1.9DG Cold starting

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TONYT25T25
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1.9DG Cold starting

Post by TONYT25T25 »

According to handbook accelerator should not be used when starting from cold. My engine fires and cuts out unless I gently encourage it by using the accelerator pedal a bit. This method allows it to tick over by itself after about a minute, and it eventually settles down to normal tick over a short time later by pressing the accelerator pedal again after the engine warms up more. Is this a normal issue or should I look into it more. What are the recommended spark plug and rotor arms, there are so many option out there. Tks
1984 Campervan 1.9DG Petrol WBX

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Aidan
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Re: 1.9DG Cold starting

Post by Aidan »

for a dg cold start is one full depression of the accelerator pedal and release, this puts the choke on, the choke comes off automatically as the engine warms up if everything is working properly
really cold icy weather two presses of the pedal and release, this makes the accelerator pump squirt a small load of fuel into the carb to prime it and set the choke
when hot no pedal is required to start, but on a tired set up a slight tickle may help

on the 2.1 fuel injection you don't press the accelerator pedal as the ECU gets a signal from the starter to say we are starting and it knows the temp of the air and the coolant so fuels accordingly

TONYT25T25
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Re: 1.9DG Cold starting

Post by TONYT25T25 »

Tks, choke does cut out when engine warmed up so must be ok there. Intend to buy a new rotor arm that governs the rpm as I gather this is the preferred option.
1984 Campervan 1.9DG Petrol WBX

Jeff J
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Re: 1.9DG Cold starting

Post by Jeff J »

TONYT25T25 wrote:Tks, choke does cut out when engine warmed up so must be ok there. Intend to buy a new rotor arm that governs the rpm as I gather this is the preferred option.
Get a distributor cap while you are at it, just cured what sounds like a similar problem on mine with a cap after trying rotor arms first.

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CJH
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Re: 1.9DG Cold starting

Post by CJH »

TONYT25T25 wrote:Tks, choke does cut out when engine warmed up so must be ok there.

Not necessarily. The choke does two things:
1) it operates a flap to close off most of the airflow, so as to enrich the fuel air mixture when the engine is cold. As the choke comes off the flap opens.
2) it operates a stepped cam for the fast idle screw to ride on. As the choke comes off, the fast idle screw moves down onto successively lower steps of this cam, until eventually the fast idle screw comes off the cam altogether, at which point the idle speed is controlled by the main idle speed screw.

To engage the fast idle in the first place, you have to depress the accelerator before starting the engine, as pointed out by Aidan.
This puts the fast idle screw on the top step of the cam (or the highest one necessary when it's not so cold out). *Then* you start the engine without touching the accelerator. If you're doing that but you're not getting any sort of fast idle, then it's possible that the fast idle screw isn't adjusted properly, so it isn't increasing your engine speed when cold.

Image

There are instructions for adjusting this screw. If there's a tamper-proof cap on it, it probably doesn't need adjustment, but that's no guarantee. Because this screw is so difficult to get to it should not be adjusted while the engine is running (you have to lean right over the engine), so it's a matter of trial and error. And because cold engine speed will vary depending on the amount of choke, the adjustment is specified with a warm engine, i.e. choke fully open.

So warm up the engine and turn it off, then, with the airbox and hose removed, set the fast idle screw (manually) onto the *first step down* (as shown in the photo - not the top step). Make sure the choke flap is fully open (vertical), then start the engine. Engine RPM should be ~2300. If it's not, turn off the engine, adjust the screw in or out to raise or lower that speed, then start the engine again and check it.
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TONYT25T25
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Re: 1.9DG Cold starting

Post by TONYT25T25 »

Tks again to all. It all ads to my knowledge base and others.
1984 Campervan 1.9DG Petrol WBX

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