Likely MAS/ECU issue?

[Dieselman]

More likely a parts person.

 

[Shude]

More likely a parts person.

Correct. I'm sure he could have looked it up and sold me it; would have been a random plastic thing with wires coming out of it in an OEM box for about £50

 

[BlackC55]

BTW Mr Walker has not phoned me yet ref your car????

 

[big x]

It could be the throttle body but I would of thought a fault code would have been logged.
Before doing anything I would have checked all the vacuum hoses for hairline cracks,oil blockage and strength.Under load they can collapse.
Has the operation of the kompressor been checked ? As the misfire is under partial load I wonder if it's not cutting off correctly.

adam

 

[Shude]

As the misfire is under partial load I wonder if it's not cutting off correctly.

The fault is easiest to demonstrate during acceleration from low rpms in a high gear, if that helps.

 

[milker1mbc]

Ok I'm crossing over from my own thread on the MAS problem, I had mine changed during the B service and expected to see something shiny and new under the bonnet, but there was nothing!

Was it

A. The part was internal to the air system and not the thingy attached to the airbox as first thought.

or

B. They didnt change it or just changed the internals and charged me for a new one? £240

EDIT: Its ok, spotted the new black plastic (£240) thingy

 

[Shude]

Ok I'm crossing over from my own thread on the MAS problem, I had mine changed during the B service and expected to see something shiny and new under the bonnet, but there was nothing!

Was it

A. The part was internal to the air system and not the thingy attached to the airbox as first thought.

or

B. They didnt change it or just changed the internals and charged me for a new one? £240

The MAS is attached to a pipe but it's not next to the airbox. I asked for my old one to be retained so I could examine it and as requested it was sitting in the box (from the new one) on the passenger seat when I collected my car

 

[Ian B Walker]

I have phoned Oliver and spoken to him at length with regard to the current problem. Just waiting no for Nick to turn up, he forgot last time

 

[Dieselman]

The fault is easiest to demonstrate during acceleration from low rpms in a high gear, if that helps.

That sounds like a HT voltage problem.

Fuelling should normally show most under sustained high load conditions.

 

[BlackC55]

When Ian changed the coils he did not change the rubber ends on them so I think that should be the first port of call.

 

[MBManInKen]

When Ian changed the coils he did not change the rubber ends on them

Oh dear, Ian, you should never forget to put the rubber on.

Right, I'll be on my way now .

 

[Ian B Walker]

Oh dear, Ian, you should never forget to put the rubber on.

Right, I'll be on my way now .

PMSL Its a plan I have to carry out to see if it resolves the problem, also to re solder the 4 brown wires. Also to check the wire branch behind the inlet manifold. Just wondering (probably not though) if the loom has any other sort of defect.

 

[Shude]

UPDATE:

Ian has replaced the two boots on the coil packs and it seems to have sorted it out, I have been unable to get the car to misfire like it used to.

Still need to do some thorough testing (shame!) but it's looking very good so far!

 

[fyonn]

More than 2 years of a misfiring engine, how many visits to garages, how many replacement parts, and it was an £8 part that fixed it... ?

*sigh*

glad it's sorted out now

 

[sstylos]

I hope yours problem will be solved, but mine was back after some days.
In my case I changed plugs: nothing
I changed coil packs with boots, cleaned MAS with spray, everything ok
But that lasted just for few days.
Exactly like problem disappear after service.
MAS disconection did nothing, so I don't believe its the MAF.

By the way I don't have this problem on gas-petrol but only on LPG.
So you may not see this problem again as gas-petrol may bypass this problem.

My problem is more difficult to solve it, as engineers blame LPG.

Now I saw first time an auto gearbox error in star diagnose.

I still investigate my issue.

 

[Shude]

I hope yours problem will be solved, but mine was back after some days.
In my case I changed plugs: nothing
I changed coil packs with boots, cleaned MAS with spray, everything ok
But that lasted just for few days.
Exactly like problem disappear after service.
MAS disconection did nothing, so I don't believe its the MAF.

By the way I don't have this problem on gas-petrol but only on LPG.
So you may not see this problem again as gas-petrol may bypass this problem.

My problem is more difficult to solve it, as engineers blame LPG.

Now I saw first time an auto gearbox error in star diagnose.

I still investigate my issue.

This really does sound like a fuelling problem, especially if it works fine with petrol but misfires with LPG!

Good luck with your diagnosis.

 

[amwebby]

I have been experiencing the same problem for the last six months. It was intermittent and seemed to be trigered by fast acceleration or decceleration.

Thinking it was the MAS I waited until the next service and asked the local MB dealer to investigate the faults and advise me.

They advised me it would cost £150 to analyse the faults stored on the system.

So I went to PWM, who charged me an hour's labour to diagnose the fault, which they did by taking a record of the fault codes, clearing the memory and taking the car for a test drive (1 hours labour = £55)

They discovered that one upstream 02 sensor was dead, and this was the cause of the fault.

A new sensor fitted (£109 plus 1.5 hours labour and she nows runs as smooth, fast and sweet as a nut.