309 D turbo losing power

[Gsbx1220]

Hi

Probably one for the old school diesel guys, but any thoughts much appreciated.

I have a 1993 GLX D Turbo which very occasionally loses power. This doesn’t happen every drive and isn’t related to engine temperature or fuel level in the tank.

The car will under light throttle feel if it’s losing power, and when more acceleration is applied it will not respond. If the clutch is dipped, the revs will die. After a short while the car will come back to life if nothing ever happened.

The car starts very very easily from cold, even in freezing temperatures, doesn’t smoke on start up, and none visible under hard acceleration. Idle speed is sitting at just under 1000 RPM.

One thing I have noticed is that there is very very occasionally a slight Diesel weep at the stop lever. However, this isn’t seen all the time. I can’t always replicate this by wiggling the stop shaft with the engine running, so I’m not sure if this is of concern.

There doesn’t seem to be a weep at the accelerator shaft.

Car has just hit 100k miles!

Goes like the clappers otherwise.

I’m teaching my young nephew (it’s his car) to drive in this, so I want it to be spot on!

Any thoughts.

[mickthemaverick]

Hi Richard,
I'm one of the old school guys but I run on Weetabix so not much use to you!

However for what it's worth this sounds to me like the occasional bubble in the fuel supply, if you have a diesel leak of any sort it indicates you may get air in where diesel is getting out and hence a bubble in the fuel line means some cycles with no fuel to the injectors and hence no power. Just a thought!!

[Gsbx1220]

Cheers.

I was going down the air route. The car has the Purflux style fuel filter. We replaced the filter back in November , but the genuine Peugeot / Purflux filter didn’t come with any seals. My thought that these seals are past their best, and letting air in. I have new seals on order.

[Gsbx1220]

I have bought a pump seal kit. There are 2 versions. One with just the throttle shaft seals and top plate O ring & full kit.

I bought the full kit as it has the seal for the stop lever. The other doesn’t.

Bought from here https://injectionpumps.co.uk/product/co ... uel-pumps/

[mickthemaverick]

Good plan, let us know how it goes when fitted.

[Stickyfinger]

Also possible that you have a small split in the (pressured) side of the intake and are loosing boost

[RichardW]

I seem to remember that Lucas pumps are sensitive to air leaks as they use the pressurised diesel internally for control.

[CitroJim]

I seem to remember that Lucas pumps are sensitive to air leaks as they use the pressurised diesel internally for control.

Not nearly so much as a Bosch pump. They really do suffer badly with even small air leaks.

That said, I'm very much of the opinion the problem you are having is indeed caused by a small air leak somewhere... It's unlikely to be the small leak at the cold start lever boss. It's worth checking all the pipery from the fuel filter to the pump and the fuel filter itself. The difficulty is that small leaks along the pipes rarely leak diesel as they are under suction when the engine is running.

Another set of pipes to check are the injector leakoff pipes, especially the blanking plug on the end of the last injector in the daisy-chain.

Also give the diesel return line back to the tank close scrutiny too... This can become blocked due to algal growths in the bottom of the fuel tank. A good blow down the pipe with an airline can fix this!

A good way to determine if it is air leaks is to temporarily replace the fuel pipe from the filter to the pump with a length of translucent pipe. If you then see air bubbles in that pipe you are on the way to fixing the issue.

At risk of teaching you to suck eggs, be aware that diesel and bare skin do not mix well and diesel can be the cause of a nasty variant of contact dermatitis so always wear protection. Also be aware that high pressure diesel sprays can cut skin like a knife and do some considerable harm.

If all this fails to resolve or determine the issue, there is a know problem with the Lucas pump whereby the metering needle valve internal to the pump can become gummy and stick. This usually manifests itself as a refusal to rev. The engine will start fine and idle but just won't rev. It's rarely an intermittent problem but worth bearing in mind.

[RichardW]

I seem to remember that Lucas pumps are sensitive to air leaks as they use the pressurised diesel internally for control.

Not nearly so much as a Bosch pump. They really do suffer badly with even small air leaks.

I couldn't quite remember which was which, but I knew you would know, Jim!

[Gsbx1220]

Hi guys,

Thanks for the replies.

On Friday we replaced the leak off pipes as they were rock hard. Didn’t replace the end cap because I thought that would be OK.

Fuel hose in engine bay is original & is also quite hard. We have new hose to fit, but was going to do that at the same time as fitting the new filter housing seals.

I will blow through the return line as well

The car revs freely and pulls like a train. This fault doesn’t happen on every journey. Maybe could go a few weeks without happening.

Otherwise the car is absolutely mint and has been very very well looked after all its life. I prefer it to my BX!!

BTW, I am very well aware of working with Diesel. Many years ago I had a colleague who was an HGV fitter who had to give his trade up because of contact dermatitis.

[Gsbx1220]

Ok,

Update. We have replaced the fuel lines from where they join onto the metal fuel pipes at the bulkhead to the filter. The seals in the filter housing have been changed also. This is the filter housing that uses the Purflux C180 paper element, so I think it was the seal at the top that seals the aluminium element housing.

The car has now done around 150 miles and seems OK, so possibly now sorted. But we are not stopping at that, the pickup hose from tank to metal pipe will be changed too.
Just doing it bit by bit to give us an idea of where the issue may have been.