No 3 injector pipe changed.engine sounds terrible...

[lentulus]

Hi there. My 1989 1.6 td [jx] van passed its MOT a day ago [bar a spot of rust}. However, coming back from the test, smelled unburned diesel. Stopped, to find injector pipe on no 3 cylinder spraying out just above the union nut [engine end]. Fitted a new pipe from Brickwerks. Engine started ok, but if run at anything above idle, the clattering is awful... the idle is surging too. It's a tired engine at 220k but was running happily [before the MOT] and has done 400 miles since a new cambelt was fitted ,10 days ago, without any issues. Any advice on how best to proceed would be gratefully received.

[bigherb]

Is the new injector pipe the same length as the old one including all turns it makes ?

[lentulus]

As best can be measured, using a piece of string, the new pipe appears to be approx 8mm longer than the original...

[davidoft1]

Pull the injector pipe off and make sure it's got a hole in it etc, sounds like diesel knock , usually over fueling or unburnt fuel, how long have you run it for ?

[lentulus]

Before fitting the new injector pipe I did test to see it was clear [blowing through it]. I have started the engine twice and on both occasions run it for a minute, then stopped it, horrified by the shuddering and noise.Not keen to start it again, for fear of causing damage : could it already be damaged?

[Oldiebut goodie]

Did you bleed the pipe before tightening up, injector end?

[lentulus]

OBG - I did not do this - but I should have?

[Oldiebut goodie]

You normally need to bleed the air out, leave the engine running and just crack open the injector end of the pipe until fuel is coming out rather than air then re-tighten. With a bit of luck that should solve it. Some engines are able to self bleed, some not.

[davidoft1]

As oldie but goodie says, needs to run for a few minutes, you also need to bleed out the air by undoing the pipe at the injector end until the air is gone

[lentulus]

Thank you for taking the time to post [especially on a Bank Holiday!] Have done as you both suggest, bleeding over the course of several minutes. The engine eventually settled and sounded normal on tickover. So I gradually opened the throttle to 'fast tickover'. At a certain point,the revs. seemed to increase dramatically [without more throttle] and the exhaust blew out considerable gray smoke, accompanied by the harsh knocking sound from the engine. I released the throttle and the revs.[and knocking] sound from the engine very slowly died back, but the gray smoke continued... so I switched off. Even before this 'runaway' the exhaust was a thin white smoke - which it has never done before - apart from a 'normal' puff on start up, which used to clear in less than half a minute.
I should add that the mechanic who changed the cam belt two weeks ago made a point of inviting me to see the noticeable sideways play at the injector pump drive spindle, before he put the new belt on...[he also said there might be an injector issue...]

[davidoft1]

That's just unburned fuel, keep it running until it stops smoking

[Oldiebut goodie]

Did you touch any of the other injector pipes?

[lentulus]

OBG - yes, in the sense that I tweaked the No 4 pipe ever so slightly [ without slackening its union nuts] to avoid a contact with the new no 3 pipe. Also at the initial fire up after the repair I did briefly Slacken and nip up each injector union [in turn ] to see that fuel was issuing. It was.
After the longer run this afternoon fuel was seeping from the joint between the exhaust pipe and the silencer inlet

[ajsimmo]

It's possible that muck has got into the injector in the process of changing the pipe. This could jam the needle and cause the injector to hose, which would give you the unburnt fuel out the exhaust. It's harmful to run it like that as it can wash the bore of lubricant causing bore and piston damage, and dilute the engine oil with fuel.

Sent from my B1-830 using Tapatalk

[lentulus]

Well, this morning, I put the old No 3 injector pipe back on, started up and bled. Noticed the engine ran quite well whilst bleeding . When nipped up, NO FUEL SPRAYING OUT where leak was originally spotted! Same horrid knocking from engine when 'opened up' , BUT with the same no 3 injector pipe slack [and fuel fizzing out of the union] engine could be opened up with virtually no knocking....Might this add weight to ajsimmo's suggestion that the No 3 injector is in some way fouled up?