Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 08-02-2013, 06:15 PM
Registered User
 
Join Date: Jul 2013
Posts: 9
82 300SD AC Comes on only after "gunning it"

To get my AC to come on I have to give my car a good rev up. If I take off slow and drive slow it will stay off the whole drive. From a cold start it I gun it it will come right on. Cold engine and all.

I jumpered the two switched, low pressure and the one by the accelerator, I changed relays, topped off the R12. Once it comes on it works fine.

I drove home the other night and never accelerated forcefully and it stayed off. The next morning I took off fast and it came right on. Now I just turn it on by gunning it right after taking off.

Any ideas?

Reply With Quote
  #2  
Old 08-02-2013, 06:49 PM
compu_85's Avatar
Waiting for his Model 3..
 
Join Date: May 2008
Location: Springfield VA
Posts: 5,174
It might be cracks in the climate control pushbutton unit / computer board. The vibrations from high rpms might "fix" the connection and get the system to command the compressor to turn on.

-J
__________________
1991 350SDL. 230,000 miles (new motor @ 150,000).

2013 Fiat 500E. 20,000 miles, 80 miles at a time.
2012 Passat TDI. 95,000 miles. More space, power, and fuel economy than the Benz
2004 Touareg V10 TDI. 150,000 miles. One of 450.
1999 Jetta TDI. 310,000 miles.
1992 Jetta ECOdiesel. 156,000 miles. 1 of 48. Sold.
1991 Jetta ECOdiesel. 430,000 miles. 1 of 700. Sold to VeeDubTDI, totaled in front of our house
Reply With Quote
  #3  
Old 08-02-2013, 07:18 PM
Registered User
 
Join Date: Nov 2004
Location: North central Texas
Posts: 2,588
May be normal as some will not allow the compressor to engage until rpm comes up off of idle. It's a feature to eliminate the load of the compressor during starting.
Reply With Quote
  #4  
Old 08-02-2013, 10:43 PM
Registered User
 
Join Date: Jul 2013
Posts: 9
I should have said I also replaced the ACC unit with a rebuilt one. I guess if it is normal I will just have do drive a little more aggressively.
Reply With Quote
  #5  
Old 08-02-2013, 11:11 PM
Registered User
 
Join Date: Aug 2011
Location: Carolina
Posts: 1,416
Vacuum leak.
__________________
Current fleet
1992 300D "IceBerg"
1984 300D "Blues Mobile"

1978 300CD "El Toro" Gone on to be born again
Reply With Quote
  #6  
Old 08-03-2013, 11:15 AM
Registered User
 
Join Date: Nov 2004
Location: North central Texas
Posts: 2,588
Quote:
Originally Posted by Matteo View Post
I should have said I also replaced the ACC unit with a rebuilt one. I guess if it is normal I will just have do drive a little more aggressively.
Does the tach work?
Reply With Quote
  #7  
Old 08-03-2013, 11:23 AM
compu_85's Avatar
Waiting for his Model 3..
 
Join Date: May 2008
Location: Springfield VA
Posts: 5,174
I don't believe an 82 has a clima / rpm sensor relay.

-J
__________________
1991 350SDL. 230,000 miles (new motor @ 150,000).

2013 Fiat 500E. 20,000 miles, 80 miles at a time.
2012 Passat TDI. 95,000 miles. More space, power, and fuel economy than the Benz
2004 Touareg V10 TDI. 150,000 miles. One of 450.
1999 Jetta TDI. 310,000 miles.
1992 Jetta ECOdiesel. 156,000 miles. 1 of 48. Sold.
1991 Jetta ECOdiesel. 430,000 miles. 1 of 700. Sold to VeeDubTDI, totaled in front of our house
Reply With Quote
  #8  
Old 08-03-2013, 11:28 AM
vstech's Avatar
DD MOD, HVAC,MCP,Mac,GMAC
 
Join Date: Mar 2006
Location: Mount Holly, NC
Posts: 26,389
clutch air gap is too large.
__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
Reply With Quote
  #9  
Old 08-03-2013, 11:32 AM
Registered User
 
Join Date: Nov 2004
Location: North central Texas
Posts: 2,588
Quote:
Originally Posted by compu_85 View Post
I don't believe an 82 has a clima / rpm sensor relay.

-J
'82 may not...

I change my answer to a loose connector at the compressor.
Reply With Quote
  #10  
Old 08-03-2013, 12:03 PM
compu_85's Avatar
Waiting for his Model 3..
 
Join Date: May 2008
Location: Springfield VA
Posts: 5,174
Quote:
Originally Posted by vstech View Post
clutch air gap is too large.
I was just watching a video where someone explained this. He tested it by switching on the AC then poking the clutch plate with a tool, which gave it enough assist to be pulled in.

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000).

2013 Fiat 500E. 20,000 miles, 80 miles at a time.
2012 Passat TDI. 95,000 miles. More space, power, and fuel economy than the Benz
2004 Touareg V10 TDI. 150,000 miles. One of 450.
1999 Jetta TDI. 310,000 miles.
1992 Jetta ECOdiesel. 156,000 miles. 1 of 48. Sold.
1991 Jetta ECOdiesel. 430,000 miles. 1 of 700. Sold to VeeDubTDI, totaled in front of our house
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

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 On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 12:09 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page