Technical JTD stuttering while accelerating

[siwilks200]

Hi all

I changed the EGR valve (Inc the lower pipe) because it was stuck or the electrics had gone. This fixed a big acceleration/maf sensor warning I had.

Afterwards i noticed that whilst accelerating it stutters and at the same time it releases a hiss and I lose power when it stutters. It eventuality picks up though.

Months later i took the idle control valve off and cleaned it all as well as the egr from build up and oil. No fix.

Weeks later i see a lot of oil around the idle control valve and mostly around the small black plastic actuator that controls the valve. It looks like a oil is spraying out around the whole area. Probably I made the seal worse this time.

My question is does this sound like a leak and is there meant to be a gasket in between where the black air hose connects to the idle control valve because I don't have one. But there is a metal gasket between the idle control valve and the head.

Is the hiss the egr valve working. It has been said that sounds like the turbo working.

A nice image breakdown of this area would be useful to see the gasket positions. Thanks

 

[Davren]

is there meant to be a gasket in between where the black air hose connects to the idle control valve because I don't have one.

The JTD engine doesn't have an idle control valve. The part you're referring to is an anti shudder valve. Its sole function is to stop the engine running on after you switch it off. The butterfly should be permanently open, except for immediately after switch off, when it should close for a few seconds, then re-open.

I think there's a square section sealing ring fitted in a groove on the face of the plastic pipe flange where it bolts to the anti shudder valve. Perhaps yours is worn, compressed or fell out when you took the valve off.
.

 

[Artermis]

Stuttering and hissing is classic boost leak issue.

I'd suggest that you've either got a leak on the EGR you've been working on where it's not seated or sealed properly - or one of the boost pipes has split.

Splits in boost pipes can be very difficult to spot. A leak can only be a small pin hole when the engine is off or idle but the rubber hoses expand more than you'd think under boost, so that pin hole becomes the size of a penny.

You'd have to take the pipes off to properly inspect them but you can try and find in place. It's possible that you'll see or find oily wet spots where charged air is being leaked.

 

[siwilks200]

I think there's a square section sealing ring fitted in a groove on the face of the plastic pipe flange where it bolts to the anti shudder valve
.

Thanks. I am chasing Fiat to see if they can clarify the gasket situation - hard to find whether it does or not online!

 

[siwilks200]

Stuttering and hissing is classic boost leak issue..

Thanks. Do you refer to the Turbo as the boost? Which pipes should i be inspecting....the narrow black rubber ones around the EGR/air inlet, or around the Turbo (which i think is on the left of the engine as in the pic with a pipe (yellow highlighted) that goes to something on the right)

 

[siwilks200]

The JTD engine doesn't have an idle control valve. The part you're referring to is an anti shudder valve..

Fiat say there isn't a gasket between the black pipe and the anti-shudder valve (what they call the throttle body) but there is one between the throttle body and the inlet manifold.

so i wonder where all this oil coming from then, it coats the valve actuator (no.8 on the pic)....perhaps it's a small hard to find pin hole in a rubber pipe?!

I use a short hose pipe to the ear to try and find an air leak (works great) but can't find one hanging over the engine - only when its driving do i hear the hiss (so yeh sounds like it's somewhere on the turbo boost system)

 

[Davren]

Thanks. I am chasing Fiat to see if they can clarify the gasket situation - hard to find whether it does or not online!

ePER doesn't list it as a separate part for the Stilo, however it does list one for the Doblo fitted with the 1910 8 valve JTD engine. I would imagine it's the same size, but can't be sure.
.

 

[Davren]

Fiat say there isn't a gasket between the black pipe and the anti-shudder valve (what they call the throttle body) but there is one between the throttle body and the inlet manifold.

The flange is made of hard plastic, the valve body is aluminium. Very unlikely they would rely on them sealing without a gasket or "O" ring.

A common place for leaks is where the rubber pipe to the intercooler passes through side part of the engine undertray in the left wheel arch.

i wonder where all this oil coming from then, it coats the valve actuator (no.8 on the pic)....perhaps it's a small hard to find pin hole in a rubber pipe?

Clean the oil off, then run the car on short trips and inspect for where the oil is leaking from. As well as my previous suggestions, perhaps the flange cracked when refitting it.
.

 

[siwilks200]

The flange is made of hard plastic, the valve body is aluminium. Very unlikely they would rely on them sealing without a gasket or "O" ring.

A common place for leaks is where the rubber pipe to the intercooler passes through side part of the engine undertray in the left wheel arch.



Clean the oil off, then run the car on short trips and inspect for where the oil is leaking from. As well as my previous suggestions, perhaps the flange cracked when refitting it.
.

ok i will remove and inspect all of the above, thanks!:slayer:

oh by the way, what is the removable black plastic actuator called that attaches to the throttle body/anti shudder valve. presumably its electrically actuated with a vacuum hose on the bottom? thanks

 

[Davren]

oh by the way, what is the removable black plastic actuator called that attaches to the throttle body/anti shudder valve. presumably its electrically actuated with a vacuum hose on the bottom? thanks

It's a vacuum operated diaphragm actuator that opens and closes the butterfly. It's controlled by an electric vacuum valve (item 2 in the first diagram below) attached to a vacuum chamber at the back of the engine.

Regarding the flange "O" ring seal..... I'm 99% sure I saw one there when I removed the pipe to fit a new clutch to one of my JTDs few years ago. Because the flange and seal are both black, and the seal sits flush with the flange, it can be difficult to see.

I suspect Fiat told you there isn't one because ePER doesn't show it for the Stilo. For the Bravo JTD, ePER shows it as a gasket, however it's listed as the same part number as the Doblo one (post 7 above) that's shown as an "O" ring. ePER diagrams are just for parts departments to locate a part number, they don't always show an accurate diagram of the part.
.

 

[siwilks200]

Regarding the flange "O" ring seal..... I'm 99% sure I saw one there when I removed the pipe to fit a new clutch to one of my JTDs few years ago. Because the flange and seal are both black, and the seal sits flush with the flange, it can be difficult to see..

when i had a brief look yesterday i did feel a lip towards the inside diameter but assumed it was part of the plastic as it felt like it - i will check

For the Bravo JTD, ePER shows it as a gasket, however it's listed as the same part number as the Doblo one (post 7 above) that's shown as an "O" ring.

seeing as i can't get a stilo gasket (they dont even supply the metal one on the other side anymore!!), and if i need to renew mine, id hope a doblo o ring might fit. failing that i could just add gasket sealant to the flange/s?

 

[Davren]

seeing as i can't get a stilo gasket (they dont even supply the metal one on the other side anymore!!), and if i need to renew mine, id hope a doblo o ring might fit. failing that i could just add gasket sealant to the flange/s?

OR.... make one with PTFE string, or several turns of twisted PTFE tape. PTFE gas tape (yellow dispenser) is thicker and stronger than normal tape (white dispenser).

If your "O" ring is still there, but too compressed to seal properly, wind several turns of twisted PTFE tape into the groove, then refit the "O" ring.
.

 

[siwilks200]

A common place for leaks is where the rubber pipe to the intercooler passes through side part of the engine undertray in the left wheel arch..

regarding locating this specific area the attached diagram doesn't really help with the descriptions!

i assume the intercooler is no. 1 (heat exchanger) and the pipe i need to inspect is to the right of that?

should i check the others for leaks too or might it be any of the rubber egr pipes? ( i hear check them all!)

ta

 

[Davren]

i assume the intercooler is no. 1 (heat exchanger) and the pipe i need to inspect is to the right of that?

should i check the others for leaks too or might it be any of the rubber egr pipes? ( i hear check them all!)

Item 1 is the intercooler, but it's the hose to the left, not right of it in your ePER diagram that chafes on the undertray. It's the one that goes to the bottom of the intercooler.

A few years ago, I noticed that mine was chafing on the undertray and a groove had worn into the hose. It hadn't worn all the way through, so I wrapped it with self amalgamating tape and twisted the hose a little so it wasn't as close to the plastic undertray. After a while, the tape melted into a black gooey mess, so I fitted a new hose and trimmed the plastic away from it. It only needed a few millimetres, as in the before and after photos below.

Yes... you need to check all the pipes and hoses. I only pointed this one out because it's a known problem, so a good place to start.
.

 

[Artermis]

A few years ago, I noticed that mine was chafing on the undertray and a groove had worn into the hose. It hadn't worn all the way through, so I wrapped it with self amalgamating tape and twisted the hose a little so it wasn't as close to the plastic undertray. After a while, the tape melted into a black gooey mess, so I fitted a new hose and trimmed the plastic away from it. It only needed a few millimetres, as in the before and after photos below.

Yes... you need to check all the pipes and hoses. I only pointed this one out because it's a known problem, so a good place to start.

Sounds fairly classic.

Amalgamating tape is a good temp fix whilst you source a replacement hose if necessary.

I know in the Alfa 16v applications the lower charge pipe is known for fouling the gearbox / bell housing and wearing through.

The problem you have to look out for is that with the engine off the clearances look just fine but when under boost the pipes really do balloon out, more so as they age I'd suspect. So what looks good at idle will rub under load and make a good slice as it balloons and shrinks again and again.

On my Alfa 16v application I replaced the majority with hard piping and then changed to front mount intercooler (FMIC) when the intercooler got punctured.

I just chopped the factory pipes down and used the bends in the factory pipe as you would silicone hoses to join the metal pipes.

 

[siwilks200]

After a while, the tape melted into a black gooey mess, so I fitted a new hose and trimmed the plastic away from it..

did you purchase the pipe new from Fiat? or is a cheaper place good enough? ie:

http://www.ebay.co.uk/itm/FIAT-STIL...453920?hash=item1c777840e0:g:3rYAAOSwy4hUUlis

 

[Davren]

Fiat only supply it as the complete pipe (Item 3, post 13 above) which is the metal pipe with both hoses already attached to it. Fiat price about £140.

The hose in your eBay link looks like the same one I bought, but mine came from a seller in Poland and cost £35.

EDIT: This is the only way Fiat supply it.
.

 

[siwilks200]

Found this so far on that pipe and currently adding amalgamation tape for a temp fix. Can't see real holes but yeh, it's enough! Doesn't look great huh. Stupid fiat

 

[siwilks200]

Tape hasn't fixed the stuttering so I'll carry on with the throttle body seal...it's obviously leaking hence spraying oil.

Useful to know about this intercooler pipe problem though. Mine was wearing in two places!

 

[siwilks200]

hi Dave
.

Can I just ask if your Stilo or any Stilo is actually meant to give a couple of hisses before it picks up? I'm still unsure if this is caused by the EGR valve opening and closing or if it's the turbo

I don't really mind The hisses but I don't want the stuttering. it seems to be better now but not Perfect. perhaps changing the hose will make it perfect