l0w320 0 Report post Posted July 15, 2011 hey there guys ive got a 325i manual e30 and about a couple weeks ago it developed a strange noise that sounded almost like a exhaust leak? i got a small leak welded up but didnt seem to make any difference, so i took it to ray at hellbm to see what he thought of the situation, and he thought it sounded like it had a misfire. so i got new spark plugs and leads, which made a little bit of difference but still doesnt sound or run right. i have checked the dizzy cap and it appears to be fine... only other thing i can think of would be the coil pack? any other suggestions as to what it might be? NB i have not done a compression test yet... Quote Share this post Link to post Share on other sites
pureboiracer 0 Report post Posted July 15, 2011 When does this noise occur? is it all the time? at certain revs or under certain acceleration/deacceleration loads? Things to check: Coil ( although this usually results in a missfire under load or high revs.) Injectors (weather they are opening properly or if the spray is correct. also check plugs etc.) Intake air leak. Faulty sensor, ie crank position, throttle position or afm plugs, leads, dizzy, rotor, spark advance (depending on what style of dizzy it has.) Fuel pressure and flow contamination of sparkplugs Air fuel ratio tappets cam timing Quote Share this post Link to post Share on other sites
l0w320 0 Report post Posted July 15, 2011 When does this noise occur? is it all the time? at certain revs or under certain acceleration/deacceleration loads? Things to check: Coil ( although this usually results in a missfire under load or high revs.) Injectors (weather they are opening properly or if the spray is correct. also check plugs etc.) Intake air leak. Faulty sensor, ie crank position, throttle position or afm plugs, leads, dizzy, rotor, spark advance (depending on what style of dizzy it has.) Fuel pressure and flow contamination of sparkplugs Air fuel ratio tappets cam timing hey there oli. this noise occurs all the time and gets worse under acceleration almost sounds kinda of v8ish... have put new plugs and leads on which seemed to make it a little bit better. will be trying a coil and afm from a mates 325 and seeing if that makes any difference. as you said could be a number of things though.. :/ Quote Share this post Link to post Share on other sites
pureboiracer 0 Report post Posted July 15, 2011 When it is running try (carefully) pulling a lead off a spark plug one at a time, if the engine rythm or noise changes then its ok, if there is one that you can pull off without making any effect to the engine (or substancially less than the others,) then that is the cylinder that is missfiring. if you can put it down to one cylinder then the injector would be the 1st place to look providing its getting spark ok. If none of the cylinders are able to be singled out then start looking at the other stuff. Quote Share this post Link to post Share on other sites
l0w320 0 Report post Posted July 15, 2011 When it is running try (carefully) pulling a lead off a spark plug one at a time, if the engine rythm or noise changes then its ok, if there is one that you can pull off without making any effect to the engine (or substancially less than the others,) then that is the cylinder that is missfiring. if you can put it down to one cylinder then the injector would be the 1st place to look providing its getting spark ok. If none of the cylinders are able to be singled out then start looking at the other stuff. alright i will try that. thanks for the advice oli much appreciated Quote Share this post Link to post Share on other sites
