Pagoda SL Group

W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: ctaylor738 on October 26, 2009, 21:20:06

Title: Can I adjust the WRD this way?
Post by: ctaylor738 on October 26, 2009, 21:20:06

I am at the point with my cold running problem where I am convinced that my 230SL is not getting any extra fuel for warm-up, or at least not enough to offset the added air.  Winter is not going to be any fun if it behaves like it did on a cold day last week.  So I think this means increasing the space between the WRD and the pump with shims.  It is currently shimmed with  .5 and .1 mm shims.

Given that the gizmo in the pump is spring-loaded and is pressed down by the rod in the WRDand is thus under pressure, can I simulate additional shims by simply not tightening the screws all the way, leaving a gap and measuring it with a feeler gauge?  Try a cold start and if not enough improvement, back off another .25 mm or so?  Then make up the shims when I know the amount to raise the WRD.

Thanks

Title: Re: Can I adjust the WRD this way?
Post by: ja17 on October 29, 2009, 03:44:19

Hello Chuck,

Yes, this is a valid test procedure I have used.  Loosening the hold down screws will rich-en the mixture by allowing the assembly to raise. If you find out the pitch of the screw thread, then count the turns you can get an accurate dimension. Not good for a fix, since this will also alter warm running!

I would make certain that the "heat feeler" (the coolant thermostat unit in the WRD, pin moves outward as engine temp. increases) is moving to specs and the slide valve is free  in it's bore. Remember, adjustments in the WRD will change mixture at all temperatures not just cold. Changes in the bottom stage (oval shims) will change the mixtrue in all speed ranges and will not alter the closing temperature of the aux. air supply to the WRD.  Changes in the upper stage  (adjustment nuts or round shims), also change the mixture at all temperatures but changes here will also change  temperature that the auxiliary air to the WRD is shut off. The heat feeler is most important and really does all the cold temperture adjustments. It has a set demension to travel as engine coolant temp. changes. Check the heat feeler.


So it seems to me that adjustment of just the cold temperature mixture without altering the warm running mixture is very limited. The root of the problem is often inadequate fuel supply or pressure, defective heat feeler, Stuck slide valve in the WRD, previous mis-adjustments, or worn or damged IP.

Basic engine tuning items should always be checked first (ignition, timing etc.).

Title: Re: Can I adjust the WRD this way?
Post by: wwheeler on October 29, 2009, 17:13:09

What are the specs for the heat feeler? I looked in the Tech manual but couldn't find anything specific.

Title: Re: Can I adjust the WRD this way?
Post by: Shvegel on October 30, 2009, 01:45:57

Hey,
Is Falls Church anywhere near Portsmouth? I am going to be in Portsmouth for the next 6 weeks and would love to help.

Title: Re: Can I adjust the WRD this way?
Post by: ctaylor738 on November 01, 2009, 01:24:35

Falls Church is a Washington DC suburb, and about 200 miles north of Portsmouth.

You are welcome to visit, send me a PM.

Not sure where to go with this, though.  I think the pump needs to come out and be looked at by someone who can fix it.  An alternative may be to go back to the misadjusted linkage, with the pump "leading" the air a bit.

Title: Re: Can I adjust the WRD this way?
Post by: ja17 on November 01, 2009, 06:01:55

Hello chuck,  if you have the early injection pump with the long heat feeler it should move 0.5mm for every 10 degree C increase.