Why the difference in performance

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dfossil

Well-Known Member
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349
Location
Staffs
If I put my 05 Freelander 1 TD4 flat out up a local hill locked in 4th (Weston Bank near Stafford) my Hawkeye gives me circa 205kpa boost and a fuel pressure of 85000kpa at around 60mph over the top
If I put my Daughter's 02 Freelander 1 TD4 up the same hill in the same way it is noticably quicker and records 215kpa boost and 108000kpa fuel pressure.
At tickover my low fuel is 374kpa and hers is 389kpa - both pretty reasonable and not too dissimilar I think.
What could be giving the difference in performance? I don't think either has been remapped - both have cleaned inlet manifolds and cleaned EGRs (vac pipe nipped)
Her's is manual - mine is Auto and has (according to the engine barcode) had a Rover75 engine fitted at some time. Would that account for it? - different injectors maybe?
What other parameters could be significant?
 
Yours isn't running to full power. Mine (also an auto) shows boost at about 220 Kpa and a maximum rail pressure of around 135,000 Kpa.
Low pressure rail needs to be as high as possible, the higher the better .
 
Yeah - down on power - why?
- no oily air leaks - reasonable economy - no noticeable turbo lag, it shows progressive boost pressure increase all through the rev range.
Could this be pump or fuel filter related? - or is it more likely the ECUs are getting some duff info?
 
Just done that - it drops to about 310kpa if I rev the bollocks off it and go up the hill in 3rd - it gets circa 109000kpa high pressure doing that - still down on yours and still down on our other one at the lower revs
 
What other parameters could be significant?
Click to expand...
129 bhp ( rover 75 lump ) versus 150 bhp ( FL2 td4 manual ) . ??
assuming both are in stock tuning ..
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
torque @ 'x' rpm differences ..
vehicle weights
gearbox differences ..
?????
~~~~~~~~~~~~~~~~~~~
 
Actually we're talking about my F1s - which according to Rave are only 112HP and 260NM torque - All I know is it said on the service history for mine that engine and turbo were replaced "supplied by customer" and the barcode labels suggest the lump was from a Rover 75 rather than a Land Rover. - I don't know which bits would have been carried over but it looks all Freelander - I'm not familiar with the '75.
On vehicle weights etc I'm comparing two freelanders - not a F1 to a '75 - so that's not the issue I'm addressing.
 
The ECU calculates how many mg of fuel to inject 'per bang' given the throttle peddle position - which is (presumably) the only known constant - ie 100%.

If the fuel pressure is reduced by 20%, it will increase the time the injector is open for by an appropriate amount to compensate. If the injectors are different to that which the ECU expects, then maybe its not injecting the correct amount of fuel. I dunno if the injectors on the '75 (which may have come over with your engine) are different to Freelander - but I believe the manual and auto injectors are different (dunno why) which may also be an issue if the wrong ones are installed.

If the boost pressure is down, that, on the face of it, may limit the amount of fuel the ECU injects. It would on my L Series, however, on the TD4, doesn't the ECU use the MAF flow to determine how much oxygen is getting into the cylinders? Have you compared MAF readings?

Is your daughter's also an auto, do they read the same RPM at same speeds?
 
The Daughter's is manual - If I remember correctly the FL1 Auto injectors were upped a bit over manual - but I have no idea what a '75 would be - and whether it was a manual or auto '75 engine that was used - any help on identifying injectors would be great.
I did check that both FL1s registered both sensors 100% when throttle is floored according to Hawkeye.
 
Last 3 digits of injector code. Usually on label on injector body:
030 Rover 75
049 TD4 Freelander manual
130 TD4 Freelander auto.

Don't ask me what is different but probs the power band for different gear ratios and power to weight.
 
So I have the correct injectors - see piccy - 0445110 130 - thanks again for the info Andy - looks like when the engine was swopped they also swopped the injectors unless they were also used on some variant of the '75
 

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I now have an auto TD4 with a 'manual' engine and injectors. Works well. More economical than the old engine, even before the crank broke!! Maybe slightly less power than my other auto with 130 injectors but not measured it.
 
Just followed the test procedure from that youtube vid above and got the following readings for voltage from the blue/black wire on the pressure sensor.
ignition on 0.5v
Idle 1.45V
3000 rpm 2.5v
- which suggests the high pressure fuel regulator is functioning as it should and the o ring etc does not need replacing.
So back to the low pressure side.
At full chat the low pressure is getting low - 310kpa or flashing even lower (bit busy trying to stay in lane and read hawkeye at the same time)
So - as I have never changed the fuel filter and I know that prior to my ownership the poor old pig got scant attention I have ordered a pierburg pump and a bosch filter (I don't like doing things twice)
I'll report back when I have fitted them.
 
Nodge68 said:
Yours isn't running to full power. Mine (also an auto) shows boost at about 220 Kpa and a maximum rail pressure of around 135,000 Kpa.
Low pressure rail needs to be as high as possible, the higher the better .
Click to expand...

- so while waiting for my new low pressure fuel pump and filter to arrive I thought - out of curiosity - why not unplug the MAF and see how she runs on default. - Bingo - car feels much perkier and I get fuel rail pressures similar to my daughter's car up the hill in 4th. - and if I rev the nuts off I get fuel pressures etc like Nodge68
So - somewhat sheepishly I find that I have been driving happily for three years in my £300 TD4 '05 facelift HSE with a sleepy 'ole engine. In my defence it was still quicker that my previous car which was a Xantia diesel - and no DTCs have ever been recorded by Haweye. Economy was reasonable. Towing was perfectly acceptable. Starting is no problem. On the motorway although no kick in the back from 70 would easily slip up to 90+ (never tried to go any faster but it would have)
The pump & filter change is routine maintenance in my book - But now I'm tempted to get a new MAF - or try to clean the existing one.
 
So the EDC isn't seeing sufficient air mass through the MAF, which is limiting fuel delivery to keep within the smoke map.
Well done.
 
GrumpyGel said:
If the boost pressure is down, that, on the face of it, may limit the amount of fuel the ECU injects. It would on my L Series, however, on the TD4, doesn't the ECU use the MAF flow to determine how much oxygen is getting into the cylinders?
Click to expand...
That'd be a yes then :rolleyes:

Which raises the question of what the MAP sensor is there for. Maybe it is used for the ECU to control the turbo (vanes)? Maybe as a backup to the MAF and maybe uses a more conservative mapping from it if its used.
 
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