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  #1  
Old 10-21-2008, 10:54 AM
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Location: hutto,texas,78634
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81 380 sl runs better

ive read some of the posts about this subject. im more familiar with the diesel's so please bear with me.
this car has been sitting for a year. it did start and run, had fouled two of the plugs on the passenger side. after that repair noticed that it would run rich but it did keep running.
specs on the car built 7-81 wdbba45a8bb008335.

the car has had one previous owner and he donated it to charity. all maintainance looks to have been done but he left no records in the car. a/c( 134a) exhaust, tires, fluids, and battery all look recent. state inspection expired 11-2007. you can see the minor body damage in the front. ive been driving the car and it runs better every time i drive it.

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81 380 sl runs rich-p1010020.jpg   81 380 sl runs rich-p1010019.jpg  
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85 300 sd 168k current driver
85 300 sd parts
81 380 sl 125k
84 190 d 160k just bought!

Last edited by mgerdes; 10-24-2008 at 05:02 PM.
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  #2  
Old 10-27-2008, 01:38 PM
Engr693's Avatar
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Seeing that it has been sitting a while. Did you put new gas in? Sometimes the old gas will gum up the internal injector orifices. Use some injector cleaner or put in a can of sea foam. Give it some time to work its way thru the system.
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1973 450SL
1999 Silverado 4X4 Ext Cab
1999 Mercury Sable
1972 450SL Parts car

Previously owned keepers:
1967 MGCGT - 3L-6
1972 Mustang Fastback - 351C

Current Cylinder Index: 37
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  #3  
Old 03-03-2010, 09:07 PM
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Quote:
Originally Posted by mgerdes View Post
ive read some of the posts about this subject. im more familiar with the diesel's so please bear with me.
this car has been sitting for a year. it did start and run, had fouled two of the plugs on the passenger side. after that repair noticed that it would run rich but it did keep running.
specs on the car built 7-81 wdbba45a8bb008335.

the car has had one previous owner and he donated it to charity. all maintainance looks to have been done but he left no records in the car. a/c( 134a) exhaust, tires, fluids, and battery all look recent. state inspection expired 11-2007. you can see the minor body damage in the front. ive been driving the car and it runs better every time i drive it.
Realize this is an old post...but hopefully you will see this. What did you do to repair the two fouled plugs? The reason I am asking is that I have a similar situation in the #4 cylinder. Try to find a cure for it. Thanks in advance.
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Old 03-03-2010, 09:40 PM
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just cleaned them and put them back in, they were in good shape, just fuel fouled from a bad warm up regulator( i think). i have not replaced it yet but from what i have read thats got to be the problem, thanks. mark
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  #5  
Old 03-04-2010, 09:26 AM
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The warm-up regulator would make it run rich on all cylinders. If you are having problems with one or two, it is more likely the fuel distributor or injector(s).
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Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe
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  #6  
Old 03-04-2010, 09:59 AM
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i should have been more clear, all the plugs were black, but when i bought the car the 2 back ones on the pass side were not hitting. i cleaned them, drove the car to blow the cobb webs out, then watched it idle for a few minutes. slowly the vacume would come down, exhaust get rich, and then it would finally die. one day ill drive it, runs good all day, idles good. then the next day, first stop i come too it will start to load up.
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  #7  
Old 03-04-2010, 11:50 AM
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Usually, warm-up regulators have the opposite problem, they don't supply enough fuel when the engine is cold, or help enough with enrichment when you try to accelerate.

I would check the oxygen sensor. If it is worn out and giving a low reading, the lambda system will try to enrich the mixture. A quick test is to disconnect it and see if the mixture situation improves.

You might also check the fuel distributor piston for movement. Jumper 30 to 87 at the fuel pump relay so the pump runs. Press the air sensor plate down and be sure that it moves easily, and that it returns to rest smoothly.

If you have an old-fashioned dwell meter or even a multimeter, you can check the on/off ratio, which will tell you what the system is doing to try to control the mixture. Lots of posts on this.
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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe
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  #8  
Old 03-04-2010, 01:24 PM
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thanks for the reply, guess its time to get the car back on the road! btw, i have checked the piston in the distributor, its ok. i have not checked the oxy sensor until just now. i moved the car around to my shop after not starting it for a long while. started and ran good, no chugging. turned it off after 2 minutes, raised it up, grabbed the o2 sensor and unplugged it. started the car, it ran good for 1 minute or so, then rpm slowed to about 500, started chugging but did not die. ran like this for 5 minutes. raced it up a couple of times but it returned to steady 500 rpm but black smoke rich. temp by this time is almost 80c. turned off, plugged o2 back in, started car, ran as before but got worse steadily until car died within 30 seconds. thanks again, mark
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85 300 sd 168k current driver
85 300 sd parts
81 380 sl 125k
84 190 d 160k just bought!

Last edited by mgerdes; 03-04-2010 at 03:36 PM.
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  #9  
Old 03-14-2010, 02:15 PM
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Whatever happened with this?
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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe
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  #10  
Old 03-14-2010, 02:20 PM
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Originally Posted by ctaylor738 View Post
Whatever happened with this?
if you read my previous post what direction should i go in next, or what else can i check. thanks
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85 300 sd parts
81 380 sl 125k
84 190 d 160k just bought!
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  #11  
Old 08-17-2010, 08:47 AM
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380 running rich

i adjusted the fuel at the top of the breather with much success. it still may need some fine tuning but no more chugging, vacuum gage is far left and idle is good. i turned it counter clockwise . peering down the hole with a flashlight the pot looks to have been adjusted many times before.
i had a ratio of 11% that doesnt jive.
13.5 b+
pin 3 was 11.9-12.1
runs good.

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85 300 sd 168k current driver
85 300 sd parts
81 380 sl 125k
84 190 d 160k just bought!

Last edited by mgerdes; 08-31-2010 at 06:57 PM.
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