huwjones 0 Posted October 21, 2006 (edited) Afternoon chaps, It's been a few weeks now since I installed an Mi16 (out of a Mi16x4) into my 309. The engine was fine before I removed it from the 405. It's a very good unit with around 85K under its belt and all compressions are at 200 PSi. The engine is misfiring badly under load and it has a very lumpy idle when warm. The misfiring is still present when cold, it just idles better. I've replaced everything apart from the wiring loom and the actual fuel rail. Here's a video of the car just revving at standstill, I hope it's picked up the misfire in the exhaust - the sound doesn't work on my PC so I can't tell! 309 video Under load, the misfiring is quite severe. It doesn't really start until it reaches 2500 rpm, pulls fine up until that point. The only 2 imperfect things about the car I know of, is the unknown age of the fuel filter and a poor exhaust manifold (I re-angled it myself, but I've missed a spot with the welder, causing a leak). However, I'm inclined to think it's an electrical problem. As I said, pretty much everything electrical, apart from the loom, has been replaced. I'd appreciate any advice or info, I'm running out of ideas now I'm going to grab the oscilloscope from work tonight so I can see what's going on at the primary side of the coil. Cheers Edited October 21, 2006 by huwjones Share this post Link to post Share on other sites
Doof 11 Posted October 21, 2006 Doesn't sound exactly like my misfiring problem on my 8v but i was amazed at the effect tightening up a very loose earth connection made. Might be worth going over the connections and cleaning them up. Share this post Link to post Share on other sites
huwjones 0 Posted October 21, 2006 I've checked and double checked all earth connections. I even ran a separate earth to the battery, incase the earth strap was failing, but it made no difference Share this post Link to post Share on other sites
huxley309 0 Posted October 21, 2006 what about the ignition amp did you replace that? Share this post Link to post Share on other sites
huwjones 0 Posted October 21, 2006 Yup, that's the first thing I tried. I've even tried 4 different ones, all with the same results I presume an air leak on the inlet tract wouldn't cause this, due to the fact that the tacho is jumping. Am I right in thinking this? Share this post Link to post Share on other sites
ada205 2 Posted October 22, 2006 Are you using the 309's loom using a dizzy adapter, or are you using the Mi's loom, ecu, ect? Your symptoms remind me of a problem i had years back with an evil miss on a 1.6. I also had the rev counter jumping around like yours, and the fault turned out to be fly lead from dizzy to ignition amp. Share this post Link to post Share on other sites
jackherer 543 Posted October 22, 2006 I presume an air leak on the inlet tract wouldn't cause this, due to the fact that the tacho is jumping. Am I right in thinking this? yes 100% electrical. I had a similar issue with my Mi16 that took ages to find, it turned out the starter motor was failing (despite starting the engine fine everytime) and somehow intermittantly draining so much voltage the engine would misfire and sometimes cut out totally. I didn't figure it out until the starter suddenly burnt out in a cloud of smoke and even then I thought it was unrelated, I was surprised to find it all working OK after fitting a new starter. I'm sure yours is something much simpler though Share this post Link to post Share on other sites
huwjones 0 Posted October 22, 2006 I'm using the loom out of the 405, so I was convinced that I could just 'plug and play' with this engine! Interesting about the starter. I can't remember if I've checked the voltages while the car is running, might be worth a go... Thinking about it, when I first started the car after the conversion, the (almost new) ignition coil burnt itself out , to this day I have no idea why. I put a new coil on and off she went. I wonder if it has something to do with that Thanks for the replies Share this post Link to post Share on other sites
