Cuts out at Junctions

[Statler]

Ok the story so far. '91 340 1.4. Bought two years as a cheap runabout till I got a 'proper' car. Thing is I never have, as this car has entered my soul. Comfy, roomy, great turning circle, easy to work on....you know the score. However it refused to start three weeks ago. Mindful of advice on 'Mania' site I checked for shakey carb. Bingo; all5 screws half out. Tightend 'em down including the injector (?) jet (large one between carb barrels) which was loose and preventing carb top from seating properly. Ran fine until two days ago when it would start cutting out as revs dropped at junctions. (trapped between bus, road works, and police car...most embarrassing) Running with choke 1/4 open helps but still runs rough. Adjusting mixture screw ('volume' screw?) makes NO difference to idle speed at all.
Trawling though the site I have drawn a list of likely causes a) Warped carb base b) blocked vacum hose c) loose nuts on manifold d) Fuel cut off solenoid - on this last , disconnecting the lead from the cut off made no difference to the rough tickover and 'hunting'. Also when connected fuel continued to pour into the carb for several seconds after ignition turned off. This is the first real problem I have had with the car (apart from replacing perished fuel lines at tank soon after purchase). Would anyone like to bet on the most likely culprit? Site really helpful so far and nice to know I am not alone in my admiration for this animal ...rated I seem to remember as no 42 in the 100Crap Cars book.

[5lab]

i'd check the nuts again - the carb tends to come loose after a while - maybe your bolts are worn.. it definately sounds like an air leak from somewhere - failing that check the rocker cover is on fairly tight and not leaking air, and that all the air hoses running to/from the carb are plugged in and not shot

failing that, could be any one of those things - why not come to the devon meet in early oct and i'm sure it'll get fixed

Hugh

[Dustydick]

Hi, I'm guessing from my experience with m/cycle carbies that the needle and seat on the carby float bowl aren't closing properly, causing the carby to flood. This will cause excess fuel to enter carby throat, making mixture adjustment impossible, rough running as engine tries to cope with poor air/fuel ratio and hunting/shaking of engine continuing to splash fuel into carby throat, especially while decelerating rapidly. Pop the top off the float bowl and carefully clean out the rubbish accumulated in the base of the bowl. If it continues to occur, replace the needle and seat. You could try lapping the old needle into the seat by using a bit of lipstick (You have to be on good terms with the girlfriend to get away with this one) as apparently it acts as a mild cutting paste. Hope this helps -
if you want to avoid fine particles of muck getting into the carby then throw away all your old metal fuel cans and use the plastic ones.
Also keep your fuel tank topped up to full if not using the vehicle for a while to avoid the tank rusting.
Every carby I have ever rebuilt looks like it has a tablespoon of muck in the bottom due to build up of fine particles getting through the fuel filter.

The carby could also have a blocked idle jet system, hence it responding to the use of partial choke (which is increasing the base idle rpm setting of the carby butterfly, allowing richer choke circuit to operate and therefore negating blockage in idle system circuit) Again this blockage could be caused by muck being stirred up in the carby bowl due to loose manifold to carby mount bolts allowing a jarring disturbance of sediment. Simply remove the carby from engine (after getting the correct gasket rebuild kit) and strip down carefully, blowing all passages clean and scrubbing clean interior and exterior. It looks difficult to do but after you've rebuilt your first carby, you'll find a reason to do it to pass a wet winters day, it's that easy and enjoyable. Set your float height carefully by tilting the carby bowl until it just seats the neddle, not by pushing it down by hand (finger) otherwise the spring in the needle could cause a false setting, resulting it too high a fuel level when the carb is reassembled, which will cause flooding and rough idle. Rebuild your carby over a clean bench too, following safe handling/disassembly techniques in a well ventilated area away from any ignition sources and wear fuel proof gloves to avoid any contact with petrol - unleaded fuel is nasty stuff. I use newspaper under my carby parts to allow me to hear any small parts dropping and also to stop them bouncing off across the room. If you do drop anything, find it immediately before continuing to rebuild/clean, as 5 minutes later something else is liable to fly off on your first rebuild and you'll be left with the frustration of not being able to find them all ten minutes after they've tried to escape. I also use thin clear plastic hose to blow the passages and jets, quality tools to disassemble the carby (especially a "good as new" screwdriver to loosen frozen screws), plenty of clean white rags, wooden icecream sticks and quality carby cleaner spray. It's about a three beer job too.
The type of trouble you describe with your engine/carby happens all the time over here with some of our rough, neglected roads the government keep promising to repair but instead forget about while they give themselves 7 bloody % pay rises....Bastards. (The latest pay rise is justified by saying it will attract better politicians - WHAT?!?! Not fat lazy donut eating H.Simpsons?)
Cheers and feel free to give me a yell if you get stuck with anything, Dusty.

[Statler]

Thanks Hugh and Dusty. A Devon meet? Sounds interesting. As for the sick beast ....ho hum. Today was replacing perished hoses, check nuts and also see if the solenoid is working. The jury is still out on that one but I replaced the tube for the vacum advance thingy and that seemd to help. All nuts, manifold and carb, still snug. Ticks over more reliably but still hunts continually. Also replaced distributor cap and discovered cause of squealing noise from cold start up (which I assumed was water pump on the way out). The shaft carrying the rotor arm has about 10-15mm end float on it and you can feel the 'sqealing' through it.
I would like to think that a straightforward carb clean would do the job but at 91k miles I've a feeling it might be lots of age related factors coming together. Also since flushing the rad today there is coolant coming from the water pump housing - actually the shaft I think. Not a good day overall. However thanks for the support guys, and I will let you know the conclusion.

[MJ]

Hopefully you'll get it sorted, and welcome to V3M from a fellow Devonian

Details of the Devon meet Hugh mentioned can be found here http://www.volvo300mania.com/forum-uk/v ... php?t=3531. We're not sure if it's going to be the 6-8th october, or the week before yet.

[shimon340]

hi there....

have you check fuse number 10 or the wiring to the solenoid idle valve? if fuse 10 goes, you loose the idle jet on the carb so the engine will run on choke but once warm and the choke is pushed in, as the engine slows to idle it stalls due to the lack of the idle jet. Ive had these sumptoms on two of my 340s...

keep us posted, hope you get it sorted soon

shimon

[foggyjames]

at 91k miles I've a feeling it might be lots of age related factors coming together.

That's a good one, tell another My Nessy (also a 1.4) has 193k and is still going strong...however...it did exactly what you've described today when my housemate was driving it.

It turned out to be only firing on three cylinders due to a loose plug lead. Something to consider...especially if your ignition 'service items' (leads, distributor cap, rotor arm) haven't been changed for a while.

On the other hand, carb problems are common on these cars, as those heavy air-pans literally shake the carb apart.

I strongly suggest you come along to the meet. There'll be at least one other 1.4 there (because I'll be bringing Nessy), and plenty of knowledgable folk (and Hugh ) to help out.

cheers

James

[5lab]

I strongly suggest you come along to the meet. There'll be at least one other 1.4 there (because I'll be bringing Nessy), and plenty of knowledgable folk (and Hugh ) to help out.

B&stards. i actually had a sparkplug blow up on leah.. drank like a fish the whole way home :S

[Statler]

No news yet. Waiting for the week end and bits from the breakers. But James..193k! I am impressed, and inspired! I shall survive! Incidentally, what bits have failed along the way? Random thoughts re COAJ a) It might be running on 3 when underweigh but definitely not at tickover.b) Halfords distributor caps ARE rubbish, I agree. c)The no.10 fuse sounds too good to be true but I will check it out and be mighty grateful if it does the trick. d)I will try to make (at least some of) the Devon meet....always thought the 340 would be an ideal Plymouth Dakaar vehicle. Cheers Statler.

[foggyjames]

To be fair, 182k of that was done before I owned it....and one certain Mr 5lab was the PO for ~30k IIRC. It's a bit of a mess bodywork wise, so I can learn the tricks of the trade and it'll only look better, no matter how bad a job I do (in theory!). Plus having got to 182k, I decided it deserved to see at least 200k.

It sat for just over a year waiting for me to take it on, and here's what I've done since.

Carb rebuild (mainly because Hugh swapped the good carb for a trashed one while it was stood!).
Inlet and exhaust manifold stud/gasket repair.
Extensive rust repair (it is a 300, after all).
Clutch output shaft bent (no real idea why...could only have been due to jacking on the prop or something....very unusual)
New clutch & battery (consumables).

Off the top of my head, that's about it. It has done 10k since then without batting an eyelid....about 8k of which was on the same oil which was put in it before it was laid up for a year.

Having said that, we're now running into some problems. The head gasket has had enough, as it swaps oil and water (could also be a mis-seated liner, etc). Having said that it doesn't run hot, and isn't down on power, so in theory you could been pouring oil and water in and it'd keep on going.

We've also hit the ignition system problem as discussed before. New arm, cap and leads will be with me tomorrow night for just over £20...so that should knock that on the head. All are of unknown age and origin, and all look well and truly knackered.

Stuttering once you put the engine under load is either worn ignition components, or (more commonly on 1.4s) running massively lean due to an air leak from the carb. Definitely try to come along to the meet if you possibly can. We're a friendly bunch, honest!

cheers

James

[Statler]

Two days on from investigative surgery and she is ticking over like a watch and pulling away cleanly. Dusty, good on yer mate. It was dirt in me carbies allright. Bits of what looked like gasket were floating in the bowl. When I tightened the carb top down I must have dislodged some goo. Clean and blow through all ok. Squealing noise turned out to be rotor arm on point of disintigration and new water pump went on without any problems. I am feeling smug and about to set off for Oxford - so watch this space for tales of mechanical disaster on the M5 'Pride goeth before a fall and a haughty nature before destruction' etc. Nevrtheless thanks to all who have proffered help and fascinating theories. Hope to get to Crediton for (some ) of next weekend.
Cheers
Statler

[SteveP]

Great news! I'm sure the 340 will do you proud after a little fettling! On another point coming back from Dorset yesterday, I saw around 5/6 cars broken down over 150 miles most of which were under 5 years old... a 1-2 year old BMW 3 series on a Recovery truck took the biscuit though!

[foggyjames]

New Beemers are shocking - Bertiebandit (RAC man) says they have a way higher 'tow ratio' than anything else, given the numbers on the road.

Nessy had the same problem I think - dirt dislodged when tightening the carb down!

cheers

James

[petefarrell360]

So true Steve, on the M40 the other night, there was a car every mile or so for about 10 miles and not one of them was more than 5 years old! And form memory two were BMW's! Had to laugh as I ploughed on by in the old van!
Pete

[foggyjames]

I drove to London and back last night...around 300 miles in Nessy. On the way, I saw 4-5 breakdowns (which weren't puntures). My favourite was a nearly-new Espace which was busy turning its underbonnet area into smoke on the side of the M1...although it smelled more like massively cooked brakes/clutch/even tyre smoke?

...and, of course, I saw the obligatory BMW E46 3-series being pulled onto an AA wagon. Owned.

cheers

James