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  #1  
Old 06-21-2004, 10:05 PM
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Join Date: Jun 2004
Location: Dublin, Georgia
Posts: 4
Question '88 190e losing power after warm up

Hi Everyone, Hope you can help. I have a 1988 190e 2.3 and it's losing power once engine has warmed up to operating temp. It will drive fine until warmed up. Once this happens, it will run and idle extremely rough and the economy needle would be pegged. No acceleration at all. If I turn it off and right back on, it idles smooth again and can rev it up fine as long as it's not in gear. Once in gear it will drive for about 50 to 100ft and then loses power again. While in this state, if I put in neutral or park and try to rev, no power and sometime the Air intake will pop. Normally, I would suspect fuel filter, pump, vacuum, etc. but I think that should happen all the time. Thought about EGR valve but cannot find one on this car. This also happened last year and it fixed itself while I was revving it to troubleshoot. Had air cleaner off and hose disconnected from head cover and saw puff of white smoke? and then it ran fine after that for a year. This time it won't fix itself. Any ideas?

Thanks

Last edited by JohnWK; 06-21-2004 at 10:27 PM.
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  #2  
Old 06-27-2004, 05:47 PM
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Join Date: Jan 2004
Location: Maine
Posts: 44
lose power

HI, I am getting the same symptoms with my 87' 300e at warm up. If i give it a little gas at a time the engine will run smooth but when I go to accelerate the engine stalls or pops . Start up to warm up is great until it gets to operating temp. Any help would be appreciated.

thx Vinnie
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  #3  
Old 06-28-2004, 12:32 AM
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Join Date: Jun 2004
Location: Dublin, Georgia
Posts: 4
Okay, After reading about other problems with stalls even though my symptoms are different, I decided to disconnect my EHA Valve. The engine ran fine and I was able to drive it without it losing power. Built a test harness and performed test on EHA and seems to test okay. Pulled the OVP relay and that seems okay also although I didn't take it apart to check solder connections. So if it's not the EHA or OVP, what else can it be? Before disconnecting EHA, I was not getting any computer error codes and now the only error is the EHA one because it's disconnected. If you've had this problem before, please help. I hate to purchase and replace parts on a trial and error basis as these are expensive parts and I'm currently unemployed.

Thank You.
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  #4  
Old 06-28-2004, 03:50 AM
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Join Date: May 2002
Location: NH
Posts: 23
Starved for fuel after warm up

My 88 560sl did the same thing yesterday. I was driving on the highway and it started to lose power. I would stop the car and restart it, it would run fine for about 3 minbutes then lose poer again. After about 20 restarts I pulled the ovp and it ran fine. I had a spare ovp but the same problem was there when I installed it. It must have something to do with the fuel computer or idle control because that's the only fuel systems related to the ovp. Let me know if you find out and likewise.
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  #5  
Old 06-28-2004, 09:08 AM
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Join Date: Oct 2002
Location: Toronto, Canada
Posts: 700
This is usually related to electronics in the car since they are what controls the fuel mixture once you reach operating temperature. Things to check are OVP, O2 sensor, Fuel mixture, I had the same problems also but not to this extent and the fuel mixture was the problem. Cloged fuel filter will usually cause problems constantly warm up or not. Also check for any vacuum leaks in the engine, justlisten for hissing and do a good visual inspection.

now back to work

xp
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  #6  
Old 06-28-2004, 11:14 AM
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Location: SoCal
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Quote:
Originally posted by JohnWK
Okay, After reading about other problems with stalls even though my symptoms are different, I decided to disconnect my EHA Valve. The engine ran fine and I was able to drive it without it losing power. Built a test harness and performed test on EHA and seems to test okay. Pulled the OVP relay and that seems okay also although I didn't take it apart to check solder connections
If disconnecting the EHA allows it to run ok, then the OVP is not the problem. The principal input used by the electronics to control the EHA is the O2 sensor, so I would first suspect it is indicating a false 'rich' reading - i.e. not working.

Steve
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  #7  
Old 07-02-2004, 02:08 AM
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Join Date: Jun 2004
Location: Dublin, Georgia
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Thanks for the help.

XP, I checked vacuum lines and cannot find any leaks. However, I believe that was the cause the first time this problem occurred a year ago. This time is different.

Steve, I will check the O2 sensor this weekend. Tried to check but the meter I was using did not have a millivolt range (cheap). Will get another one. Which is the wire to the sensor? Pulled up carpet and there's two connector. One with 2 wires and the other with one wire.

John
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  #8  
Old 08-22-2004, 11:13 PM
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Join Date: Jun 2004
Location: Dublin, Georgia
Posts: 4
Thumbs up Fixed

Thanks to everyone. I was finally able to order and install a new Oxygen sensor and install it. Hooked up back the EHA and everything is working fine now. I really appreciate this site as it has helped me to get some things fixed and saved putting vehicle in the shop.
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  #9  
Old 08-22-2004, 11:31 PM
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Join Date: Mar 2003
Location: Southern California
Posts: 2,040
Quote:
Originally Posted by JohnWK
Thanks for the help.

XP, I checked vacuum lines and cannot find any leaks. However, I believe that was the cause the first time this problem occurred a year ago. This time is different.

Steve, I will check the O2 sensor this weekend. Tried to check but the meter I was using did not have a millivolt range (cheap). Will get another one. Which is the wire to the sensor? Pulled up carpet and there's two connector. One with 2 wires and the other with one wire.

John
Single wire connector is signal and two wire is heater. Pull the single connector far enough out to get the VOM probe on it - should read about 500mv with the engine at operating temp.

Also check the "duty cycle":

www.landiss.com/mixture.htm

Duke
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