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 ShopForum > Technical Information and Support > Tech Help

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 09-05-2003, 11:31 PM
fahrgewehr2's Avatar
Registered User
 
Join Date: Aug 2003
Location: Wilmington, NC
Posts: 1,264
126 300se warm-up question

Hi all,

Have a question. 90 300se - is MUCH faster off the line (much more power) when first starting out in the morning. After motor is becoming warm (temp gauge is between 50 and 80C) there is a hesitation. After car is fully warmed up, everything is smooth, but engine is not as fast as it is when it first started.

I hope this is not confusing. I have seen 2 posts with this same question in the past, and neither recieved a reply.

O2 sensor is new. Mileage at 20mpg. Car starts cery easily. Valve job done 20k ago. Getting 50% flucuation at warm idle.

Mystery...any ideas?

Mike
__________________
'90 300SE 298k
-300K and it gets put into retirement.
'80 300D 255k Purchased new by family in 1980.

Had a:
1973 220 (gas)
1980 300SD
1992 400E
Reply With Quote
  #2  
Old 09-08-2003, 11:55 PM
fahrgewehr2's Avatar
Registered User
 
Join Date: Aug 2003
Location: Wilmington, NC
Posts: 1,264
Anyone? Any suggestions would be nice. Thanks, Mike
__________________
'90 300SE 298k
-300K and it gets put into retirement.
'80 300D 255k Purchased new by family in 1980.

Had a:
1973 220 (gas)
1980 300SD
1992 400E
Reply With Quote
  #3  
Old 09-09-2003, 01:36 AM
Registered User
 
Join Date: Nov 2001
Location: North Central Kentucky
Posts: 1,065
Sounds like your warm up regulator is a bit goofy or perhaps you have a bunch of vacumm leaks and the rich mixture when cold is compensating for incorrect air-flow reading. Usually there is a procedure and table for testing the regulator with a presure gauge and valve. Remember making my own to work on CIS VWs a long time ago. JC Whitney had one for less than $60 and I may just buy one. That control presure is almost everything to the CIS system.
Reply With Quote
  #4  
Old 09-09-2003, 02:26 AM
fahrgewehr2's Avatar
Registered User
 
Join Date: Aug 2003
Location: Wilmington, NC
Posts: 1,264
Thanks for the response Bob. I too suspect vacumm leaks. The vacumm hoses in the engine compartment are pretty cheap on fast lane (sold by the meter) so perhaps I should replace them all and see what happens. Shotgun diagnostics, I know, but cheap.

Where is the warm up regulator located?

Thanks again for your response. Mike
__________________
'90 300SE 298k
-300K and it gets put into retirement.
'80 300D 255k Purchased new by family in 1980.

Had a:
1973 220 (gas)
1980 300SD
1992 400E
Reply With Quote
  #5  
Old 09-09-2003, 08:58 AM
Registered User
 
Join Date: Nov 2001
Location: North Central Kentucky
Posts: 1,065
Figures I should look a the CD before talking. They don't use an old style warm up regulator for control presure on these engines. Looks like it is all managed with the EHA (on the side of the fuel distributor) and the diaphragm presure regulator. Just means that you have to check the sensors. Big one here is probably coolant temp sensor. Looks like it should be 2.5k ohms cold and 340 ohms hot (all readings plus or minus 15%).
Replacing vacumm lines can't hurt. As the engine ages, little vacumm leaks always creep in. You get enough of them and it gets beyond the ability of the lambda system to make up for them. Keep an eye out for gaskets going bad. You can usually spray a little carb cleaner along the gaskets and listen for an RPM change to spot where the gasket is bad. Sealing rings at the injectors are another place for leaks. Some folks just replace them to be sure.
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 11:42 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2011 Pelican Parts - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page