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  #1  
Old 09-29-2012, 05:54 AM
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Exclamation struggling to start and stay running

ok girls and boys,

patient is w126 chassis 1987 420sel

she tries to die (successfully i might add) when i step on the gas pedal...also has very tough time starting....cranks over fine but since she sits a bit....

so im thinking obvious things like fuel filter and fuel pump relay to start....

pls advise any other ideas...

lyle in west texas

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  #2  
Old 09-29-2012, 06:50 AM
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Lyle, first step would be to replace the fuel filter which should be done every 60,000 miles.
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  #3  
Old 09-30-2012, 01:58 PM
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I have the same problem with my 420SEL ! Except now it will not start at all. Good strong spark,compression good and even.It will not try to start w/ starting fluid !!!
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  #4  
Old 09-30-2012, 07:17 PM
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lyle_H:

1. Check the over voltage protection (OVP) relay, there is a fuse on top of it and it is located on the firewall a bit left of center.

2. Ensure that BOTH fuel pumps are running.

3. Ensure that the cold start valve is spraying fuel during a start attempt.


James Peters:

Check OVP, your description sounds like no power to the fuel pumps.
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  #5  
Old 10-01-2012, 06:11 AM
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an update...

what i did was have my local guy wire my fuel pump to the battery and put a switch in, so i manually turn on the fuel pump, so i have power to the fuel pump....

could i still have an OVP issue?

lyle in west texas
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  #6  
Old 10-01-2012, 10:24 AM
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Location: Rudy,Arkansas
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I has good fuel pressure and will not try to start even with starting fluid. You can hear the pump spool-up at key on.
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  #7  
Old 10-01-2012, 10:29 AM
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Question starting issue

to james peters:

right now car is idling rough....how does one know if the second fuel pump is running without getting under the chassis? i am but one person

lyle in texas
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  #8  
Old 10-01-2012, 11:57 AM
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Answer

You really need to understand the system, and how to diagnose issues.
These should help.

Fuel Injection

************************

https://www.google.com/search?q=bosch+jetronic+fuel+injection&oe=utf-8&aq=t&rls=org.mozilla:en-USfficial&client=firefox-a&um=1&ie=UTF-8&hl=en&tbm=isch&source=og&sa=N&tab=wi&ei=jLhpUJKeLKy20AHMqYGABQ&biw=1280&bih=883&sei=H7lpUNyUOK-O0QGYv4CQCg#um=1&hl=en&client=firefox-a&hs=gcj&rls=org.mozilla:en-US%3Aofficial&tbm=isch&sa=1&q=1987+420sel+bosch+jetronic+fuel+injection&oq=1987+420sel+bosch+jetronic+fuel+injection&gs_l=img.12...0.0.2.20912.0.0.0.0.0.0.0.0..0.0...0.0...1c.W3kwIfayHmE&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.&fp=b3de46ad5252a728&biw=1280&bih=883




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