E90 318i cutting out - help please

Nonoperational

E90, 2009. Only have a short time. Cutting out periodically when coming from revs down to idle, for example if coming to traffic lights from speed. Seems worse when coming from high speeds and only with clutch depressed or in neutral.

To put a non technical description on it, its like the rev counter needle is too heavy and falls to 0 on occasion. Sometimes it will dip to 400 revs and pick up.

Drives perfectly otherwise. Smooth idle, revs to red line.

Would appreciate any help. Quite dangerous because it can cut out coming to turnoffs etc.

No fault codes stored.

Four Phucs Ache

I have experienced your symptoms on 2 cars over the years both petrol both of which were caused by either of the following.

You might have an air leak. Check hoses/ breather pipes for a crack or hole. When the intake pressure drops after driving the ecu can't measure the loss/ compensate and it cuts out.

Does the rev counter "hunt" as in slightly jump up and down 50 - 100 rpm?


Dirty fuel filter can cause similar issue.

Idle control valve might be filthy and cause similar again.

This may not register a fault code so its a case of starting small and basic fault finding.

Nonoperational

Four Phucs Ache wrote: »

I have experienced your symptoms on 2 cars over the years both petrol both of which were caused by either of the following.

You might have an air leak. Check hoses/ breather pipes for a crack or hole. When the intake pressure drops after driving the ecu can't measure the loss/ compensate and it cuts out.

Does the rev counter "hunt" as in slightly jump up and down 50 - 100 rpm?


Dirty fuel filter can cause similar issue.

Idle control valve might be filthy and cause similar again.

This may not register a fault code so its a case of starting small and basic fault finding.

Thanks a million.

The rev counter is stable at all times as far as I can see apart from when coming down the revs in neutral or with clutch depressed. When it should stop at 900rpm it dips to 500, then 400, then back to 900 if it doesn't cut out.

I think its prudent to go as you suggest based on what I read online too, check hoses, replace fuel filter, clean idle control valve. I'm not certain it has an idle control valve so if not maybe the valvetronic solenoid needs replacing.

Thanks again.

mickdw

Assuming it's a manual, Drive it down through the gears at all times - never be coasting. This will ensure that you don't get into lethal situation where it cuts out on a bend or something. If in gear at all times, you only have to worry about when you are coming to a stop and is certainly not dangerous at least.

Nonoperational

mickdw wrote: »

Assuming it's a manual, Drive it down through the gears at all times - never be coasting. This will ensure that you don't get into lethal situation where it cuts out on a bend or something. If in gear at all times, you only have to worry about when you are coming to a stop and is certainly not dangerous at least.

Yep thats what we do. Booked in for a look Thursday so hopefully will be able to find the issue.

Alanstrainor

It could be a fuel pump. I honestly don't think it would be a blocked fuel filter, Irish fuel is good and I would think it rare that a petrol filter actually gets blocked.

punisher5112

In my petrol car it was a cracked air hose and the throttle body was loose plus 1 bolt was missing and the rest were loose to the point of the mechanic couldn't understand how the car still drove.

Bmw123d

Nonoperational wrote: »

E90, 2009. Only have a short time. Cutting out periodically when coming from revs down to idle, for example if coming to traffic lights from speed. Seems worse when coming from high speeds and only with clutch depressed or in neutral.

To put a non technical description on it, its like the rev counter needle is too heavy and falls to 0 on occasion. Sometimes it will dip to 400 revs and pick up.

Drives perfectly otherwise. Smooth idle, revs to red line.

Would appreciate any help. Quite dangerous because it can cut out coming to turnoffs etc.

No fault codes stored.

I’ve plenty of experience on bmws as we specialize on bmws.
Your problem is either one of two things.
It’s going to be down to needing spark plugs or a faulty injector.
Those engine eats spark plugs out of it. And the injectors give trouble also these are the only area of concern for that engine. It’s a very good engine apart from the two problems stated.

Nonoperational

Thanks guys

Where do you work BMW? Anywhere in Munster?

Bmw123d

Nonoperational wrote: »

Thanks guys

Where do you work BMW? Anywhere in Munster?

I’d help ya out no problem but I’m in Leinster

Nonoperational

The fact that there is no fault codes stored would make it unlikely to be an injector?

Bmw123d

Nonoperational wrote: »

The fact that there is no fault codes stored would make it unlikely to be an injector?

Incorrect info.

These injectors go bad and cause the car to run like muck. The injectors don’t fail fully hence no fault code stored for the bad injector.
Have u ever worked on these engines
If you have you would no what I’m talking about

Nonoperational

Bmw123d wrote: »

Incorrect info.

These injectors go bad and cause the car to run like muck. The injectors don’t fail fully hence no fault code stored for the bad injector.
Have u ever worked on these engines
If you have you would no what I’m talking about

Nope. Although the car runs perfectly apart from the cutting out on occasion. Smooth out.

Nonoperational

Well the ‘BMW specialist” said there was no fault codes stored and the car was fine, don’t be coasting. Very helpful. Unsure where to go from here. Any recommendations in the Cork area?

enumbers

Before going to far into investigating I would be looking at air leaks , any decent independent will have a smoke machine which can pressurize the intake system with smoke to check for any leaks , other than that throttle body would be another likely cause if no other driving issues

Nonoperational

Yeah. Drives 100%. I’ll look into another mechanic. It’s a family member who is driving it and the ‘BMW specialist” they took the car to took €80 to read the fault codes and fobbed them off. Pretty rotten behavior tbh.

Still quite hard to fathom how they say that the car cutting out is normal behavior.