Driving with faulty coil pack

Topper Harley

Right, so I've a 2007 BMW 320i e92. The engine management light is on, it's idling rough sometimes and doesn't have full power. I had a mechanic take a look at it and it's due a service anyway so he says with the service, replacing the coil pack and spark plugs it should be grand.

Problem is, I've to make a trip from Dublin - Galway - Maynooth - Galway - Dublin this week. About an 800km round. I've read conflicting reports as to whether it's safe to drive the car in this condition. Some say you're filling the cylinder with petrol which is just left in it and this will cause damage while others say that the car's computer will stop fuel from being injected into the cylinder when it's not firing.

I'd rather not risk it even if it was deemed ok but I'm kind of short on alternatives. Can anyone clarify for me whether or not I'd be ok to drive it for the week.

Decent Skin

Topper Harley wrote: »

Right, so I've a 2007 BMW 320i e92. The engine management light is on, it's idling rough sometimes and doesn't have full power. I had a mechanic take a look at it and it's due a service anyway so he says with the service, replacing the coil pack and spark plugs it should be grand.

Problem is, I've to make a trip from Dublin - Galway - Maynooth - Galway - Dublin this week. About an 800km round. I've read conflicting reports as to whether it's safe to drive the car in this condition. Some say you're filling the cylinder with petrol which is just left in it and this will cause damage while others say that the car's computer will stop fuel from being injected into the cylinder when it's not firing.

I'd rather not risk it even if it was deemed ok but I'm kind of short on alternatives. Can anyone clarify for me whether or not I'd be ok to drive it for the week.

If all was in order your computer would kick you into "limp home mode", but if that kicks in early in an 800km trip it'll wreck your head, keeping revs low and making overtaking and cruising practically impossible.

porsche boy

I'd rather be cautious here. It is possible for a car to cut the feed to individual injectors if required but if it doesn't then unburned fuel will be fed down the exhaust to the catalytic converter where it ignites and damages the cat. Can he not service it before you go? Or maybe another garage...

savagethegoat

relatively cheap and easy job, why don't you just get it done?

Topper Harley

Decent Skin wrote: »

If all was in order your computer would kick you into "limp home mode", but if that kicks in early in an 800km trip it'll wreck your head, keeping revs low and making overtaking and cruising practically impossible.

It feels like it's in limp mode but the actual limp mode warning light isn't on. If it's not damaging the car, I can put up with it. The alternative is to do it on a motorbike but I've far to much gear to lug around for that.

Atlantic Dawn

Could you not just get the mechanic to fix that on its own tomorrow? Whether it does damage or not driving it at reduced speed for those journeys will be a pain

Topper Harley

porsche boy wrote: »

I'd rather be cautious here. It is possible for a car to cut the feed to individual injectors if required but if it doesn't then unburned fuel will be fed down the exhaust to the catalytic converter where it ignites and damages the cat. Can he not service it before you go? Or maybe another garage...

savagethegoat wrote: »

relatively cheap and easy job, why don't you just get it done?

I left it to be done during the week but he didn't get round to it. In fairness, I told him I could manage on my bike for two weeks but now this week I actually need the car. And I'm heading off this evening so it won't be done before I set off. The only alternative is beg/borrow/steal a car from a friend or family.

Decent Skin

Topper Harley wrote: »

It feels like it's in limp mode but the actual limp mode warning light isn't on. If it's not damaging the car, I can put up with it. The alternative is to do it on a motorbike but I've far to much gear to lug around for that.

Gut feeling would be that if something isn't quite right then get it dealt with ASAP - feeling limp but with no warning light isn't right, and it implies the computer hasn't quite caught the error.

Has an anti pollution fault shown up ? That would mean the fuel is in the cat and the car is dealing with it on the fly rather than going full-out limp, but definitely wouldn't take a long trip in that scenario.

Speaking as someone who jumped a timing belt that was due within 1500 miles and heard a minor tick and left it as "ah the service is due next month and it's not a major noise"; down €1400 as a result.

Topper Harley

Decent Skin wrote: »

Has an anti pollution fault shown up ? That would mean the fuel is in the cat and the car is dealing with it on the fly rather than going full-out limp, but definitely wouldn't take a long trip in that scenario.

No, just the engine management light. I'm making calls now to see if anyone can spare a car for the week. If it's something relatively fuel efficient I might make a saving on fuel costs and pay it forward as thanks.

Decent Skin

Topper Harley wrote: »

No, just the engine management light. I'm making calls now to see if anyone can spare a car for the week. If it's something relatively fuel efficient I might make a saving on fuel costs and pay it forward as thanks.

Don't know about your model but in the Pug the eng man light was the one that came on if the cat was under pressure; it is the "engine management" that reins in the fumes from reaching the cat.

GerryDerpy

I drove my BMW for too long with a miss fire due to faulty coil and it clogged a cat converter. The coil is a cheap and easy fix, the new cat cost me €350 to put right.

Topper Harley

Grand so. This has removed any doubt whatsoever. I won't be taking the car this week. I've got a lift to Galway and back. I'll still have to sort something for the trip to Maynooth and back to Galway but I'll cross that bridge when I come to it.

Thanks for the advice, everyone.

macnug

Topper Harley wrote:

Grand so. This has removed any doubt whatsoever. I won't be taking the car this week. I've got a lift to Galway and back. I'll still have to sort something for the trip to Maynooth and back to Galway but I'll cross that bridge when I come to it.

On a side note a grand seems very expensive for a service, coil pack and plugs.

Decent Skin

macnug wrote: »

On a side note a grand seems very expensive for a service, coil pack and plugs.

Where was that ? Definitely missed it.

pablo128

macnug wrote: »

On a side note a grand seems very expensive for a service, coil pack and plugs.

He said 'it will be grand', not 'it will be a grand'.

Topper Harley

macnug wrote: »

On a side note a grand seems very expensive for a service, coil pack and plugs.

He's gonna put speed holes in the bonnet too.

Topper Harley

pablo128 wrote: »

He said 'it will be grand', not 'it will be a grand'.

I could be wrong, but I assumed he's joking.

Mandzhalas

Just unplug coil pack, that way ecu will cut off fuel supply from that cylinder and no damage to cat will be done. Drove my 02 bmw for week on 5 cylinders with no long term issues, It just ran rough as one cylinder down