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Technical 115 JTD Economy Drive

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Technical 115 JTD Economy Drive

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JamesAtthews

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Joined
Dec 8, 2010
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Location
Scarborough
Hi All

I've got a question which I know may have been asked before, however I want to ask it again as I think it might lead to a re-map which I would also welcome owners views on.

Basically, I have a 115 JTD Multipla which on a good motorway run at 65mph will happily return 42/3 on the computer, which as we all know equates to aorund 50mpg. All this seems perfectly normal, but then we hit the town, and on a week doing the school run (2.0miles) there and back twice a day, and then the associated town based running about, and we're blowing 20 litres in a week, for literally 25 miles. At this rate, the bus looks cheap!

It's recently been serviced, and the EGR and MAF have been cleaned, which haven't improved or worsened the situation. I have noticed that when my wife sets off in first, it blows a lot of black, unburnt diesel smoke out, just before changing gear. I don't know whether we both have heavy right feet, or if this is normal behaviour. My old 406 HDI which I hated and nearly killed me and drained my wallet would manage a lot higher MPG around town, and was phenomenal on a long run. Whats wrong it???

My questions are:

Does this sound normal to you all?

What can I do to improve the town based MPG, will blanking the EGR have a massive effect, and will a remap really deliver the 10% economy improvements that the manufacturers seem to claim?

Answers on a postcard, and I hope that this will give us all something to thing about/ consider seeing as though diesel appears to be accruing value faster than gold.

Cheers

James
 
Unless the EGR is sticking, you won't get a significant benefit from blanking the EGR, I've done it but only to make sure the damn thing didn't stick as cleaning it is a royal pain in the a$$.
MAF is another matter, best way of testing it that I know of is disconnecting it and see what happens to the fuel consumption.
FWIW, I get 31 (fuel computer) around town and 40-44 on a run depending how hard I'm driving (MAF disconnected - tried cleaning it but no joy).
 
I had a jtd 110 and had similar issues
On town mpg 28 on a run did 48mpg
I bought a tuning box as was cheaper than remap and made a huge difference
more power altrough was a bit brutal but mpg was over 40mpg on short journeys and managed easy 60 mpg on long journeys
i went from scarborough to london stansted airport and back with half tank and that was with 2 adults one child and 3 suitcases
Now i own a galaxy tdi but i miss the multipla but im gonna go to the remapping route next
 
Just over 4 gallons to do 25 miles is not good. Unless you are spending a LOT of time sat in traffic there is something amiss.
 
Hi

Thanks for your responses so far, I'm glad that I'm not alone in thinking that something is wrong. I will try and unplug the MAF for a week to see if it improves things any. I'll keep you all posted, but it's good to hear that the tuning box has helped somewhat. Can I ask which tuning box that you got, TurboPip, and you did well to get that far with half a tank!

Cheers

James
 
Hi

Many thanks for your comments, but now I could do with a little help. TurboPip, the CR Tech is the box I've seen, and I'm glad that you've had good results.

I unplugged the MAF and went for a 2 mile drive, no problems. I then parked up and stopped it, and when I came back to it, disaster, the MIL light came on. Now I have plugged it back in, but am not sure whether it needs to be reset by a code reader, or it will right itself when it realises that the MAF is there and fine? I have turned it off, locked it and re started it 10 times or so, but the light is still on. I don't think I've disturbed the wiring of the MAF or anything, but I don't know. Any ideas?

I think I might be ordering a code reader!

Cheers

James
 
FWIW I have a 115 jtd and unplugging the maf does not cause a light to come on.
I did notice it guzzled diesel with it disconnected in comparison to having it connected.

A vag com cable from eBay (tenner) and fiatecuscan free will read and clear codes.
Marty.
 
Disconnecting the MAF should throw up an engine management light and an error (P110?).
My 115 definitely does as I'm currently running with MAF disconnected until I can find a Bosch at the right price.

James, you need to take it for a couple of runs with MAF connected and the error should go, if it doesn't you can clear the errors by disconnecting the battery overnight, make SURE you have the radio code before doing this.
 
Last edited:
Hi

Many thanks for your replies. I have run the car with the MAF back in and the MIL is still on. I have ordered an ELM code reader, and have downloaded the Fiat software so will be able to play.

I think there was a change at some point in the production of the 115 version, as there are 2 MAF's listed, one at £90 and one at £190, and guess which one mine is!!! Momoe, I found a Bosch version of the expensive one on a website for £93 + shipping of £5, which is the same price as the cheaper one. I will post the link tonight for you if this is of any help to you. From the guys on here, it's been made clear not to buy the cheap non Bosch junk, so I will be ordering one shortly for this company.

Marty, on a second note, I have read with my scanner that I can look at real values from the MAF, so I wonder if I could possibly compare the values with you, just to confirm if I'm looking in the right area to begin with.

Cheers

James
 
JamesAtthews said:
20 litres in a week, for literally 25 miles. At this rate, the bus looks cheap!
Click to expand...
Well town driving will cause your economy to drop like a stone. But that's 5MPG by my math. There are Italian supercars that will do better! I really can't see it burning that much fuel.....

However, my 2 penneth... If you are doing 2mile short runs in a diesel, it's really not good for it. Do you know if the 115 JTD's are fitted with Diesel Particulate Filters? (DPF). These systems use a diesel flush mechanism. Mazda's in particular had BIG problems with DPF as the fuel goes into the engine and mixes with the oil - thinning it and blowing the engine. They say you need long runs for the DPF to complete it's flush cycle. Have you done an oil change recently? These should also be increased if you are doing short runs. May be something to look at if the 115 does have a dpf (I've got a old school 105).
 
I realise that you may have something engine related going on, but something else for you to consider when it's due for a service........my local mechanic has been using the Forte engine flush treatment for the last 4 or 5 services, it's an oil treatment used to flush the old oil out (you will see I'm no mechanic) and is very good for preventing smoking and other emissions problems. From memory it's only about an extra tenner and my multipla, which has 134K on it, still does an average of 45-50 to the gallon with a mixture of town and motorway miles.

Hope that helps
 
Hi All

Many thanks for all of your posts, and to answer a number of questions with one post, please see as follows:

1) Replacement MAF:The website selling the expensive Bosch MAF at the price of the cheaper one is http://www.maf-shop.com/product_inf....html&XTCsid=1ae64776c66b0187465c9bce9fb07d64

i think I will order one of these if the MAF is goosed.

2) DPF: Luckily as mine is the last of the original (and best) Multipla's, it luckily didn't get fitted with a DPF and all of the grief and expense that goes with them.

3) Engine flush: As mine is a high mileage car, and all my 13 other cars have been, I have always used the engine flush as a mechanic friend recommended it. I was initially sceptical, but when I saw the clots of sludge coming out with the oil, I have used them religiously since, but even so thanks for thinking of that.

I'll keep you updated when I get my code reader and will post the MAF sensor results if anyone is interested to compare. It will also help me to see if my problems lie within this area of the system or not.

Cheers

James
 
Is this 2 miles each way, or there and back? Either way, the engine is not going to get warm before stopping again. The worst reading we got out of ours was and indicated ~4 MPG, and that was whilst doing a paper round (very stop start).

2 miles really isnt long enough run time for a DERV (as mentioned), you'd be better off taking it for an hours blast (70 miles an hour or faster) down the local dual carriageway, taking it to 4K RPM whilst joining. Look in the mirror as you do it, and i'd wager you'll see a huge amount of smoke pour out the back.
 
Hi

When we do blast it, there is a huge trail of black smoke, and soot on the road, so I know it gets a good clear out and chance to run fully, it's just the town driving that it seems pitiful on, but I think this might just be normal for this car, as it shares the aerodynamics of a brick and is quite heavy.

Many thanks for your help.

Cheers
 
James, it's not normal! Yours is probably the worst mileage for any JTD Multipla that's been posted on here - aerodynamics might be significant at speed but not in town and for it's size the Multipla isn't overly heavy, about the same as a Picasso or a Mondeo.
Suggest you fill it up, make a note of the mileage and when you next fill it up again, work out exactly what your consumption figures are, if it's as bad as you say then the correct fix will save you ££££'s.
 
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