Wiring help

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GuerillaPro10

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Hello everyone,

I am finishing up work that someone else started on a '73 3.0 cs. They changed the starter and cleared out all the "pluming" with out labeling what wire went where. there are two wire sets that I am confused with and was hoping someone could give me a lead as to where they should be connected.

The first set looks like two wires that go from the upper right side of the manifold to 2 relays located below the coolant res. I would assume that one of these connects to the starter.

The second is a set of 4 wires that go from that 2 relay contraption and lead to the carburetor.

any help is greatly appreciated.
 

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Maybe I can help: I have a 74 which I converted from Zeniths to Webers and then to D-jet FI, so I have some familiarity with the wiring.
In my car the two sets of wires (as far as i can tell from your pix) control the auto chokes, fuel shut-off solenoids, and cold-start thermistor valves used on later Zeniths. Do you have these? IIRC, the connectors for the shut-off solenoids are smaller than the other connections which you should be able to match up. The two small square relays under the coolant res operate these connections and are energized when the car is starting and/or running.

The starter wires are not shown in your pix, I'm pretty sure. The starter wires in my car are a separate harness with two wires: one connects to the distributor (top spade), and the bottom spade is the start lead from the ignition switch. No relay is involved in either of the starter leads.
Hope this helps.
 
Thank you very much Bill.

My problem now is that I cant get fuel into the system. (no fuel into the fuel filters) There are two hoses that are coming from the same place in the engine compartment. one with the fuel filter, one without. I know they connect to either the conntection with the spliced hoses or to the part that is connected to the manifold... but Im not sure in which fashion.
 

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The picture is fuzzy but the mechanical pump I see is attached to the head and does not have fuel line on the cabin side. Fuel from the tank goes to this fitting a filter is usually in line prior to the pump on mechanical pumps and EFI.

There is also usually a fuel and/or vapor return line.
Jon
 
fuel line i.d.

1) The line in your palm connects to the fuel pump on the head.( fuel filter)

2) The other line appears to be water. There is a rear tap on the block/ head that connects to the rear choke housing. It's the longest of the small hoses. Water goes through both choke housings as well as the bottom of the intake manifolds in a closed loop.

3) The chokes are wired in series with the cold start valve and idle solenoids. Power from the rear carb choke housing, rear csv ( rectangular aluminum box), idle solenoid ( round cylinder screwed into the base of the carb) and continues the same for the front carb. They usually have angled connectors if original.

Hope this helps.
 
OK.."61porsche" may be right about the water hose, and that is easy to check by tracing the hose back to the rear of the head. But given your picture which seems to show two hoses going down towards the left wheel, it looks to me like you have a fuel supply line AND and a fuel return line..this is how my '74 CS was equipped. The fuel supply line, with the filter, goes to the fuel pump inlet. The fuel return connects to each carb near the fuel supply connection, at the front of each carb. There is a vacuum operated valve which regulates fuel supply to the carbs as needed..the excess flows back to the gas tank.This set-up helped cure vapor lock problems by keeping cool fuel constantly circulating to the carbs. I'm not sure if pre-1974 cars had this feature or not. But, if you look at your gas tank, you will see two hoses connected in the fuel sender, confirming you have a fuel return system (not to be confused with fuel injected cars, which also have a fuel return, but they are separate.)
Let me know what you have, and perhaps I can help. If there is only one hose to your fuel tank, then 61 Porsche may be right, the other is a water line...lemme know what you find out.
 
The `73 does not have a fuel return line. If it is the vapor recovery line it will have a braided cloth cover.
 
Thank you to all for your help, shes running. I think the other line was a fuel return line and I am able to crank her over; however, the issue now is that the engine is shaking (much more than before hand) Its not holding a smooth run... when it drops down to idle, it seems as if it wants to die but keeps going. Is this due to too much air being in the system?

Also, there is no smoke... the engine is just shaking, not an excessive amount but enough to be an issue.

Im also worried about the coolant reservoir. The coolant is bubbling which makes me think something is connected wrong.
 
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This one is interesting...no smoke is better than smoke.
You did a conversion. Your description leads to these thoughts.

Is the fuel supply at proper pressure? Did the mechanical pump get it's inlet mesh screen cleaned out? Is the tank pickup filter clean?
Have all the vacuum connections been tightened and configured properly?
Did the distributor get removed and re-installed? It could be just one tooth off what is the idle rpm, timing?

Your "I think the other line was a fuel return line " where did you connect this?
Jon
 
Imbalanced

1. Carbs:

a.) Near the air jets on top of each carb is a drilled hole; closest to the the vent. Closing it with a corresponding change to smooth idle means there's an air leak somewhere to chase down.

b.) Your pictures of the choke butterflys indicate backfire(s) usually caused by too much advance.

c.) Your pictures indicate the vacumn can and cold start valves have been worked on recently( clean) compared to the bodies (not so clean). Both can be a cause for air leaks; tighten them all up.

d.) Retighten everything related to fuel/ air. Some parts have to settle down to stay tight.


2. Plugs- they usually can tell you where the imbalance is. Bank to bank ( cyl 1-3 or 4-6) or individual cylinder. Vacumn guage works too. The not so obvious balance is opposing stroke- 1+6, 2+5, and 3+4 whereby a shaking is most obvious because one firing cancels the forces of another or doesn't when there's something amiss. Normally a straight 6 is relatively smooth by design which is why BMW ( and many others) has used it since the early 1900's until recently new advances and consumer demands were made.

3.) Bubbling coolant- Can mean you need to rebleed or just turbulance. Not uncommon to rebleed several times.

4.) Don't know about return lines on carbs- easy to check. Just look up underneath the driver's side or pull a trunk panel. Personally, I'd plug it since the pump has to work twice as hard, it's one less thing to leak or fix, and gas today is reformulated with alcohol and carbed cars seem to suffer vs. FI.

5.) You're pump doesn't have a screen; it's a newer version with a stamped cover.
 
b.) Your pictures of the choke butterflys indicate backfire(s) usually caused by too much advance.


There is backfire... how can I fix this
 
advance

Advance is timing. Turn the distributer slightly counter clockwise 1/4". If you have a timing light, it would be best to do so that way ( vacumn can disconnected). Basically, the engine is firing early before the intake valves close and the charge is coming back through the carbs. But several factors can contribute to the situation.

a.Wrong fuel mixture; usually rich as in at start up. Floats wrong..runs lumpy... fuel should not be dripping or coming out the center venturi at idle.( Dark and wet plugs)
b. Valve adjustment/Burned/ leaky valve. Vacumn guage needle swing.
c. Loose chain- can contribute up to 10 degrees advance and usually why the cam seems to be advanced when a new chain is threaded vs. cam covers off.( Visual- with the rocker cover off and the crank set at TDC, there is a parting line on the front of the cam which lines up with the bearing cap.
d.Top end/ valves junked up with deposits- run it hard for a while- usually cleans up.( blow it out.)

But you said it was running better before. This indicated it's something that was done recently.
 
Adding to my previous post and further from 61porsche's...
If it is running rough and you have verified no vacuum issues and have proper fuel set up (including carb internals which should be ok since it ran ok before)...
Check timing and or re-install the distributor. If you do not have the ability to dial in timing and idle wont settle down with current dist placement, pull it out and re-install it by rotating it one tooth. Make sure you have the TDC marks on crank and cam in proper orientation...from your description they are probably ok. Just check the dist.

Jon
 
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