Thread: How to completely get rid of MAF on de-EGR'd TD5

Originally Posted by Dougal

Evidence:

Exhibit 1.
TD5's without EGR still have a MAF.
Exhibit 2.
A bad MAF causes all sorts of running issues not related to EGR.
Exhibit 3.
The injector signals in your test were running against one of the (many) other limiters in the ECU and therefore changes in the MAF signal will not affect them in that part of the operation.

consider me as the other side's advocate not that i'm contradicting you

about exhibit 1:
somewhere sooner the economical reason was mentioned... i have to make some calculations to see what's more expensive to modify internally a ECM as to accept a completely MAF-less engine or to leave the MAF alone... i've never said that the MAF doesnt affect management when it's faulty cos i'm aware that then it disturbs the management, my theory was based on the presumption that it's MAINLY for EGR(cos i relied on RAVE and my oscilloscopical test)

about exhibit 2:
again i agree that a bad MAF disturbs the management(bad for me and AFAIK for the ECM too meaning open/short circuit or completely wrong signal).... but what i did it was to emulate somehow the MAF's behaviour as to leave the management without fault codes(didnt throw any air flow fault codes on mine with the mod) ... this mod didnt cause running issues, not on mine nor on others who did it... from memory there were two defenders and 3 manual EU2 D2s
(based on our debate here i've already tried to modify the title of my thread to mention "suitable for manual EU2 modells" but i couldnt)

about 3:
i dont understand what you mean, i'll try to explain in a nutshell what i did and tell me what's wrong: i used a proffesional multiport signal generator and gave feed and inputs on all the ECM's pins as in the description from RAVE(as much as we blame it i have'nt got a different source, except nanocom guide which on the pin disposal/requirement chart is the same), based again on official data from RAVE/nanocom files i set the voltages of the MAP. IAT, ECT, FT, CKP, AAP sensors as to simulate a running engine at normal operating temperature..then i started to play with the TPS and MAF inputs first independently and after that bridged together

i regret now that i didnt take the whole thing on film but i didnt even dream that i'll have such debate on this but those who saw that can confirm that the output signal to injectors has a strange waveform, it's like a mixage between a rectangular(at the bottom) and a sine wave(at the top) graphic which modifies it's values on the ms scale more and on the voltage scale less when some RELEVANT inputs are modified too(that's not very relevant though) ... what's relevant is that the less variations on that output i saw when i was playing with the MAF signal and much more when i touched the MAP input...also as it was expected it died when i messed with the CKP signal or flattened when i exagerated with the ECT input... but as i expected the EGR modulator output was very sensitive to MAF inputs which confirmed for me what RAVE said... it's a long story cos i've played many hours untill i've got bored... my bad that i didnt make a log but that's a hobby for me and i dont want to write a book about that

so knowing these what do you mean by "running against many other limiters in the ECU" please....cos this is the only point where we can get to a final conclusion(which i'm up to accept when i'm convinced) and it's the only relevant one as the other two are too relative statements...i can accept any explanation just be aware that i have a proffessional malformation and i see everything from an electronic point of view

I tried this mod today....

On a 2001 Td5 Auto. 210k.Triumph Rover Spares Chipped ECU. MAF is definatley in need of replacement.

Owner three years..

I ran the truck up to temp around town and drove a further 50kms up and down the highway. ( we do mostly highway kms )

I am "quietly confident" that it is doing what SIERRAFERY said it would.

I feel it has a much more LINEAR or SMOOTHER acceleration. Especially at 100 plus kms.

The vehicle does not feel so HEAVY this may sounds strange .

There was no extreme differences in gear change either. Although I did feel it HELD the gear for longer while accelerating on the merge lanes. Like it does in sport mode.

Yesterday ( The day before the MOD )I traveled over 300kms in it with the family so I am confident that I can FEEL the difference.

As for EGT's this is a concern to me and I have not decided how I will monitor these.

I have a digital temp gauge a "homemade watchdog" and I can say that there is no noticeable difference in engine temp from yesterday.

I have decided to cut the "MOD BRIDGE" tomorrow and install connectors so that I can easily disconnect it.

That's all for now..

Cheers......

EDIT............I forgot to mention the EGR has been removed......

much obilged that you've tried it too ... strange thing that for some it works and for others it doesnt ...so let's keep the debate alive and try to understand together what's going on and what makes the difference then maybe we'll get to a well argumented conclusion ...to start from somewhere could you tell me the ECM part number from your car? eventually what other mods

@DiscoDB it would be nice to know that about your's too(I mean at least ECM part number but perfect would be to know the transmission ECU part number too)

just got a feedback from a member on other forum who has an auto and it doesnt work well for him neither ... but he has a boost box which can mix up things


anyway what we all can agree i hope it's that it cant damage anyting on a short run

Originally Posted by NWTASD2

I feel it has a much more LINEAR or SMOOTHER acceleration. Especially at 100 plus kms.

The vehicle does not feel so HEAVY this may sounds strange .

As you noted in your opening statement that your MAF may be faulty. To confirm this when you remove the mod, do a comparison run with the MAF connected and without. If you can not detect a difference, or it runs better with it disconnected the this confirms the MAF is faulty.

If you have a faulty MAF then it defaults to a compromised value which it would appear to mean it could be under fuelling at higher revs. So with the MAF Mod now simulating a closer approximation to the expected mass air flow you are now getting better fuelling at high revs.

The other reason the vehicle does not feel so heavy would suggest that at lower revs the ECU thinks it is getting more air and this (combined with the other inputs) is saying it is OK to give more fuel for less throttle position.

And this is another data point which supports that the MAF is in fact part of the calculations that go on inside the ECU to determine fuelling rates (regardless on whether it is the primary input or a secondary input).

Continues to also support that this mod (should that be the Sierrafery MAF Mod) can give a better approximation of the mass air flow compared to if you have a faulty MAF. Could even give an improvement if it is close but slightly overstating air flow by allowing more fuel to be added.

Mr. Sierrafery - I have not tried the mod as I would appear to have a correctly working MAF, and for fear of having my reputation shot down by the purist (heh heh) I already have mods to give me an estimated 380+ Nm of torque without needing to trial the MAF mod. I am tempted to trial to see if it is a quick fix for a faulty MAF but have a few other tasks I need to sort first.

sorry DiscoDB, i was thinking to dswatts who did it and i named you instead

this whole thing has began as an alternative to a faulty MAF though, tried to figure out something on a friend's request cos his car "eated" MAFs at breakfast... 2 or 3 per year(Td5 defender) that's how it all started ... i didnt mention that in my first post and it appears like it's a tuning mod... no, it wasnt my intention that but it came out so i see now... my bad (unfortunately i cant edit my first post cos i would have made some corrections untill now)

In regards to running both a MAF and MAP sensor. The MAF will detect the air mass flowing into the engine, but unless the ECU has the allowance it won't compensate/calculate around a boosted system. This is where the MAP sensor comes in, Manifold Absolute Pressure, allows for variance in ambient pressure by temp and altitude plus the extra air mass from the turbo (the primary purpose).

Noted earlier was a reference to MAFless tunes available. Many (most) of these replace the MAF with a MAP sensor which does the same job but is more sensitive and outputs a better resolution signal.

Many aftermarket ECU's have a MAP sensor built into their case surface mounted to the board as it only requires a small hose run into the ECU to do the same job as a MAF and not insubstantial wiring harness.

So I'm thinking that the MAF and MAP signals interact in the calculations as both mass and manifold pressure will give total volume which is variable by boost pressure to allow fuelling compensation by boost pressure.

MAF interaction with EGR would come into play when recirculating is taking place as the ECU would need to know when it is occurring as it would need to allow for air mass (clean) and air mass (recirculated). But this would also depend on where the EGR is plumbed back into the inlet tract. If before the MAF then it's part of the calculated air mass (and potentially part of the issue of "eating" MAF's as the dirty air could (would) be contaminating the sensor. If it's plumbed back in after the MAF then the ECU would need to know when it's operating and use a base figure for the recirc mass added to the primary mass with its adjustment for boost.

Originally Posted by sierrafery

consider me as the other side's advocate not that i'm contradicting you

about exhibit 1:
somewhere sooner the economical reason was mentioned... i have to make some calculations to see what's more expensive to modify internally a ECM as to accept a completely MAF-less engine or to leave the MAF alone... i've never said that the MAF doesnt affect management when it's faulty cos i'm aware that then it disturbs the management, my theory was based on the presumption that it's MAINLY for EGR(cos i relied on RAVE and my oscilloscopical test)

Cheaper for about 2 hours coding or cheaper to supply a MAF to thousands of vehicles?
There's no contest there.

Originally Posted by sierrafery

about exhibit 2:
again i agree that a bad MAF disturbs the management(bad for me and AFAIK for the ECM too meaning open/short circuit or completely wrong signal).... but what i did it was to emulate somehow the MAF's behaviour as to leave the management without fault codes(didnt throw any air flow fault codes on mine with the mod) ... this mod didnt cause running issues, not on mine nor on others who did it... from memory there were two defenders and 3 manual EU2 D2s
(based on our debate here i've already tried to modify the title of my thread to mention "suitable for manual EU2 modells" but i couldnt)

We have a member with a bad TD5 MAF in this very thread.

Originally Posted by sierrafery

so knowing these what do you mean by "running against many other limiters in the ECU" please....cos this is the only point where we can get to a final conclusion(which i'm up to accept when i'm convinced) and it's the only relevant one as the other two are too relative statements...i can accept any explanation just be aware that i have a proffessional malformation and i see everything from an electronic point of view

This is simple engine control operation. You seriously need to learn this stuff before you start hacking away with ECU inputs.
Download the free version of WinOls, download some binary files and start learning.

The ECU contains a huge array of limiter tables which place a hard limit on fuel at each rpm under different conditions.
The easiest to understand are torque limiters (for anti-stall, rpm limiter and also to protect the driveline) and smoke limiters.

You need to understand these limiters and how they work with each input before you can claim any sort of improvement with modified signal behaviour.

Originally Posted by clubagreenie

In regards to running both a MAF and MAP sensor. The MAF will detect the air mass flowing into the engine, but unless the ECU has the allowance it won't compensate/calculate around a boosted system. This is where the MAP sensor comes in, Manifold Absolute Pressure, allows for variance in ambient pressure by temp and altitude plus the extra air mass from the turbo (the primary purpose).

The MAF sensor will measure the higher air-flow from a turbo producing boost. But it won't be able to tell you how much boost you've got. One of my cars (Nissan YD22) is exactly this. Turbocharged EFI diesel with a MAF but no MAP sensor.
They installed MAP sensors with the upgrade to commonrail to meet EU3.

The only engine I've personally come across with MAP but no MAF is the Nissan YD25 of the same era fitted to 2wd Navaras in AU and NZ. I have no idea why they did this, it was sold at the same time as the YD22 above which have a MAF but not MAP. The engines are only different in bore/stroke and turbocharger model.

There may be others (haven't check early toyota EFI diesels). But those are the ones I have experience with.

Originally Posted by clubagreenie

So I'm thinking that the MAF and MAP signals interact in the calculations as both mass and manifold pressure will give total volume which is variable by boost pressure to allow fuelling compensation by boost pressure.

MAP can tell you what the density (with temp measurement) and boost is. But it can only estimate the flow-rate based off engine VE and RPM (big margin of error).
MAF can tell you what the mass flowrate is. But it can only estimate the density and boost (with downstream temp measurement) based off engine VE and RPM (same problem as above).

To meet EU3 and beyond it appears you needed both. You are correct with EGR comparing expected flow-rate to actual.