Ken's misfiring 328i thread.

Some of you have sort of been following this in the OT since this happened on my birthday (the 30th). I decided it's time to give it it's own thread.

Back Story: Car was running perfectly fine and i parked it at my friends house and we went out. We came back and it was snowing and there was a parking ban in affect so i moved the car to the backyard, it was still running fine. A few hours later I had to move the car for the plow and it had a hell of a time in the 12" of snow we had, and it was missing.

The next day i went out and saw/smelled a fuel leak and found out that a couple of my injector seals and let go. I replaced all 12 o-rings on the injectors and fired it up... still thumping away on 5 cylinders it sounded like. I let the car get warm and drove it approx. 7 miles home and even driving it didn't work out the miss. I let it sit a week and started it today to move it. It had a hard time starting like it wasnt fully igniting or compressing but it did turn over and run. I eventually got it in my back yard and shot this video.

Things I am going to check, Injectors, plugs, coils, DME compartment, and hopefully compression numbers. I have no clue where to begin thinking other than the obvious. it's not blowing coolant or oil, and it's not sending out raw fuel either. If you hit the throttle quickly the engine stumbles and then catches up.

Did you ever determine which cylinder is missing?

If so does swapping coil packs move the miss?

Kenny, I'm thinking go back to the root cause of what caused the injector seal blow out in the first place............ this is kind of out there, but what about the possibility of a blocked or restricted fuel return line? That could give the FPR fits and could explain the injector seal blow out.
It could also be a problem with the FPR being sticky and bouncing between low fuel pressure and not regulating max pressure.....that could explain the seal blow out too and the misfire.

Originally Posted by jonesin

Did you ever determine which cylinder is missing?

If so does swapping coil packs move the miss?

it's either #4 or #5. i havent tried swapping coils yet.

Originally Posted by dc_wright

Kenny, I'm thinking go back to the root cause of what caused the injector seal blow out in the first place............ this is kind of out there, but what about the possibility of a blocked or restricted fuel return line? That could give the FPR fits and could explain the injector seal blow out.
It could also be a problem with the FPR being sticky and bouncing between low fuel pressure and not regulating max pressure.....that could explain the seal blow out too and the misfire.

i checked that, and it doesn't seem to be the issue, my old o-rings were pretty worn out and the injectors appeared to have unseated themselves from the rail, the square clips were on but not tight. it doesnt seem to have a problem with fuel delivery now. i'm leaning towards a blocked injector or a burned plug/coil. even though the car didn't get hot while i was toiling away in the snow i'm going to check compression numbers to be sure the HG didn't randomly let go... after all it's a high mileage engine.

I couldn't watch the video at work (streaming video is blocked ) but I just listened to it now. It sounds more like an exhaust valve isn't sealing than an actual miss. Hard to tell for sure. If you're going in to swap around coil packs it'll only take couple more minutes to do the compression test. If you get a low cylinder, do a wet compression test too and see if the reading comes up (bad rings) or stays about the same (valve or possibly HG).

Originally Posted by dc_wright

I couldn't watch the video at work (streaming video is blocked ) but I just listened to it now. It sounds more like an exhaust valve isn't sealing than an actual miss. Hard to tell for sure. If you're going in to swap around coil packs it'll only take couple more minutes to do the compression test. If you get a low cylinder, do a wet compression test too and see if the reading comes up (bad rings) or stays about the same (valve or possibly HG).

i hope it didn't burn a valve the last thing i feel like doing is pulling the head before im ready for the turbo. just to double tap as ive never done a compression check on a BMW before, you just pull the plugs, bring cyl 1 to TDC and go from there, right?

Pull the plugs, disable the fuel pump and ignition (pull relays), screw the compression gauge into cylinder one. Spin the engine for 5 or 6 revolutions. Stop. Read the gauge and record the reading. Move to cylinder two, reset the gauge to zero and repeat. Do that for each cylinder. You should have 156 psi minimum (180-ish is better), but the main thing is they need to be within just a few pounds of each other.

For a wet test, repeat the process, but squirt a couple of shots of your favorite motor oil into the spark plug hole before screwing in the gauge.

Originally Posted by hornhospital

Pull the plugs, disable the fuel pump and ignition (pull relays), screw the compression gauge into cylinder one. Spin the engine for 5 or 6 revolutions. Stop. Read the gauge and record the reading. Move to cylinder two, reset the gauge to zero and repeat. Do that for each cylinder. You should have 156 psi minimum (180-ish is better), but the main thing is they need to be within just a few pounds of each other.

For a wet test, repeat the process, but squirt a couple of shots of your favorite motor oil into the spark plug hole before screwing in the gauge.

well that seems easy enough. i really hope i don't have bad compression numbers. I REALLY don't want to have to rebuild/buy a head

seafoam through the brake booster and see if any change =D

I recommend that Ken buys a new BMW and sends me his exhaust.

Originally Posted by ZeGerman

I recommend that Ken buys a new BMW and sends me his exhaust.

you would like that, wouldn't you Sadly if I do decide to sell this one to get an M3 the exhaust is going with the car so i can justify the asking price

Gonna be hard to recoup the money for your aftermarket parts if you sell it. You'd be much better off selling them all individually, as much of a pain as that is.

Originally Posted by ZeGerman

Gonna be hard to recoup the money for your aftermarket parts if you sell it. You'd be much better off selling them all individually, as much of a pain as that is.

yeah I know. I figured if I sell the car for 4k I'd be okay with myself. and i still have a whole sh!t ton of parts in my garage that i can keep for the next one or sell. first things first though, i have to wait on good weather to start poking around in the engine and see what's up with the dang thing.

Originally Posted by custm42435

seafoam through the brake booster and see if any change =D

This^ if you get a low compression cylinder in both the dry and wet test. The year before last I had a rough idle and figured it was time for a plug change. While I had the plugs out I did a compression check and oh crap I had cyl. #5 at 80 psi. Did the wet compression test and got the same. I wasn't losing any coolant or seeing any cooling system pressurization so I was pretty certain it was a valve issue. With the low but not near zero reading I thought one possibility was some carbon stuck on the lip of a valve. I Seafoamed through the brake booster hose ( 2 cans worth, multiple cycles) and the miss went away. I rechecked compression and low and behold all 6 cylinders right around 165 psi. Been fine ever since.

Originally Posted by dc_wright

This^ if you get a low compression cylinder in both the dry and wet test. The year before last I had a rough idle and figured it was time for a plug change. While I had the plugs out I did a compression check and oh crap I had cyl. #5 at 80 psi. Did the wet compression test and got the same. I wasn't losing any coolant or seeing any cooling system pressurization so I was pretty certain it was a valve issue. With the low but not near zero reading I thought one possibility was some carbon stuck on the lip of a valve. I Seafoamed through the brake booster hose ( 2 cans worth, multiple cycles) and the miss went away. I rechecked compression and low and behold all 6 cylinders right around 165 psi. Been fine ever since.

i'll keep this in mind if it comes down to it

Alrighty folks, we have updates, AND a resolution.

the first step i took was to pull the coils while the car was running. Wouldn't you know it that the 1st coil, cylinder #1 was the cuprit. I pulled the harness and absolutely NADA happened. so I followed this lead and yanked the plug. it looked fine.


then i put it back in and swapped coils. Nothing. The engine was still misfiring on #1. You know what that means. Time to pull the injectors. This time i actually managed to get them out of the intake without popping them loose from the rail and making a huge mess. I pulled injector number one and it looked exactly like this:


Somehow i managed to mush it when i was putting it together after installing the o-rings. I'd also like to mention that upon pulling the fuel rail/injectors it was a dead giveaway that this injector wasn't working because it was the only injector that was bone dry.

so i unbent the contact, stuck it all back together and voila we had liftoff

glad to hear!!



df

Woot! That was hard to diagnose, but at least a free fix.

Love that "super charger" wine!



Glad to hear this had a happy ending. Nice weather up here too today to do this.

Great job, thanks to everyone for thinking that one out loud so I could follow the logic.

Originally Posted by durtyMD

Great job, thanks to everyone for thinking that one out loud so I could follow the logic.

A fellow South Carolinaian!

Yes a fellow sandlapper with a black 328is to boot.

Sweet! I may have to get to a Columbia area meeting one day.

update. i started the car for the first time in a week or so and then took it for a quick test run. about halfway through the test run it started missing again, different this time though, it was only consistent under load, if i backed off of the throttle it would cruise fine, and idle alright but the second you put any throttle into it, it starts hopping around and running funny. i did a quick coil swap but that didnt fix anything, in fact it caused a misfire that wasn't present while idling(to clarify i just unplugged each coil one at a time i didnt pull and swap) im thinking fuel again. the injectors look like they've had it. i haven't gone into the DME compartment as i haven't seen a need to, there's no ice or anything built up on the cowl and the firewall is dry.