Losing power and fuel

Post by **tommyj** » 31 Oct 2005 07:15 pm

Great website btw.

I was wondering if anyone could help with an issue that has been developing.

I have a 340 GL 1.4 that has been losing power and economy lately. It starts and idles fine. However, when the car is moving at reasonable speeds and I put my foot further than half depressed the car judders and begins to slow down. When looking out of the rear view mirrors you could see white smoke coming out of the exhaust. With very careful use of the right foot the fuel economy on a long haul averaged 27mpg, which is much less than it has managed previously. However, yesterday I was reduced to less than 50 mph on the M1, and it took an age to get up to speed.

Basically, the car seems hungry for air. The air filter has been changed, and the air intake is working fine. Spark plugs and HT leads are new and the engine is not misfiring.

Could this be a carb problem (I had the carb tubed by a garage fairly recently)?

Could it be exhaust (there is a quietish rasping from below when accelerating or changing gear), though I can see no abnormalities?

Any ideas/suggestions welcome...

T

Post by **340GLT** » 31 Oct 2005 08:02 pm

Sounds like a vacuum/breather problem mate!! I rebuilt my carb on my 1.4 recently and it is 10times better most garages dont like doing full carb rebuilds any more but when the weber 32DIR is working right it is a good carb!!
When the engine is running pop the bonnet and get your head around the carb to see if you can hear any sucking noises!! I'm reckoning a blocked second choke in the carb mind!!
Did you say something had recently been done to the carb at a garage?
Cheers Adam

Post by **tommyj** » 31 Oct 2005 08:17 pm

I took rusty into the garage a few months back to get the carb sorted out as the idling speed had dropped to 500rpm or so. They didn't have time to clean it, but tuned it up for me as a quick fix (for free!). It then worked well, but I left the country for 4 weeks, and when I got back - it seemed a different car.

I can't hear any sucking noises from the carb. I can take it to the same garage as they seem willing to refurn the carb if necessary. Before I do this I want to be sure that its not anything else more simple.

Could it be exhaust manifold?

Thanks,

Tom

Post by **340GLT** » 31 Oct 2005 08:29 pm

I very much doubt it would be manifold!!! Oh hold on i forgot to say check that the carb top is tight to the base as this sometimes causes the problem. The best way to check is undo the 10mm nut on top of filter box, remove filter and undo the 8mm nuts on top of carb, three of them. Then remove the filter box completely and check the 5 slot head screws are tight on top of the carb!!
If these come loose you have this same problem you describe!!!
Hope that helps
Cheers Adam

Post by **tommyj** » 31 Oct 2005 10:12 pm

last time I checked the carb, it was tight Having said that, its a good idea to check again. Cheers

Post by **5lab** » 31 Oct 2005 11:49 pm

air leak is easy to sorce

with the car running normally, spray some wd40 (or similar), around the carb and the rocker cover if the revs rise, you've got a leak.

that said, white smoke sounds like oil - i would suggest at a wild guess - there *could* be some leak letting air into the rocker cover (a very common problem), and the air being sucked into the carb is being mixed with oil, which is causing the smoke? just a thought..

Post by **V6 Man** » 01 Nov 2005 12:18 am

Hugh, white smoke is usually water - grey/blue smoke is oil, brown smoke is too much fuel

Post by **foggyjames** » 01 Nov 2005 12:22 am

Black smoke is rich, I'd say....I should know

Hate to be a doom merchant, but sounds like it might be a head gasket failure. It might be worth trying a compression test.

cheers

James

Post by **Chris_C** » 01 Nov 2005 01:24 am

Erm, may be completey wrong area, but when did it last have a dizzy cap and arm? Kar's usual reason for economy and power going shocking is that (buy a Volvo one, Halfords ones are crap, before anyone else says it) Oh, difference between a Volvo(ducilier) and halfords caps? Volvo have a carbon centre contact, not brassy coppery metal, so won't oxidise as much.

Don't think that's give white smoke, but worth a look, 'specially on a 1.4, they eat the things

Post by **pettaw** » 01 Nov 2005 04:49 am

Yep, James is right, IMO, carby problems are normally poor idling or pickup, not normally full throttle problems and not normally white smoke.

Take the oil filler cap off and see if there's any milky deposits there. 90% sure is the head gasket failure. I would think that the dodgy running from before has overheated something and either cracked the head or warped it causing failure.

Changing isn't too difficult, Will Plummer is the man for this as he has done it before a couple of times on the 1.4s, but get the head skimmed at an engineering works to reflatten it otherwise the HG will go again.

Post by **tommyj** » 01 Nov 2005 07:51 pm

Adam, you were right, and I'm a donkey for missing it, the carb was loose. Much better under power now. Fuel economy is still not good, and the exhaust smells of petrol. Time to get the carb cleaned and tuned I think.

Post by **5lab** » 01 Nov 2005 07:59 pm

well oil is normally black if its being burned, but it seems to go white (in my experiance) if it just gets very hot (ie spils on an exhaust manifold..)

Post by **340GLT** » 01 Nov 2005 08:08 pm

No probs mate glad to help, if the fuel economy is bad you could try turning the mixture screw down. It the scre on the passenger side of the carb, towards the base, it faces the passenger wing!!! 340pw

Cheers Adam