Idling fast once warm.

[JamesKT25]

I have started to notice that when running on petrol the van seems to hesitate when pulling under load. It has also started to idle fast once warm, i think its something to do with the choke, maybe its stuck open or something. Is this a common thing or anyone have any ideas where to start?

The van has stopped idling on LPG, its splutters and dies, but i dont think this is linked. I have no history of the lpg system being serviced so i'm not too bothered about it working until i can get it to gasure. But it may be linked :S

[kevtherev]

There is a fast idle mechanism on the pierburg
Check that it is free to rotate.

A choke will open when the engine warms up, so sticking open is not the issue.

Hesitation upon acceleration has a few suspects.

Air leak into the inlet side
Timing
Transfer jet blocked
Idle jet blocked
Accelerator pump diaphragm punctured.

[JamesKT25]

Where is said mechanism? I'm still yet to buy a haynes manual.... Only owned the van 7 months

Its almost like the power pauses when i try to accelerate until i let off the throttle and re apply it gradually.

[kevtherev]

it's the stepped cam on the right

[JamesKT25]

How stripped down do i need to get the carb? Should i buy a gasket set? Which jets are the two you mentioned. The furthest ive got into the carb is taking the air ducting off and nosing inside...

[kevtherev]

How stripped down do i need to get the carb? Should i buy a gasket set? Which jets are the two you mentioned. The furthest ive got into the carb is taking the air ducting off and nosing inside...

you can move it without dismantling anything.

so you took the ducting off..was the engine warm? or cold?

[JamesKT25]

Cold. Just undid the three bolts and lifted it off. But instantly realised i was 100% what was what so put it back together. Should i only remove it whilst cold/hot?

[kevtherev]

so did you see a brass flap covering the throat

like this, with a little gap (3mm)



when it's warm it should be like this..flap open



you can leave the duct off while you watch the choke open (takes about 6mins)
Before you start the cold engine set the choke and idle speed by pressing the accelerator fully once, then turn the key.
It should idle at about 2000 rpm until you blip the throttle, then it should idle at 1500rpm, as it warms up the cam rotates, steps down a bit more on the cam.. and the engine settles down to 900rpm

[JamesKT25]

In the top picture. The cable to the right with the red connector. What is that meant to connect too? Mine isnt on anything.... I will have to check that flap to see if it moves! Thanks for the help Rev!

[kevtherev]

In the top picture. The cable to the right with the red connector. What is that meant to connect too? Mine isnt on anything.... I will have to check that flap to see if it moves! Thanks for the help Rev!

yours will be connected to a yellow connector
This is the choke heater, it switches on when you turn the key, and switches off (signal comes from the temp 2 switch on the thermostat housing) when the coolant reaches 87 deg C.
The choke heater helps open the choke flap.
It connects to the manifold/ carb de icing heater circuit.

[kevtherev]

OK here it is laid out
you have..

a manifold heater .........Thicker pink wire that disappears under the manifold
carb heater
and a choke heater

the manifold heater will be the larger red/pink wire, with a white connector and needs to be through the sender switch( from thermostat housing on late cooling system) and relay No1..


NOTE these pictures are from an earlier cooling system, so the coolant pipes might confuse you.
ALL you are interested in are the wires



here is the thicker wire with the white connector, then the black wire runs off too..

[JamesKT25]

Thats awesome thank you! I will get it re connected. What its purpose? Excuse my constant questions, i like to learn this stuff!

[kevtherev]

The choke heater helps open the choke flap.

[JamesKT25]

ah cool ok. thanks again, i shall report back once ive tried it tomorrow.

[kevtherev]

If you split the autochoke housing
this is what you find

here is the bi-metal spring that the heater heats up..as it unwinds it opens the flap

click on the picture



I heat it up with the hairdryer and it unwinds