Recent coil/misfire problems
 

About two weeks ago I started getting the SES light. I had noticed that it was missing a little when started cold, I figured that was what was tripping the light. Foxwell told me it was cylinders 2+3 acting up. It always smoothed out after running a minute or so. Last week it was taking more time to run on all six, sometimes a couple miles. So I bought two coils and replaced 2+3. Put in a new battery about this time also. I should point out that the plugs were done about 6 weeks ago with iridiums. The new coils initially seemed to fix it, for a day or two anyway. Today when started to come home from work (a 40 mile trip) it was rough again and the SES came back. I drove it home but noted rough running most of the trip. When about 30 miles into the commute it smoothed out and began running smoothly on all six. When I got home Foxwell told me I had misfires on cylinders 3,4,5+6! These must have been intermittant as It wouldn't run on just two! So what I have done is swapped coils 1+3 with each other. #1 has never misfired according to the scanner, so now we'll see if the miss follows the coil or not. If the skip stays in cylinder 3 (with the known good coil) where do I go? Look at injectors? I only run premium and now it has a can of Seafoam in it. I'll report how it runs tomorrow morning with another cold start and 40 mile drive. TIA

Seafoam is way way overrated IMO. It's just a bottle of light oil carrier/light solvents....IMO. I think Amsoil is a good flush, but even that, just run it for 15 min and dump it out

Todays cold start yielded a single cylinder misfire, definetly not two or three. I let it idle and it cleared up and ran smoothly in less than a minute and was fine for my entire commute. It did not trip the SES light. After swapping 1+3 coils yesterday, this tells me it was probably cylinder 1 that misfired. I will pull the codes at lunch and see if I have a pending code for the misfire. If no pending code, I'm not sure what I'll do. :dunno: Suggestions welcomed.

The STRANGEST thing just happened. Started the X to go to lunch. As usual it started with a miss, and tripped the SES. Drove it about 3 miles and parked. While parked I decided to clear the codes. Foxwell said cylinders 3,4 and 5 were at fault. I let it run while I cleared the codes and heres the weird part, the instant the codes cleared so did the miss! Normally I would chalk that up to coincidence but this is the second time in as many days it has happened. WHAT is going on? Why would/could clearing a code rectify a misfiring cylinder? :dunno:

If the DME picks up a bad enough problem with a cylinder it can cut fuel to that cylinder cutting it out completely for emmissions reasons. When you clear the code it resets that process.

Not familiar with the 3.0i but if it has it check the plug on the valvetronic is not loose

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What could be a significant enough problem? It runs great after the codes are cleared. The problem starts with a cold start, every day now it is a lumpy idle in the morning. Some days take longer to smooth out than others. Is the timing or duration of the injection pulse different when cold? I would assume so. What "controls" the injectors? The DME? Should I search for pending codes elsewhere? If so, where? Should I have done anything when I installed the new coils or battery? TIA

That sounds like a good idea but I have no clue where that plug would be on the 3.0i...:dunno: I'll look at the parts diagrams and see if I can figure it out. Thanks

This is where you need to start, concentrate on diagnosing the rough idle at start up. Not sure about the Foxwell scanner though.

I'm beginning to doubt my coil diagnosis. They may not have been the problems afterall. I guess now I look at the injectors (something I know even less about). One encouraging note, this mornings cold start, although it did stumble a little, it smoothed out quickly (~30 sec.) and didn't trip the SES light.
I'll pull the codes and see if I have a pending misfire code.

Would a misfire due to a poorly operating injector be enough for the DME to shut that cylinder down? I did run a can of Seafoam through this last tank, maybe it actually helped and that's why it didn't act so poorly this morning.

Thanks for the help, I need it! :dunno:

Could be the misfire is associated with a fuel cutoff. Clearing the code clear the misfire counter so the DME isn't shutting off an injector until it reaches a certain number of misfires on the counter.

There is a ton of stuff that can cause your problem. I would lean towards looking for a vacuum leak to start. It would be nice if you where sure that you are reading all of the codes as there should be a clue as to what else is going on to cause the missfire. When the engine is first started it has the least amount of adaptability to compensate for problems, use that to your advantage to find the problem.

I think this is exactly it, because it starts with a minor misfire but it won't trip the SES light until it has run a while or the misfire is bad enough to make running very rough.

I have a mity-vac to check vacuum, but I have no clue where to start on the X. Wouldn't a code show for a vacuum leak? I guess I'll do a full scan with the Foxwell, not just the DME and see what turns up. Thank you upallnight you have given me good advice. Thank you also EODguy and 80stech for adding to this. It's 16*F this morning (thats -9C for your smart metric folks), I'll start it shortly and see if its better/worse with the very cold weather.

First thing I did was read the codes, a complete scan, before I started it. Nothing found, other than the persistant air bag and side light codes. This mornings cold start yielded the standard lumpy idle, but it did smooth out in about 30 seconds and no SES light. I then read the codes again and the typical misfire of 3+5 showed up, but that was all. Sometimes the misfire stays for several minutes or miles and I have to kill the SES light with the Foxwell. Then it starts and runs fine until the next cold start.

What vacuum leak would go away in less than a minute? It seems to always include cyl. 3. The others vary but 3 is always one of the ones with a miss. Is there a cold start solenoid or circuit that turns off a few seconds after a successful start? Could the injectors be malfunctioning? How hard are they to swap from cyl. to cyl?

Thanks in advance for any additional advice, I'm not sure where to go from here. Coils and plugs are both new.

I am having an idle misfire with my 3.0 X5. Originally my plugs were worn and changing cleared it. I would try a bottle of Techron (larger bottle) and good gas (Shell or Chevron) and see if that helps. Intake deposits or injector deposits can cause this type of problem. Vacuum leaks such as failed PCV hoses or separator or intake boot cracks along with valve cover gasket leak are all common failure points on M54 engine.

Thanks Jeff O, I generally buy good gas and only premium. The current tank (filled yesterday is Citgo), last tank had a can of Seafoam in it. I'll get a bottle of Techron and give it a try.

As for the vacuum leaks I'll do some research to find where the PCV is on this thing then do some vacuum testing. I've noticed no oil leaks around the VC. The snorkel between the fresh air scoop and the air filter intake hose has a crack but it is on the fresh (unfiltered) side of the air filter, so that shouldn't affect it.

If I run across anything else pertinent I'll post. Thanks again for the help.

Could this be weather related?
 

We have had a cold snap lately (just coming out of it today), I have also noticed some mayo on the dipstick and oil fill cap. I know these are related to the cold weather problem with the EGR valve/system. Temps (when I start in the morning) have been in the teens F. I know thats not cold for some of you but my X, I am sure, doesn't have any cold weather options. I have read this situation can cause an idle misfire? Need I look into this more or am I way off the track? Hopefully it will start well tomorrow morning with the warmer weather. TIA. :thumbup::thumbup:

If it starts misfiring when you first start up but go away after the engine has run for a while, I would look into a leaky injector. Just like a flooded engine, a flooded cylinder will not run correctly. It is only after the engine has run enough to clear the cylinder that the misfire is no longer present.

If it is exclusively on 4,5,6 I would check your grounds for that bank. I had an issue with 1,2,3 a couple months ago. Turned out to be a seeping Valve Cover Gasket, was getting oil everywhere and down in the wells, but also shorted out my ground.

Would this be enough of a misfire to trip the SES light and make the DME shut that cylinder off? If it doesn't smooth out on its own and trips the SES, I have to clear the codes for the misfire(s) and it then runs smoothly.

I looked at the grounds, they are firm and dry, the wells are dry also. IIRC the misfires I have been in 2,3,4 and/or 3,4,5. It seems to always include #3 and never 1 or 6 though. :dunno:

Thanks for the help guys, this is all good stuff. :thumbup::thumbup:

Once the SES light is tripped, the DME shut off fuel to the cylinder that is misfiring. If the flooded cylinder can clear itself before the SES light is tripped the DME will not shut down the injector.

An injector that is shut down by the DME due to misfire can be reset by just turning off the engine and restarting the engine. The misfire counter will reset itself when the engine is turned off. You do not need to clear the code.

That is good to know and much less cumbersome than pulling out the code reader. I'll give it a try in about an hour when I leave for work. But if the SES is tripped the injector will stay off until the code is cleared? A restart won't help?

Thank you for the enlightenment. :thumbup::thumbup:

Start this morning (at 46*) was better than most. Started with a mild misfire but smoothed out in about 15 sec. and no SES or need for a restart. I'm encouraged. I'll try a bottle of techron and hope that cleans up a leaky injector (or three) and see how it goes from there. We have warmer weather through friday, but colder weather returns for the weekend and next week.

How much mileage is on your X? If you haven't been using an additive to clean the fuel system on a regular base, I would look for a shop that can perform professional fuel injectors cleaning service.

https://www.youtube.com/watch?v=9UKEON2wIkA

i actually like that idea. i think i could use the same on both our cars.

Or if you're a DIYer and don't mind spending money on tools, you can get this:

https://www.ebay.com/itm/Auto-C-100-....c100677.m4598

That's cheap I guess I know what my Valentine's gift is going to be


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The X has 294,5XX miles. I just got it in November. I don't know a lot about the history and even less about the fuel system. I like the idea of cleaning and testing the injectors though.

With that kind of mileage on a 14-year-old X that equates to roughly 21,000 miles per years. She been driven hard and put away wet. The 50,000 miles warranty only lasted 2.5 years.

I hope you mean to yourself, because TRUST me a bad gift such as stretchy pants is unwise. On the other hand the doctor says there shouldn't be any scarring....[emoji38]

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From wife to me.

[emoji38]

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Problem solved!
 

It turns out after two treatments (one really) of injector cleaner I have solved the cold start misfire issue. For the past several days, and some were quite cold, the X has started and run smoothly. No misfires and no SES lights. I used a half bottle of Techron in a half tank of fuel, then a full bottle and the ramainder of the first bottle in a 20 gal.+/- fill up. It has not misfired now in several days. Many thanks to Jeff O and upallnight for pointing me towards dirty/sticking/leaking injectors as my problem.

possible maf?
 

I'm having a similar issue with a misfire cylinder 1 with fuel cut.
loss of power, i unplugged my maf and power was restore but still have the check engine light and rough idle.
possible the maf or vac leak.
also with maf unplugged i dont get the misfire code. just a maf code

You should start a new thread on your problem.

Glad you finally fixed the problem and didn't fire the parts canon like so many people do on this forum.

And I'm glad you mentioned the injector cleaner. I never did that and only get rare occasional rough start with cylinder fuel cut off.


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