General inlet control valve

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General inlet control valve

mexnick

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I recently followed one of the helpful guides on how to clean the inlet control valve on my stilo 1.9 jtd. Previously the car had started running like a pig eventually barely managing to get up a hill. When I took the valve off it was almost completely blocked up! cleaned it all out and also got out as much as i could from the other side (casing that extends over the top of the engine). Initially the car improved immediately, no more smoke out the back either. Over time though it has started to run a bit rough again also with some smoke when i put my foot down.

any ideas on what might be happening? I've thought about putting some diesel engine cleaner through the system to see if that helps but wondered if others had advice?

Thanks
Nick
 
I recently followed one of the helpful guides on how to clean the inlet control valve on my stilo 1.9 jtd.

When I took the valve off it was almost completely blocked up!

Out of curiosity, which guide did you follow. :confused:

The JTD engine doesn't have an idle control valve. The vacuum operated butterfly valve on the inlet is an idle cutoff valve designed to stop the engine running on after switch off. It should be permanently open except for a few seconds after switching the engine off, when it should close for about 3 seconds, then open again. I've never known one to be "completely blocked up". If it was, the engine wouldn't start at all.
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I recently followed one of the helpful guides on how to clean the inlet control valve on my stilo 1.9 jtd. Previously the car had started running like a pig eventually barely managing to get up a hill. When I took the valve off it was almost completely blocked up! cleaned it all out and also got out as much as i could from the other side (casing that extends over the top of the engine). Initially the car improved immediately, no more smoke out the back either. Over time though it has started to run a bit rough again also with some smoke when i put my foot down.

any ideas on what might be happening? I've thought about putting some diesel engine cleaner through the system to see if that helps but wondered if others had advice?

Thanks
Nick
Are you referring to the egr valve? Gets clogged with mixture of oil and soot.
 
Out of curiosity, which guide did you follow. :confused:

The JTD engine doesn't have an idle control valve. The vacuum operated butterfly valve on the inlet is an idle cutoff valve designed to stop the engine running on after switch off. It should be permanently open except for a few seconds after switching the engine off, when it should close for about 3 seconds, then open again. I've never known one to be "completely blocked up". If it was, the engine wouldn't start at all.
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its on the first page on the guide link for stilos : https://www.fiatforum.com/stilo-guides/83260-cleaning-your-inlet-control-valve.html

It does say it refers to a 1.6 model however. I've looked at other threads where it has been referred to as the idle cutoff so not really sure which it is. It wasn't completely blocked, just almost. There was a definite marked difference after i'd cleaned it though. Previously it was struggling to fire properly with plenty of black smoke as soon as you put your foot down. This all went away straight after cleaning the soot out of this part but as said, it's now getting back towards where it was before...not firing properly and black smoke starting to appear again?
 
Black smoke is a sign of running rich in a diesel.

Does the car pick up and turbo come in very suddenly over about 2,500rpm? If it does - the EGR valve is blocked. We can talk you through sorting that out.

If it doesn't, its possible you have a boost leak somewhere and you're losing some charged air, which is resulting in running rich. If this is the suspect then you'll have to start checking the turbo hoses for either dirt / soot / oil sludge around the pipe joints / connections and for any deposits on the pipe which might suggest it's got a hole in. You'd have to check the intercooler in the wing to make sure that's not got punctured too.
 
its on the first page on the guide link for stilos

It does say it refers to a 1.6 model however. I've looked at other threads where it has been referred to as the idle cutoff so not really sure which it is.

That explains it.... only the petrol engines have an idle control valve.

As already posted, I suspect you've cleaned the EGR (Exhaust Gas Recirculation) valve outlined red in the photo below. The idle cutoff valve is outlined yellow.

As posted by Artermis, check for leaks in the boost pipes. A common place for leakage is where the intercooler hose passes through the left side of the engine under tray. The hose can chafe on the edge of the plastic. I replaced the hose and increased the size of the cutout in the plastic when mine wore through
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That’s all really helpful! I’m working away from home this week so provided no other work crops up I’ll get under the bonnet next week and try your suggestions. Much appreciated, great with pictures too! Thank you
 
If the egr valve is clogged and held partially open then the turbo pushes lots of air straight into exhaust instead of cylinders. This causes black smoke due to over fueling.
 
Black smoke is a sign of running rich in a diesel.

Does the car pick up and turbo come in very suddenly over about 2,500rpm? If it does - the EGR valve is blocked. We can talk you through sorting that out.

If it doesn't, its possible you have a boost leak somewhere and you're losing some charged air, which is resulting in running rich. If this is the suspect then you'll have to start checking the turbo hoses for either dirt / soot / oil sludge around the pipe joints / connections and for any deposits on the pipe which might suggest it's got a hole in. You'd have to check the intercooler in the wing to make sure that's not got punctured too.

You might have a point about the turbo suddenly kicking in, never noticed what the revs are at but it does seem to do as you've suggested. Is the EGR valve a head ache to do? It looks fairly accessible from above although I've noticed there are a few hoses/pipes attached.
 
Very easy to do... just dont drop the bolts into the engine bay and you will be fine... also some string or tie wraps will help to hold wires / pipes.
 
Had the egr off and gave it a clean, the spring mechanism was sticking so sprayed a load of wd40 down and now moves freely, couldn’t budge the bolts holding the metal pipe attached below unfortunately so couldn’t get into that bit to clean it out. Just put it all back together and is lumpy when at low revs, am wondering if this might have something to do with the fuel filter? Had to disconnect a hose to get at the egr and so suspect I may need to prime the fuel line in case some air got in there, any advice??
 
Had the egr off and gave it a clean, the spring mechanism was sticking so sprayed a load of wd40 down and now moves freely, couldn’t budge the bolts holding the metal pipe attached below unfortunately so couldn’t get into that bit to clean it out. Just put it all back together and is lumpy when at low revs, am wondering if this might have something to do with the fuel filter? Had to disconnect a hose to get at the egr and so suspect I may need to prime the fuel line in case some air got in there, any advice??
The fact that you car started means no priming of fuel line required.
 
Tried disconnecting the injectors one by one with engine running and seems injector 1 isn’t working or wiring is faulty which is a different thread. Thanks for all the help on this one, have found another useful thread on injectors so will jump onto that now!
 
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