340 1.4 rough ans slow idling

[Two340'sman]

Yes, this 340 has electronic ignition.

Wooden pistons too!

[Two340'sman]

Just a bit of an update, used the car for a few short trips, seems better than it was, put in some super unleaded as kindly suggested, seems to be a further slight improvement. Going to use the car for a couple of short trips in the next few days, we'll see what happens.

Booked in for an MOT on Monday 5th.

Had a seat belt waning light come on whilst I was driving, found the insulation on the wire on the belt stalk worn through and intermittently shorting to earth.

Insulated it and that seems OK now.

[Two340'sman]

Hi all.

I may have discovered something, several short trips in the last couple of days, the first two car behaved fine, the third trip, back to rough tickover and stalling.

Today, I ran the engine and is playing up again.

About two years ago I fitted new old stock ignition leads, thought I'd measure their resistance, each lead was a about 10 K Ohms. Thought the was a bit high, so opened another new old stock pack and each lead was about 4 K Ohms.

Fitted these, and engine idled very smoothly. Tomorrow, I'll go for a test drive.

MOT still booked for Monday.

A good weekend to all.

[Two340'sman]

Overall, good news, car passed the MOT today.

Yesterday, three short trips and car was perfect.

Today, started off for the MOT and rough idling and stalling again (faulty ignition leads was a red herring) Stopped before I arrived at MOT and adjusted idle speed up a bit.

Engine was ticking over fine whilst tester was checking many things, but when he came to do emission test, the rough idling returned. He said it sounded rich and there was a little black smoke coming out.

He told me to take the car round the block to clear it out, I did this, though thought it was not the cure. I was in the car when he retested and held my foot slightly on the accelerator to give approx 1000 RPM. He passed it, think he was being lenient, I did not ask for the emission test sheet, thought best to keep quiet!.

At least now I have time to do other various checks, including the hot compression test, that is when I find my tester.

Pic of the car taken on returning from the MOT

DSCF0327 by A60man, on Flickr

[Laird Scooby]

Congrats on the pass! At least you have a year to sort it out now!

Does this rough running mainly happen when it gets hot?

[Two340'sman]

Originally Posted by Laird Scooby

Congrats on the pass! At least you have a year to sort it out now!

Does this rough running mainly happen when it gets hot?

Thanks, I was very pleased to get a pass.

I think this rough low tickover does tend to be when the engine has warmed up, but it can revert to normal tickover by itself.

My friend's 340 is booked in at the same garage for MOT this Thursday, I may go with him.

He bought his 340 about 10 years ago, it was a low mileage one, around 25,000 Miles, a 1.4 fairly basic model, has the five gears, wind up windows, no rev counter.

He's a retired Mercedes mechanic, 30 years there.

[Two340'sman]

Yesterday, morning, 10 mile round trip through traffic, car behave perfectly.

In the evening, 2 mile trip to Aldi, car misbehaved, bad idling and stalling. Got back home and engine started to tickover fine again!

Today, went my friend to MOT his 340, it passed no problem.

[Laird Scooby]

Originally Posted by Two340'sman

Yesterday, morning, 10 mile round trip through traffic, car behave perfectly.

In the evening, 2 mile trip to Aldi, car misbehaved, bad idling and stalling. Got back home and engine started to tickover fine again!

Today, went my friend to MOT his 340, it passed no problem.

There's a simple answer, don't shop in Aldi!

Joking aside, was the 2 mile trip a bit more stop-go-stop-go than the earlier trip?

Congreats to your friend on the MoT too!

[Two340'sman]

The Aldi trip was the same sort of driving as the 10 mile one.

Will put a few more miles on the car and see what happens.

The friends car now has about 45,000 Miles on the clock, about 25,000 when he bought it.

[Clan]

Originally Posted by Two340'sman

Yesterday, morning, 10 mile round trip through traffic, car behave perfectly.

In the evening, 2 mile trip to Aldi, car misbehaved, bad idling and stalling. Got back home and engine started to tickover fine again!

Today, went my friend to MOT his 340, it passed no problem.

Just about the only thing that can cause problems with a B14 is the RENIX ignition computer after 3 years , Always carry a spare and try and locate one whilst they are still around second hand ... there are different part numbers/maps in them for the various engines and model years but ANY One will get you home in an emergency ..