Annoying Engine Idle

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Dubmatix
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Annoying Engine Idle

Post by Dubmatix » Sun Nov 29, 2009 12:26 am

Vicky developed a rough running problem earlier this year whilst at a Geocaching event in Brean Sands. She now occasionally runs on three cyls shortly after start up but this clears after a minute or two. Recently she's taken to not idling at all until hot. If you dip the clutch to pull up in trafffic the engine just stops!

Been checking it out today, looking for air leaks in the Idle circuit pipes as the Idling air and fuel is controlled by the LH carb and piped to the RH manifold.
I kinda hoped there'd be a pilot jet like a VW single carb but there doesn't seem to be.

As far as the 3 cyl running is concerned, this started after i changed the dizzy cap so i have been paying close attention to HT leads etc and testing all that today, all seems fine. Need to have a look at the plugs yet though to see if any have been fouled.

There is ONE piece of fuel hose that i haven't changed and it IS in the Idle circuit link pipe so i am going to try swapping that...albeit a little crappily. It should be 11mm fuel hose but i can't find any anywhere! So 12mm it is with clips! Maybe this willl cure the crappy idle.

Does anyone know what that rectangular module is on the LH carb...described as mixture enhancer, it has a 12V feed from ign live (same feed from the cut off valves and chokes). Is it a heater?

J

surfcarrot
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Re: Annoying Engine Idle

Post by surfcarrot » Sun Nov 29, 2009 11:12 am

hi john. sorry to hear ur having probs.

when i had idling problems i had to check the 'electro magnetic cut-off valve'. i had to take the wire off and touch on something to see if it clicked.

sorry i'm a bit vague but as you know i'm still a novice (and always will be!)

i have a haynes manual if you want to borrow it?

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Dubmatix
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Re: Annoying Engine Idle

Post by Dubmatix » Mon Nov 30, 2009 9:40 pm

Thanks Craig. Does your manual cover the 2000cc engine and the twin carbs? I am using the other one (Bentley manual...VW...not Bentley...) and it does mention that test for the solenoid valves. I tried it and they seem fine. To do that test you put the ignition on, then unplug the cable from the sol valve and it should click as it closes the valve.

Although saying that, the one on my first beetle tested fine like that but when unscrewed from the carb body, the plunger on the solenoid valve had been cut off with pliers! This meant that it clicked when tested but didn't actually cut the fuel off ever!

Anyway, i have a lead for some 11mm fuel hose....a VW shop called German Supply in Toronto shows it sells it on it's website...it's a long way but i can get some in a week or so!
Going to do that first and then make sure my chokes are working right and my vac lines are all correct.

surfcarrot
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Re: Annoying Engine Idle

Post by surfcarrot » Tue Dec 01, 2009 9:43 pm

yeah its the right manual. it has a good exploded pic of the solex carb that helped me know what i was looking at! hope you sort it

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Dubmatix
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Re: Annoying Engine Idle

Post by Dubmatix » Fri Dec 04, 2009 8:46 pm

The symptom is still there. I have replaced the "11mm" piece of pipe on the idle circuit, cleaned the points (filed and gap checked but not checked the condenser yet) and checked all other rubber parts in the inlet side including the vac take offs for the brake servo. There is a valve in the servo pipe on the other side of the bulkhead tin apprently, not checked that yet. The engine seems to pull better, the points have helped there i think.

Do i need to adjust the chokes to stay on longer? Does anyone else tweak their choke settings for winter? It's ok whilst they are on, then they drop out after a few minutes and then she won't idle until hot. It sounds to me like an air leak...but i canne find it....
It's just the period between choke off and being hot that she's a pain. maybe she needs tweaking for colder weather?!
Good stuff here on carb how to...
http://www.thesamba.com/vw/forum/viewtopic.php?t=173175

:geek:

lmpd
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Re: Annoying Engine Idle

Post by lmpd » Fri Dec 04, 2009 9:04 pm

john, you need to run this by a guy called fish on thelatebay.com
he has an encyclopedic knowledge of all things vw and would be only to pleased to point you in the right direction

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Re: Annoying Engine Idle

Post by Dubmatix » Sat Dec 19, 2009 8:07 pm

Thanks Impd. I think i am on the way to sorting it. There is an air leak in the manifold to head joint on the RHS. I discovered this by spraying WD40 on the joints at tickover and listening for increase in RPM. Got some new gaskets to sort. Also the thermostat is bu66ered so it's getting the full quota of cooling air at start up which is a no no....

Work has stopped currently as the bush in the end of the carb linkage shaft shot out and went down the fresh air pipe into the RHS heat exchanger.... :evil: :evil: :evil: so i have had to remove the exhaust and will tackle the Heat exchanger in the week!! Grrrrr!
It was because of this i noticed the thermostat though so not entirely a waste of time!

I did try to access the Heat Exchanger from the fan housing by removing the fan too but the duct is too small to get your fingers down...not put that back together yet either! Too many parts stacked up on the garage floor now!

I have put a shout out for a spare thermostat on Vzi and Latebay...hopefully someone will have one!

J

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Re: Annoying Engine Idle

Post by Dubmatix » Wed Dec 30, 2009 12:08 pm

New Gaskets arrived yesterday for the RHS Heat Exchanger to head so i can now take it off to shake tht carb linkage bush out....! When the rain stops!

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Re: Annoying Engine Idle

Post by Dubmatix » Thu Dec 31, 2009 11:30 pm

Removed the RH HE earlier on, and the pesky little bush is now removed!
Going to repaint it all before it goes back together so now need some VHT paint.

The annoying bush!

Image


John

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Re: Annoying Engine Idle

Post by Dubmatix » Mon Jan 04, 2010 10:42 pm

Thermostat....can anyone spot the fault? :D

Image

Image

I have to wait for the replacement...

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