Vauxhall Combo 1.3cdti inlet manifold has a hole in it...

[MeldrewsMate]

I started hearing this blowing noise when in the outside lane of the motorway (that doesn't happen very often) and doing 70mph (that happens even less often), clearly a sound reflecting off the central Armco barrier through my open window on a hot day. 100 miles later the check engine light came on. After several days of town driving the light went off, and after a further 200 miles of motorway driving at my usual speed of 55 to 60 mph it returned.

On inspection there was (and is) a small (diameter about 5mm) hole in the plastic inlet manifold, which I intend to repair today.

Are any special tools or techniques required to remove and replace the inlet manifold?

What are the combination of ignition key and pedal presses needed to have the dash lights flash (indicate) the stored fault codes?

Does the EGR valve discharge into the inlet manifold via a 3/4" (or so) flexible pipe? With the inlet manifold removed, would this be an opportunity (at 140,000 miles) to clean out the EGR and its port?

Finally (though not relevant to this specific post) what conditions cause the EGR to open, and to close....the hissing/blowing stops consistently around 2 seconds after the throttle is released (on over-run), and for a short time when using more throttle than normal (say at the start of a hill, or accelerating)?
Does the EGR valve have proportional control, ie can the ECU set it to 25%, 50%, 75% open?


Regards, MM

 

[Burnerman]

Wondering if I'm the only person wondering how the inlet manifold has a hole in it?
Anyhoo there's some info on replacing the thing on youtube or whatever, and the egr pipe does discharge into the inlet manifold. The engine ecu decides when the egr valve is opened (its closed on tickover and starting up for example) and if you've got that far its well worth cleaning or renewing the egr valve itself.
Sorry - I've no experience of this task on the Vauxhall.
John

 

[Mottie]

Wondering if I'm the only person wondering how the inlet manifold has a hole in it?

When I did my apprenticeship at Vauxhall, we were always changing inlet manifolds on Viva's/Chevettes. They had just two branches serving 4 cylinders but they also had two tiny branches that the exhaust gas went through to pre-heat the manifold and the fuel mixture. When you used to get a noise sounding like a burnt inlet valve popping up the carb, we had to unbolt the manifold, turn it upside down and pour water into the exhaust branch. If it came out of the inlet branch, it had burnt through inside and needed replacing. It was quite common.

 

[Burnerman]

The 1.3 ctdi has a plastic affair, doesn’t it?
I’ve replaced a Transit one but that had ingested a turbo vane and shot it out of the side
John

 

[MeldrewsMate]

The 1.3 ctdi has a plastic affair, doesn’t it?
I’ve replaced a Transit one but that had ingested a turbo vane and shot it out of the side
John

Yes John, it's plastic, and surrounded by all sorts of paraphenalia. I started the job, but then realised it would take several more hours to get the inlet manifold off....so I bunged-up the hole with glass fibre supported by sticky tape (the hole is underneath, near to where the EGR is). The EGR itself has multiple things surrounding it and its fixing bolts....I get the impression this is one of those vans where it's best to save up those little jobs to do all at once and with the engine out!!! Not proud of my 'temporary' repair, but will monitor it for signs of re-failure.

Incidentally, my OBD reader (knock-off ELM327 from Ebay) wouldn't work, and hasn't since I got windows 10. I installed Scantool v1.13 (the last version before they started checking for genuine chips) onto an old Vista laptop, and with a bit of fiddling with drivers (well, several hours worth) I got it to read the sensors. The EGR appears to be modulated by the ECU. Its dc resistance (for those who are interested) was about 10 ohm.

 

[MeldrewsMate]

Wondering if I'm the only person wondering how the inlet manifold has a hole in it?

I'm a little ashamed to say that I probably had a small contribution to generating the fault.
Several years ago, soon after getting the van, I would occasionally see the 'check engine' lamp come on, associated with a loss of power. Assuming it to be fuel starvation (because it always coincided with more spirited driving) I initially changed the diesel fuel filter to no effect. After getting hold of a fault codes reader which reported 'excessive turbo boost' I found that the turbo wastegate was stuck/seized in the closed position...and it still is. Presumably the faster than normal trip up the motorway caused the EGR to discharge hotter gases than normal (ie too hot for the manifold but not high enough pressure to trip the 'overboost' alarm), thus blowing a hole directly opposite the EGR discharge port.
I've a 300 mile trip coming up this week, though at 'normal' 50-60mph speeds so I don't expect a repeat.

Some supplementary questions, if I may.
Is the 1.7 cdti a direct replacement for the 1.3? If I'm going to have to take the engine out I may as well have a benefit at the end.
Does the 1.7 cdti have its own unique failure areas?

MM

 

[Mottie]

I’d imagine the final drive gearing would be different on a 1.7 compared to a 1.3.

 

[cdbe]

1.7 is completely different to the 1.3 and won't swap. I had same problem with stuck waste gate on my 1.3, I ignored it for a long time as it ran quite well in limp mode (engine light came on in my case). When I got my ELM from eBay and it diagnosed the problem I was able to free it off in about 5 minutes by poking and prodding the linkage with a long metal rod from underneath. It's a while since I had it but I seem to recall they responded well to blocking off the egr - with a blanking plate with a small hole in which lets just enough smoke through to keep the sensor happy. Short self tapping screw and a rubber washer might be good enough to plug that hole in the manifold.

 

[MeldrewsMate]

...Short self tapping screw and a rubber washer might be good enough to plug that hole in the manifold.

I considered that, but it was such a faff to get anywhere near to removing the inlet manifold (always something in front of the something in front of the bolt I wanted access to) that I ended up sealing the hole with araldite supported with sticky tape; and it seems to have held so far. I also had to consider the catastrophic damage that could be caused by any repair material being sucked into the engine when the manifold was/is under partial vacuum, and further turbo damage on its way out.

 

[Mottie]

I also had to consider the catastrophic damage that could be caused by any repair material being sucked into the engine when the manifold was/is under partial vacuum, and further turbo damage on its way out.

I don’t think Diesel engines have any noticeable vacuum in the inlet manifold, that’s why they need a vacuum pump for the brakes.