Grounding issue? - Team Camaro Tech
Electrical & Wiring Troubleshooting electrical.

 
LinkBack Thread Tools Display Modes
post #1 of 7 (permalink) Old May 3rd, 09, 05:43 PM Thread Starter
 
Join Date: May 2009
Posts: 2
Grounding issue?

I own an 85 Camaro Berlinetta and have been having a few intermitent problems with my digital dash. The temperature sensor is generally off by about 30-50 degrees. In addition, the tach/speedo will cut out togethor or the voltage display will drop and the coolant warning light will come on. I don't experience all of these at the same time, but they do act togethor (tach/speedo, voltage/coolant warning). I'm pretty sure this is a grounding issue but wanted to make sure before I tore the whole thing out. If everything sucked at the same time I'd be convinced, but since its intermitent and changes between displays, I was wondering what anyone elses thoughts were. In addition, if you know whether the issue is internal to the dash PCB's or whether its in the wiring, I'd appreciate feedback.

Thank you
Some Random Guy is offline  
Sponsored Links
Advertisement
 
post #2 of 7 (permalink) Old May 4th, 09, 05:07 PM
David
 
Join Date: May 2005
Location: Denver, CO (SE)
Posts: 18
Re: Grounding issue?

It may well be a grounding issue. It might also be a voltage issue with the dashboard's power supply.

Can you nail down when it happens?

1) Does it happen when it's cold, or when it's warm (outside)?
2) Does it happen before or after the dash has been on for awhile?
If you think it is temperature related, you can check it with a hair dryer. That can heat up a given connection really fast; don't overdo it. Trace back until you find the one that flakes out under heat. You can also use freeze mist (or, actually, just a can of compressed air used to blast dust out of a computer held upside down) to cool down a junction to below-zero very fast. In general "cold solder" joints will have thermal problems.
3) Does it happen when the dash gets vibrated?
4) Does a good smack to the dash help? Those tend to be connectors underneath screw heads that are making intermittent contact.

Tracking down stuff like this can be difficult and make people invent entirely new swear words. You may have, for example, a flaky fuse, or oxidation on the fuse contacts, in the fuse box.

I've had stuff like this happen, and I finally adopted a "overkill: stomp the bugs flat" approach that usually nails it down quickly.

What I usually do when this sort of thing happens is bring two wires from the battery, +12V and Ground. Fuse them BOTH AT THE BATTERY in case you run into a nasty short. You can find some easy inline fuses at Radio Shack. 5 amps is plenty. Bring the wires through the firewall, with some tubing around them at the firewall to protect them from being sliced there. Tape over the ends of these two wires when they are not actually connected. You really really really do not want a live +12V wire to battery +12V flopping around. Trust me. The cloud of blue smoke you get when it shorts out is something else.

Fire up the car, and one at a time, connect these two wires to the power and ground for the dash, as -close to the dash as possible-, again, -only- when the dash is already powered up. (If you power up the dash with the ignition off, the power will backfeed to the ignition switch and turn other things on, and that can turn ugly in a hurry.) Tape the connection; it's only temporary.

If the dash stabilizes while either the dash +12V is connected to battery +12V, or while dash ground is connected to battery ground, there's your problem. hat you can do now is follow the dash pwr and ground back and find the place where adding +12v or ground doesn't help anymore; between that point, and where it does help, is your problem.

I hope this helps.

-- thanks,

Dave
comcain is offline  
post #3 of 7 (permalink) Old May 4th, 09, 06:34 PM
Banned
Alan
 
98blackburb's Avatar
 
Join Date: Feb 2007
Location: Indian River Chevrolet,
Posts: 3,632
Re: Grounding issue?

Get ahold of Everrett
98blackburb is offline  
 
post #4 of 7 (permalink) Old May 4th, 09, 10:47 PM
Super Moderator
Bess-68's rule
 
Everett#2390's Avatar
 
Join Date: Sep 2000
Location: Va Beach VA
Posts: 31,853
Garage
Re: Grounding issue?

As Dave suggested, the biggest problem with digital dashes is cold solder joints either on the board itself or the power supply.

Troubleshooting as Dave suggests and being patient and observing all the symptoms will help localize the problem.

Looking for cold solder joints requires a black light and a magnifying glass. A cold solder joint will show up as a crack in the solder, black light brings it out. If you chose to resolder, use a 25 watt pencil, a very clean tip, wipe the hot tip on your jeans, good resin solder, 63/37 ratio, a good heat transfer to melt, meaning a clean tip and a spot of solder on the tip. Solder melts, remove the heat. A good solder joint will be a shiny silver, not a dull gray color.

Give a man a rescued dog for the health of both their souls. May 2017 ROTM Winner - Thank you!
'
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
CUBS - 2016 World Series Champions - Thank you, Joe Madden enjoy your next chapter.
Everett#2390 is offline  
post #5 of 7 (permalink) Old May 6th, 09, 08:24 PM Thread Starter
 
Join Date: May 2009
Posts: 2
Re: Grounding issue?

It seems to be vibration related. Usually a good whack around the dash or a few bumps in the road will bring lights back or put the gauges back into the proper ballpark. As for the hairdryer, I'll have to wait for one of my female housemates to get back into town next week.
Some Random Guy is offline  
post #6 of 7 (permalink) Old May 7th, 09, 09:01 PM
Gold Lifetime Member
Art
 
Join Date: Nov 2008
Location: Greentown, PA
Posts: 353
Re: Grounding issue?

My 84 Berlinetta was acting up in a similar manner(actually worse as it cut out completely). The ground on the thermostat housing that is attached to the stud was corroded, cleaned the ground and issues were resolved. I still have the shop manual from that car somewhere, I'll see if I can find it.

Artie

67 Camaro
99 T/A Daily Driver

Previous:
67 Camaro Traded for my 98
68 Camaro Street/Strip
98 Camaro Race car Best ET 9.08 @ 152 1.18 60'

Dyno sheets don't win races, see you at the track
SRGN is offline  
post #7 of 7 (permalink) Old May 8th, 09, 01:30 PM
David
 
Join Date: May 2005
Location: Denver, CO (SE)
Posts: 18
Re: Grounding issue?

I think you're getting ground loops because the system ground (and very possibly the chassis ground, as was noted) are going bad.

I would have a close look at your battery, its clamps, and particularly at its Gnd cable to engine, and the engine to frame strap. I'd actually unscrew these cables to their engine connection (and frame end) and make very sure both the cable's end and the engine end are nice shiny metal. A good wirebrush is a big help here. You also want to check for corrosion in the cable where it's covered by the battery clamp. That one bit me. This could be as simple as a corroded negative clamp.

If that doesn't fix it, then you've certainly done no harm, and it sure postponed the day when you'd have to do this anyway.

If it's not fixed, I'd probably run a (fused!) ground from battery and bring it to the dash ground, and see if that doesn't cure it. Then you can take it wire by wire in steps and find the bad segment.

-- hope this helps,

Dave
comcain is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome