Peugeot 306 hdi - Lack of power, turbo failure?

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Wed 7 Nov 2012 18:31
Peugeot 306 hdi - Lack of power, turbo failure? - scfc_151

I have a 2001 306 hdi with 210,000 miles

The problem I have at the moment is a lack of power. The car seems to tick over fine, engine sounds sweet and it actually drives fine but just feels like a car without a turbo.

When pushing it a bit on a motorway slip road for example I dont feel the power surge that I use to. I dont know if this is because im use to it now or it actually has lost power.

Just for further information ive posted a while back about a high pitch whistling noise when driving. This happens when the revs have stayed constant for a few seconds. I never actually got to the bottom of this.

Also recently the EML came on so I bought a diagnostic tool for the laptop which showed up an error code for the throttle position sensor. However, this was replaced a couple of years ago so im wondering if it just requires a wiring modification for this car?

I was also wondering if the MAF sensor could be at fault? ive heard of a few people that disconnected it and suddenly made the car have more power.

If the turbo was at fault would there be any other symptoms of this other than a lack of power?

Thanks in advance

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Wed 7 Nov 2012 19:58
Peugeot 306 hdi - Lack of power, turbo failure? - Peter.N.

Have you checked the turbo piping and intercooler for leaks? The whistle you are hearing could be due to a split/disconnected air hose.

Edited by Peter.N. on 07/11/2012 at 19:58

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Wed 7 Nov 2012 20:05
Peugeot 306 hdi - turbo failure? - Collos25

The EML light is a sure sign of limp home mode which substantiates your lack of power check for leaks as Peter says it sounds that way if power returns by disconnecting the MAFits a sure sign its faulty.

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Wed 7 Nov 2012 20:23
Peugeot 306 hdi - turbo failure? - scfc_151
Hi guys

Theres no noise like rattling or anything. There is quite a lot of black smoke while under load or heavy acceleration but not under normal driving conditions. The car has never been in limp home mode as it revs to whatever you want and theres no problem with top end speed just seems to have no poke.

Ive had a look for leaks on hoses etc from the turbo and I cant see any but to be honest the access is terrible on my car. This model also doesnt have an intercooler (wish it did)

Thanks for the replies

Edited by scfc_151 on 07/11/2012 at 20:24

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Thu 8 Nov 2012 01:11
Peugeot 306 hdi - turbo failure? - BenG

Black smoke under load suggests the engine is running rich. One cause of this can be an air leak, resulting in less air reaching the engine than is output by the turbocharger. This is also consistent with your lack of power. Boost leaks can be hard to find as the hole only opens up under boost pressure.

Worth another look for leaks - look for tell-tale oily marks / spray as the intake air contains oil from the turbo bearings - some passes through into the air stream.

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Thu 8 Nov 2012 17:56
Peugeot 306 hdi - turbo failure? - dereckr

I’m not suggesting that your problem is exactly the same but…

My Xsara HDi (same engine plus intercooler) suffered a decline in power at around the same mileage. I had considered changing the MAF. I had had no EML warnings, so there were no codes stored.

The problem came and went for a while, but was remedied when the EGR valve was replaced. The EGR was original fitment, so the garage struggled to release the rusting bolts (access is difficult). The diaphragm unit was leaking vacuum which may have been affecting other devices sharing the vacuum lines, the turbo being one of them.

I also replaced the rubber hose vacuum lines to the turbo, electro valves and the EGR. Where the hoses touch the engine, the heat and age had made them very soft and (possibly) liable to collapse under vacuum. New hoses were relatively inexpensive from Citroen. The MAF remains original. The repair cost me around £300.

The performance increase was immediate and I have had no re-occurrence in the 17k miles I have driven since.

Edited by dereckr on 08/11/2012 at 17:56

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Thu 8 Nov 2012 19:28
Peugeot 306 hdi - turbo failure? - scfc_151
Hi

Thats great info ill have to have another good luck underneath. I think ill be taking all of the plastic off because its such poor access.

Just out of intrest dereckr did your car have a whistle when the revs were constant?

Cheers
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Thu 8 Nov 2012 22:11
Peugeot 306 hdi - turbo failure? - dereckr

The “whistle” from the turbo is normal, after all that’s the sound it makes when it’s working.

It’s never intrusive on the car and is barely audible to passengers. Only on the motorway under acceleration in fifth does it become more pronounced. Even under steady state conditions and quite light throttle settings, the turbo is working, if the load on the engine demands it.

Access to some of the engine parts is a big issue with these installations. It’s a lot of engine in a medium vehicle. Even as an enthusiastic amateur mechanic I wouldn’t even try and get to the EGR, manifold and turbo myself. I trust the garage I use and was happy with the outcome. I use the car every day to commute and can’t afford the down time for major DIY repairs.

Just one more thing.

These motors are good for high mileages, but at over 200k, any car engine (and I don’t care who makes it) is getting towards the end of its life. Mine has done 226k now and up until recently has remained oil tight from the mechanicals and clean (relatively) from the exhaust. I elected to have the cam belt changed at 200k and the related problem fixed, but you have to call a halt somewhere. The snag for me is that the vehicle drives so well, you would never guess the mileage from the driver’s seat. If it was showing its age in other ways, I would have got rid of it ages ago.

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