Leaking injector? (pic of pistons)

[KnockTurtle]

TU3 engine been causing me lumpy start up.

[tapkaJohnD]

2 and 3 look very clean indeed. Water getting in?

JOhn

[KnockTurtle]

I put the engine back together but still having the lumpy start up (only for approx 5 seconds).
The piston on the right was thick with carbon deposit (compared to the others) and has a small clean patch near the inlet valve.
My thoughts are... the injector is leaking petrol when the engine is off and the leaked petrol has soaked and softened the carbon resulting in the clean patch.

[mickthemechanic]

Hi

Did this problem arise after any other work was carried out. Many moons ago I had a similar problem on a Peugeot engine after the wrong inlet manifold gasket was supplied and it was obstructing the injectors preventing the fuel from mixing with the air correctly.

[KnockTurtle]

I've had the car since 2010 and the inlet manifold hasn't been off in the time I've had it.

[chammyman]

Well easy to check then, turn it off and watch a pressure tester, if it drops quick then you may beon the right track.

You might also just have a faulty check valve in the pump.

Or better way pull the fuel rail up and look at the injectors after priming them.

[Mignon]

Looks to me like a blown head gasket between 2 and 3 letting water in. Water ingress cleans pistons very thoroughly.

[chammyman]

Mignon said:

Looks to me like a blown head gasket between 2 and 3 letting water in. Water ingress cleans pistons very thoroughly.

He said its the same after doing the headgasket though

[Boosted LS1]

I agree with Mignon. Maybe the heads warped and the gasket isn't sealing. A cylinder pressure test's in order.

[Mignon]

The tops of the liners on 2 and 3 look very different from those on 1 and 2 so again I suggest the head gasket was not sealing. Did you check the head for straightness or get it skimmed before refitting it?

[tapkaJohnD]

see post 2
JOhn

[KnockTurtle]

I think its the lighting making 2 and three look clean.




I didn't get it skimmed

[KnockTurtle]

I have a fuel pressure tester on order.
I might pull the injectors out this weekend.
If I disconnect the coil then turn the engine over for 10 seconds then reconnect the coil, it will start perfectly.
Its not losing any water.


Thanks for all the replies

Edited by KnockTurtle on Saturday 22 July 17:23

[chammyman]

So have you taken this apart twice or is is still the same pictures from before but the issues the same since its back together?

[KnockTurtle]

All the pictures are from the same occasion

[GreenV8S]

KnockTurtle said:

If I disconnect the coil then turn the engine over for 10 seconds then reconnect the coil, it will start perfectly.

Your theory of a leaking injector is plausible. I don't know what state the engine is in now, but if it's assembled then you might be able to confirm the theory by pulling the plug on the suspect cylinder, turning the engine over to the intake stroke, and run the fuel pump. Either an endoscope or a rag shoved into the plug hole would reveal fuel dripping into the chamber.

A fuel pressure leakdown test would not IMO be conclusive because some leakage is normal and the gauge doesn't tell you where the leak is.

If you get evidence to support your theory then you'll need to pull the fuel rail to replace the injector so you will get an opportunity to repeat that test with the injector in fresh air so you can see the leak directly.

[KnockTurtle]

I'll pull the fuel rail regardless, easy enough job, cheers

[KnockTurtle]

I got the fuel rail out and found the leaking injector on the left cylinder.

https://www.youtube.com/watch?v=0SxM-fs8XU0

Got a new part ordered ready for tomorrow.

[GreenV8S]

Keep the old one - it isn't expensive to rebuild them.

I don't think you said how old the engine is, but if you think this might be an age related failure you could consider getting the other injectors serviced and flow checked while you have them out.

[KnockTurtle]

My injectors are manufactured by Valeo, are they interchangeable with Bosch?

Not sure if this link will work:

https://www.123spareparts.co.uk/car-parts/PEUGEOT/...

Part numbers are same 1984 EO.

My injector:

Edited by KnockTurtle on Sunday 23 July 21:50