330i N53 hesitation

[SoupAnxiety]

A coil pack failed on my 330i N53 a few weeks ago, it triggered limp mode and an EML. Before this I had the usual symtoms of hesitation, gradually getting worse until failure. I bought the revised Delphi coil pack from BMW, fitted it and the EML was cleared.

I've got a slight hesitation again, affecting low and mid revs under load. Cylinder 6 failed previously, do coil packs fail in pairs? The other five coils are a Bosch part, the version BMW offered as a quality enhnacement before the final Delphi version was released. At the moment the hesitation isn't enough to register an EML or any "silent" fault codes.

Being an N53 it's destroyed its injectors previously, replaced with index 11 injectors all round and these symptoms don't match the usual cold start injector niggles. I'm using NGK spark plugs and these are 40k old.

Is it a reasonable assumption that it'll be plugs or another coil?

[Sam.]

I found mine ran like a dog on NGK plugs.

Fitted bosch plugs and it was 10x better.

It was hesitating at low and mid rpm. Felt like a constant misfire until it was up into the higher RPM

[bmwmike]

Funny I found mine ran better on NGK which when compared to the bosch are slightly shorter..!

Only coilpack I've had fail was a new one I'd installed preventatively. It failed outright with an EML and a shutdown cylinder (misfire).

I carry 3 spares in the boot and a code reader.

If I were you I'd just wait and let it fail. Carry a spare.

Also anecdotally I found that I had a random misfire I could feel (no codes no EML) during warm up when the car had been used for a lot of very short trips. Those stupid piezo injectors take a lot of power as do the coil packs. I think a flatish battery can cause misfires.

[SoupAnxiety]

Thanks for the replies. I've had the NGK plugs for 40k, and even if it is the plugs it was fine for the previous 39k so I have nothing against NGK. They are the supplier according to Real OEM.

I'll order a precuationary coil pack if the problems persist after it's had a kitchen sink service with a plug change. I left it too late last time and waited until cylinder shutdown and EML. £24 on eBay for the Delphi coil, £53 at the dealer which I had to get as I was desperate.

The battery is the original 2009 battery, and I'm not using the car as much. Fuel bill has gone from £70 a week to £70 a month...!

[bmwmike]

I got quoted 90 quid each for the coil packs by cotswolds on another forum. Had to ask if they'd quoted for injectors by mistake! Sub 30 quid is about right i think.

[Sam.]

I've had i think 7 coils so far on mine. 2 injectors.

Bosch coils from ECP for £20 a pop

[bmwmike]

These engines run very hot. I regularly see 120c on the oil temp. I imagine that's not great for coils. The injectors have internal filters which cant be changed but no inline filter between the tank and the HPFP. Daft.

[SoupAnxiety]

The new hesitation isn't enough to register a fault code. As it was cylinder 6 which failed a few weeks ago, would cylinder 5 be a logical guess? Not sure if they fail in pairs or what the firing order is.

Glad to see it's not just me suffering. If it's an injector that's kaput I'll be devastated, I've drank the Kool-Aid about index 11 being the one true fix.

[bmwmike]

SoupAnxiety said:

The new hesitation isn't enough to register a fault code. As it was cylinder 6 which failed a few weeks ago, would cylinder 5 be a logical guess? Not sure if they fail in pairs or what the firing order is.

Glad to see it's not just me suffering. If it's an injector that's kaput I'll be devastated, I've drank the Kool-Aid about index 11 being the one true fix.

Sorry to break it to you but index 11 injectors are not the one true fix. Replacing injectors everytime they fail seems to be the only true fix BMW could manage.