tweedandbriar
Active Member
- Posts
- 258
- Location
- Somerset
Low Rev Throttle Response, at a loss now!
- Thread starter tweedandbriar
- Start date
This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
Way above my pay grade I’m afraid. I would’ve come asking on here too. @sierrafery is a td5 guru too and very helpful so may be able to offer advice.
- Posts
- 10,371
- Location
- A bit sarf of Dorking
It's just a matter of finding out what each of the measured functions is and what it's supposed to do, then you can scroll down the columns looking for numbers that are higher or lower than they should be. I like dragging into a worksheet and graphing it because it makes it really obvious, and lets you see how one output behaves in relation to others. I'll get you last log and look at it later on Sunday and try and explain a bit more.
sierrafery
Well-Known Member
- Posts
- 17,870
- Location
- Arad/Romania
Hi, i just saw this thread as i was mentioned by @resto_d1 cos i'm active only in the D2 and Td5 sections, i didnt read the whole story but i watched your nano log and i can tell that you have to change the MAP sensor as it's IAT side is erratic, you can see that on column L starting from position 414 untill the end where from 469 it becomes 119.9 which is the value for it's complete failure(actually it should be 120 but not so relevant)...unless there is a bad contact on the IAT input cos it seems to occur only when the engine warms up but that's not uncommon so chasing a wiring issue while the sensor was not ruled out first would be feckless... buy only Bosch sensor if you dont want to spend on genuine LR which is the best don't go cheap with this one cos it's way too important. If with new MAP is not better we'll speak then cos for the symptom in title it can be other things too.
BTW for you(and others) to know for Eu2 engine if the EGR was bypassed the MAF sensor is irrelevant, for future reference see attachment
Last edited:
tweedandbriar
Active Member
- Posts
- 258
- Location
- Somerset
Thanks, I'd appreciate that!
tweedandbriar
Active Member
- Posts
- 258
- Location
- Somerset
Thanks appreciate your feedback! My EGR is banked off - so does this make the MAF entirely redundant?
sierrafery
Well-Known Member
- Posts
- 17,870
- Location
- Arad/Romania
99.9% yes, there can still be some slight involvment through the EGR management's "back door" for fuelling but i couldn't find a 100% correct theory for that, in reality on Eu2 engine a good one makes no difference if it's connected or not though one with a short to ground or to supply can mix up the management a bit so better drive it with it disconnected if it becomes suspect, as your's is new and genuine it can't hurt
- Posts
- 10,371
- Location
- A bit sarf of Dorking
I don't think you read the last log. Maf is now reaching the 400s which it didn't prior to the last work.
And this is it compared to rpm. Looks fine to me.
- Posts
- 10,371
- Location
- A bit sarf of Dorking
Unfortunately though, Track 3 is still showing nonsense.
For now I'd switch it back to 2 track with Nanocom and see how that goes. I'm still struggling to see how the potentiometer can be giving more than 5V, so the fault is probably elsewhere.
For now I'd switch it back to 2 track with Nanocom and see how that goes. I'm still struggling to see how the potentiometer can be giving more than 5V, so the fault is probably elsewhere.
sierrafery
Well-Known Member
- Posts
- 17,870
- Location
- Arad/Romania
I read the log which was in the post i quoted and saw what's the main issue... though you should neglect throttle track 3 which is completely irrelevant for Eu2 engine as it's mapped for 2 track throttle or if the TPS is the early modell it doesnt even have the 3'rd track physically, setting a Eu2 engine to 3 track is the real nonsense.
- Posts
- 10,371
- Location
- A bit sarf of Dorking
The above is the latest log.
His car was originally set up to read the third track, and if it's got it why would you not use it?
sierrafery
Well-Known Member
- Posts
- 17,870
- Location
- Arad/Romania
And in that too is clearely visible that the IAT goes to 119.9 at a time then the ECU goes to a default fuelling calculation so the MAF reading will also fail as the boost is limited by the ECU while there are moments when the IAT is OK then the power is restored... the IAT reading is the main issue in this case and untill the MAP/IAT sensor is not replaced everything else is irrelevant with the condition that the throttle setting to be 2 track as necessary... if with the new sensor the IAT reading does the same then it's a wiring issue on that particular circuit
It was set wrong unless the engine and ECU were replaced with Eu3 type... for Eu2 3'rd track is not in the fuel map
tweedandbriar
Active Member
- Posts
- 258
- Location
- Somerset
So, if I have understood correctly - if its an Eu2 (not sure how I can definitively verify this?) should I not merely reset the throttle to 2 track and disconnect the MAF altogether?
sierrafery
Well-Known Member
- Posts
- 17,870
- Location
- Arad/Romania
1. If it's an MSB ECU like from factory it's definitely Eu2, if your ECU was changed to NNN and remapped for EU2 read with nanocom in Td5 engine settings - Info the "fuel tune ID" and "Config ID"(same page with throttle settings) and report then i'll tell you but if the engine was not changed it should be Eu2 which must be set to 2 track throttle and the MAF plugged/unplugged should not make much difference if it's new and good. If you felt a noticeable difference with MAF connected means that it was coincidental with the moments when the IAT was not on default or there is a wrong Eu3 fuel map
In a nutshell, set it to 2 track, don't bother with the MAF for now and replace the MAP sensor ASAP, untill then nothing is very relevant as the IAT input is erratic and that one is vital to be OK for the engine to run well.
In a nutshell, set it to 2 track, don't bother with the MAF for now and replace the MAP sensor ASAP, untill then nothing is very relevant as the IAT input is erratic and that one is vital to be OK for the engine to run well.
- Posts
- 10,371
- Location
- A bit sarf of Dorking
Ohhh, sorry! I now that you were referring to 119.9 on the IAT, earlier I thought you were talking about the MAF!
I hadn't noticed that, but I think we're both at the conclusion that there may be a wiring problem. Whether or not the track 3 info gets used, the ECU is still thinking it's getting well over 5v from it, and the throttle pot can't do that - and is the reason I'd suspected wiring.
The recent part loom installation has made a significant difference to how it's running. Again though, the IAT and Trk3 are on different ECU plugs, points to 2 faults or one earth problem?
sierrafery
Well-Known Member
- Posts
- 17,870
- Location
- Arad/Romania
My conclusion at this point after i've seen loads of live data logs from various Td5s is that the MAP/IAT sensor is fubar, those 3'rd track readings are all false and commpletely irrelevant(they are created by the software out of nothing, it happens) cos as the vehicle is 1999 MY and the throttle pedal original it has only two tracks physically but even if it was changed to a 3 way TPS one there is not even a wire for 3'rd track in the loom and i doubt that the main under-dash harness was replaced.
If it is a wiring issue it's on the IAT circuit only, any wiring issue on the TPS circuit it would trigger the MIL(engine malfunction) warning in most cases and a specific "driver demand" fault code logged.
sierrafery
Well-Known Member
- Posts
- 17,870
- Location
- Arad/Romania
To end the discussion about the 3'rd track on Eu2 engine, i attached log's snapshot which i took long time ago from my well running vehicle which has 2 track pedal, no wire for 3'rd track and set normally to 2 track with the original MSB ECU (which was not remapped then)... you can see at the bottom of the pic those irrelevant and false 3'rd track readings... IMO it's a software glitch which i didnt bother to find a logical explanation for
Attachments
tweedandbriar
Active Member
- Posts
- 258
- Location
- Somerset
@boguing ...on that point, I noticed that the thicker gauge black wire going into the Red ECU Connector had been spliced at some point. I think it may be the earth to the ECU(?). Either way its intact - I just wonder what the PO was up to?
@sierrafery ...its an MSB ECU thats for sure. I have a Disco II thats running really well - could I try the MAP sensor off that in the Defender and see if that makes a difference? In the meantime I'll order another in.
"...any wiring issue on the TPS circuit it would trigger the MIL (engine malfunction) warning in most cases and a specific "driver demand" fault code logged...." - I was getting that error, but for some reason it never came back even before I changed the TPS loom.
sierrafery
Well-Known Member
- Posts
- 17,870
- Location
- Arad/Romania
yes, that's a good test eventually put the fender's MAP into the D2 to see what happens
tweedandbriar
Active Member
- Posts
- 258
- Location
- Somerset
<edit> I should have said I did swap the MAP sensor and also changed the pedal back to 2 track!
Longer drive this afternoon, was pleasant to drive, much less 'aggression' and just felt smoother (if a smooth TD5 Defender isn't an oxymoron!!)
Good points - drove well from cold, better when warmed up. Accelerated smoothly and went like a train when asked.
Bad points - none really, other than a couple of instances of 'Bunny Hopping' but I think that was down to me being in too high a gear and expecting too much (I am used to driving the Disco II Auto).
I can't say it was a palpable improvement from last night with the original MAP sensor on, if it was it was subtle. Finally, not sure of the Nano log shows it, but I stalled her, my fault and more to do with over estimating the turning circle and having to do a swift three point turn on a dodgy country lane!
Here's the Log: Nano 07_07_24
Longer drive this afternoon, was pleasant to drive, much less 'aggression' and just felt smoother (if a smooth TD5 Defender isn't an oxymoron!!)
Good points - drove well from cold, better when warmed up. Accelerated smoothly and went like a train when asked.
Bad points - none really, other than a couple of instances of 'Bunny Hopping' but I think that was down to me being in too high a gear and expecting too much (I am used to driving the Disco II Auto).
I can't say it was a palpable improvement from last night with the original MAP sensor on, if it was it was subtle. Finally, not sure of the Nano log shows it, but I stalled her, my fault and more to do with over estimating the turning circle and having to do a swift three point turn on a dodgy country lane!
Here's the Log: Nano 07_07_24
Last edited:
