D2 TD5 surging full acceleration issue

[John_D4]

15P engine, 2000 D2 TD5, D2a intercooler, TRS remap, EGR delete

I’ve recently replaced the exhaust manifold and had to remove the turbo because of 2 broken studs. I had a friend who’s a toolmaker remove the turbo studs.

Since reinstalling I’ve noticed that it’s surging on full acceleration. Initially I thought that I’d run out of fuel as the gauge is out by a 1/4 tank every so often.

According to the Nanocom the turbo max boosts at 1.36/1.38bar (I haven’t played with the waste gate rod) which is 19.7-20.0psi this is the reading where the car jumps or surges like its running out of fuel.

Fault code in transmission section:
140692

Faulty waste gate? Hoping it’s not the TPS as they’re $800. I’ve ever had this issue until after I reassembled the manifold & turbo. I did put the thin rubber hose with the clip back on and I’ve checked the intercooler clamps. No other fault codes. There weren’t any wires attached to the turbo fro what I remember, but I’d need to check that for certain.

[Lemo]

Hi John,

Was the old manifold leaking a lot? Could be getting more exhaust gases to the turbo now making it over boost?
Sounds like it's fuel cutting due to over boost? But you should get an over boost fault on the Nanocom if this happens?

A few things to check

Waste gate modulator and the three hoses all connected to the correct locations and no holes?
Sticky waste gate or actuator? How many thread are between the nut and smooth part of the rod? I think factory is 11, maybe 13????

MAP and MAF sensor, remove and give a good clean with MAF cleaner.

Can you do an input fuelling log with the Nanocom and post up the file?

Cheers Lemo

[John_D4]

Hi John,

Was the old manifold leaking a lot? Could be getting more exhaust gases to the turbo now making it over boost?
Sounds like it's fuel cutting due to over boost? But you should get an over boost fault on the Nanocom if this happens?

A few things to check

Waste gate modulator and the three hoses all connected to the correct locations and no holes?
Sticky waste gate or actuator? How many thread are between the nut and smooth part of the rod? I think factory is 11, maybe 13????

MAP and MAF sensor, remove and give a good clean with MAF cleaner.

Can you do an input fuelling log with the Nanocom and post up the file?

Cheers Lemo

Thanks Leno. I’m working the next 3 days, so I’ll get a chance to do that Thursday morning all going to plan.

Couple of questions:

A) where can I get MAF cleaner? I use carby cleaner followed by compressed air to do the ECU. Same stuff?
B) how do I do an input fueling log?

[twr7cx]

I'm not sure about your fault code on the transmission. Might or might not be related given a different area. If you clear it does it reappear? If so, immediately? After driving for a while? After heavy acceleration only? etc.

MAF cleaner is available from auto parts stores such as Repco. It's not cheap - more than normal electrical cleaners/degreasers, etc. but for the cost of the MAF better to be safe than sorry although I suspect it might just be a rebranded electrical cleaner.

Being a 15p Euro 3 model and with your boost pressure so mucher higher than factory I would be suggesting that your running beyond the MAFs capabilities. I had this issue years ago on my D2a shortly after purchasing and bringing to Tasmania with the stock turbo at only around 18psi as adjusted by the previous owner. Some technical information is available at The Mysterious MAF Patch | DiscoTD5.com (http://www.discotd5.com/td5-tuning/mysterious-maf-patch) I think.

You can try to identify this by driving with your Nanocom Evolution connected on Discovery 2 / TD5 / Input Fuelings and then I think it's page 3 that gives you the MAF readings in "g/hr" at the bottom. If, at WOT or heavy acceleration, you see this figure going beyond 650 then your pushing the limits of the standard MAF sensor and ECU calibration. If its going from these high numbers to 0 then it's definitely gone beyond its ability to read.
To do Input Fueling log in CSV file format, hit the blue floppy disc button, choose save location on the SD Card and file name, drive while it records, when done, and before you turn off the engine (depending on your Nanocoms setup), click the blue floppy disc button again to save it and write to the SD Card.

Another method to test or confirm is to just unplug the MAF sensor and test drive. On the 15p/Euro3 motors though the MAF sensors readings do seem to also effect other systems such as automatic transmission so there may be some other abnormalities with it disconnected.

The easiest solution is to wind down the waste gate rod so that you get back to stock boost levels (I think this is around 14psi so your running significantly higher at the moment). If the problem goes away great. If it solves it but you still want to increase the boost for the extra power then there's a few options such as electronic trickery (boxes and modified MAFs) and software tuning (perhaps TRS may consider modifying their remap for you to suit) discussed in Increased power TD5's - what have you done to solve the MAF issues? (https://www.aulro.com/afvb/technical-chatter/261952-increased-power-td5s-what-have-you-done-solve-maf-issues.html)

Good luck. I solved my issue with it back in 2012 era and it's resurfaced now as the electronic trickery box has gone and failed on me. This time I'm looking at the ECU tune solution as it seems to be a superior solution in terms of vehicle operation and ongoing reliability.

[Tombie]

Surging will be over boosting.

Either the WGCM is faulty
MAF going out of range
Waste Gate needs a small tweak backwards

[Jazzman]

I've had the same issue for a long time, but I recently resolved it by replacing:
The vacuum hoses to the to the waste gate with SAE30 rated fuel line. This is reinforced so it doesn't blow up like a balloon, gives a more consistent (responsive) boost to the waste gate.
Boost modulator. (The boost modulator can cause this issue too, it fills with oil - sometimes cleaning it can help)
Clean the sensor in the air box (D2a's have one - not sure about D2's)
Check the wires going to the boost modulator sensor are OK, mine were not making a great connection and have since been re soldered.
Cleaning the MAP sensor in the intake manifold may also help and is worth doing anyway.

As twr7cx mentioned page 2 of the instruments screen on Nanocom will give you the MAF reading, when it surges you might find this drops to 0 or goes out of range.

Cheapest and easiest thing to do is replace the 1/4" hoses, considering they've recently been disconnected it would be a good place to start.

Mine was not the TPS, probably don't go down that path first. Best of luck as it is frustrating, i know.

[John_D4]

Thanks guys. Looks like I’ve got heaps of things to do. I’ll get back after I’ve had a play with it.

[discorevy]

agree with above , did you remove wgm before moving the air con compressor?, if not it could get damaged , the surge can happen if your right on the edge of overboost and not log a fault . I'd back the rod off by a turn especially as between not having an exhaust leak any more and the weather getting cooler it might have been only just overboosting

[John_D4]

agree with above , did you remove wgm before moving the air con compressor?, if not it could get damaged , the surge can happen if your right on the edge of overboost and not log a fault . I'd back the rod off by a turn especially as between not having an exhaust leak any more and the weather getting cooler it might have been only just overboosting

No. All I did was undo the hoses and the exhaust manifold and exhaust pipe bolts and removed it. I didn’t move the air con.

[John_D4]

Still haven’t had time to open the bonnet but I did ‘play’ with the point of surging on the way to work. The air flow maxed at just over 430 and dropped to mid 300’s during surging periods, then yo-yo’d in time with the surging. Max boost seems to be 1.38 bar although I did spot 1.4 bar briefly. I’m just driving it keeping the boost to less than 1.3 at the moment.

Really sounds like the waste gate to me also, but I’ll run through the other suggestions when I can.

Curious tho, is a $100-$150 boost box a consideration? I do have a jayco outback camper trailer.

[steve_a]

Worth bypassing the WGM and connecting the hose directly to the turbo outlet and see if you still have the issue.

The WGM only actuates to STOP the boost from the turbo outlet, but it may be getting sticky and getting stuck in the mode where it uses the inlet side to keep it closed.

[twr7cx]

Instead of guessing and wondering what to do next to solve the issue, just wind back the boost to factory range to see if it eliminates the issue. It's fairly fast and free to do and takes it back to a known start point. From there you can consider the many options available but otherwise your going to keep adding layers onto guesses on what the issue is.

If the issue remains at stock boost levels then you've got an issue such as faulty sensor, stuck wastegate, faulty modulator, etc.

If it's gone then you've identified the cause being high boost level. From there the cheapest solution is to gradually increase the boost to find the point that it reoccurs and then slightly lower to the highest point that it doesn't occur. All free.
If you want more, then it's going to cost you. Electronic trickery is one option, but you will need to know which is causing it, seems likely to be the MAP sensor, so a turbo boost box should solve that or having your ECU retuned to take advantage of the maximum output voltage of the stock MAP sensor or to fit an uprated MAP sensor (there's a 3 bar VAG discussed in TD5 updated MAP sensor - anyone using? (https://www.aulro.com/afvb/technical-chatter/261957-td5-updated-map-sensor-anyone-using.html) which is well priced and I've ordered to try).

[Tombie]

Worth bypassing the WGM and connecting the hose directly to the turbo outlet and see if you still have the issue.

The WGM only actuates to STOP the boost from the turbo outlet, but it may be getting sticky and getting stuck in the mode where it uses the inlet side to keep it closed.

Am I misinterpreting what you’re communicating? [emoji41]

The WGM keeps the Wastegate from beginning to open at lower RPM to prevent bleed of boost from the turbo as it comes up.

So when the WGM sticks in the ‘bleed to atmosphere’ position boost can peak above ECU thresholds.
Plumbing directly from discharge point to turbo can show if this unit is faulty for sure, with a corresponding loss of bottom end performance.

If the WGM is getting on a bit, it’s worth just replacing it. They aren’t expensive.

Considering the recent disturbance to the area, I’d also be looking at hose condition and potential leaks / splits - or even hoses attached to wrong ports if removed.

The other common cause is sticking Wastegate. Undoing the bolts on the actuator and working the arm back and forth along with some Penetrating spray at the pivot Bush can be beneficial.

[steve_a]

Unpowered (i.e. no connection or PWM signal) the WGM port is from turbo outlet to WGA. Fail safe mode. So this is the same as 200/300 and Def TD5 (I'm told).
When being actuated it connects the WGA port to the inlet near the MAF. This provides a vacuum holding pressure to keep the WG closed.

The logic for operation is probably something like this:
if pressure > 1bar
if pressure < max
increase pwm
else
decrease pwm
endif
else
unpowered
endif

It avoids having to keep the WGM powered (with heating issues) and if it fails then you get the same as if it wasn't there.
With no WGM the WG will gradually open to 100% as boost increases, with the WGM the WG should be variably opened based on the control signal to keep boost both under control but not not lost.

The issue is I guess if it gets sticky then perhaps it turns off while keeping WG closed and so it won't open it up because the port doesn't get connected back to turbo outlet.

It's a nice fail safe design in general. You could probably just unplug the WGM to see if it's the second condition, since it now shouldn't overboost unless the rod is set wrong.

If you look at nanocom logs, they show WGM % at 0 until you get above a pressure then operating from 100 down to 0 as pressure rises. No idea what the start point of operation is though, never looked close enough.
The loss of bottom end is no worse than a 200/300 or def td5 in standard form. I never really noticed an issue :)

[John_D4]

So I lengthened the wastegate rod about 3/4 the width of the locking nut. It seems to have helped as the surging is better. I’ll lengthen it a bit more. Still seems to boost 1.3bar before it surges (down from at least 1.4).

I think it had about 15 threads before adjustment.

I’ll repost the results when I drive home tomorrow morning.

[Jazzman]

So I lengthened the wastegate rod about 3/4 the width of the locking nut. It seems to have helped as the surging is better. I’ll lengthen it a bit more. Still seems to boost 1.3bar before it surges (down from at least 1.4).

I think it had about 15 threads before adjustment.

I’ll repost the results when I drive home tomorrow morning.

Good decision.

1.3 Bar is pretty much the max boost, it equates to 18.85 PSI. 1.4 bar is 20.3 PSI which is technically over boost. So winding it back first is the right call.

Just for the record, I've experienced the same symptoms as you describe even with a boost box. Don't go down that path until you are sure the surging is a result of over boost.

[sierrafery]

1.3 Bar is pretty much the max boost, it equates to 18.85 PSI. 1.4 bar is 20.3 PSI which is technically over boost. So winding it back first is the right call.


Sorry to contradict you but the factory set overboos limit is at 1.42 bar calculated by the ECU by extracting the AAP reading from MAP reading...below that value the surging can be caused by too high air flow while the MAF reading exceeds 680kg/hr which is very common, winding back the wastegate would partially cure the symptom cos as the turbo will not spin so fast due to more wasted exhaust gas the sucction will be lower as well... one cause i've seen was low reading MAP sensor compared to a gauge fitted to the EGR blanking port so that would be a relevant test, if the MAP is "tired" and reading lower than the reality the sucction through the MAF will be higher at a certain MAP reading while the real boost is higher as well so it's normal to be higher air flow if you see what i mean... this symptom can be caused by a slight boost leak somewhere, even through the wastegate valve's diaphragm or who knows where

[John_D4]

Sorry to contradict you but the factory set overboos limit is at 1.42 bar calculated by the ECU by extracting the AAP reading from MAP reading...below that value the surging can be caused by too high air flow while the MAF reading exceeds 680kg/hr which is very common, winding back the wastegate would partially cure the symptom cos as the turbo will not spin so fast due to more wasted exhaust gas the sucction will be lower as well... one cause i've seen was low reading MAP sensor compared to a gauge fitted to the EGR blanking port so that would be a relevant test, if the MAP is "tired" and reading lower than the reality the sucction through the MAF will be higher at a certain MAP reading while the real boost is higher as well so it's normal to be higher air flow if you see what i mean... this symptom can be caused by a slight boost leak somewhere, even through the wastegate valve's diaphragm or who knows where

This all started after I’d removed the turbo & gave it to a friend to drill out a broken stud. Until then I had no issues. I would have thought it a bit coincidental if the MAP sensor were to fail at the same time, but I’m not a mechanic (well...until I bought this car!). I haven’t seen my MAP over mid 400’s and definitely not as high as 600 (nanocom readings). I have been wondering if the small rubber hose might be due for replacing as it’s probably 18 years old. That can’t cost much, so I might do that ‘just in case’. I recall someone earlier suggesting sae30 rated hose (?). I’ll see what pirtek have next week.

[rangieman]

I bought some silicon hose from supa crap as i needed extra for my boost gauge so did the whole lot simple[thumbsupbig]
No need for flash exy pirtek stuff[wink11]
Only prob is the colour is blue would have prefered black but it match`s the turbo hoses now [bigrolf] Looking a bit ricey now [bighmmm]

[John_D4]

So now I’m at 1.18bar with the wastegate module at 40% (last screen on nanocom). I don’t know if 40% is good or not. Going to try another tweek to see if I can get closer to mid1.25/1.3bar.

Seems to be running fine. No issues with full acceleration now.

On another matter, how long is recommended before I recheck the nut torque on the bolts? It’s been a couple of hundred km now.

[AK83]

..... I haven’t seen my MAP over mid 400’s and definitely not as high as 600 (nanocom readings) .....

MAP, or MAF?
Don't confuse the two.
MAP on the inlet manifold : MAF is the airflow meter.

As instructed on here, I did WGM bypass on brother's TD5 when it started to surge. no surge. replaced WGM(about $60). done! [thumbsupbig]

We thought about adjusting the rod too, but only if the WGM bypass didn't help.
So he still gets his 1.4(whatever)BAR max boost according to the nanocom.

Do you have an EGT(exhaust temp gauge)?
With lower boost, and using a modded/chipped ECU, there could be the possibility that your exhaust could be running hotter/too hot too.

[twr7cx]

This all started after I’d removed the turbo & gave it to a friend to drill out a broken stud. Until then I had no issues.

It's likely that with the broken stud there was some leakage of exhaust gas which can result in the turbo not spinning as much. When my exhaust manifold broke studs and was leaking I experienced a decrease in performance, fixing the issue perked the motor back up as now the full exhaust gas flow was going to spin the turbocharger.


So now I’m at 1.18bar with the wastegate module at 40% (last screen on nanocom). I don’t know if 40% is good or not. Going to try another tweek to see if I can get closer to mid1.25/1.3bar.

Seems to be running fine. No issues with full acceleration now.

Glad to hear that it resolved your issue. If you desire to increase the boost pressure back up then there are options as I mentioned earlier, some ECU tune tweaking could likely be enough.

[AK83]

.... If you desire to increase the boost pressure back up then there are options as I mentioned earlier, some ECU tune tweaking could likely be enough.

I think John had TRS 'chip' his ECU a while back already.

[John_D4]

I think John had TRS 'chip' his ECU a while back already.

Yes and I don’t think Phil will adjust my tune for free if at all

[John_D4]

I’ll play with the WGV bypass these days off also

[twr7cx]

I think John had TRS 'chip' his ECU a while back already.

That's great, but what I'm talking about is someone who will apply the modifications in the tune to the MAF and MAP as appropriate to resolve the issue being experienced with the higher boost. There's some discussion in the Technical Forum if you want more details of what I mean or I've linked it previously in this thread.

[John_D4]

That's great, but what I'm talking about is someone who will apply the modifications in the tune to the MAF and MAP as appropriate to resolve the issue being experienced with the higher boost. There's some discussion in the Technical Forum if you want more details of what I mean or I've linked it previously in this thread.

I did have a look at that link but I had some trouble digesting. I’ll take a more thorough look at it. From what I recall it involved changing the sensor to a larger 1?

[twr7cx]

I did have a look at that link but I had some trouble digesting. I’ll take a more thorough look at it. From what I recall it involved changing the sensor to a larger 1?

In regards to the MAP sensor, that is one option to move to an uprated sensor such as a the Mercedes Benz or VAG units which are both direct fits. But there is also some adjustment in the parameters of the standard MAP sensor which may suffice.

Then there's also options with the MAF sensor.

[John_D4]

The waste gate is definitely doing funny things. It was set the other day to around 1.2, then last couple of days it’s only reaching 1.08 or so and not holding a steady reading.

I’ll look at trying the bypass tomorrow. Correct me if I’m wrong, but from what I’m reading that will tell me if it’s the WG solenoid. If that’s ok, can I open the waste gate and visually check and clean it without breaking it? Or is it a take to a turbo shop deal?

Also, if my airflow is no greater than 400’s or so is there any benefit in changing the MAP sensor for a larger one?

[lyhoon94]

The waste gate is definitely doing funny things. It was set the other day to around 1.2, then last couple of days it’s only reaching 1.08 or so and not holding a steady reading.

I’ll look at trying the bypass tomorrow. Correct me if I’m wrong, but from what I’m reading that will tell me if it’s the WG solenoid. If that’s ok, can I open the waste gate and visually check and clean it without breaking it? Or is it a take to a turbo shop deal?

Also, if my airflow is no greater than 400’s or so is there any benefit in changing the MAP sensor for a larger one?Hi John_D2,

I don't think an internal wastegate actuator can be opened or if it can, I dont think theres much point to it as I believe the internals aren't serviceable.

I was looking at a few replacement options and have the three below

Oem:TD5 Turbo Waste Gate Actuator (https://www.sp-4x4.com/Land_Rover_TD5_Waste_Gate_Actuator_p/sp5002.htm)

Forge:Adjustable Actuator for Defender or Discovery TD5 | FMACTD5 | Forge Motorsport (https://www.forgemotorsport.co.uk/Adjustable_Actuator_for_Defender_or_Discovery_TD5--product--1033.html)

Turbosmart:Turbosmart IWG75 Landrover TD5 17psi – T.I. Performance (https://www.tiperformance.com.au/products/turbosmart-iwg75-landrover-td5-17psi/)

Hope I didn't misread your post and that this actually helps.

[AK83]

.... If that’s ok, can I open the waste gate and visually check and clean it without breaking it? Or is it a take to a turbo shop deal?

....

Do you have a compressor?
Do you have a blower gun/nozzle/duster doodad attachment?
If yes to both, use blower attachment on the hose into the wastegate, and watch the movement of the actuator arm as you add air pressure .. smooth/notchy/none at all .. etc.

Even a bike pump would work .. the trick is to get the air into the hose .. into the WG actuator, without leaking too much of it.
If using a compressor, moderate the amount of pressure, remembering that the WG usually runs with about 0-20psi.

[John_D4]

Hi John_D2,

I don't think an internal wastegate actuator can be opened or if it can, I dont think theres much point to it as I believe the internals aren't serviceable.

I was looking at a few replacement options and have the three below

Oem:TD5 Turbo Waste Gate Actuator (https://www.sp-4x4.com/Land_Rover_TD5_Waste_Gate_Actuator_p/sp5002.htm)

Forge:Adjustable Actuator for Defender or Discovery TD5 | FMACTD5 | Forge Motorsport (https://www.forgemotorsport.co.uk/Adjustable_Actuator_for_Defender_or_Discovery_TD5--product--1033.html)

Turbosmart:Turbosmart IWG75 Landrover TD5 17psi – T.I. Performance (https://www.tiperformance.com.au/products/turbosmart-iwg75-landrover-td5-17psi/)

Hope I didn't misread your post and that this actually helps.

Thanks for that

[John_D4]

Do you have a compressor?
Do you have a blower gun/nozzle/duster doodad attachment?
If yes to both, use blower attachment on the hose into the wastegate, and watch the movement of the actuator arm as you add air pressure .. smooth/notchy/none at all .. etc.

Even a bike pump would work .. the trick is to get the air into the hose .. into the WG actuator, without leaking too much of it.
If using a compressor, moderate the amount of pressure, remembering that the WG usually runs with about 0-20psi.

Yes I do. That’s a great idea. I’ll do that today and report back. Thanks

[John_D4]

It's not the wastegate on the turbo. I removed the bolt at the turbo end and it moves very freely.

In this video I have attached a air blower set to 20psi to the intake hose. Notice the rod moves then stops and moves a bit more. I haven't checked the solenoid yet, but I'm wondering if the actuator is on the way out.

YouTube (https://youtu.be/itvj1tPrN2c)

[John_D4]

Did find this however. Cleaned with carby cleaner.

Edit: weird I added a pic of a gunked up MAP. Now it’s gone.

[twr7cx]

Also, if my airflow is no greater than 400’s or so is there any benefit in changing the MAP sensor for a larger one?

You are confusing MAP and MAF sensors there (not the difference in the third letters - 'P' and 'F'). Air flow through is measured by the MAF sensor. 400kg/hr (although Nanocom incorrectly states g/hr) is well within it's range.

This has no or little bearing on uprated MAP sensors.

[John_D4]

So in the end, thanks to everyone’s advice, I’ve learnt more about the TD5 engine. It seems that the issue was a really gunked up MAP sensor. After winding back the turbo I finally got it into my head the difference between a MAP & MAF sensor (P= pressure - inlet manifold, F = flow so measures air flowing into the turbo). I checked the MAP, took a pic which vanished, and cleaned it with carby cleaner and compressed air. I’ve already been told on Facebook that carby cleaner probably wasn’t the best choice so I’ll buy some contact cleaner when I go to the auto shop next tine.

The surging seems to have disappeared along with the randomly varying turbo boost readings. So now I’ve spent the last few days gradually adjusting the boost to just under surge point. I’ve got it around 1.25 bar now. I’m wondering if I can squeeze a couple of extra points out of it.

Unfortunately at foot flat to the floor acceleration it’s throwing a fault code that I’ve already started a thread titled ‘flashing MS & D’ where I’m trouble shooting that. Plus my damn exhaust manifold is leaking at number 3 about 200-300k after flattening and reinstalling. I guess it’ll have to come off and I’ll deweb it this time. Did momentarily think about a new AlliSport high flow manifold but it’s in the que behind the long range tank, rear draws, high lift jack/shovel holder, etc.

I did find a cracked/perishing air inlet corrugated pipe. I think I’ll upgrade it to an AlliSport 1 tho.

[twr7cx]

Leaking manifold is a pain, I found it lowered boost levels a bit and was causing high EGT. I highly recommend ceramic coating the manifold. I dealt with warping manifolds for years and this was part of the solution for reliability. www.jet-hot.com.au - Hi Performance Coating (http://www.jet-hot.com.au) Lowers the under bonnet temperatures too.

[John_D4]

Leaking manifold is a pain, I found it lowered boost levels a bit and was causing high EGT. I highly recommend ceramic coating the manifold. I dealt with warping manifolds for years and this was part of the solution for reliability. www.jet-hot.com.au - Hi Performance Coating (http://www.jet-hot.com.au) Lowers the under bonnet temperatures too.

Agreed. Only issue is that the ceramic dudes have a 2-3 week lead time & this is a daily drive. Might invest in a 2nd manifold and get it done.

[twr7cx]

Agreed. Only issue is that the ceramic dudes have a 2-3 week lead time & this is a daily drive. Might invest in a 2nd manifold and get it done.

APT Offroad (http://aptoffroad.com.au) used to do them on exchange basis. Your deposit was refunded upon return of your current manifold.

Otherwise source one from a wrecker, have that done and then fit. Keeps the vehicle on the road.