TD5 EGT

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Originally Posted by sierrafery

It seems that your's is low on boost if you get only 15psi, the standard D2 Td5 is set to go up to 230 KPa MAP reading which at average 100KPa ambient presure means 1.3Bar(close to 19psi), 15psi is very close to 1Bar which is the default mode for faulty AAP sensor, the Td5 Defender is a bit lower(MAP=210, around 16psi) cos it doesnt have the wastegate modulator... mine went up to 1.22 Bar reading with nanocom then i shortened the wastegate rod and now i get 1.31 under full load with the original ECU...even with the remapped one the boost is almost the same just that it has better throttle response and more power at low revs

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Thanks for the info. I think my problem is the wastegate actuator. I had to back the boost off so the boost would not fluctuate at high revs (Factory max boost approx 18psi) The over boost limp home mod is totally different to what is happening when it plays up.

So now I need a new actuator or turbo to hopefully fix my EGR issue at the least help diagnose the issue.

That fluctuation mignt be the so called wastegate creep which occurs mainly when the modulator is not working well or missing... IMO better refit your modulator cos it will reduce that symptom and increase boost as well, or at least if you want a direct setup not through electronically controlled modulator fit an inline boost controller cos this can help too, as the more tight is the wastegate rod the worst the wastegate creep it is and with such boost controller you can let the rod more "relaxed" cos you'll reduce the pressure to the wastegate actuator valve, something like in this list: Manual Boost Controller: Turbo Chargers & Parts | eBay

Quote:

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Originally Posted by sierrafery

It seems that your's is low on boost if you get only 15psi, the standard D2 Td5 is set to go up to 230 KPa MAP reading which at average 100KPa ambient presure means 1.3Bar(close to 19psi), 15psi is very close to 1Bar which is the default mode for faulty AAP sensor, the Td5 Defender is a bit lower(MAP=210, around 16psi) cos it doesnt have the wastegate modulator... mine went up to 1.22 Bar reading with nanocom then i shortened the wastegate rod and now i get 1.31 under full load with the original ECU...even with the remapped one the boost is almost the same just that it has better throttle response and more power at low revs

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I'm not so sure about that. I was always under the impression that standard boost was 1 bar.
I just had a quick google and everything I could find indicated that that was correct.

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Originally Posted by Phat-Customs

I'm not so sure about that. I was always under the impression that standard boost was 1 bar.
I just had a quick google and everything I could find indicated that that was correct.

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No ofence but then i must say that the sites which made you think that the standard boost is 1 bar are wrong, i'll try to make a demonstration:

1. if 1 bar is standard why would it be considered limited default mode for faulty AAP sensor?

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Originally Posted by ENGINE MANAGEMENT SYSTEM - TD5 - DESCRIPTION AND OPERATION 18-1-11

In the event of an AAP sensor signal failure any of the following symptoms may be observed:
l Altitude compensation inoperative (engine will produce black smoke).
l Active boost control inoperative.
l Turbocharger boost pressure limited to 1 bar (14.5 lbf.in 2 ).
l EGR altitude compensation inoperative.

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2. My statement about 1.3 bar is confirmed by nanocom guide too when it describes the MAP reading(quoted from the attached file):

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Originally Posted by DIAGNOSTIC FUNCTIONS OF THE TD5 ENGINE

MANIFOLD TURBO PRESSURE(Kpa): at idle speed must be equal to the ambient pressure 100Kpa and it
goes up to 210 (Defender) or 230 (Discovery) at engine maximum load

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i hope we can agree that 230KPa MAP with 100 AAP = 130KPa boost => 1.3 bar;)

Quote:

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Originally Posted by sierrafery

That fluctuation mignt be the so called wastegate creep which occurs mainly when the modulator is not working well or missing... IMO better refit your modulator cos it will reduce that symptom and increase boost as well, or at least if you want a direct setup not through electronically controlled modulator fit an inline boost controller cos this can help too, as the more tight is the wastegate rod the worst the wastegate creep it is and with such boost controller you can let the rod more "relaxed" cos you'll reduce the pressure to the wastegate actuator valve, something like in this list: Manual Boost Controller: Turbo Chargers & Parts | eBay

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Originally Posted by Jazzman

Mods:
I bypassed and disconnected the boost control valve thing between the turbo and the intercooler pipe and turned the boost down because I was getting large boost fluctuations at 3K RPM. After disconnecting and bypassing the valve thing these fluctuations have gone. - Suspect faulty boost actuator.

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I understand your point but it is the reverse of my symptoms. With it removed boost fluctuations are delayed by 100 rpm. With boost adjusted low, close to 1 bar, no fluctuations.

If I reconnect the boost control valve I will not be able to rev passed 3000 rpm as the boost will fluctuate.

I thought it might be a diaphragm issue.

Interesting... yes, in this case the wastegate actuator valve should be ruled out cos it's suspect, are you sure there's no leak in the pipe from the intercooler to wastegate? though you should not neglect this http://www.aulro.com/afvb/2423934-post21.html either(only first paragraph) cos as the turbo on td5 has internal wastegate which opens on boost applied to the actuator the first symptom of a leaking valve would be overboost so just to make it clear whan you get those fluctuations are they growing peeks of boost or how?

about the actuator, if you can afford one of these Adjustable Actuator for Defender or Discovery TD5 would be an improvement...i have one and it really makes a difference

I just replaced my actuator with a low mileage spare. I left the adjustment as it was with the vehicle it came from (leaving the actuator rod longer than the old actuator) as the ECU I am using also came from that vehicle. The very surprising result is smoother running, more power, no throttle delay and much more responsive, but even more surprising is that the annoying and hard to eliminate 2,200 rpm hand brake shoe rattle and vibration has disappeared. Perhaps the actuator adjustment has a more complex relationship to drivability than simply the amount of boost. I had no idea that the actuator may have been faulty or adjustment that would appear to give less boost could make this improvement, I just changed it on a whim after reading this post.
Nick

Hi, did you change the ECM and the actuator at the same time?... cos if you did it might be a better fuel map too, though the actuator itself can make a difference, i'm sure that shortening the rod without hitting the overboost level will improve things if you want to try

The ECM was changed about nine months ago and made a significant improvement then to the smoothness of the engine and gear changes in the auto. I noticed that it had a different chip to the original ECM, the year of the vehicle was 2001 a year later and probably has better mapping. I'll try and shorten the rod a little and see what changes I get.

Thanks
Nick