Discovery 2 TD5 POwer Loss - no codes on Nanocom

[Juljon]

Hi All, I've just had the manual transmission out of my D2 to repair the fifth gear. It has sat for a couple of weeks with the battery disconnected. I've refitted the gearbox, no issues. However I now do not get any power. Boost is down below 0.5 bar max. It feels like it's in limp mode but there are no codes on the Nanocom. I've tried disconnecting the MAF, no change. I suspect a wiring oe ECU issue but without codes I'm not sure where to look next. Any suggestions would be welcome...

Update - Cleaned MAF, disconnectd MAP, tried a different ECU - no change still no codes.



Last edited by Juljon (https://landroverforums.com/forum/posthistory.php?p=941394); Today at 06:57 PM.

[Slunnie]

Are all of the small turbo boost modulating hoses still attached? Also the electrical connection to the boost modulator?

[shack]

And if you check what Slunnie has suggested with no change, can you post a log from TD5 instruments here?

[Captain_Rightfoot]

Is there lots of black smoke when there should be boost?

[Juljon]

Hi, yes the hoses are on. One thing that is strange is that there is no wastegate modulator, there is what looks like a pressure sensor "T"eed with a line to the output side of the turbo. Probably a mod from a previous owner. There is no black smoke, I get the feeling that the fuel is being regulated and after a bit more research and thinking about it last night I think the MAP sensor/wiring may be the problem.195249I've attached the instrument readout - note the boost pressure which does not get above 0 bar. The boost pressure on the physical pressure gauge is max 4psi but the MAP sensor is not giving anything above 0. I'll have a look at the sensor today.

[Tins]

There are a few issues which won't throw codes. D2 was code reading infancy.

You can try it without the wastegate modulation, as Defenders didn't have one. Although it sounds like the PO may have already done that.
I suppose you've chacked the usual suspects, like oil at the red plug? It can migrate further down the chain as well, into the fusebox etc.
Other than that, I'll leave it to the likes of shack, who knows far more than I do.

[AK83]

Had a 'similar' issue when I first got my D2a on the road.
Limited boost too. Sorry I can't remember what the boost reading was, only that my D2 on the same road(slight undulations) had more boost with less throttle input.

Wastegate was stuck .. maybe half open or whatever. Checked all lines etc.
Connected the compressor to it with an air gun and ever so light input to it and could see that it wasn't returning to the closed position(ie. sticking open).

Check the wastegate arm on the exhaust side. Spray outside with something lubey(I use Inox). year later still working fine.

[Tins]

Had a 'similar' issue when I first got my D2a on the road.
Limited boost too. Sorry I can't remember what the boost reading was, only that my D2 on the same road(slight undulations) had more boost with less throttle input.

Wastegate was stuck .. maybe half open or whatever. Checked all lines etc.
Connected the compressor to it with an air gun and ever so light input to it and could see that it wasn't returning to the closed position(ie. sticking open).

Check the wastegate arm on the exhaust side. Spray outside with something lubey(I use Inox). year later still working fine.

Good point. I'd forgotten that mine did that too, after a period of inactivity. Probably going to do it again now, if it ever goes again.

[Slunnie]

Actually, the other thing that might do this also is when the fuel pump goes bad, just before it completely fails.

[Captain_Rightfoot]

Actually, the other thing that might do this also is when the fuel pump goes bad, just before it completely fails.
If you had full throttle and no smoke, there isn't enough coal going onto the fire. :o. If lots of smoke plenty of coal.

[Juljon]

I've just checked the MAP sensor connected to a separate air supply and the Nanocom reads pressure so I don't think its the MAP sensor anymore. It really does feel like the fueling is being limited, it's not at all intermittent and I can take my foot partly off the accelerator without any noticeable change in performance which tells me that the fuel is being restricted. I would expect fuel pump or filter to be more intermittent/varied. As I mentioned in my first post I have had the gearbox out and back in. Same gearbox, just fixed thew fifth gear. It was fine before I removed the box and the symptoms have started since fitting the box back. I suspect I have damaged a wire/sensor or something somewhere, just don't know where else to look.

[Juljon]

Checked the wastegate and ran it with it clsed with a cable tie, no change.[bighmmm]

[shack]

Hi, yes the hoses are on. One thing that is strange is that there is no wastegate modulator, there is what looks like a pressure sensor "T"eed with a line to the output side of the turbo. Probably a mod from a previous owner. There is no black smoke, I get the feeling that the fuel is being regulated and after a bit more research and thinking about it last night I think the MAP sensor/wiring may be the problem.195249I've attached the instrument readout - note the boost pressure which does not get above 0 bar. The boost pressure on the physical pressure gauge is max 4psi but the MAP sensor is not giving anything above 0. I'll have a look at the sensor today.What altitude are you at? Something is wrong with that log i think.

Could you do another log from the TD5 engine inputs fuelling page please?

From memory that's the correct description.

[Juljon]

What altitude are you at? Something is wrong with that log i think.

Could you do another log from the TD5 engine inputs fuelling page please?

From memory that's the correct description.

Hi, I'm at about 300m above sea level. Here's the csv file. 195250

I have just checked the MAF but the readings appear to be okay, at least I'm getting readings. Boost is low, as good as 0 but everything mechanical is working as it should. The ECU is just not allowing fuel when the accelerator pedal is pressed.

[Juljon]

Now disconnected the MAF but no change, still very low on power, no fuel, no boost.

[shack]

For some reason on the first log, AAP was reading 113kpa, you would need to be a lot below sea level for that to be correct.

But the second one looks ok, I think it's a nano bug.

I can't see anything outrageously obvious in the log.

As you said, it's possible some wiring got damaged, but I can't really see how.

[Slunnie]

Now disconnected the MAF but no change, still very low on power, no fuel, no boost.
How many kms are on it?

Fuel Pumps last about 120,000km give or take, if its very roughly a multiple of that.

[shack]

The fuel pump is definitely running?


Run a purge cycle with the engine off and ignition on, you should be able to hear it fairly easily.

[p38arover]

Thread originally posted in the wrong area. Moved to Disco 2.

[Juljon]

Already changed the fuel pump. I'm setting up to check the fuel pressure at the FPR. Still don't see how this is linked to the gearbox change but I have to check everything I suppose...

[Juljon]

OK, so I checked the fuel pressure and it is around 6 bar. I believe it should be 4 bar but is that a minimum or could the ECU not like the higher pressure? That pressure was taken at the FPR temp sensor hole. I am now totally out of ideas!!

[discorevy]

OK, so I checked the fuel pressure and it is around 6 bar. I believe it should be 4 bar but is that a minimum or could the ECU not like the higher pressure? That pressure was taken at the FPR temp sensor hole. I am now totally out of ideas!!

Is is possible you or someone else have swapped the fuel lines going into the FPR? top line should come from the chassis.

4 bar would be measured on the return from memory

[AK83]

.... Still don't see how this is linked to the gearbox change but I have to check everything I suppose...

Could be just the act of sitting there unused. I think Discos get like that and my D2a did.

I've got a few cars to drive, and mostly I use the super economical 307Hdi ... so D2a sits for a while. IIRC about over a month on it's last run.
So had to move it to hook up trailer to get trailer to mate in Melbourne. I keep D2a on trickle charger all the time when not in use. SO 'power issues' due to low battery, etc.
Has been going well up until the trailer move/hookup. Next day had to drive to Mel ... missus to airport then trailer to mates'. On the way down, hit a roo. Not hard, just under car and damage to plastic bar.
That was before all the hills around Bendigo area, so hot the hilly area and suddenly it's got no power. I thought, no way a 6x4 trailer would cause that much power loss up 'barely' hills, and then hit some of the slightly steeper stuff(the stuff that slows trucks to 40-60k/h) and I'm also struggling too. Hard to keep at 80 and down to third, etc.

So why after no work being done, car just sitting for a bit over a month and MAF just decides to stop working? To confirm, I used the MAF out of the D2, and yep, new MAF time(for one of them).

You say it all started after you repaired gearbox. Not knowing what you/your mechanic or whoever did or didn't' do, but was the exhaust removed? Did something accidentally fall into exhaust and block it up?

This is not to cast aspersions on anyone, and sometimes multiple hands can make a mess of things .. who knows what someone else did .. etc.

As I remember it, ECU doesn't know fuel pressure, only fuel temp.

[Juljon]

Hiya, thanks for the thoughts. The fuel lines are correct. Everything was fine until I had the gearbox out and replaced. I did it myself so only one pair of hands have been on it except for the wife helping to push the box back onto the engine, difficult for one when your under the vehicle.... It was just to repair the fifthe gear, didn't even replace the clutch or open the tranfer box. Just changed out the fifthe gear and put it back together again. Part of that was to split the exhaust at the flange near the the gearbox but it just hung under the car while I worked on the box. It sat for about a month while I waited for parts.

I've disconnected the MAF so that removes that part - apparently the MAF is only necessary for "efficient" running of the engine. So posts even suggest that power is increased when it is simply disconnected.

I am now down to checking the exhaust. AI suggests that I should be getting boost regardless of the ECU and the sensors so I'll start by checking the exhaust for blockages. I'm pretty sure nothing could have fallen in but I'll have to check for DPF, etc.

[Captain_Rightfoot]

Already changed the fuel pump. I'm setting up to check the fuel pressure at the FPR. Still don't see how this is linked to the gearbox change but I have to check everything I suppose...
Just a thought.. the big earth lead onto the engine got done up tight?

[AK83]

Hi, yes the hoses are on. One thing that is strange is that there is no wastegate modulator, there is what looks like a pressure sensor "T"eed with a line to the output side of the turbo. Probably a mod from a previous owner. .....

You said this earlier.
Could this 'sensor' be a regulator? One of those adjustable needle valve things?
If it's a T with a sensor, and sounds like you have a turbo pressure gauge ... could it be blocked or something.

You could still try to do a bypass and connect one of the turbo regulator hoses direct to the wastegate solenoid.

Sorry can't remember which hose goes where, but some years ago again I had a failed WGM, and the tip is to bypass it, and connect direct to the wastegate solenoid.
What should happen is that you will get 'overboost' .. IIRC at about 3500 .. too much boost and the ECU sees this and causes a limp mode, and I think you may get a MIL on.
If that happens, just switch off, and it should disappear until the next time you have the issue.

Or, take a photo and post it here.

[discorevy]

In post 5 you mentioned a mechanical gauge reading 4 psi and 0 at the MAP sensor.

If the "T" you mentioned was off the pipe just downstream of the Turbo, could be where they have put the feed for the gauge?, if so, this could mean there is a large leak between the two.

If the motor was tilted back while fitting / removing the box, which, incidentally, doesn't require removal to change a 5th gear set, (did you replace the rear support bearings?) it's possible the intercooler hose to intake has come off or kinked, worth a check.

If that's ok, remove the intake to turbo hose with airbox lid and check for restrictions, as well as checking the compressor impeller on the turbo is free and not touching.

[Juljon]

Thanks for all the ideas.

On the mechanical gauge, on further inspection this is "T"ed into the signal pipe which comes straight from the pressure side of the turbo and feeds to an electrical pickup which reads the boost pressure in the cab. Totally separate and not linked to the vehicles systems, an add on by a PO. The boost modulator has been removed as well.

I'll take the advice on checking for restrictions in the exhaust and turbo pipes, hoses, intercoolers etc. I also believe that there is a link to a clutch switch that cuts fuel when the clutch is depressed, that's something else to check and sounds to be something that could be the problem.

[shack]

It won't be the clutch switch, it doesn't really "cut fuel" in the way you are thinking.

It's simply for surge damping, if it were somehow causing issues, the engine would simply behave like it does when in low range.

[Juljon]

Hi All, great news is that it is fixed. Top marks to @Discorevy!! I checked the pressure side of the turbo by disconnecting the pipe from the turbo to the intercooler and blowing air down it. Loud noise of escaping air from the other side of the engine bay truned out that the hose from the intercooler to the inlet manifold had been pulled off when the engine was tilted back to remove the gearbox. It was just sitting half obver the connection so was blowing some air into the manifold but not enough to produce any power. Replacing the hose has fixed it.

Thanks all for your ideas and assistance.

[AK83]

..... truned out that the hose from the intercooler to the inlet manifold had been pulled off when the engine was tilted back to remove the gearbox. .......

Yeah, had to be something so simple, and turbo hoses coming loose is a common cause for non pressurising turbo(and total lack of power).

Happened to my nephew some time ago. His call was to tell me his D2 wad dead coming up some steep hills, motor blown. Did I now want the shell?

My first instinct was one of the turbo hoses popping off under high pressure load, he probably didn't tighten the clamps enough or something when he last did some work. bingo!

[discorevy]

Hi All, great news is that it is fixed. Loud noise of escaping air from the other side of the engine bay truned out that the hose from the intercooler to the inlet manifold had been pulled off when the engine was tilted back to remove the gearbox. It was just sitting half obver the connection so was blowing some air into the manifold but not enough to produce any power. Replacing the hose has fixed it.

Thanks all for your ideas and assistance.

Nice one, and thanks for getting back with the fix, it'll no doubt help someone reading this thread with the same issue in future. Quite a few don't bother