The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 11-16-2005, 09:13 PM   #1
jermasaurus
Registered User
 
jermasaurus's Avatar
 
Join Date: Dec 2004
Location: New Lenox, IL
Posts: 442
Computer in my 85 (Questions)

Hey, I believe the computer in my 85 basicly retards the advance when a knock is sensed. My truck originally had a 305 with the non-feedback quadrajet. The wiring has been removed for a while now since I installed an intake and carb. I haven't been running the vacuum advance either.

I went to hook the vacuum advance up again, and it spark knocks like crazy when you rev it a little. I tried ported and non ported sources, and set the base timing back to 4 degrees, but still knocks.
So i guess I need to hook the computer back up. I have the wiring around still.

My question is, can anyone tell me what all needs to be hooked up for the computer to retard the ignition properly? I am thinking maybe just the knock sensor and the wire(s) going to the distributor. I can't remember what the other ones went to, and I think one may not have been plugged in when I got the truck.
Any suggestions?
-Jeremy
jermasaurus is offline   Reply With Quote
Old 11-16-2005, 09:57 PM   #2
86swb
Born a Chevy Man
 
86swb's Avatar
 
Join Date: Apr 2005
Location: Navarre, Florida
Posts: 10,221
Re: Computer in my 85 (Questions)

I did not think the '85's had a computer? Is this something that someone added to your truck?
__________________
John or 86 (Viet Nam combat Vet-BIG RED ONE) '65-'66

*1986 Chevy SWB Silverado
*1984 Chevy Longbed Silverado

New Kia Sportage (Wife's car and she loves it)

CHEVY, American made w/pride!


If you can read this, YOU NEED TO THANK A TEACHER!
If you can read this in ENGLISH, PLEASE THANK A SOLDIER!
GOD BLESS AMERICA AND BLESS OUR FIGHTING TROOPS
86swb is offline   Reply With Quote
Old 11-17-2005, 12:44 AM   #3
jermasaurus
Registered User
 
jermasaurus's Avatar
 
Join Date: Dec 2004
Location: New Lenox, IL
Posts: 442
Re: Computer in my 85 (Questions)

Not so much a computer, just a contraption behind the glovebox. It's original. I have seen it mentioned here before and I am pretty sure people agreed all it does is retard timing or somthing.
-Jeremy
jermasaurus is offline   Reply With Quote
Old 11-17-2005, 01:27 AM   #4
apstguy
LED King
 
apstguy's Avatar
 
Join Date: Jan 2003
Location: Sacramento, CA
Posts: 2,087
Re: Computer in my 85 (Questions)

It is the ESC computer. I think Federal ESC trucks have a 4 pin connecto to the distributor, knock sensor, and power. Someone correct me if I am wrong. Of course I have the full blown computer which is a whole other animal.
__________________
Tyler

1985 C10 305 w/ Bowtie OD TH700R4 3.42 LSD 202,000 miles
2006 Ford Focus ZX3 5-speed Stick
2016 Chevy Spark EV
Gone: 2002.5 VW GTI 24v VR6
Gone: 2008 VW R32
apstguy is offline   Reply With Quote
Old 11-17-2005, 02:57 PM   #5
Captkaos
www.73-87chevytrucks.com
 
Captkaos's Avatar
 
Join Date: Dec 1999
Location: Birmingham, AL
Posts: 6,935
Re: Computer in my 85 (Questions)

It is the ESC, you can bypass it and run a normal HEI:

http://www.73-87.com/7387garage/drivetrain/escrepl.htm
__________________
Chris Lucas
1973 Chevy C-10
1978 GMC Jimmy (2WD) - SOLD
1987 R10 twin turbo LS
1991 R3500 SRW CrewCab
1985 K5 diesel swapped project
1989 K5 2WD conversion w/ Vette susp Project
Captkaos Customs
73-87chevytrucks.com
Captkaos is offline   Reply With Quote
Old 11-17-2005, 03:22 PM   #6
benoit454
Chris
 
benoit454's Avatar
 
Join Date: Nov 2004
Location: Monaville, WV
Posts: 3,737
Re: Computer in my 85 (Questions)

I wonder if my 86 4x4 has it?

Alot of thing underhood unhooked and some I found the other day underneath.
__________________
Chris



GIT R DONE!!!!!!

Check out all our rides,
http://www.cardomain.com/id/benwa454
benoit454 is offline   Reply With Quote
Old 11-17-2005, 03:27 PM   #7
Captkaos
www.73-87chevytrucks.com
 
Captkaos's Avatar
 
Join Date: Dec 1999
Location: Birmingham, AL
Posts: 6,935
Re: Computer in my 85 (Questions)

Quote:
Originally Posted by benoit454
I wonder if my 86 4x4 has it?

Alot of thing underhood unhooked and some I found the other day underneath.
It will most likely have it.
__________________
Chris Lucas
1973 Chevy C-10
1978 GMC Jimmy (2WD) - SOLD
1987 R10 twin turbo LS
1991 R3500 SRW CrewCab
1985 K5 diesel swapped project
1989 K5 2WD conversion w/ Vette susp Project
Captkaos Customs
73-87chevytrucks.com
Captkaos is offline   Reply With Quote
Old 11-17-2005, 03:31 PM   #8
SSC's76
No No
 
SSC's76's Avatar
 
Join Date: Jun 2005
Location: Pueblo Colorado
Posts: 1,781
Re: Computer in my 85 (Questions)

Quote:
Originally Posted by benoit454
I wonder if my 86 4x4 has it?

Alot of thing underhood unhooked and some I found the other day underneath.
It should have it. It's not bad to have one in operating condition for a cruiser but like the tech artical mentions most quit working a long time ago.
__________________
1976 Custom Deluxe SWB Med FMB.3/4 Drop.
Gen VI 454, Muncie HD 3 speed With Modified OE Hurst Shifter, 3.73 12 bolt, GMPP HO roller cam, Hooker headers, Performer intake with modified Q-jet, Accel distributor. Best 1/4 12.3 @108. Funnest run 19.84 @88 full 1/4 mile burn out.
1997 K1500 ext cab 5.7 stock except muffler
SSC's76 is offline   Reply With Quote
Old 11-17-2005, 05:48 PM   #9
benoit454
Chris
 
benoit454's Avatar
 
Join Date: Nov 2004
Location: Monaville, WV
Posts: 3,737
Re: Computer in my 85 (Questions)

LOL I'd say so the other thing that gets me is it has the 700r4 which I know is electronic lock up TC. I am wondering if it's working or not because this thing has almost no power, new cam, lifters, headers, and runs good and once the truck gets going it rolls fine but getting it started really sucks. It starts up great and real quick so I know it's in timing right(need to put a light on it though for sure) but from take off is when it sucks. But it's got I dunno what gears and 33x12.50's now. Factory ditributor as far as I know, suposed rebuild in 96 but doesn't seem that way, had leaking broken valve cover gaskets, broke and leaking oil pan gasket, and fuel pump gasket was leaking, but on tear down it had a double roller chain set. I wonder if it's running bad because of that retard computer?
__________________
Chris



GIT R DONE!!!!!!

Check out all our rides,
http://www.cardomain.com/id/benwa454
benoit454 is offline   Reply With Quote
Old 11-17-2005, 06:42 PM   #10
Captkaos
www.73-87chevytrucks.com
 
Captkaos's Avatar
 
Join Date: Dec 1999
Location: Birmingham, AL
Posts: 6,935
Re: Computer in my 85 (Questions)

You can probably fix the lockup problem also:
http://www.73-87.com/7387garage/drivetrain/lockup.htm

What year is your truck Chris?
__________________
Chris Lucas
1973 Chevy C-10
1978 GMC Jimmy (2WD) - SOLD
1987 R10 twin turbo LS
1991 R3500 SRW CrewCab
1985 K5 diesel swapped project
1989 K5 2WD conversion w/ Vette susp Project
Captkaos Customs
73-87chevytrucks.com
Captkaos is offline   Reply With Quote
Old 11-18-2005, 12:53 AM   #11
benoit454
Chris
 
benoit454's Avatar
 
Join Date: Nov 2004
Location: Monaville, WV
Posts: 3,737
Re: Computer in my 85 (Questions)

It's an 86

After reading that I don't know if that's the problem or not, since it sems to only matter in 4th, it drive great after you get going just take off stinks horribly. It shifts real quick, normal, and if hard acceleration it shifts very slowly like hangs the gear for a good while.
__________________
Chris



GIT R DONE!!!!!!

Check out all our rides,
http://www.cardomain.com/id/benwa454

Last edited by benoit454; 11-18-2005 at 12:57 AM.
benoit454 is offline   Reply With Quote
Old 11-18-2005, 04:32 AM   #12
apstguy
LED King
 
apstguy's Avatar
 
Join Date: Jan 2003
Location: Sacramento, CA
Posts: 2,087
Re: Computer in my 85 (Questions)

Chris, it sounds like you have a problem with the TV cable on your 700. Here is how to adjust it: http://www.73-87.com/7387garage/drivetrain/tvcable.htm
__________________
Tyler

1985 C10 305 w/ Bowtie OD TH700R4 3.42 LSD 202,000 miles
2006 Ford Focus ZX3 5-speed Stick
2016 Chevy Spark EV
Gone: 2002.5 VW GTI 24v VR6
Gone: 2008 VW R32
apstguy is offline   Reply With Quote
Old 11-18-2005, 01:21 PM   #13
benoit454
Chris
 
benoit454's Avatar
 
Join Date: Nov 2004
Location: Monaville, WV
Posts: 3,737
Re: Computer in my 85 (Questions)

I'll have to try that you think that may be why it has no get up or go from take off?
__________________
Chris



GIT R DONE!!!!!!

Check out all our rides,
http://www.cardomain.com/id/benwa454
benoit454 is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 12:37 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com