405 turbo ineffecient

fodtommo · Unread post by **fodtommo** » 11 Jul 2008, 12:48

me again!

Problem as follows:

new to me 405 1.9dt glx - non cat, very good cond for 170k. regular servicing etc.

The turbo is only just working - it feels almost like a GLD!

when you put your foot down the turbo does not come in at 2200rpm like the other 1.9tds ive owned - you only feel it a little bit when you hit 3500 maybe.

The filters are all new and there does not appear to be any sign of oil in the induction pipes and no smoke from the exhaust, so I think the Turbo unit is ok.

My other observation is that the top end is very rattly. it is worse on intitial start and does quieten after a minute as the oil gets around - previous owner used GTX magnatec which i think is a bit thin for one of these-

However it remains rattly.

My thoughts are that the fuel pump is slightly out of time - would explain the rattle?

A friend is adamant it is the EGR valve - i have never touched these before - where do I start?

other possibility is boost control from fuel pump?

Any thoughts gratefully recieved - I will be tackling the problem on Sunday!!

Unread post by **CitroJim** » 11 Jul 2008, 13:03

Hi Tom,

For the boost problem, given there are no leaks in the ductwork or intercooler, check the small pipe from the top of the injection pump Bosch Side on a Lucas) to the intercooler. This pipe senses boost and alters the pump fuelling to compensate. It very often perishes and leaks. If not that, you'll have an air leak somewhere between the turbo and inlet manifold.

Later 1.9TDs (Only those with a semi electronic injection pump) do have an EGR valve. Look on the RH (as you look under the bonnet) side of the exhaust manifold and you'll see a little thing that looks like a lantern. It operates on vacuum via an electrovalve. You can defeat it by pulling the vacuum line off it. The controlling electrovalve often fails. If you cannot see a little lanter-like thing then you have not got one

A rattly top end is usually valve clearances. Check them and if they're out you'll need to reshim. It's a bit of a task but i have an Excel spreadsheet, should you need it, to help in calculating the new shims needed. I also have quite a selection of shims.

I've also know the problem being caused by loose cam caps or where cam caps from another head have been fitted. On these engines, the cam caps are line-bored and are thus matched to the head and cannot be swapped over.

Also, check that sufficient oil is reaching the top end. When you lift the rocker box there should be a lot of oil sitting around the cam and valve buckets.

fodtommo · Unread post by **fodtommo** » 11 Jul 2008, 13:09

ahh now there is a small amount of oil appearing to come from the front of the intercooler - i havnt had the car long enough to check all these things!

if there is oil coming from the i/c I have a good one on the other pug and could easily swap them - would this hinder the boost performance if it is leaking?

Unread post by **CitroJim** » 11 Jul 2008, 13:27

fodtommo wrote: would this hinder the boost performance if it is leaking?

Yes Tom, an intercooler leak will certainly reduce bost.

Not such a problem on a 405 but do check that none of the big turbo hoses are kinked or constricted. It's a coomon problem on Xantias and cause a severe reduction in boost.

fodtommo · Unread post by **fodtommo** » 11 Jul 2008, 13:35

Thanks Jim

You are a mine of very useful information!!! i will change the I/c...

fodtommo · Unread post by **fodtommo** » 14 Jul 2008, 08:03

Thankyou Jim

I removed the intercooler to find the rubber sealing ring between the intercooler and the manifold blown out, swapped it for the one off the other car and hey presto - boost! turbo spins up beautifully now.