 08-12-2009, 07:05 PM

Where is said computer?

bigbadjohn84 · 08-12-2009, 07:12 PM

they controlled the spark in some of the computer controlled advance in the big cap HEI units as well something in those 80's junker QJets. no offense. the early model QJets are not as bad as everyone makes them out to be though.

thump16 · 08-12-2009, 07:17 PM

same as 84 c-10. The computer is Located behind the glove box mounted under dash in that area(metal box with wires going into the engine bay). Look up ESC computer. It controls spark through your distributor and when it goes out it gives all kinds of false symptoms from bad timing to fouled plugs. There are a few write ups on how to disable it on this forum and the link below.

http://www.73-87.com/7387garage/drivetrain/escrepl.htm

I ditched mine and ran a HEI distributor and I also helped a buddy run his stock distributor by following the directions given in the how to write up.

bigbadjohn84 · 08-13-2009, 02:55 PM

I second that. disable it, you'd be glad you did lol. it's junk

Sniper X · 08-13-2009, 03:09 PM

All they were designed for is to try and get better mileage out of a carbureted truck with the carby. After the carb went to a TBI or injection, the computer took care of all sorts of stuff like anti knock, timing, spark advance, fuel rations and other stuff. Back then, all it controled was the HEI distributor. I feel if you bought a normal HEI and swapped it out you would be better off.

Jonboy · 08-13-2009, 04:51 PM

The computer in your 85 will listen for knock, and pull timing accordingly, if needed.

JohnC · 08-13-2009, 04:57 PM

They mainly take up space.

60ratrod · 08-13-2009, 05:16 PM

did it take one of these to tune??

60ratrod · 08-13-2009, 05:16 PM

or how bout one of these??

Jonboy · 08-13-2009, 05:18 PM

Quote:

Originally Posted by 60ratrod

did it take one of these to tune??

I have always heard to use a paper clip to put it into field service mode, then use the Pong controller from a Colecovision game to run it.

Sniper X · 08-13-2009, 05:20 PM

Quote:

Originally Posted by Jonboy

I have always heard to use a paper clip to put it into field service mode, then use the Pong controller from a Colecovision game to run it.

Right, and to do HP mods, you could use a Pac Man game card, just plug it in and the truck would handle way better!

Manbearpig · 08-13-2009, 05:26 PM

My 84's computer controls the choke and spark advance I believe.

Well it doesn't anymore, but it did.

bigbadjohn84 · 08-13-2009, 06:38 PM

1985-GMC · 08-13-2009, 08:20 PM

What was the first year for computers I always thought it was 87? Did all trucks have em or just ones in states like California.

andrewmp6 · 08-13-2009, 09:58 PM

The mid 80s gm put the same set up on everything.My 83 grand prix had the same useless ecu thing on it a simple carb and dizzy swap its gone.

08-12-2009, 06:28 PM	#1
87Bob Registered User Join Date: Nov 2007 Location: Franklin Indiana Posts: 635	Anyone know what the computer in an 85 does? I am trying to figure what the computer in an 85 does and how to dump off the truck? When I make my engine swap I want to get rid of the Q Jet and go with something more tune able. __________________ My Truck's not leaking its marking its territory!

08-12-2009, 06:57 PM	#2
tylerg. Registered User Join Date: Sep 2008 Location: Magnolia, TX Posts: 72	Re: Anyone know what the computer in an 85 does? 1985 c-10's have computers? Last edited by tylerg.; 08-12-2009 at 06:58 PM.

08-12-2009, 07:05 PM	#3
Driveway Dreams I have car A.D.D. Join Date: Feb 2009 Location: Greeley, Northern Colorado Posts: 4,147	Re: Anyone know what the computer in an 85 does? Where is said computer? __________________ -Gerald Building vehicles in memory of the first "car guy" I ever knew, my Grandpa. Bob Dunham 1935-2009. Rest in peace. 61 GMC Suburban SOLD The 86 build thread SOLD Are you a Colorado member?Click here.

08-12-2009, 07:12 PM	#4
bigbadjohn84 Registered User Join Date: Feb 2008 Location: Florala, AL Posts: 398	Re: Anyone know what the computer in an 85 does? they controlled the spark in some of the computer controlled advance in the big cap HEI units as well something in those 80's junker QJets. no offense. the early model QJets are not as bad as everyone makes them out to be though.

08-12-2009, 07:17 PM	#5
thump16 Registered User Join Date: Jul 2005 Location: Valdosta GA Posts: 708	Re: Anyone know what the computer in an 85 does? same as 84 c-10. The computer is Located behind the glove box mounted under dash in that area(metal box with wires going into the engine bay). Look up ESC computer. It controls spark through your distributor and when it goes out it gives all kinds of false symptoms from bad timing to fouled plugs. There are a few write ups on how to disable it on this forum and the link below. http://www.73-87.com/7387garage/drivetrain/escrepl.htm I ditched mine and ran a HEI distributor and I also helped a buddy run his stock distributor by following the directions given in the how to write up.

08-13-2009, 02:55 PM	#6
bigbadjohn84 Registered User Join Date: Feb 2008 Location: Florala, AL Posts: 398	Re: Anyone know what the computer in an 85 does? I second that. disable it, you'd be glad you did lol. it's junk

08-13-2009, 03:09 PM	#7
Sniper X Registered User Join Date: Aug 2009 Location: Albuquerque New mexico Posts: 169	Re: Anyone know what the computer in an 85 does? All they were designed for is to try and get better mileage out of a carbureted truck with the carby. After the carb went to a TBI or injection, the computer took care of all sorts of stuff like anti knock, timing, spark advance, fuel rations and other stuff. Back then, all it controled was the HEI distributor. I feel if you bought a normal HEI and swapped it out you would be better off.

08-13-2009, 04:51 PM	#8
Jonboy Slots go on anything! Join Date: May 2003 Location: Richardson, TX Posts: 5,957	Re: Anyone know what the computer in an 85 does? The computer in your 85 will listen for knock, and pull timing accordingly, if needed.

08-13-2009, 04:57 PM	#9
JohnC Registered User Join Date: Feb 2009 Location: Oklahoma Posts: 7,461	Re: Anyone know what the computer in an 85 does? They mainly take up space.

08-13-2009, 05:16 PM	#10
60ratrod yes, i do Join Date: Jun 2007 Location: Spokane, wa Posts: 2,734	Re: Anyone know what the computer in an 85 does? did it take one of these to tune?? Attached Images __________________ ERROR 404....... SNAPPY COMEBACK NOT FOUND _______________________________________________________________________________________________ -60 Chevy C10, dead 350/good th350 combo, sitting on a 76 c10 blazer frame, built from 11 different vehicles "the abomination" -07 gmt900 silverado 1500 lt xcab z71, granite blue -81 suzuki gs650g "shelah"- current project -81 kz1000m1 csr "sarge" -next project (just beautification) -07 kawasaki vulcan classic vn900

08-13-2009, 05:26 PM	#14
Manbearpig Registered User Join Date: Mar 2009 Location: Midland, Tx Posts: 418	Re: Anyone know what the computer in an 85 does? My 84's computer controls the choke and spark advance I believe. Well it doesn't anymore, but it did. __________________ 1972 GMC C10 Last edited by Manbearpig; 08-13-2009 at 05:26 PM.

08-13-2009, 06:38 PM	#15
bigbadjohn84 Registered User Join Date: Feb 2008 Location: Florala, AL Posts: 398	Re: Anyone know what the computer in an 85 does?

08-13-2009, 08:20 PM	#16
1985-GMC Chevy Enthusiast Join Date: Jul 2009 Location: Canyon Lake Texas Posts: 2,024	Re: Anyone know what the computer in an 85 does? What was the first year for computers I always thought it was 87? Did all trucks have em or just ones in states like California.

08-13-2009, 09:58 PM	#17
andrewmp6 Registered User Join Date: Jan 2009 Location: Louisville,Ky Posts: 5,811	Re: Anyone know what the computer in an 85 does? The mid 80s gm put the same set up on everything.My 83 grand prix had the same useless ecu thing on it a simple carb and dizzy swap its gone.



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