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 > The 1973 - 1991 Blazers, Jimmys, and Suburbans Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 12-09-2012, 11:49 PM   #1
SoCalSlaughter
Registered User
 
SoCalSlaughter's Avatar
 
Join Date: Aug 2010
Location: Ventura
Posts: 151
Red face Setting timing

Ive been trying to set the timing on my 90' Suburban for about an hour now, Ive read on many forums to disconnect the "Set timing" wire, but I cant find the right location, some say next to the ecm behind glove box, some say by steering shaft and some say next to distributor. Ive set the timing to 0 and reconnected both wires behind glove box and by steering shaft, and the truck seems to have had lost alot of power and throttle responce. Idle isnt very steady, goes between 700-900. Any ideas? Thanks!!
SoCalSlaughter is offline   Reply With Quote
Old 12-10-2012, 12:02 PM   #2
68Timber
I know the pieces fit
 
68Timber's Avatar
 
Join Date: Nov 2007
Location: MONTGOMERY, AL
Posts: 5,523
Re: Setting timing

Should be a tan wire under the top of the carpet behind the glove box if I recall correctly. Did it have the idle problem before you set the timing?
__________________
John

79 2wd Blazer (Bruiser)
85 M1009 Blazer (Sarge) build
74 Honda Z50 build
68Timber is offline   Reply With Quote
Old 12-10-2012, 03:44 PM   #3
SoCalSlaughter
Registered User
 
SoCalSlaughter's Avatar
 
Join Date: Aug 2010
Location: Ventura
Posts: 151
Re: Setting timing

It had a problem of after starting the trucks idle would be slow, around 500 until I gave it alittle rev then it would idle at 700 perfect. So I checked the timing to make sure it was within spec, and the timing notch on the balancer was about an inch past the timing mark plate. So probably advanced 14-16 btc
SoCalSlaughter is offline   Reply With Quote
Old 12-10-2012, 07:13 PM   #4
68Timber
I know the pieces fit
 
68Timber's Avatar
 
Join Date: Nov 2007
Location: MONTGOMERY, AL
Posts: 5,523
Re: Setting timing

I've only had one TBI truck that never gave me any trouble so I'm not schooled in trouble-shooting them. But I'd start with checking injector spray patterns. Has it sat up much recently? After you pat the gas and get it up to a 700 rpm idle is it smooth? Also they're real picky about fuel pressure being in spec to run right. EGR malfunction is also common.
__________________
John

79 2wd Blazer (Bruiser)
85 M1009 Blazer (Sarge) build
74 Honda Z50 build
68Timber is offline   Reply With Quote
Old 12-10-2012, 08:03 PM   #5
Jonboy
Slots go on anything!
 
Join Date: May 2003
Location: Richardson, TX
Posts: 5,957
Re: Setting timing

The timing connector "should" be just to the right of the engine. It is a tan, single wire with a single weather pack connector. That may make all the difference in the world if you didn't have the right connector unhooked.
Jonboy is offline   Reply With Quote
Old 12-10-2012, 08:18 PM   #6
SoCalSlaughter
Registered User
 
SoCalSlaughter's Avatar
 
Join Date: Aug 2010
Location: Ventura
Posts: 151
Re: Setting timing

It does have a stumble when i lightly put my foot on the throttle, but drive fine after that. Almost everything on the truck has been replaced about a year ago. Wouldnt rule out any of those parts going bad already, but I was told the throttle shaft that goes threw the TBI after years will become loose and cause a vaccum leak by the throttle blades. And Ived checked the injectors as the truck is running with a flashlight and they seem fine. I will advance the timing to 4 btc and reset the ecu and see if that fixes the problem
SoCalSlaughter is offline   Reply With Quote
Old 12-10-2012, 08:49 PM   #7
68Timber
I know the pieces fit
 
68Timber's Avatar
 
Join Date: Nov 2007
Location: MONTGOMERY, AL
Posts: 5,523
Re: Setting timing

How many miles are on it? Just curious.
__________________
John

79 2wd Blazer (Bruiser)
85 M1009 Blazer (Sarge) build
74 Honda Z50 build
68Timber is offline   Reply With Quote
Old 12-11-2012, 03:19 AM   #8
SoCalSlaughter
Registered User
 
SoCalSlaughter's Avatar
 
Join Date: Aug 2010
Location: Ventura
Posts: 151
Re: Setting timing

Bought the truck in 2009 with 113k, currently has 157k
SoCalSlaughter is offline   Reply With Quote
Old 12-13-2012, 01:07 PM   #9
LEEVON
Moderator
 
LEEVON's Avatar
 
Join Date: Jul 2006
Location: Ozark, MO
Posts: 4,888
Re: Setting timing

There is a 10a fuse that blows if you reconnect the brn/wht wire with the ignition on, or even sneeze at it for that matter. I can't remember what it's called on the fuse box but its something like "ECM2". Same as running with the wire disconnected, you will have no advance.
__________________
'20 Silverado Trail Boss ~ '17 Tahoe ~ '79 K15 Sierra Grande ~ '76 Blazer 2wd ~ '71 Cheyenne swb ~ '55 Pontiac Safari ~'50 3100 bagged ~ '80 Wife ~ Late model kids
LEEVON is offline   Reply With Quote
Reply

Bookmarks

Tags
set timing, timing, timing adjustment


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 07:20 AM.


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