306 hdi only 37 mpg?

[scfc_151]

I have a 2001 2.0 hdi with 213,000 miles

The mpg is only 37 average. This is services every 6000 miles so the air and fuel filter is clean. It doesnt feel down on power and runs well.

Is there any reason it could be so low? Im not heavy footed, the brakes arent binding and tyre pressures fine.

Would a plannet peugeot diagnostic tell me anything if I could find one anywhere near Stoke on Trent?

Many thanks

[Jonny81191]

That is a bit low, are you doing lots of short journeys?

[scfc_151]

Yeah they are short journeys to be honest but I used to get around 45mpg with town driving

I was wondering about a diesel leak off test for the injectors

[Jonny81191]

So you've had the car a while and it's suddenly dropped?

Is this over a couple of tanks?

Yeah a leak off test certainly wouldn't hurt.

[Poodle]

Does she rev easily under load? When does she come on boost?

[scfc_151]

I wouldnt say suddenly dropped this is over a while but when I speak to the mechanic all I get is "well it is winter they do use more".
I understand that but even people hammering them get above 40mpg!

Its revs easily enough turbo comes in about 2700?

[Toms306]

The EGR is probably stuck open if it's not already blanked.

Tbh to get mpg that bad it's gotta be a mixture of things.

[Dum-Dum]

37mpg is impressively low lol. On your short journeys when does the car warm up by?

[scfc_151]

With regards to the egr i did try to blank it off but could barely get my hand to it. I did disconnect the solenoid and blank tge vac pipes for a while but made no difference.

The main use is to and from work at the min which is only about 3.5 miles each way so it barely gets warm. I was considering swapping to a small petrol but a new baby boy means I wanted to keep a bigger car and obviously money constraints mean I need to keep it on the road for a while

[Jonny81191]

Turbo comes in at 2700rpm? On a stock hdi? I'd be looking for a boost leak. Like a really big boost leak

[Poodle]

Yeah, boost leak could be the problem, or the maf. I was actually thinking it might be a blocked cat at that kind of mileage.

[scfc_151]

The cat was replaced about 18 months ago and a genuine maf sensor about 2 years ago.

Sorry with regards to the turbo I was getting my wires crossed. I was thinking about when somebody was talking about injector tick some time ago. It kicks in at about 2300.

How would I check for a boost leak and where should I look? Ive looked at the turbo before its difficult to access really and I couldnt see any splits in pipework.

Just one point I dont know if is related to anything atall. When the temperature drops below 6 degrees outside when. I apply the brake the revs drop to the point where it feels its going to stall but never does and revs come back when I take my foot of the brake. When the car warms up it seems to to away. I know this might have nothing to do with it but ive posted this on other forums and still dont have an answer.

Cheers

[rd070707]

I have the exact same issue with the revs dropping when I brake, but again only when cold

[scfc_151]

I have the exact same issue with the revs dropping when I brake, but again only when cold

Really? Well please let me know if you solve it. Ive had mechanics look for leaks etc but no one can explain it

[Midnightclub]

Out of interest, what's your 'normal' running temp?

[scfc_151]

Out of interest, what's your 'normal' running temp?

Normal running temp is just over 80 degrees

[Toms306]

I have the exact same issue with the revs dropping when I brake, but again only when cold

My estate used to do this.

I just assumed it's because the vac pump puts a bit of load on the engine and obviously engines are less efficient/harder to keep idling when cold. That said, the ECU should be able to deal with it...

[rd070707]

Yeah it isnt normal, my last hdi didnt do it, it's so annoying trying not to brake hard in the morning lol. Would love to solve it too

[Dum-Dum]

I'd be looking at swapping the glow plugs in the coolant heater to get it to warm up quicker (as well as checking for boost leaks and properly blanking the EGR).

[L.J]

might be worth changing the thermostat?
could be running slightly colder than it should be

[Dum-Dum]

Nah 80*C is absolutely normal for these cars.

[scfc_151]

I did replace the coolant and thermostat while I was at it to look after it for the winter

[C.A.R.]

When my MAF was left unplugged my MPG dropped to the low 40s. Not quite as low as you're experiencing but it could be a problem?

This, combined with lower ambient temperatures (diesels can lose 10-15% efficiency in the cold winter months in my experienced) might help towards resolving your problem?

[scfc_151]

When my MAF was left unplugged my MPG dropped to the low 40s. Not quite as low as you're experiencing but it could be a problem?

This, combined with lower ambient temperatures (diesels can lose 10-15% efficiency in the cold winter months in my experienced) might help towards resolving your problem?

The maf was replaced with a genuine one about 2 years ago and gets cleaned every service. I did check the electric connection just incase

[Poodle]

How have you been cleaning the maf? They're relatively fragile, could have been damaged...

Also, 2300 is fairly late for the blower to come on song, another factor pointing to possible maf issues.

[scfc_151]

How have you been cleaning the maf? They're relatively fragile, could have been damaged...

Also, 2300 is fairly late for the blower to come on song, another factor pointing to possible maf issues.

Just sprayed with electrical contact cleaner and left so it should be ok

[DeeTurbo]

Some contact cleaners leave a film of lubrication behind that could throw the values it reads. You really should use something that evaporates of leaving nothing behind, eg brake cleaner.

[Poodle]

How long have you had the car? I wonder if it could be the lower temperatures causing higher consumption, my mpg has dropped by 3-4 over the summer-time figures.

[scfc_151]

Yeah it isnt normal, my last hdi didnt do it, it's so annoying trying not to brake hard in the morning lol. Would love to solve it too

Hi sorry to drag up an old thread just wondered if you solved the problem


Thanks