1973 E9 3.5L engine Weber carbs need additional ignition advice

pickman

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I fired up the car today to check the AC conversion and GOT COLD AIR!!! Need a bit more refrigerant.

Now need to upgrade the plug wires and the plugs - been using 1975 vintage and I see that the forum has a lot of advice almost too much to absorb. My driving will be over the road. I need to confirm the the plugs are (sparking plugs) the proper heat range, and the plug wires are really old so any suggestions? The engine is running rough and too rich this requires remedy to obtain a decent idle to complete the AC fill.

Many of the members have helped with the ignition coil and distributor, not to mention the AC conversion. One question on the AC when does the AUX fan kick on is there a temperature/pressure switch?

I appreciate your advice and where best to get the parts to bring the car up to the 21 century.
 

pickman

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I checked the AUX fan and it did not energize when the compressor started. It's probably the relay as I tested the fan and it works well. My relay was badly corroded took apart and attempted to clean? I have a Hella replacement be simple to check.
 

sfdon

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“ The engine is running rough and too rich this requires remedy to obtain a decent idle to complete the AC fill.”


Fill at 2000 rpm until the temp doesn’t go down any more and the pressure doesn’t take off.
 

pickman

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I have confirmed the fan runs well with 12VDC power. Waiting on plugs and wires to replace the 1970 vintage before tackling the idle issues to final fill the low side AC. Appreciate the advice on the idle speed. I did confirm my main objective with the retro that the evaporator and TXV are still leak free- and can commence with re-installing the interior- boy will there be a lot of question on this adventure!
 

Ohmess

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Check too the flying fuse on the power side of the fan. It is a separate wire running from the battery through the nose past the fan to the relay. I had corrosion in the fuse holder.
 

pickman

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I got the engine idling at 2000 -ROUGH - using the original distributor and coil. Added refrigerant to the low side until the evaporator tube started to sweat - was about 2/3 of a can and got lots of cold air just then the lower radiator hose blew off the pump what a mess. Initially I added two cans to the high side with the car off that worked well.

I notice the Weber's DO NOT like a low idle at all and I have some engine missing I think upgrading the wires, coil and distributor will be a vast improvement? Could not have got cold air without the forum and your help have detailed photos and notes of the process. Thanks!
 

Stevehose

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Did you evacuate the system with vacuum before adding freon?

Sounds like your carbs need adjusting. Have you adjusted the mix screws?
 

pickman

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I have not tried to adjust the screws as yet. I did evacuate the system and let stand for a week to confirm no leaks.
 

pickman

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I am no Carb expert far from it! I have a Weber manual and tuning instructions but have not had a lot of luck so far. I have yet to install the air filters -not sure this has any negative tuning effects? I am wondering about the distributor it is the original and I was advised to upgrade to the 123 model - looking at the plugs they indicate it's running rich it smells this way also.
 

Ohmess

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Pickman -- I had Weber 32/36 DGAVs in my car when I bought it; I suspect that is what you have. If you post pictures, I can confirm.

Given your status, I would not yet change to a 123 distributor. You would just be adding variables to a situation that is not well characterized.

Instead, I would do basic tune up stuff first. You have already mentioned plugs and plug wires. I would also do a distributor cap and rotor, along with a fuel filter. Make sure your fuel hoses and vacuum lines are in good shape, with no visible cracks. Then, make sure your linkage is working properly. It needs to move smoothly with no binding and stop at full throttle before stressing the throttle spindles. Also check that the throttle plates close fully when you are not moving the linkage. You need good spark, good fuel delivery and good controls before you start carburetor tuning. Otherwise you won't be able to isolate problems that appear during the tuning process.
 

Stevehose

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And once you have done Ohmess' suggestions then you can turn each carb's throttle stop screw out until it doesn't touch the linkage then back in until it barely does then in another 1/8 - 1/4 turn. Then turn idle mixture screws of each carb (not the thorttle stop screws) in until they seat (gently) then back them out 1 1/2 turns. This is your starting point. At idle, screw one in until the idle starts to drop then back out until it comes back up and doesn't increase any more. Then another 1/8 turn out or so. Repeat for other carb. Do you have a synchronmeter with the weber rubber adapter that fits into the venturis? You'll need to synch the carbs. Also check timing.
 

pickman

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Thank you for this advice best starting point, will review the manual to make sure I use the proper screws. As I have a converted fuel injected engine the timing mark on the flywheel may not represent the exact timing for the carburetor version a bit of guess work?

ALSO I finally checked the AC relay under the coil and found the lead to the AUX fan has only 6 volts once energized. I had repaired this a long time ago as it was badly corroded. That's not enough voltage to power the fan- the fan works fine when powered with 12VDC - any suggestions on a replacement relay??
 

Ohmess

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On your timing mark comment, if the engine ran before you acquired the car, I would not yet mess with moving the distributor to change the timing. I would presume the timing is close enough to get the car running. Here again, I would concentrate on the more basic stuff first. After you get the car running, if you are concerned about the timing marks on the flywheel, seek out one of those timing lights that will allow you to alter when the light illuminates. I borrowed a very nice Snap On from a buddy of mine and if I set it to -15 degrees (with my advance set at 15 degrees BTDC at idle), it lights on the TDC mark.

Interesting point on the relay. I have checked several of the non-working can relays I have laying around and have found that the 85/86 side is very consistent at around 64 ohms. (The newer ones are even higher at around 90 ohms.) The 30/87 connection, however shows significant resistance when I physically touch the contacts inside the relay. This would be consistent with the voltage drop you are seeing. If I can isolate the source of this resistance, I can probably fix the relays.

I replaced the can relay under my coil with a modern SPST Bosch relay having an integrated mounting tab; like this: http://terminalsupplyco.com/Store/Product.aspx?pc=TYR-004-1250
 

Stevehose

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If you are unsure of the timing marks, remove the valve cover and spark plugs and rotate the engine (I grab the alternator belt) until the cam lobes of #1 cylinder point directly away from the valves. See if the front pulley mark lines up with the notch in the timing chain cover. Put a little white paint in the pully mark so you can see it easier with the dial back light. The rotor should also be close to #1 plug wire in the distributor.
 

Stevehose

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If you don't care about an original can relay for the fan just get a bosch or hella 4 spade relay and match up the wires to see if it works.
 

pickman

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I have an old Hella relay it too is bad - not much I can do with the can relay and the voltage drop best recourse (for now) order the Bosch. I did remove the idle mixture screws, cleaned and reinstalled per the above instructions Monday the new wires arrive at which time I will again begin the tuning process. Attached are photos of the Weber carbs.
 

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