Poor MPG

[DennisTheMenace]

Yes please Steve

 

[Blue Marlin]

Hi, all,

I have been reading this thread with interest, and have a similar problem : I did attempt to disable the EGR with the wiring alteration shown in another thread, but it did not work, and I am now nearly 10 mpg down on previous use.

I think that possibly the MAF sensor is now damaged, my question is where and which make is it best to buy as a replacement ?

Thanks, Paul

 

[DennisTheMenace]

Hi Paul

All i did was disconnected my MAF and tried it. you will get the MIL light on but it should go when you plug the MAF back in. My car with it plugged in was quite lumpy at tickover, initially i thought it may be a duff injector. But with the MAF disconnected it ran smooth

TBH with what i have read stick with OEM, the cheapo stuff on ebay will either make your car run like a dog (i think its what mine has) or wont work at all.

 

[Blue Marlin]

Hi Paul

All i did was disconnected my MAF and tried it. you will get the MIL light on but it should go when you plug the MAF back in. My car with it plugged in was quite lumpy at tickover, initially i thought it may be a duff injector. But with the MAF disconnected it ran smooth

TBH with what i have read stick with OEM, the cheapo stuff on ebay will either make your car run like a dog (i think its what mine has) or wont work at all.

Thanks D the M for the info, I assume for OEM it is Mail Dealer only ?

 

[DennisTheMenace]

If the MAF is Bosch you can get one through their service centres. i have read it may be pierburg (sp?) i suppose the only way to tell is check its markings

 

[DennisTheMenace]

Right, Steve has changed the MAF and double checked the injectors sensors etc. before the MAF was changed driving like miss daisy would see close to 40mpg.

If that hasn't improved i am going to shoot it....

 

[DennisTheMenace]

looks like shooting it is the best option. possibly the injectors are borked

 

[television]

I do not have a clue on this as to why, I would have thought that the emissions would be all wrong if it was burning it

 

[Steve@Avantgarde]

Have checked everything on this car. No fault codes generated and actual values suggest everything is in spec. Even the load state of the DPF is spot on which it wouldnt be if it was dumping lots of fuel.

My suggestion has been that someone has been in messing about with the injectors, none of the quantity corrections were coded which we discovered on the initial visit and it may have second hand injectors or possibly worn or cheap nozzles.

Previous experience of carwood rewinds attempts to overhaul injectors that camberley autofactors and GSF supply have caused me fuel economy issues in the past.

I

 

[television]

Have checked everything on this car. No fault codes generated and actual values suggest everything is in spec. Even the load state of the DPF is spot on which it wouldnt be if it was dumping lots of fuel.

My suggestion has been that someone has been in messing about with the injectors, none of the quantity corrections were coded which we discovered on the initial visit and it may have second hand injectors or possibly worn or cheap nozzles.

Previous experience of carwood rewinds attempts to overhaul injectors that camberley autofactors and GSF supply have caused me fuel economy issues in the past.

I

That is the only plausible thing left

 

[DennisTheMenace]

Right, time to put a closure on this. Removed the ECU and redone the thermal paste on the ECU, at the same time I noticed 2 misfits have been lightly grilled. So the issue with my car is a buggered ECU that has foxed everyone, I will try and get some pics up later.

Still might shoot the bastard thing though....

 

[Dogfish]

Stick with it Dennis.
From what I have read she is just testing your "commitment" to her!

When she is well again and running sweetly you will love her again.


Don't shoot her.

 

[DennisTheMenace]

this thing has certainly tested my patience Dogfish!

Anyway, Booked the car into MB Dorchester and had the ECU replaced, the wife has said it feels a lot more alive than when she drove it in. Halfway up the ****** country until sunday but cant wait to drive it and now hopefully enjoy it!

Only other things that need sorting now are drivers door glass (anti glare stuffed) and a new rear wiper motor.

After much thought it was worth giving the ecu a go as its in ****** good condition. Plus it will cheer the father in law up when i collect them from the airport in the merc rather than a Prius!

 

[Steve@Avantgarde]

As an aside the actual symptoms of this fault was cylinder 4 was intermitantly dumping diesel. Mainly from cold. You could see the quantity correction go from +5.1 to 0.00 as soon as it came off cold start. Then for no reason at all you could see the economy plummet when driving. If you connected STAR at that point you could see No 4 injector dumping fuel then it would go back to normal.

Having exhausted all the injectors, wiring and quantity control valve the only thing it could be was the ECU. I was glad when Denny here texted me the picture of the scortched ECU. It confirmed my suspicions.

 

[Roy W]

Any idea on how the ECU got into this state in the first place?
What caused the ECU damage?

 

[Steve@Avantgarde]

None at all. Never seen this or a fault like this before in my upteen years on this product. A real one off.

 

[shaggy]

so all is good with the MPG now?

 

[DennisTheMenace]

Steve, there are 2 possibilities.
1.n previous owner fitted a tuning box, or just tried to fiddle with it in some way to get more power and that caused the fried chips!

2. The thermal paste had gone rock solid, which would mean that its heat soaking abilities would have gone out of the window. There is heat damage to the board, I will try and get the pictures up later. So it could also have been a rare manufacturing fault.

Either way its now sorted, will see you at the next service!

 

[Steve@Avantgarde]

so all is good with the MPG now?

So it seems.

Out of interest Denny, whats the average MPG now?

 

[DennisTheMenace]

I haven't yet had a chance to drive it as have been working away. Will check mpg tomorrow