↓ Advertise on Defender2 ↓

Home > Td5 > Surging and hesitations
Post Reply  Down to end
Page 4 of 5 <12345>
Print this entire topic · 
Stripygitface



Member Since: 16 Sep 2014
Location: Kent
Posts: 61

Watching this with interest as it seems exactly the same problem I have.

I have been wondering whether it could be the fuel pump starting to fail.

Post #823129 3rd Apr 2020 1:40pm
View user's profile Send private message View poster's gallery Reply with quote
Dexterdog



Member Since: 23 Jun 2018
Location: gloucestershire
Posts: 99

Hi Blackwolf,
Is the throttle position sensor the little box on the side of the throttle pedal that comes with the pedal itself ? If it is then yes changed that and made no difference. If it's something else can you direct me to where it is pls
Thanks for the help[/s]

Post #823132 3rd Apr 2020 2:07pm
View user's profile Send private message View poster's gallery Reply with quote
blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 12026

United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey

Yes, that's it. Rules that out then. Big Cry

Post #823140 3rd Apr 2020 2:57pm
View user's profile Send private message View poster's gallery Reply with quote
Dexterdog



Member Since: 23 Jun 2018
Location: gloucestershire
Posts: 99

Hi Chaps,

I have made some progress and I have now found a way to reproduce the problem consistently.

Previously the problem would only be present on light acceleration and intermittently. Happens when cruising say at 50mph but also when slow in low ratio off road. Sometimes slight hesitation (usually when cruising but can be kangarooing when driving slowly. Drive it hard and no problem. However reproducing was hit and miss and sometimes would drive fine for miles

I have now found that if I back off the wastgate actuator all the way, the problem becomes easy to reproduce and is present in more of the first part of the accelerator pedal travel (once the turbo gets going the problem disappaears), wind it back to normal position its less obvious and only for less of the pedal travel, wind it on another thread, it goes away more and for less of the pedal travel.

That says to me the problem is off boost because backing off the actuator makes it present more and its more obvious?

I think that once the turbo is coming into play earlier (which I am doing by adjusting the actuator) the problem disappears. I cant get rid of it completely by adjusting the actuator but I can influence it and make it more or less obvious and more persistent

What I need help with is interpreting what that could be other than the long list of things I have already gone through already ...see below.

Any help gratefully received !

(all usual main culprits checked and changed, EGR delete, MAF, FPR, Injector seals, injector harness, loom now dry and no oil at red plug, fuel filter, no fuel leaks anywhere in system that can be seen, fuel temp sensor changed, turbo no play, intercooler pipes all ok, been remapped and map checked, wastegate actuator moving freely, tps on pedal ok)

Post #837545 16th Jun 2020 4:43pm
View user's profile Send private message View poster's gallery Reply with quote
rallysteve



Member Since: 10 Feb 2014
Location: South Yorks
Posts: 1494

United Kingdom 1984 Defender 90 V8 Petrol PU Caledonian Blue

Have you checked and cleaned the MAP?

Steve 02' 110 TD5 Double Cab
84' 90 3.9 V8 Caged Pickup Build Thread

Mobile Diesel Heater Build Thread

Post #837551 16th Jun 2020 4:56pm
View user's profile Send private message View poster's gallery Reply with quote
Dexterdog



Member Since: 23 Jun 2018
Location: gloucestershire
Posts: 99

MAP was in hell of a mess but from what I can see thats not unusual until EGR delete done. Now cleaned up.

In terms of testing, I have disconnected for short drive and the problem still persists. Not sure if that is telling me its not the MAP or the MAP is dead ???

Is there any other way of testing it ?

Post #837556 16th Jun 2020 5:05pm
View user's profile Send private message View poster's gallery Reply with quote
achuakh



Member Since: 12 Apr 2012
Location: Singapore
Posts: 149

Singapore 2002 Defender 90 Td5 SW Oslo Blue

at this point, there's not much you can do than to use a diagnostic tool that can log the system request when taking it for a drive and look for any anomalies vs randomly changing parts on the vehicle.

if you can get hold of the fuel map from the ECU, you can reference the data from the log to those values to see if there's anything that's causing it, like hard limiting due to a particular value caused by the sensor data or the map requires a certain cheat circuit (as you mentioned it's a "stage 2" map).

i've seen a lot of remap which will ramp up the "torque limiter" and then it's becomes very jerky due to it referencing the "driver demand" map directly.

these are my own view and you are welcome to disagree. From the land of the most expensive land rover defenders on planet earth. At 125k for a XS 110 csw and you get to own it only for 10yrs! Please find me a good reason to stay on this island.

Post #838252 19th Jun 2020 11:26am
View user's profile Send private message View poster's gallery Reply with quote
Dexterdog



Member Since: 23 Jun 2018
Location: gloucestershire
Posts: 99

Hi Folks,

Well I am a long way down this route. I promised to update as I found the issues.

I had oil in the loom which was throwing various fault codes that would not clear. Loom now changed but still have the hesitation and stutter.

I am fairly sure I have got to the root cause but could do with a wee bit more help if poss.

By adjusting the wastegate actuator I could increase the amount of pedal travel that the stutter / hesitation lasted for. Once the turbo spooled up the hesitation went

This led to more investigation around this area and I have now found that the wastegate spring is broken (I think).

My understanding is that the wastegate should spring back into position. Mine flaps around with no resistence, .

I am hoping this is the cause of my problem which is why just as the turbo comes on boost I get a hesitation but can then "drive "through the problem and the car drives fine.

Would stutter / hestitation be a symptom of the wastgate spring being broken ?

Can you rebuild the spring? or is it a new turbo ?

Thanks for any help

Post #840213 28th Jun 2020 1:13pm
View user's profile Send private message View poster's gallery Reply with quote
mk1collector



Member Since: 17 Sep 2009
Location: West Yorkshire
Posts: 6729

England 2004 Defender 110 Td5 CSW Bonatti Grey

Unplug the MAF and drive it around for a day and see if it feels better. Ray
My build thread
http://www.defender2.net/forum/topic17615.html

Post #840218 28th Jun 2020 1:30pm
View user's profile Send private message View poster's gallery Reply with quote
Dexterdog



Member Since: 23 Jun 2018
Location: gloucestershire
Posts: 99

Hi, thanks for reply but I am way past unplugging MAF in terms of investigation. Def narrowed down to when turbo just coming on boost and as said wastegate appears to be broken

Post #840219 28th Jun 2020 1:50pm
View user's profile Send private message View poster's gallery Reply with quote
roel



Member Since: 08 Aug 2009
Location: Lelystad
Posts: 1841

Netherlands 2003 Defender 90 Td5 PU Caledonian Blue

The actuator has indeed a spring. the turbo pressure pushes against the spring and at the adjusted pressure it will compress the spring and the bypass will open. It is hard to pull enough on the actuator rod to get it moving. So if the rod that comes out the actuator is moving freely the actuator is broken.

As a test you could adjust it as short as possible so it won't move. But note that the bypass will not open so you could get high turbo pressures and the ecu will reduce power.
As I read you problem is at low rpm so I assume below 1800 rpm. As you stay below that I think you will be safe. Roel

1984 90 2.5 na Diesel - RR V8 (1994-2001)
1997 Camel Trophy Discovery 300TDI (2001-2009)
2005 G4 Discovery III 4.4 V8 (2008-2018) It's gone but it still hurts.
2003 90 Td5 (2009-now)

Post #840304 28th Jun 2020 8:49pm
View user's profile Send private message View poster's gallery Reply with quote
custom90steve



Member Since: 21 Jan 2010
Location: South West England
Posts: 18027

United Kingdom 

Try replacing the MAP & MAF. I know it’s not a cost you’d like to hear but I found cleaning does not always work.
Eventually, service life comes to an end and performance is jeopardised.

Also, have you had a look at the clutch switch? I believe on a TD5 you can simply unplug it. (Puma is not as simple.)

Then there is the turbo actuator is it free and moving correctly?
If it was a Puma the VCV can be very similar in these problem you’ve described when it’s not working correctly too.

I do t know much about the TD5, but these things I’d look at. Definitely sounds fuel or air metering related but things like the clutch switch can cause odd issues. Make sure grounding points and battery clamps are all clean and tight too. Diesels Lives Matter

Post #840433 29th Jun 2020 12:21pm
View user's profile Send private message View poster's gallery Reply with quote
Dexterdog



Member Since: 23 Jun 2018
Location: gloucestershire
Posts: 99

Thanks, MAF replaced. MAP swapped for another (lent by a mate) and made no difference. Actuator is moving freely as is wastegate arm (now realise there is no spring but it must drop back into hanging straight down to be truly freed off)

Any other suggestions ?

Clutch switch - will try disconnecting next as not tried that yet Thumbs Up

Post #840439 29th Jun 2020 12:34pm
View user's profile Send private message View poster's gallery Reply with quote
custom90steve



Member Since: 21 Jan 2010
Location: South West England
Posts: 18027

United Kingdom 

Anything free is worth a shot. Thumbs Up Diesels Lives Matter

Post #840462 29th Jun 2020 2:45pm
View user's profile Send private message View poster's gallery Reply with quote
Dexterdog



Member Since: 23 Jun 2018
Location: gloucestershire
Posts: 99

Hi Chaps,

Sorry to ask for yet more help. Any turbo gurus out there ?

I had an idea today. I took the bonnet off and drove down the road watching the actuator. It does not move at allno matter how much the turbo spools up.

The wastegate is free (I have diconnected the arm and freed it off)

I am guessing (hoping) the actuator is knackered.

If the diaphragm or spring in the actuator is broken would that cause stuttering just as the turbo starts to spool up....poss through pressure being pushed the wrong way through the actuator ? and then once the turbo really gets going it drives fine ?

I am guessing it would also explain why it goes like a rocket once you have it wound up because the turbo pressure is not being released ?

Post #840644 30th Jun 2020 10:28am
View user's profile Send private message View poster's gallery Reply with quote
Post Reply  Back to top
Page 4 of 5 <12345>
All times are GMT + 1 Hour

Jump to  
Previous Topic | Next Topic >
Posting Rules
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum



Site Copyright © 2006-2020 Futuranet Ltd & Martin Lewis