Cold Start Problem

[5String43]

I had hoped that as the weather got warmer my car would be a little easier to start from cold. But the warmth hasn't helped at all.

A wrench I trust told me, after checking and adjusting pressures, that he felt that the WUR was the problem, and that I needed to source a remanufactured one. I looked into that, but during the course of ordering, the tech there at the reman facility told me that the WUR didn't really go to work unless the ambient temperature was quite cold - perhaps as far down the scale as 32 degrees. He said my car's cold-start problem likely was the result of a bad fuel distributor. He said a diaphram inside that gets pinholes in it, leading to cold-start problems.

I should note that once it is warm, the engine leaps into life and runs fine - though its fuel economy is quite poor.

So now I'm baffled. I do not wish to continue throwing money at the thing by trying solutions that may work, or may not work. But I would like to solve the problem.

Any thoughts? Thanks in advance.

[boyt911sc]

Originally Posted by 5String43

I had hoped that as the weather got warmer my car would be a little easier to start from cold. But the warmth hasn't helped at all.

A wrench I trust told me, after checking and adjusting pressures, that he felt that the WUR was the problem, and that I needed to source a remanufactured one. I looked into that, but during the course of ordering, the tech there at the reman facility told me that the WUR didn't really go to work unless the ambient temperature was quite cold - perhaps as far down the scale as 32 degrees. He said my car's cold-start problem likely was the result of a bad fuel distributor. He said a diaphram inside that gets pinholes in it, leading to cold-start problems.

I should note that once it is warm, the engine leaps into life and runs fine - though its fuel economy is quite poor.

So now I'm baffled. I do not wish to continue throwing money at the thing by trying solutions that may work, or may not work. But I would like to solve the problem.

Any thoughts? Thanks in advance.

Ask him what was the cold control fuel pressure? What made him think that the WUR was the culprit? Is he familiar with the CIS engines? The reason I asked these questions is due to the fact that CIS is an outdated fuel injection system and even good mechanics tend to ignore learning how it works. The last CIS cars are probably 25-30 years old already.

Tony

[sobamaflyer]

Originally Posted by 5String43

I had hoped that as the weather got warmer my car would be a little easier to start from cold. But the warmth hasn't helped at all.......He said a diaphram inside that gets pinholes in it, leading to cold-start problems.

I should note that once it is warm, the engine leaps into life and runs fine - though its fuel economy is quite poor.

So now I'm baffled. I do not wish to continue throwing money at the thing by trying solutions that may work, or may not work. But I would like to solve the problem.

Any thoughts? Thanks in advance.

I have similar troubles, and seems to get worse as the weather gets warmer. Car runs great once it's started. The short answer (and I'm regurgitating something I've still not gotten around to myself) is you need a set of pressure gauges to tell you where it's loosing cold pressure from if you don't want to keep trying a part here and part there.

FWIW......I happened to be at a car show a few weeks ago, ready to leave, did my typical crank her half a dozen times before she'd idle routine, the much revered guru that has been putting together the "found 30 years later" car walked over and told me precisely what that tech told you. Said I either have a bad accumulator or pinholes in the diaphram...... Now he said there's a kit w/ that diaphram in it for only a few $.....but I've not gotten that far.

He did tell me if I popped the airbox cover and gave the little mixture arm a little tickle it'd start right up, and X4-5 starts now he was dead on. Why do all the women in my life need to be primed before.........nevermind

[5String43]

Well, I'm not goin' anywhere that 'priming women' business, though certainly I know whereof you speak.

But 'little mixture arm'? You mean the plate that you can lift to make the injectors squeal?

And if you find the rebuild kit for the distributor, man, I'd love to learn about it.

Thanks - Jon

[sobamaflyer]

Yes, the little arm that makes the injectors squeal, press it for a few seconds till the whine evens out, crank and voila the car starts on the first crank.

A quick internet search found this today:

BOSCH FUEL DISTRIBUTOR DIAPHRAGM FOR 6 CYLNDER ENGINES | eBay

At $29 it may be worth a try? I'm not sure why PP doesn't stock the item as so many of us beg for fuel distributor rehab, and it may be different (but I doubt it, as my reading indicates CIS is CIS across many different cars, Volvo, Mercedes, Delorean, others)

[brd]

You try disconnecting the cold start injector at the back (and leaving it disconnected when trying to start it)?
If this is leaking, it can be flooding the engine and make it difficult to start.


(modified re-use of image from forum ... somewhere )

BRD

[47silver]

if you raise the arm and the injectors spray you have good pressure. If when the car is warm it runs good then i dont think that the cold start valve is leaking or it would cause you to run very rich.
On my 1975 when the key is in the crank position (turning over the starter), 12vdc is applied to the cold start valve + side. The negative side goes to the thermo-time switch which is located on the back left side of the engine. The TTS allows current to flow to ground when the engine is cold and opens the circuit when the engine is warm.

To trouble-shoot:
1. Remove the plug from the cold start valve. Very difficult to get too and a royal pain. If you remove the boot it is a bit easier.
2. Use a meter, have someone crank the engine you should have 12volt to ground on one of the terminals. if so that is good if not then you have a wiring issue. I had the same problem and traced it to a bad connection at the starter solenoid.
3. If you have power you have to test the valve. You can remove the wire on the thermal time switch and put it to ground. when you crank the key, look inside the air box and you should see (75 air box) or hear it on the later ones with the manifold arrangments.
if you dont hear or see a spray then the solenoid on the valve is bad.
if you see a spray then i would say your thermal time switch is bad.

[limble]

I bought the diaphram for the fuel distributor but I haven't been able to locate info on how to rebuild it. Anybody know?