Disco 2 Slightly down on power and economy - MAF?

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MJI

MJI

Well-Known Member
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Location
Worcester
Seems to have dropped a bit, 1 or 2 mpg and say 5 to 10 bhp.

No fault codes but air pressure drops on full throttle to 97 from 100 and cannot get MAF over 620.

Normally no drop and out of range on full throttle.

Does this sound like MAF?
 
The more important reading in this case is the MAP , AAP drop up to 4 units under load is normal and 620 MAF not bad, is it Eu2 or Eu3 ?
 
No EGR

Removed air filter element for drive to work, a bit better hitting 660 on the AFM, only dropping to 99 at worst on the AAP

MAP mid 120s at low throttle, full bore mid 210 say around 215 or so
 
That MAP at 660 MAF is low, it should be at least 230, clean the sensor and if no change replace it eventually ... if still the same you might have delaminated boost hoses or slight boost leak or wastegate issues
 
Just in case.

Any MAPs to be avoided?

2 pipes are silicon

How would I test for waste gate?

Thanks
 
New air filter and cleaned MAF and now it hits 675 on MAF and goes high.

MAP still 215 or so
 
I can tell you but IMO you dont need that as long s the MAP stays at 215 or if the MAP doesnt go higher( to at least 230) with MAF unplugged... high sucction with low MAP reading means that there's a boost leak or low turbo outlet(boost) power cos the turbo spins fast hence the high air flow on sucction while the boost at the inlet is low. Clamping the MAF is not the cure in your case believe me cos even if it's not described in any document i can tell you 100% sure(based on hundreds of hours of study) that the ''MAF cut-out" syndrome is made on purpose as the fuelling to be reduced at extra high sucction for "turbocharger overspeed protection" cos if the MAF reading is accurate and it exceeds 680 as tu cut out it means that the turbo is spinning at a dangerous level alrready and it can burn out fast ... if the turbo is old better replace it's cartridge to rule out worn blades
 
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sierrafery said:
I can tell you but IMO you dont need that as long s the MAP stays at 215 or if the MAP doesnt go higher( to at least 230) with MAF unplugged... high sucction with low MAP reading means that there's a boost leak or low turbo outlet(boost) power cos the turbo spins fast hence the high air flow on sucction while the boost at the inlet is low. Clamping the MAF is not the cure in your case believe me cos even if it's not described in any document i can tell you 100% sure(based on hundreds of hours of study) that the ''MAF cut-out" syndrome is made on purpose as the fuelling to be reduced at extra high sucction for "turbocharger overspeed protection" cos if the MAF reading is accurate and it exceeds 680 as tu cut out it means that the turbo is spinning at a dangerous level alrready and it can burn out fast ... if the turbo is old better replace it's cartridge to rule out worn blades
Click to expand...


VEry interesting thanks
 
All 6 Jubilee clips took a half turn at least each, will test again later.

If no leaks what else could it be?
 
OK no leaks at ends of hoses, car will not go over 215 except once it hit 220 when MAF unplugged.

This is very odd. Running a mild remap so in the region of 170bhp, told was at limit for standard intercooler.
 
Yes you'll have to do that cos that 215 is low.... check the wastegate first, eventually clamp the pipe to the valve and drive it so to see if it goes to overboost or not and if not it's certainly a boost leak or worn turbo... my bad that i didnt take a pic of the cartridge i removed from mine before fitting the uprated billet chra to show how the blades were burned out
 
Leaving for a few days as it is hot, but asked Mike for the ranges of MAF and MAP I should be expecting if everything is OK.

I personally think I will need a better intercooler, and the hoses are suspect (Britpart but only 2 fitted, the IC to manifold one doesn't)
 
Not heard back but I can quite easily put it high 600s on MAF, NO LEAKS, boost no higher than 219.

Looks like the tune is just over the limits of the MAF.

My tune is a little revvy to suit std TC and auto box.

Can trigger anywhere between 3000rpm and 4500rpm
 
MJI said:
Not heard back but I can quite easily put it high 600s on MAF, NO LEAKS, boost no higher than 219.

Looks like the tune is just over the limits of the MAF.

My tune is a little revvy to suit std TC and auto box.

Can trigger anywhere between 3000rpm and 4500rpm
Click to expand...
Sorry but for me the above statement has no logic... IMO, you didnt listen or you can't understand ..each way you are lost m8 as long as you dont check well the inlet path for leak. :rolleyes: .... i'll not say more cos it seems it's futile while you are speaking of tunes and revs with 215 MAP reading at high sucction :confused:
 
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