[W126 Coupe] how do you adjust

[Dick Spellman]

Hi Gary,

Just check the pressures chart in the manual so the shop will be using the
correct values for your model year.

Take care,

Dick

On Mon, Jul 19, 2010 at 1:47 PM, Gary <garysalas at yahoo.com> wrote:


> it was running very rough, then stopped running.  would turn over.  i took

> it to the garage and the fuel pressured it and the FD was the problem.  i

> probably should just take it back to them and have them do the fine tuning

> since they have the tools.    i'll give them a copy of your info, can't

> hurt.    thanks

>

>  ------------------------------

> *From:* Dick Spellman <dick.spellman at gmail.com>

> *To:* Mercedes Coupes Mailing Lists <mbcoupes at mbcoupes.com>

> *Sent:* Mon, July 19, 2010 9:37:12 AM

> *Subject:* Re: [W126 Coupe] how do you adjust

>

> Gary,

>

> You need to put a fuel pressure gauge on the fuel distributor (fd).  At a

> minimum you can connect to the cold start valve outlet (upper fd chamber) on

> the fd to obtain overall pressure.  Ideally, you want a gauge that permits

> connections to both upper and lower chambers (two hoses with a shut-off

> valve on one)) so you can measure the difference between upper chamber and

> lower chamber pressures (referred to as differential pressure) in the

> manual.  Typical fuel pressures would be 5.3~5.4  bar overall.  When

> isolating lower chamber pressure it should be approximately 0.4 to 0.45 bar

> LESS than the overall pressure.  This would be your differential pressure

> which is in the manual.

>

> So, as an example upper chamber is 5.3 bar and lower is 4.9 bar,

> differential is then 0.4 bar.  Without knowing the pressures it is difficult

> to recommend a set of steps to remedy your problem.  Two quick questions:

>

> 1. did you replace the rubber o-ring (seal) at the base of the fd when you

> swapped out?  If not, a vacuum leak (large) will likely exist where the fd

> bolts down on the air flow meter housing.

> 2. what running conditions did you have prior to the swap?

>

> Good luck,

>

> Dick

>

> On Sun, Jul 18, 2010 at 10:57 PM, Gary <garysalas at yahoo.com> wrote:

>

>>  the fuel distributor.  i put one from a donor car and need to adjust

>> because the car just turns and turns   thanks for the help

>>

>> The MB Coupes Website!

>> W126 SEC Mailing List

>> Postings remain property of MB Coupes, L.L.C.

>>

>

>

> The MB Coupes Website!

> W126 SEC Mailing List

> Postings remain property of MB Coupes, L.L.C.

>

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