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TD5 Defender low on power


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Hi all.

I've finally got my 90 (My first 90!!!) back together again, it needed a few new body panels after a bit of a roll. I brought it rolled and this is the first time I've driven it, the drivetrain is standard, it's on 35 inch tyres and the ECU has been remapped.

The problem with it is that it is really guttless down low, say under 2000 rpm and really isn't that impressive above 2000rpm, though it still goes ok. I know of another vehicle with the same ECU map and it goes very well.

I think I'm being realistic about performance, I previously had a Discovery that I had fitted 35's to and had increased fueling/boost, it was much more drivable than the 90.

Here is what I have tried so far.

1. Replaced fuel and air filter.

2. I have access to a Rovacom and have checked the faults, no faults logged. I did notice that the power balancing was between -5 and +10 depending on cylinder at idle?

3. Replaced the MAF, small improvement but very minimal.

4. Replaced the injector loom, runs smoother at idle but no change to power.

5. I have a boost gauge installed in the inlet manifold, this shows about 16psi as max boost.

6. I have disconnected the wastgate actuator and the engine will log an over boost fault however there is no noticable change in engine performance, from everything I have read it should almost be undrivable once overboost is reached?

I'm not really sure where to head next with fault finding. I have noticed that it never smokes which intruiges me given that it has been remapped, I would have expected some smoke.

The next things on my list to do are:

Check that the wastgate is closing completely

Check fuel pressure

Adjust the injectors

Borrow another ECU to try in my vehicle

Clean/replace the MAP sensor

I've done a lot of searching on various forums etc trying to find information on the problem I'm having however I can't seem to find any info. Has anyone experienced or heard of similar problems?

I'd be very interested to hear your thoughts, I running out of ideas!!!

post-2727-1220326704_thumb.jpg

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What year is the Defender??

If post 2002 get rid of the CAT, and fit a none CAT down pipe

Clean the MAP sensor (and personally I'd remove the EGR set-up - which may actually be causing problems)

Whose Remap are you running?

When you hit overboost, the ECU will cut fueling... which on some Td5's is very abrupt. You could try running slightly more boost (17psi) although, with the extra fueling from the remap you 'may' need to run a box to stop the ECU seeing the increased boost, and thus hitting boost cut.

With the Rovacom on, go for a drive with the live page on (or recording) - what max value do you see on the manifold pressure?? should be 220Kpa ish at full throttle on a hill (thus max boost pressure reached).

Also, what value do you see from the MAF?? - should be 55 - 60kg/hr at idle.

Ian

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Hey Ian,

Cheers for the reply, I forgot to say, it's a 2002 model, has the programmable ECU but no CAT, EGR or Wastegate Modulator.

Not sure who the map came from, it was in the vehicle when I got it, the previous owner can't remember whos it was but says it used to go well. I plan on building a "boost box" but I want to get the truck running with remaped fueling without making any other mods.

I haven't been for a drive on the hills with the Rovacom on, but isn't 220kPa a bit high, I remember reading somewhere that the over boost setting is something like 24psi(165kpa). With the wastegate actuator disconnected ie wastegate disabled I only see about 22psi on my boost gauge.

I'm seeing 60kg/hr at idle from the MAF, was the same with both the old and the new one, so I've ruled that out, I hope ; )

I'm still scratching my head, I'm going to head home soon so will have a bit more of a play.

Cheers for your help,

Mike

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has the programmable ECU but no CAT, EGR or Wastegate Modulator

Defenders never had the modulator, EGR - is this removed correctly? - or just a blanking plate??

Are you still running a centre silencer?? I have seen these partially blocked before, which can cause problems.

Do you get any fault codes logged on Rovacom - just wondered if you have the correct map? Does you water temp gauge work correctly?

I haven't been for a drive on the hills with the Rovacom on, but isn't 220kPa a bit high, I remember reading somewhere that the over boost setting is something like 24psi(165kpa). With the wastegate actuator disconnected ie wastegate disabled I only see about 22psi on my boost gauge.

Rovacom reads actual pressure - so boost pressure + ambient pressure... so as ambient pressure is roughly 1bar or 100Kpa, you should be seeing between 1bar (100kpa) and 1.2bar (120kpa) boost pressure - so a combined max of 220kpa or thereabouts.

Overboost occurs at just over 1.4bar, and then will disable fueling until the pressure drops back below it's set point.

In all honesty, next thing I'd be looking at is fuel pressure, and then the injectors.

I worked on a Disco the other day, that had previously had (at great cost) a set of recon injectors - but they were more of a CON than a RECON!!! - performance was flat to say the least!!!

Ian

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Cheers Ian,

No, it never had EGR. It was a Truckcab and it's New Zealand new so probably a different spec to UK ones with EGR etc.

Yes, still have a centre silencer, might whip it off and go for a spin and see how it goes, I want to remove it eventually anyway. One thing I have noticed is that I don't hear the whistle of the turbo at idle, might be because the silencer is blocked, will have to try.

No fault codes get logged, only get the over boost logged if I disconnec the wastegate actuator. The water temp gauge works fine, starts low moves to roughly the middle as would be expected when warm.

Ahhhh, that explains the pressure read by the Rovacom, will have to have take it for a ride up the hills and see how it reads.

I'll check the fuel pressure tomorrow!! I really hope it's not the injectors!!! Would the adjustment affect the performance much?

I'm going to whip the silencer off now and try it.

Cheers

Mike

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More experimentation tonight.

I checked the wastegate, it's free and I can only assume it is closing completely.

I cleaned up the MAP sensor as well, not too sure if it has made any difference though.

Next I tried disconnecting the the wastegate actuator again, the over boost is now operating, it will hit the overboost limit and then reduce fueling, it is still drive-able just has reduced power. Turn it off and back on again and away it goes again until it over boosts again. It's still not going as expected, I might try uploading another map to see what that changes.

I didn't get a chance to try the silencer out, though I suspect this will not revel anything as I would have thought the EGT would be very high when under power if the exhaust was blocked, also the turbo would probably not boost too well, though I will try it as I'm open to anything at the moment.

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Any injector showing power balancing in double figures at idle is not great, though we normally only worry if it is above 15. It may be an idea for you to change the injector washers which can allow combustion gases back into the fuel gallery, and possibly adjust the injectors, not that I have ever found any out by more than 1/4 turn and it never seems to make any noticeable difference.

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As Ian said, fuel pressure and then check the injector adjustment. They don't run brilliantly when the injector plungers are set all wrong, and you said the injectors have been changed? The injector balancing figure sounds a bit high to me, a good one in my experience is usually all staying under 5 and hovering around 0 to 3 most of the time.

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Cheers for the input guys, I will check the fuel pressure tonight and recheck the power balancing now after I have replaced the injector loom. Next step will be adjusting the injectors and replacing the washers, the injectors have never been out as far as I know so will beinteresting to see what effect that has.

Cheers

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Ian, you mentioned above about correct removal of the EGR. I noticed tonight that the rovacom says that the EGR modulator is enabled, since I have no modulator I'm thinking that this is a possible cause of my problems. Have you ever heard of similar problems when removing EGR?

Nope.....

By the sounds of it you might have a RoW spec Td5, but the remap is designed for a European Defender with EGR. In saying that, I've never checked that the EGR flag is set to disabled in a RoW spec - it might just be the values in the map that stop it working.

Even so, having no EGR will not cause problems - even if it did expect to see one. Although it will flag up on the fault code list, removing the EGR on Euro Spec Td5 map will not cause any running issues (apart from usually making it better) and does not put the MIL on etc etc.

I must admit, as BogMonster said, your injector compensation values are a bit on the high side... but even so, this usually just causes a rough idle, rather than lack of power. Even the Disco I worked on the other day - which has something seriously wrong with its injector physical settings - still had low figures at idle.

Although it shouldn't affect anything at lower speeds/rpm - have you checked the injector coding are correct?? I.e. cross referenced the codes on the top of the injectors to what the ECU expects?

Ian

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Even so, having no EGR will not cause problems - even if it did expect to see one. Although it will flag up on the fault code list, removing the EGR on Euro Spec Td5 map will not cause any running issues (apart from usually making it better) and does not put the MIL on etc etc.

Blanking the EGR on a ROW causes no problems or lights either, as above it usually improves matters!

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usually the fuel pump starts to show signs of failing after 100k km. Although it's still pumping, it's no longer at it's optimal. I've this problem on my Td5 and i'm just sitting around on it till the pump gives up before getting a new one. Even when it gives up, you can still start and drive the truck to get it fix, or you can attempt to change the pump yourself.

check if the fuel pressure regulator is leaking too. another common fault.

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Managed to get the bits together to check the fuel pressure/flow, discovered it was nowhere near the 4bar it should have been, sorted the problem and it a whole new vehicle. It really pulls on the hills now, and I've been for a bit of a play off road and am really impressed.

Thanks for all your help guys.

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