Turbo question

[wuvvum]

I've been having a bit of a play with the Rover of Doom (the original one) this weekend, to see if I can get it back to anything like its original performance. I bought one of those adjustable boost valve thingies off eBay and plumbed it in, but it had absolutely no effect whatsoever.

 

I then tried disconnecting the wastegate actuator pipe completely - if my (very limited) understanding of turbos is correct, if there's no pressure feed to the wastegate actuator the wastegate should stay closed, shouldn't it? This still made naff all difference - the turbo still wasn't boosting properly. Does this mean that my wastegate is borked (jammed open / leaking)? From what I can see that's the conclusion I'd come to, but I don't know if I'm overlooking something obvious.

 

It'd be a shame if the wastegate has had it, as that would mean a replacement turbo, which ain't going to happen any time soon. It'd just mean the car would get parked up in a corner and donate its EGR valve blanking plates etc. to the 400. But I've had a good run out of the old girl I suppose...

[mouseflakes]

No idea about Rovers, or any other turbos TBH, but my Delica has weak pressure relief valve on the inlet manifold - it seems to blow as soon as the turbo kicks in - the resulting loss of power effectively negating any effect the turbo would give. Admittedly it's quite noisy on the Deli so you know it's happening and I guess it would be the same on other vehicles - might be worth a check though?

[stuboy]

what lead up to the loss of power?

[wuvvum]

what lead up to the loss of power?

Me racing VAG TDIs along the M4 on the way back from Shitefest. It was going fine, then I slowed down for a bit and when I put my foot back down the power just wasn't there.

 

Tim, I had wondered about whether the pressure was escaping from somewhere else in the system, but the boost gauge is only registering 8psi (as opposed to the 17 it was boosting at before) and that takes its feed direct from the turbo, hence me thinking the problem is probably with the turbo / wastegate.

[skattrd]

I'm no expert, but it does sound like an issue with the wastegate to me as well.

 

How accessible is the turbo on the car? If you can I'd remove it to have a look at it ... easier said than done in most cases as they're often at the back of the engine and the bolts ridiculously seized. I take it theres no leaks going to the intercooler or on any of the pipework is there? I'd want to rule everything out before attempting to remove the turbo.

 

Replacement turbos can often be had much cheaper than you think if it is borked. Bad listings on ebay have been the source for many turbo's for me, and I've not paid over £40 for any of them - the best was a 99p one from a Corsa diesel I made in to a hybrid for my Mira

[HBR]

What model Rover is it? The later ones have electrically controlled fuel pumps as many other things do & the air flow meter is well known for buggering up, car runs fine but lack of power. If you have a plug with a several wires going on to the intake between the filter & turbo try disconnecting it, if it goes better it's likely the cause.

Turbo failure giving lack of power but no other running faults like serious oil consumption are rare, I have seen the wastegate linkage come apart but it's fairly obvious!

[stuboy]

check for loose pipe work?

[stuboy]

check for loose pipe work?

[wuvvum]

I've thoroughly checked all the turbo pipework for looseness / splits and it's all good. I'll try unplugging the MAF sensor and see if that makes any difference.

 

Turbo is right down the back of the engine, and access isn't great. I don't think the turbo's actually failed though - it's still boosting a bit, just not as much as it should, and there's no excessive smoke and no untoward noises apart from the hiss of the boost escaping from somewhere...

 

The problem is that there's no way of getting the turbo under load with the car stationary, without putting it on a rolling road - and I don't have access to one of those. So my attempts to fix it are a bit trial and error...

[wuvvum]

I've thoroughly checked all the turbo pipework for looseness / splits and it's all good. I'll try unplugging the MAF sensor and see if that makes any difference.

 

Turbo is right down the back of the engine, and access isn't great. I don't think the turbo's actually failed though - it's still boosting a bit, just not as much as it should, and there's no excessive smoke and no untoward noises apart from the hiss of the boost escaping from somewhere...

 

The problem is that there's no way of getting the turbo under load with the car stationary, without putting it on a rolling road - and I don't have access to one of those. So my attempts to fix it are a bit trial and error...

[Cavcraft]

Does it have a charge/boost pressure valve?

On the dreaded Passat I had the turbo kept packing up and (although your's is acting differently by the sound of it) it'd sometimes work, sometimes not. Turned out to be the charge/boost pressure valve and was a cheap fix even at a VAG specialist using new parts.

 

Some bumph here about them, God knows if it's a similar-ish set up to your Rover, or if all TDs have them, but thought it might help if you're trying to eliminate problems.

[Cavcraft]

Does it have a charge/boost pressure valve?

On the dreaded Passat I had the turbo kept packing up and (although your's is acting differently by the sound of it) it'd sometimes work, sometimes not. Turned out to be the charge/boost pressure valve and was a cheap fix even at a VAG specialist using new parts.

 

Some bumph here about them, God knows if it's a similar-ish set up to your Rover, or if all TDs have them, but thought it might help if you're trying to eliminate problems.

[alf892]

Given that you say boost is down from 16 to 8 and you can hear the hiss of the boost escaping I can't see why you need to bugger about with anything else?? OK it could be the wastegate but unless it has become disconnected it is pretty unlikely. I would try blanking all of the intake pipework (ie at turbo and manifold ends) and then pressurise with compressed air to find the leak. I know you have checked the pipework but if there is a hiss there is a leak............have you checked the intercooler for for damage/rot?

[alf892]

Given that you say boost is down from 16 to 8 and you can hear the hiss of the boost escaping I can't see why you need to bugger about with anything else?? OK it could be the wastegate but unless it has become disconnected it is pretty unlikely. I would try blanking all of the intake pipework (ie at turbo and manifold ends) and then pressurise with compressed air to find the leak. I know you have checked the pipework but if there is a hiss there is a leak............have you checked the intercooler for for damage/rot?

[triumph1300]

I used to run a rover 600 series turbo diesel and it done EXACTLY the same thing as yours. It was a split in a boost pipe which only became apparent under boost, you couldn't see or feel it when on the car, I took all pipes off and only when it was off the car and I could bend it did the split show up... Symptoms were identical to yours..

[triumph1300]

I used to run a rover 600 series turbo diesel and it done EXACTLY the same thing as yours. It was a split in a boost pipe which only became apparent under boost, you couldn't see or feel it when on the car, I took all pipes off and only when it was off the car and I could bend it did the split show up... Symptoms were identical to yours..

[wuvvum]

have you checked the intercooler for for damage/rot?

That's a good point actually - there's no rot on the intercooler that I could see, but I haven't checked properly for damage - could be a stone's hit it at speed or something. Unfortunately I don't have the facilities to pressurise the system with air to find the leak - would probably be a quick way of finding the problem, but would also involve taking the car to a garage and giving them money, which I'm trying to avoid doing unless I absolutely have to...

 

I used to run a rover 600 series turbo diesel and it done EXACTLY the same thing as yours. It was a split in a boost pipe which only became apparent under boost, you couldn't see or feel it when on the car, I took all pipes off and only when it was off the car and I could bend it did the split show up... Symptoms were identical to yours..

 

That's also something I might try as a last resort (not relishing scrabbling around in the depths of the engine bay trying to undo 15-year-old jubilee clips ) - I did check pretty thoroughly, but it's true that rubber pipes can be a pain in the arse for hiding small splits.

 

Does it have a charge/boost pressure valve?

 

Don't think so - I couldn't see one, anyway. It's not a particularly sophisticated turbo setup, to be honest...

 

Anyway, took the car for a quick drive earlier with the MAF sensor disconnected - didn't solve the power problem but bugger me she was responsive at low revs! Even more gutless at high revs though, alas.

[wuvvum]

have you checked the intercooler for for damage/rot?

That's a good point actually - there's no rot on the intercooler that I could see, but I haven't checked properly for damage - could be a stone's hit it at speed or something. Unfortunately I don't have the facilities to pressurise the system with air to find the leak - would probably be a quick way of finding the problem, but would also involve taking the car to a garage and giving them money, which I'm trying to avoid doing unless I absolutely have to...

 

I used to run a rover 600 series turbo diesel and it done EXACTLY the same thing as yours. It was a split in a boost pipe which only became apparent under boost, you couldn't see or feel it when on the car, I took all pipes off and only when it was off the car and I could bend it did the split show up... Symptoms were identical to yours..

 

That's also something I might try as a last resort (not relishing scrabbling around in the depths of the engine bay trying to undo 15-year-old jubilee clips ) - I did check pretty thoroughly, but it's true that rubber pipes can be a pain in the arse for hiding small splits.

 

Does it have a charge/boost pressure valve?

 

Don't think so - I couldn't see one, anyway. It's not a particularly sophisticated turbo setup, to be honest...

 

Anyway, took the car for a quick drive earlier with the MAF sensor disconnected - didn't solve the power problem but bugger me she was responsive at low revs! Even more gutless at high revs though, alas.

[Pillock]

Is it a variable geometry turbo thingie?

My Seat has such a beastie and it has a pushrod which is activated by some valve- if this is broken (I think it's actuated by vacuum - I pulled a pipe off the bulkhead, sucked it and the rod moved) then you lose loads of power. I only looked into this as I've got really odd power delivery and it's a common issue after fitting a recon turbo, the rod has an adjuster on it which needs to be set to the right length.

[Pillock]

Is it a variable geometry turbo thingie?

My Seat has such a beastie and it has a pushrod which is activated by some valve- if this is broken (I think it's actuated by vacuum - I pulled a pipe off the bulkhead, sucked it and the rod moved) then you lose loads of power. I only looked into this as I've got really odd power delivery and it's a common issue after fitting a recon turbo, the rod has an adjuster on it which needs to be set to the right length.

[scaryoldcortina]

Good tip for tracking a boost leak - spray bottle with water and washing up liquid in, spray the pipes/intercooler matrix and look for bubbles

[scaryoldcortina]

Good tip for tracking a boost leak - spray bottle with water and washing up liquid in, spray the pipes/intercooler matrix and look for bubbles

[wuvvum]

Had a thought today - the boost gauge gets its feed directly from the turbo via the feed pipe to the wastegate actuator - it's completely separate from the main pipework that takes the boost via the intercooler to the inlet manifold. As far as I can get my poor sleep-deprived brain around the problem, surely then if the leak was in the main turbo pipework the reading on the boost gauge wouldn't be affected, as the turbo would still be providing full boost, which would then simply be lost further down the line? The fact that the boost gauge is only showing 8 psi leads me back to thinking that the problem is within the turbo assembly itself. Unless I've completely misunderstood things again.

[wuvvum]

Had a thought today - the boost gauge gets its feed directly from the turbo via the feed pipe to the wastegate actuator - it's completely separate from the main pipework that takes the boost via the intercooler to the inlet manifold. As far as I can get my poor sleep-deprived brain around the problem, surely then if the leak was in the main turbo pipework the reading on the boost gauge wouldn't be affected, as the turbo would still be providing full boost, which would then simply be lost further down the line? The fact that the boost gauge is only showing 8 psi leads me back to thinking that the problem is within the turbo assembly itself. Unless I've completely misunderstood things again.

[Mr_Bo11ox]

If there was a leak the turbo would not be able to provide full boost, so if you have a boost gauge it should be showing you a reduced 'max boost' though whether the guage is precise enough to tell you of a small leak is another matter.

[Mr_Bo11ox]

If there was a leak the turbo would not be able to provide full boost, so if you have a boost gauge it should be showing you a reduced 'max boost' though whether the guage is precise enough to tell you of a small leak is another matter.