I have a 2002 325ci with 233,000 miles. I have been fitting misfires for quite some time. I have replace the oil separator, all of the coil packs, MAF and crank sensor. The gas filter was clogged and I was only getting 37 psi on the fuel pump. I cleaned the filter and the pressure went up to 49 psi. I picked up the car from the mechanic last year and the car was running great. When I started the car this morning the check engine light came on immediately and I could feel the misfire. I drove the car about 3 miles and the check engine light went off and the misfire went away and purred like a kitten.
I don't know what else to check to stop the misfires. Any ideas would be greatly appreciated. My mechanic is good at what he does but he is GM certified not a foreign car guy.
BTW - I have spent almost $2000 in the last 6 months trying to get this fixed.
I am not an expert when it comes to these cars by any means. I have only replaced the radiator and a coil so far. Would it be worth it to you to get the car evaluated by a shop who specializes in BMW or possibly a local BMW service department? Are there specific codes that the engine light is throwing? AutoZone and O'Reilly will run a check on their scanner for free. I know many shops charge for most things. Some will help you out if they see a possibility of winning your business.
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Jeremy
2000 323Ci Titansilber Metallic cabriolet
Thanks Jeremy, Unfortunately there are no BMW mechanics local to me.
Normally I would say smoke test the intake manifold for vacuum leaks but in your case you will have to use carb clean on cold start spray around the intake manifold gasket area ect and if the engine idle goes up after spraying a certain area,there is your leak. But the engine should be cold, because as the engine warms up things expand and seal. Also what ever cylinder is misfiring mark and move the coil pack to a different cylinder, clear faults recheck, if it comes back and didn't follow the coil pack move then you would know if is a coil pack. Also look for water in the master cylinder compartment, clogged drain. Just had a e39 hydro lock the engine because of the that and he had an intermittent misfire
Had your mechanic thought of replacing the old sparkplugs,
wth a new set of NGK plugs, to go along with the coil pack replacement?
Btw,a scan for codes may turn up clues, if only slightly helpful with a genetic scan tool.
Scan for codes,take note of them,then clear all codes.
Complete a short drive cycle, then scan for new codes that reappear.
I had just replaced the plugs when he did the coil packs.
Ok,
If possible, perform a scan.
BMW scan tool/software would be ideal,
But work with what you have on hand.
Sounds likes a vacuum leak. Problem is there when the engine is cold and the mixture is running on tables in the ECU (open loop control). Its running lean due to the unmetered air. Once the engine heats up, the ECU switches to closed loop control and uses the O2 sensors to trim the mixture rich to balance the unmetered air of the vacuum leak and the problem goes away.
Look at the large rubber tubes from the air box to the throttle body. By the throttle body there is a branch off the main tube to the idle control valve (ICV), this branch is a common spot for a hole.
Alternatively, get your mechanic to smoke test the inlet system to see where the problem is.
Last edited by Muzz258; 03-29-2018 at 07:52 PM.
1999 2.8L Z3 Roadster,
2000 3.0L Z3 Roadster,
There is only one thing more pleasurable than working on a Z3, that's driving it top down on a fine day.
Try www.bimrs.org to see if there’s a shop that specializes in bimmers in your area.
Thanks for the link Marco. Unfortunately there is nobody close.
Thanks Muzz258 for the suggestion on vacuum leak. I check that out over the weekend.
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