Mazda Rotary Club

General => General Technical => Technical Stickies => Topic started by: Si Fi on July 20, 2013, 02:30:03 PM

Title: Black smoke on start up, and intermittent idle!
Post by: Si Fi on July 20, 2013, 02:30:03 PM
Hey people,

My car hasn\'t got an mot at the moment so starting the car up every other day (mot next saturday).

couple of days ago it was completely fine and ran no problem. however just now I started her up and black smoke came out the exhaust (running rich due to how strong petrol smell was) until she warmed to optimum temperature then disappeared (baring in mind as you well know it isn\'t cold at the mo lol) , but at the same time was idling at approx 1000rpm revved the car then jumped up to 1400rpm, when revved again, then went down to 1k for a second when i realesed accelerator then straight back to 1.4k and popping every now and then through out the whole time engine was running.

any ideas guys???

going to get my oil changed along with mot as well as oil filter change and fuel filter if there not to difficult to change and a full service by a specialist.

thanks in advance,

Si.
Title: Black smoke on start up, and intermittent idle!
Post by: rx7boy on July 20, 2013, 02:37:53 PM
Starting the car up and just letting it idle every other day is not going to do the engine any favours. Your most likely fouling up the plugs leading to unburt fuel mixture (black smoke).

If you do have to start the car then allow it to reach operating temp 80-90c water temp. Then on shut down hold the revs at 3k and switch engine off keeping your foot on the accelerator. This reduces the chance of flooding and plug fouling.

Remedy for now is giving the car time to warm up and then give it some quick burst of throttle until it clears.
Title: Black smoke on start up, and intermittent idle!
Post by: Si Fi on July 20, 2013, 02:52:26 PM
ah ok. nice word \'fouling\' had to check it up on wikipedia lol. yeah when it was warmed up fully I did give it blast and did seam to settle down a bit. nice tip as well. fingers crossed for mot..... :s

cheers
Title: Black smoke on start up, and intermittent idle!
Post by: rx7boy on July 20, 2013, 02:59:46 PM
Quote from: Si Fi;861237
ah ok. nice word \'fouling\' had to check it up on wikipedia lol. yeah when it was warmed up fully I did give it blast and did seam to settle down a bit. nice tip as well. fingers crossed for mot..... :s

cheers


Make sure when you get the MOT done that you tell them to perform a non catalytic converter test. all imports do not require a catalytic test.
Title: Black smoke on start up, and intermittent idle!
Post by: Si Fi on July 20, 2013, 03:04:30 PM
nice one. yeah i checked online with VOSA and from the VIN number my VDS code for emissions test don\'t match rx7 on their chart. jap import has more power than uk model dont they as well so emissions would be slightly different.

found this the other day looking into it!

http://www.dft.gov.uk/vosa/repository/Emissions%2017th%20Edition.pdf