Limp Mode & Engine Management Light

[Lavery]

A couple of months back I put my toe down a bit in 5th and car went in to limp mode. Turned engine off and on again and all was fine. Thought nothing of it after that as it hasn't happened since....
..Until tonight!
Exactly the same, foot down in 5th and same issue. Turned off and on, then all was fine.
About an hour later the same happened but now the EML is on.

I will borrow some diagnostics and check ASAP but the previous owner had the car decatted and I've got a sneaking suspicion that it hasn't been mapped out.

If this is the case would the car be drivable or would I notice more every day problems with the car if the lambda sensor/cat is not mapped out?

Knowledge isn't great when it comes to sensors and Engine management diagnostics so any advice and help would be much appreciated.

Cheers, Dan

 

[Steven67]

I've had the same problem as you, does the light stay constant and everything's okay but when it starts flashing that's when the problems occur?

 

[Lavery]

I've had the same problem as you, does the light stay constant and everything's okay but when it starts flashing that's when the problems occur?

Nope light only popped on last night. Never had the light on before, but it hasn't gone off this morning.

 

[dann2707]

Hey dude. There isn't a lambda sensor in our cars as they're on the petrol.

You shouldn't have to map for the decat alone.

What you're experiencing sounds like sticky veins on the turbo as when you're putting your foot down in 5th the veins should take into account of this and move to provide boost up in the top end. But if they're sticky they don't move and this results in the car over boosting as they're in the position for low revs. The car realises this and shuts off most of the power to prevent damage and that's your limp mode.

A temp fix is the Mr muscle over cleansing method that loosens up the carbon build up inside the turbo housing.

 

[Lavery]

That would make sense now you say that because I have noticed that sometimes It has a bit of a flat spot further through the range at high speed.

Would diagnostics bring it up if it's the veins?

What do I have to remove/look at to access the veins?

 

[aceman]

Agree it sounds like the turbo veins that are sticking. If you get a diagnostic done it will probably have an error referring to too much positive pressure or something like that. Mr Muscle is one solution which requires you removing the EGR pipe that goes between the turbo and EGR valve which can be a bit fiddly just depends how diy minded you are or there is another less complicated way and that is a spray that you can get to spray in your inlet after the MAF that goeas through the engine and cleans the Turbo called "Revive turbo cleaner" here is a link

http://www.spdiagnostics.com/index.php/products/workshop/revive-turbo-cleaner

www.cleanmyengine.co.uk

I know Badger Bill has tried it says it works and there are some youtube videos of it being used if you have a search. Worth a try or do the Mr Muscle job if you are upto it which does the same thing but just a bit more direct in its application.

 

[Lavery]

Thanks for the info.
When I get round to fitting my new uprated turbo pipe i will give it a go.
I have a very good mechanic so I may just have him do it if I decide otherwise

 

[Lavery]

Engine management has gone off on the commute home. Will diagnostics still show the error so I can see what's happening?

 

[Badger]

The error should still be stored.

Do you do loads of town driving?

Diesels benefit from a good thrashing to clear the carbon once in a while. Pop it in 4th, keep revs over 2100rpm (save your flywheel and clutch) and give it a good blast through the entire rev-range, ideally uphill. Do that a few times and hopefully the heat from the Exhaust Gases may shift the crap.

 

[Lavery]

My commute is just over 10 miles in mainly country roads and a bypass so I always make sure it gets a good thrashing to and from work. Plus last night it got a good thrashing in west Pennines.
I barely get any smoke either.
It was on the motorway, high in the rev-range where I had my issues.

A bit off topic here but I used shell v-maxx last night for the first time and let's say I won't be going back.
Much smoother response and cold start this morning wasn't as lumpy as it's been since the temps have dropped.
Also noticed about 5mpg average increase too.