Pagoda SL Group

W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: Tywrapdave on August 04, 2013, 20:01:49

Title: 230SL Fuel supply issue
Post by: Tywrapdave on August 04, 2013, 20:01:49
First let me apologize for such a long post. Have owned a 1966 230SL for 15 years and it has been a great car. Restored it once and now have approx. 40,000 miles on that restoration. Bought the car with 150,000 miles on it. Retiring in 3 years and will restore again. So started having rough idle in gear and  at stops with car in gear.  Went through every step I can think of to rectify.  Set timing at 6 BTDC and I have a Petronix setup. If anyone can tell me how to set the dwell on that I would appreciate it. After timing I went through the linkage exactly as described in this forum and improved the idle somewhat but still the car was very boggy at low range and at 5,000 RPM it acted like it was starving for fuel. Checked all my fuel lines and removed the fuel pump. All was good. When I checked the amount of fuel in the return line under the hood I only got 750 ML. I read it is supposed to be 1 liter. Is this enough to cause my problem?  Since I have at least 20 hours invested and am somewhat aggravated I think I'm buying a new/rebuilt fuel pump. Can someone also tell me where I could find one at a decent price. Also I went through the entire FI pump setup as described in this forum and really saw little results with adjusting the idle control. I hope this is related to the fuel pump. As you can see I'm looking for suggestions as I' m frustrated with not being able to find the issue. Also the car runs fine at low temperature and I did adjust the WRD. That also helped a little but after running at 60-70 miles an hour for 10 minutes the problem returned. It appears that the car gets to about 170 degrees and the starts starving for fuel. Between 1500-4000 rpm under load it's fine. HELP!
Title: Re: 230SL Fuel supply issue
Post by: ja17 on August 05, 2013, 02:50:41
Try hooking up a pressure gauge to the metal line going to the cold start valve on the intake. Observe the fuel pressure when the engine is running poorly or seems to be starving.

Could also be an ignition coil. Don't rule out that your electronic ignition unit maight be defective (ran into this before).

Keep us up to date.
Title: Re: 230SL Fuel supply issue
Post by: Tywrapdave on August 24, 2013, 17:22:54
So have measured fuel pressure at pump using cold start line. 11 lbs running at a temp of 120 degrees. Drove the car for 20 minutes until issue started and pressure was @ 10 lbs. so fuel pump? Maybe be border line for pressure when fuel gets hot? Really don't know and before I buy a fuel  pump I need some advice. Thanks.
Title: Re: 230SL Fuel supply issue
Post by: ctaylor738 on August 24, 2013, 22:31:07
Sounds to me like you have marginal fuel flow which could be a clogged tank strainer, fuel filter, or the little screen at the inlet to the pump.  But Joe is right, the bogging at 5000 rpm could be the coil.  Suggest a new Bosch blue coil just to rule that out.

The poor idle in gear can be caused by the Constant Speed Solenoid not working or not correctly adjusted.

No dwell adjustment on a Pertronix.

Title: Re: 230SL Fuel supply issue
Post by: Rodolfo on August 25, 2013, 06:49:18
Could  be indeed be caused by a bad coil . I had the same once.Make sure you have the right one combined by the right resistance. I have the 0.9 ohm resistor in my 66 230 sl. Read the technical manual about distributor.