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Why the hell does that happen?


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#1 Big_Adam

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Posted 10 February 2007 - 11:28 PM

Evening,.

Past day I had to make the trip to Norwich, which is 20 miles there and 20back with say 10 piddling about in traffic in the city centre. So 50miles-ish round trip. Using my driving style of "drive it like you stole it" so I tore up the trip doing some were between 65-85mph all the way, El Gordo singing the A-Series serenade in the note of 4500rpm+ and I've noticed a strange thing when I drive at high speed then go back to regular traffic. It's that the idle seems to drop very low. My idle is normally around 1000 or 500 odd when very cold. So little choke. When the weathers fine or the engines warmed up in goes the choke and I carry on. Just after the drives to Norwich the idle dropped from 1000 to 500 and my oil pressure seems to go with it to around 20-30lb of pressure unless I pull the choke to pop the idel back to 1000 then the oil pressure rises back up to 40-45lb which is what it's normal at when warm.

Any idea why this happens?

#2 cowboy

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Posted 10 February 2007 - 11:50 PM

could be a gasket problem, or a loose jet,

the mixture will change if extra air gets in the system. check all your gaskets and connections.

if you have changed anything recentlly also have a look to see if you put everything back together.

#3 Monstrous

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Posted 11 February 2007 - 12:47 AM

When replacing the dash rail i had to remove the choke cable, so i undid it carb end

when putting it back on i had this same problem, the idle went very low and almost conked out, so re-adjusted the cable in the choke grip and it improved it slightly, but then noticed that the vacuum hose to the dizzy had come out of the carb, popped it back on and it was fine.

worth a check

Edited by Monstrous, 11 February 2007 - 12:47 AM.


#4 Big_Adam

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Posted 11 February 2007 - 02:05 AM

Idle onlys goes low AFTER a long jernoey like to norwich. I can pootle about town for ages without the problem.

#5 edjohnson

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Posted 11 February 2007 - 11:23 AM

coould be carb icing, this can also cause the engine to stick at high revs.

are you running a KnN cone by any chance??

cold air mixes with moisture and causes ice to form on the carb, creating an odd engine habit like you describe, and as i said before it can mean high revving too, as it makes the butterfly stick open, or shut.

edit, makes sense, as it tends to happen alot as you come off long stretches of dual carriage way.common problem is:

bomb down motorway with mini, with cone filter, come off motorway, stop at traffic lights at top of slip road, car dies. wont start.

bugger, call the RAC, RAC turns up, car starts fine. While you wait to be recovered your engine heat melts the ice, and presto your off again.


just a thought, i know your car aint dying as such but could be similar

Edited by edjohnson, 11 February 2007 - 11:26 AM.


#6 fikus01

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Posted 11 February 2007 - 12:20 PM

if that is the case i think i remember you saying your heated manifold wasnt plumbed in either which could effect it!!

#7 Dan

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Posted 11 February 2007 - 12:24 PM

And you also said the other day something about removing the hot air feed and having no problems didn't you? Well welcome to the problems! :(

#8 Big_Adam

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Posted 11 February 2007 - 01:03 PM

....sure I replied to this thread already. Oh well,

@fikus01, not it's all connected fine.

@Dan, ...... ...... nuts. Ah well, need a few problems. Life can't be perfect, be too creepy then.

#9 AlexM

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Posted 11 February 2007 - 02:16 PM

And you also said the other day something about removing the hot air feed and having no problems didn't you? Well welcome to the problems! :(


lol.

#10 fikus01

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Posted 12 February 2007 - 12:08 AM

hehe, sorry not a dig!! worth a try connecting the hot air feed back up and seeing if it remedies its self!! hot air feed will stop carb freeze better than heated manifold!

#11 Big_Adam

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Posted 12 February 2007 - 12:57 AM

nah, won't be doing that.




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