[W126 Coupe] Hesitation while driving

[Dick Spellman]

Sean,

If you suspect the problem is fuel related you need to put a set of 
gauges on the fuel distributor.  Any method of guessing will result in 
you spending a lot of time and potentially a lot of money on parts 
without working with a proper diagnosis.  These cars are easily serviced 
with fuel gauges (Star makes a nice set $80), vacuum guage (mighty vac 
so you can both pull a vacuum and read a vacuum ($30)) and a $30 VOHM 
meter (Sears is fine) that offers a duty cycle output.  Then it's just 
the cd manuals and questions here where the manual seems intimidating or 
uses unfamiliar terms.

Good luck,
Dick

On 5/2/2010 8:36 AM, Sean wrote:

> Ok . Thanks for all the imput but this did not work either.

>

>  notice that even though the fuel pump is quiet. I hear it change 

> pitch of sound every 1sec or 2. It goes higher pitched. My general 

> thought was that a pump would just up and stop?? Or am I wrong in 

> thinking this? Could it be that it is giving fuel pressure but at time 

> hesitating ?? Ordered new pump. Waiting. Did I waste my money??

>

> Sean

>

> On Apr 26, 2010, at 5:28 PM, Dan Landiss <dan at landiss.com> wrote:

>

>> Lacking the official meter, this works well:

>> <http://landiss.com/mixture.htm>

>>

>> on 4/26/2010 10:04 AM Richard K. Hallberg wrote:

>>> +1 on Mike's comment.  My 91 sec was intermittently stumbling and 

>>> would quit several times at cold start and before it reached 

>>> operating temp, would miss but not fail as the revs were up.  

>>> Everything settled at operating temp.  I cleaned the cold start 

>>> valve till I was blue in the face and reseated the FPR - nothing 

>>> seemed to help.  Jonothan, last Friday, adjusted the lambda with a 

>>> Merc meter, Mike's 3mm allen, and now there are no stumbling 

>>> problems or missing and improved power.

>>

>> -- 

>>

>> "I think it would be a good idea."  --Mahatma Gandhi, when asked what 

>> he thought of Western civilization

>>

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