PD150 ARL Engine, smoke/shuddering on start.

[Davegsm82]

As per the title, my ARL engine golf seems to be having a bit of a hard time Idling smoothly on start up.

It smokes for a good while on startup too, smells 'dieselly', both the smoke and the shuddering pretty much stops once the engine gets up to about 35-40 degrees C, as read from both the engine CTS and the Instrument cluster on VAGCOM. I have had similar issues caused by the 4 pin coolant temp sensor perviously, but this one is reading fine so I think something else is amiss. The shuddering also goes away if you raise the revs slightly, but the smoke continues until it warms.

I thought perhaps it was the valve guide seals worn, as the engine uses a small amount of oil between changes.

I fitted a replacement Cyl head to this engine about 30,000 miles ago, as it had HGF and eroded the old head. No history on the new head unfortunately.

Any suggestions for anything to try/diagnose?

 

[BobnOH]

Be sure the glow plugs are glowing.

 

[Davegsm82]

Be sure the glow plugs are glowing.

I'll be sure to check that tomorrow, pretty confident they are fine as I replaced them less than a year ago along with half the harness as it shattered when I attempted to remove it.

 

[Zak3]

It can be a faulty injector or faulty injectors loom.

 

[Davegsm82]

It can be a faulty injector or faulty injectors loom.

I'm not getting any error codes related to the injector loom, what are the symptoms you would expect from a failing loom?

I have a spare set of injectors for this car, but they will require new seals etc before fitting.

 

[Rrusse11]

"they will require new seals etc before fitting."

The copper crush washers can be re-annealed, rendering them soft again.

Heat to red, quench immediately in cold water. A propane torch and

a bit of coathanger wire will do it.

 

[Davegsm82]

"they will require new seals etc before fitting."

The copper crush washers can be re-annealed, rendering them soft again.

Heat to red, quench immediately in cold water. A propane torch and

a bit of coathanger wire will do it.

Yea, I'm quite happy annealing the copper washers but the PD injectors have a series of O-rings on the body which seal against ports in the bore. They frequently burst through unfortunately so it's not recommended to reuse them.

 

[Davegsm82]

Checked the glow plugs today, all absolutely fine, however I smashed my GP connector loom getting it off them, this will be the second one I've put on this car due to it going brittle with age.

 

[Rrusse11]

Yea, I'm quite happy annealing the copper washers but the PD injectors have a series of O-rings on the body which seal against ports in the bore. They frequently burst through unfortunately so it's not recommended to reuse them.

Oops, sorry. No experience whatsoever with PDs. I stand corrected.
Cheers!

 

[Davegsm82]

So today a couple of times I noted a slight hesitation on acceleration in 3rd gear when pulling hard. This has happened in the past but simply went away of it's own accord.

Again is this a sign of injector loom failure or something else obvious?

Oops, sorry. No experience whatsoever with PDs. I stand corrected.
Cheers!

No worries

 

[Davegsm82]

Tracked the poor idle/smoke down to the GP relay in the relay panel, relay number 167. Relay coil was open circuit, reading 500 ohms (snubber resistor only), instead of ~50ohm for a good relay, made the ECU think the relay was still good.

Car has also been slow to catch on startup, noticed battery voltage was down at 11.9v before I even turned the key, battery even though new was bad.

Also tracked an oil leak to somewhere on the rocker cover, has had new seals but still leaking as per the link below.

https://youtu.be/QC5TwUqTQRI