Blue 202 Running Very Rich/Cold start issues

[L67 Calais]

Hi All,

Before i start i have used the search function which found many useful tips but none of them appear to be the same as mine because my Idle mixture screw is still Sealed (untampered)

When i first start my car on a cold morning i press the accelerator once and slowly release it to set the choke.
It fires pretty well straight away and idles at about 1500 nice n smooth for about 5 seconds.
But then the revs slowly drop to about 800 and it starts to miss bad (Sounds like its Chugging) and throws out lots of black smoke.
It will do this for about 3 minutes then it will clear up and the revs slowly raise up to 1800 and cold-idle fine.
I have watched the carby while it does all of this and the whole time the Idle-Stepper is on its highest point.
After all of this it then slowly works its way down and idles sort of ok but still MEGA rich.
Any advice on where to start?
I know the idle stop screw has been tampered with as i can see the marks on it.

Cheers

[codfishface]

When you say it's running rich, are the only symptoms the black smoke?

This is a classic sign of valve stem seal wear. I'd try to start it without the choke to see if you still get the black smoke.

Also, erratic idle could be a vacuum leak, faulty PCV valve or tin ware/manifold leak.

Not much help with the carby I know, but hard to guess over the net.

When I was running a Varajet, I ditched the auto choke for a manual cable setup. Mucho Grande.

[VK SL 3800]

When you say it's running rich, are the only symptoms the black smoke?

This is a classic sign of valve stem seal wear. I'd try to start it without the choke to see if you still get the black smoke.
.

Errrrr sorry if im wrong but im pretty sure the stem seals only seal of oil, they have nothing to do with black smoke, and it they are so far gone that they allow air to be sucked through doesnt that normally lean out the mixture, unless youve got some serious hydrocarbons in the crankcase. I always thought stem seals would cause a big puff of blue on cold startup (my 202 used to do that about once a week) and blue smoke to pour out the exhaust under deceleration and overrun like going down a big hill when there heaps of vacuum.

[codfishface]

What I was getting at, was 2 different problems existing. If the stem seals are letting oil into the head, then smoke on start up isn't necessarily due to over rich mixture/carb problems.

I was trying to determine how MISTER VP came to the conclusion that he was running rich. Choke on will cause an overly rich mixture,of course. So what happens at start up with choke off?

[L67 Calais]

Hi, Its definately not the valve stem seals, Had that issue in a past VH. This is thick, Rich fuel smelling smoke. But if i slowly bring the revs up to 2k (If i push throttle too fast it stalls) and sit them there for 5 seconds or so then slowly back off the Chugging and missing goes away and it cold-idles fine at 1500 rpm.
Start up with choke off doesnt happen. Wont start.
Once warm and at operating temp it stalls if i apply less than a quarter throttle when trying to take off, And has a massive flatspot if i floor it at any stage, and feels gutless like the secondaries arent operating correctly, if at all.

[ari666]

timing issue.

when its cold the vac should change to full vacuum as well as engaging the choke. so if only the choke is engaging, then its already getting an air restriction, pumping the pedal will prime the pump and allow in too much fuel in its "shot".

check that your TVS is all hooked up properley.

[L67 Calais]

Forgive me mate, But..... TVS??

[codfishface]

Thermal Vacuum Switch.

On a stock blue 3.3, there should be one on the thermostat housing.

Have a look on vkberlina's web site under "How to Information"

[L67 Calais]

There is a tree on top of the thermostat, But it has nothing coming or going from it. Its just sitting there. Looks like 3 hoses need to be hooked up to it but Fark know where from?

[ari666]

from the book it looks as though the switch on the thermostat has the two top hole joined together, then one hose going to the vacuum t on the manifold. it actually looks like the TVS DOESNT advance vacuum at idle on that engine all the drawing shows is the tvs going to egr and vacuum advnace just running straight from he carby

so basically. i was wrong.

[codfishface]

Taken from OldHolden.com - TVS - Holdenpaedia

TVS (Thermal Vacuum Switch):

Operation:

On 6 Cyl Engines, a 3 Port thermal Vacuum Switch is mounted in the top of the Thermostat Housing. On V8's it's mounted on the passenger side of the front of the Engine.



The purpose of the device is to increase the Engine Speed if the Engine overheats. It does this by providing full vacuum to the Distributor from the Inlet Manifold. The increase in engine speed accelerates the fan and water pump.

Below a coolant temperature of 104 degrees, the Distributor receives vacuum from a tap in the carburettor above the throttle. (Spark Ported Advance).


Above a coolant temperature of 104 degrees, the Distributor receives vacuum from a tap in the inlet manifold (below the throttle). (Vacuum Ported Advance).

Operational Difficulties:

During a hot start the switch can be in the Vacuum Ported position which can cause kicking back during starts and placing undue strain on the cranking system.

With the throttle open, excessive advance can be present causing pinging on take off.

With the 3 port TVS operating, you should be getting Ported Vacuum under 104C. When engine temp rises over 104C, the TVS will switch to Manifold Vacuum which will be high at Idle, increasing advance and cooling the engine.

Should have nothing to do with Start Up as the engine will be cold (<104C).

Back to Carb issues?

BTW, one hose to Vac Advance module, one to Manifold Vac and one to Ported Vac on Carby. I'm guessing (if it has been bypassed) that you have a hose running from the carb to the Vac Advance module on the dissy.

[codfishface]

ari beat me to it - Again!

What state of repair is your Varajet in?

They can be pricks of things when new, let alone 20 odd years old.

[ari666]

edit* once again, i suddenly learned how to read...

[L67 Calais]

It seems to be ok. I know the idle stop screw has been tampered with (admitted by previous owner) and that most of the vac hoses are blocked or cracked so i think i will start there. Any idea how to set the idle stop screw?

[codfishface]

I replaced my Varajet with a reconditioned one ages ago. Then got the shits with it and put triple SU's on.

I have heaps of Varajet info on my old lap top tho. Only problem is I'm hella busy for the next 3 days.

Hit up goooogle until someone here comes along.

Vacuum hoses sounds like a great place to start.

[Dayvo]

could be that the jets are worn or they could be oversize or even the float level could be too high .

[L67 Calais]

just to clarify, is the front or rear lead #1? I cant get a good strobe out of either

[L67 Calais]

Sorry, For timing light purposes i mean

[codfishface]

Front is number 1 plug.

[L67 Calais]

Can anyone tell me what diameter vac hoses i need to cover every single hose in the engine bay? Im going to buy 5 metres of each tomorrow and starting there.
Cheers

[L67 Calais]

BTW, one hose to Vac Advance module, one to Manifold Vac and one to Ported Vac on Carby. I'm guessing (if it has been bypassed) that you have a hose running from the carb to the Vac Advance module on the dissy.

Hi, Yes i do. Will that affect things? There is no one way valve there either, Does that matter?

[ari666]

Can anyone tell me what diameter vac hoses i need to cover every single hose in the engine bay? Im going to buy 5 metres of each tomorrow and starting there.
Cheers

3mm OD should do fine. its just washer/wiper hose. not expensive.

[jpetrou]

Have you checked the back of the carby, where the auto choke cover is. Located next to it there is a little vacuum unit that has a small hose running from the base of the carby. What this vacuum unit does is, it cracks open the choke flap slightly by pushing against a linkage. This prevents the choke from completely blocking off the small primary barrel and allow the engine to idle smoothly under cold conditions. I have marked the area in a red border. I have attached some info to help.
To check when the engine is cold,
1. Take off the air cleaner
2. Set the choke by pressing the accelerator down and releasing it
3. Start the engine and look at the lever (refer yellow border on diagram attached) and see if it has been pulled in by vacuum unit.
4. If it does not move, you can push the lever in with your finger and see if the engine idle improves.
5. If the engine idle improves, then you have a fault with no air going to the vacuum unit or the vacuum diaphram unit needs replacing.

Hope this helps.

[L67 Calais]

Hi,

Can anyone post up as much vac diagrams as possible? VK Berlinas site is helpful but is still missing a few hoses & trees.

Mainly the tree at the rear of the motor on an auto blue 202.

[L67 Calais]

Have you checked the back of the carby, where the auto choke cover is. Located next to it there is a little vacuum unit that has a small hose running from the base of the carby. What this vacuum unit does is, it cracks open the choke flap slightly by pushing against a linkage. This prevents the choke from completely blocking off the small primary barrel and allow the engine to idle smoothly under cold conditions. I have marked the area in a red border. I have attached some info to help.
To check when the engine is cold,
1. Take off the air cleaner
2. Set the choke by pressing the accelerator down and releasing it
3. Start the engine and look at the lever (refer yellow border on diagram attached) and see if it has been pulled in by vacuum unit.
4. If it does not move, you can push the lever in with your finger and see if the engine idle improves.
5. If the engine idle improves, then you have a fault with no air going to the vacuum unit or the vacuum diaphram unit needs replacing.

Hope this helps.

Hi,

Cheers for that. I just Checked all of that, Seems ok. There is vac going to the unit. But i cant push or pull that rod at all? However when revving by hand i can see it moves and pushes open the secondaries flap Thingo.