Does this diagnosis sound right?

[YoshiBolo]

Bought a 2008 E93 back in September with 67k miles and drove about 1500 miles until November with absolutely no problem except for low oil which I added a quart of 10W60 from the dealer. About a week after that I get a lowered engine power message and the engine limits my RPM to about 4k. I immediately flatbed tow it to the shop I had planned on getting my rod bearings done as preventative maintenance.

Shop ran the codes and it was misfiring on all cylinders. The car would still start since the tow man drove it up the flat bed and also back down to the shop. But at the shop the engine would start and then stall out. They recommended to change all the spark plugs and ignition coils.

After these were changes, they told me that cylinder 4 was still misfiring. That it was either the injector or something wrong with that cylinder since there was fuel in the cylinder. Potentially a bored cylinder?!?! I waited about 5 days for the fuel to evaporate naturally and then they ran a compression test which thankfully came back normal!

Now they are going to change the injector for that cylinder but told me that I'm not out of the woods and that there could be a bent rod if the cylinder still misfires.

Am I missing anything here? They don't have the rod bearing in stock yet but I'm planning to get it done asap since I've only put about 1500 miles on the car and already am running into these issues.

Hoping once they replace the injector, the car will run normally. *fingers crossed*

Is there anything else that could have caused this or is it just an injector/sparkplug/coil issue?

[Pig Farmer]

Did you add a full liter of 10w60 when you got the low oil warning? For me, adding 400ml tops off the oil level indicator. Just wondering if you may have over filled the engine.

[YoshiBolo]

Originally Posted by Pig Farmer

Did you add a full liter of 10w60 when you got the low oil warning? For me, adding 400ml tops off the oil level indicator. Just wondering if you may have over filled the engine.

I added 3/4 of a quart and the oil indicator gauge went from 1/4 (low) to about 3/4ths full. So I don't think I over filled.

[deansbimmer]

It also shouldn't take a week after filling it with oil to start having problems if it got overfilled....Oil should be unrelated here.

Shop is on the right track. These engines have suffered failed injectors before. If they stick open then you can hydrolock and bend rods/score the bores and ruin the block. They can actuate inconsistently and cause misfires. Or get stuck and not inject at all.

If the replacement injector doesn't do anything and compression checks out then I'd check the fuel pressure through software.

[YoshiBolo]

Originally Posted by deansbimmer

It also shouldn't take a week after filling it with oil to start having problems if it got overfilled....Oil should be unrelated here.

Shop is on the right track. These engines have suffered failed injectors before. If they stick open then you can hydrolock and bend rods/score the bores and ruin the block. They can actuate inconsistently and cause misfires. Or get stuck and not inject at all.

If the replacement injector doesn't do anything and compression checks out then I'd check the fuel pressure through software.

Thanks Dean. I’ll have them check the fuel pressure if there’s still issues after they replaced injector. I’ll keep y’ll updated once I hear back from the shop. Was prepared for maintenance costs when I bought the car but didn’t think I’d need for major engine work after 1500 miles.

[doogee]

The only thing you're missing is a competent mechanic, if I'm reading this story correctly.

I hope he didn't charge you for the coils/plugs. Find a mechanic that can actually diagnose a problem instead of throwing parts at your car.

Get your car out of there.

[R3dliner]

+1 on the competent mechanic. I've ran into mechanics who thought they were the shit until I asked them do you look for scope patterns when diagnosing. He was like scope what?

[YoshiBolo]

They are saying it’s a bent rod. I’m sending it to another mechanic to get a second opinion. Thanks for the advice guys. Unfortunately I’m paying for the plugs, coils, and injector.

I think you guys are right and this shop doesn’t know what they are doing. The only reason I went to them was because they had really good reviews on yelp and were charging a good deal for rod bearing service and was the cheapest in my area.

This new shop has a guy that was at bmw for 20 years so hopefully he can help.

[carenthuziast]

Originally Posted by Pig Farmer

Did you add a full liter of 10w60 when you got the low oil warning? For me, adding 400ml tops off the oil level indicator. Just wondering if you may have over filled the engine.

When is the best time to get an accurate reading of oil level? I checked it right after a 30 min drive and was surprised to see slightly below max.

[R3dliner]

How can they claim its a bent rod without looking inside engine lol.
Do you have a exhaust? If so loose clamps can also throw misfire codes.

[YoshiBolo]

Completely stock. They are saying the faulty injector could have caused the bent rod.

[SEMOM3]

Originally Posted by YoshiBolo

Completely stock. They are saying the faulty injector could have caused the bent rod.

So the compression test came back perfect, but they believe there is a bent rod?

[yidgyi]

My cylinder 5 misfired. Did the coil/spark plug switcharoo to no avail. Faulty injector on its way out. Compression / leakdown test came back 9.3 bar out of 10. Never bent a rod. My friends also had faulty injectors. Clearly the shop you took your car doesn't know what they're doing. Take it to a local reputable shop. Malek could help you out. Hes the only one I know in Cali who does superb work due to what I've read on these forums.

[YoshiBolo]

Where’s Malek’s shop?

[Bruuuce]

for a shop, I would also recommend Lang Racing. They are in Lake Forrest, I had work done there last year.

Also, a leak down test is a better indication than just a compression test.

[MMMM3]

how does a injector problem cause a bent rod? Please explain...

[yidgyi]

Originally Posted by YoshiBolo

Where’s Malek’s shop?

MRF Engineering in Lake Forest, California.

[deansbimmer]

Originally Posted by MMMM3

how does a injector problem cause a bent rod? Please explain...

Sticks open. Too much fuel = hydrolock = bent rod.

[YoshiBolo]

Ok. So second opinion said the only reason cylinder 4 passed the compression test was due to it being full of oil. They did a leak down test and thought it was pretty normal but is having problem telling where the oil is coming from. They used a cam to go into the cylinder and said it didn't look like there are any scratches but is not 100% ruling that out.

They are asking if I want to move forward with the diagnosis of pulling the engine out to find out the problem which will be at least $2200 in labor. They said best case is probably a gasket or something to cost around $3500, worst case is a scratched valve and needing a new motor which I would then have to buy new or look for a used motor.

What do you guys think?

[Bruuuce]

I had Lang diagnose and replace a broken valve spring for less than the diagnostics you mentioned. They didn't need to pull the engine, YMMV. I was expecting the worse, but they figured it out without pulling the engine. Cyl 3 as opposed to 4, for reference.

They did figure out the valve spring was broken before they decided on the next step.

[LVI]

Did you go to one of the shops recommended in this thread? If not, why not?

The cylinder is full of oil? Did you hear any noises or notice any smoke before this? Did your car burn oil? Could be a cracked ring, bad valve stem seal or a whole bunch of other reasons but i would think this wouldnt happen suddenly. Has the new shop checked the compression again? What were the leakdown numbers from their leakdown test?

[LVI]

One more thing ... I assume the oil is not coming from a leaky spark plug tube seal or valve cover gasket leak, correct?