As long as the warm air feeds are fine, my cars need no choke when warmed up. I'll let people know how my tests go on the flappy valve.

I'd imagine the original posters problem is likely an airleak, whether hot or cold, but a blow lamp/can of coldstart/wd40 will find it!

Hi Shimon,

as to the idle problem with the 240 I would say it is simply a case of the fuel mixture/idle speed need adjusting.

With regards to the 340 1.4 I doubt that the warm air feed valve will be contributing to the running problems. I would consider running with the filter off while you are sorting it out mainly for ease of acsess to the carb.

hi guys hope you all had a good christmas
may have found the problem
i disconected the brake servo hose from the manifold and blocked the hole off the car ticked over like new so i hope its just the brake servo pipe with a leak i will get one tomorow and try it if not the car will sadly be up for grabs

hello,

yep, I've seen that before on other cars. I've seen a few nissans where the servo unit itself failed causing an air leak

When the servo pipe on my 340 failed, the car ran ok, it was just the brakes were rather hard....

it still wont tickover going to replace ther manifold gasket and all the air pipes and carb gaskets tomorow fingers triple crossed
got the car for £100 with full service history hundreds spent on it by the preveous owner at volvo its now upto £150 with money spent on bits to be honest had enough last chance

do you think it could be possesed

Just before you go replacing everything in sight, just have a check round all the joints with a WD-40 or unlit blowlamp (well ventilated area ) but if its cutting out completely just make sure that all the crankcase breather hoses are correctly positioned and particularly the restricter is in the hose that goes to the base of the carb.

If you're not sure then take that hose off and block the pipe to the inlet manifold. If the idle sorts itself out then its that restrictor that's missing, it may have been lost if someone has been working on the car and not put it all back together correctly.

The warm air hose is completely unnecessary once the engine is warmed up, not just warmed up on the gauge, cos that won't have warmed the carb or the fuel enough, I mean run 20 minutes more than that so all the oil etc is warmed through, then the spaceman flap shouldn't even be switched on. it should be on 100% cold air.

If you're out driving for an extended period, particularly hard where you're pushing a lot of fuel through the carb on a cool day, then the warm air will stop the carb icing. I remember Foggy's 240 wouldn't idle off choke at all until the engine had been running for quite a bit after the temperature needle had come up to temperature. so running it round the yard might not have been enough Shimon.

hi,

I've personally solved poor idle on the 340 but checking the crankcase ventilation pipe. There is a restriction in that which, from the factory was built into the pipe but Volvo sell an insert for the parts dept so a standard hose can be used. Its about £1.50 and is a red thing about 3 inches long. It has an open end and a pin hole at the other. however, Haynes and the greenbooks I have dont say which way round it goes!! The 340s I did this work on were oooh 3 years ago!

Anyone got a green book that shows which way? parts manual doesnt show it either

This resolved the idle concern. Check if this pipe has the restiction or if it is blocked

Adam ( 340 GLT ) has a K & N mod without the crankcase vent having the restriction and has had no idling probs interestingly. however, Ive found the lack of this restriction on the standard set up upsets the idle. The crankcase oil vapours need to be removed, released.

Hi Andy! re the 240, thats interesting. Im starting the car this weekend so will leave it a little longer to see if it sorts its self out

all the best

Shimon it doesn't matter which way round it goes, any way will do. And Adam's car must have a restriction otherwise it'll be pulling too much air direct into the manifold causing symptoms of a bad air leak. The original hoses had the restriction built into the hose directly.

doesnt matter which way? interesting? how come?

surely a large hole on the engine side would have a different affect to a small hole engine side and large hole on carb / air filter side?

yep, I thought a lack of restriction on adams car would cause probs... too much vacuum on the crankcase - its oil air but prety much all air!

im thinking the lack of restriction sucks in too much air to be tuned out by the carb

excess air gives same running faults as air leak

cheers

all the best

From the air's point of view Shimon, it doesn't see large hole then small hole, just small hole/restriction, as the large hole nearly the same as the pipe (Ok, there is some turbulent stuff going on, but that really doesn't effect the effect we are looking at).

Just as a road narrowing scheme slow both traffic equally (well, as long as they put signs as to who has priority, air doesn't have t*ssers driving, so doesn't need the signs ).

at last its sorted manifold air leak it sounds great now
thanks guys for all youre help

I'm glad you are sorted with it. BTW for other ppl's interest what method did you use to find the air leak?

to be honest just trial and error replaced manifold and carb gaskets and the air pipes