im Axle Specialists

Technical JTD power loss symptoms

Currently reading:
Technical JTD power loss symptoms

M

multihull

Member
Joined
Aug 4, 2009
Messages
31
Points
63
Location
Sunbury on Thames
Have read the posts on power loss /maf/egr/vgt problems.

I lost power suddenly after stopping foe a short while on holiday in France, engine light came on. In the lorry lane going up hill.
Noticed a flattened vacuum tube on the VGT going to the manifold. Called in at Fiat, at Montlucon, very helpful. Replaced vacuum tube, checked it on tester and said "that didn't fix it you have several error codes, drive carefully if going back to the UK tomorrow". Did so, got home, read posts and started checking.

The car will rev to 3000-3200 revs and stay there no matter how hard the pedal pushed. It is the same when not in gear and on the road in the first 4 gears, 5th stops at 2200 - not enough power.

Have removed the MAF sensor wiring - no change.
Tried connecting the vacuum pipes direct cutting out the VGT - no change.
Removed the EGR expansion pipe and cleaned the muck out, not very much, but very oily. Did not look for the EGR valve as I had not read that far.

My question is If the egr valve is stuck open will it limit the revs to the 3000 rpm mark. If so then I will take it off completely and check/clean.
If my symptom does not match EGR fault is ut a turbo failure.

Your experienced replies appreciated.

multihull
 
Hmmmmmmmm sounds like either the Egr or the overboost valve both of which will give symtems like this.

I believe you can blank off the egr and is in the forum somewhere to see but overboost valve i think just take it too fiat and get it plugged in and find out for sure.

Cant see it being the turbo, dont hear of that many turbos failing nowadays.
 
multihull said:
Noticed a flattened vacuum tube on the VGT going to the manifold. Called in at Fiat, at Montlucon, very helpful. Replaced vacuum tube, checked it on tester and said "that didn't fix it you have several error codes
Click to expand...
I think this was close to solving the problem.

You need to connect a vacuum gauge to this pipe and verify the vacuum reservoir is active. If it is then move the gauge to the 'active' side of the VGT valve and verify low pressure readings. You should also see the turbo actuator moving slightly.

Stuck open EGR will normally cause problems up to 3000rpm but then clear so doesn't sound like that's the problem.

This old thread of mine might help although in your case you have NO turbo at all by the sound of it :chin:
 
Thanks to both if you for a quick reply.


Argonaught, Thank you for the ost reference, was interested to read that a cat collapse cuts the revs above 3000 (my symptom).
I did bypass the VGT initially by connecting the 2 vacuumpipes together but it made no difference, there wasvacuum in the reervoir as it hissed when the pipe came off. But do not know if any of this made any sense in the operation. Will dig out my old vacuum gauge and recheck.

Will check for cat problems on the forum.

Will get a code reader but think the software one is preferable, need to get one of the faulty laptops working though.

Will keep this post updated.

Multihull
 
multihull said:
I did bypass the VGT initially by connecting the 2 vacuumpipes together but it made no difference, there wasvacuum in the reervoir as it hissed when the pipe came off.
Click to expand...
As a quick test when doing this, get someone to look closely at the turbo actuator (just follow tubing from VGT valve to front of engine) and confirm it moves (about 1cm) when the two tubes are connected together.

If it does then reconnect the VGT valve between the tubes and check again that the actuator moves (wont move so much). If it now doesn't move at all then you may have a duff VGT valve

It's more precise to use a vacuum gauge if you have one.

Never heard of JTD cat failure on the Forum (thought mine was going to be the 1st ;))
 
Argonaught
Thanks for clear info.
Got my old Vacuum gauge out, bought a T piece and some tubing (Tropical fish variety).
Good vacuum on engine side, goes right round the dial. The Turbo side had no vacuum reading. Not able to get someone to rev up to see if VGT kicked in.

With engine running connected vacuum tube from engine side to turbo side, turbo spindle pulled in and held in. From this presume Turbo vane is working.

Decided to do a test run with the turbo connected directly to the engine side, bypassing the VGT valve. Car runs ok, with torque but stops at just over 3000 revs in 3rd gear / 2500 in 4th. In 3rd gear at 3000 revs if load is taken off, declutching, the revs go upto 3500 and will not go above no matter the throtttle pedal position. Repeated this with the MAF removed, no change.

Disconnected the vacuum tube, so it was running open, and continued test run. Performance down, but max revs remained the same, 3000 appx nothing would increase it.

Back home, reconnected vacuum direct - turbo to engine, disconnected air input on engine side of intercooler and started motor, plenty of air being pumped out.

I may have a faulty VGT, but with the turbo connected directly would the revs stop around 3000.

Does VGT feedback cause a rev limiter?

Is a fuel feed problem likely to give the same results.

This is going to be a garage job if I am not careful and I do not like to give it to a garage and say "I do not know what the problem is!". I do not mind giving it to them with a defined problem.

Thanks for all assistance so far.

Multihull No power
 
This should have been on previous post.

Though it may seem like the salvage Stilo, it is not that bad at all.
It starts every time, it is more than comfortable to drive - did just over 1200 miles through N Spain & France (in the lorry lane uphill) apart from the power lack no problems; takes me & 2 crew down to the boat with all our stuff including O/B, oars and lifejackets; and there is still room.

Multihull
 
Got a software EOBD reader and pulled the fault codes off:
PO46 Turbo Boost circuit range/performance problem
P0101Mass or Volume Air flow Circuit Range/Performance Problem,
P0404 Exhaust Gas Recirculation Circuit Range/Performance ,
PO638 Throttle Actuator Control range /Performance.

Had ordered and purchased Boost Valve so fitted it more in hope than expectation.

Restarted and got same results.
This fault came on suddenly and the MIL light does not go out at all.

I do not believe that I have 3 (was 4 maybe) faults. But where to start.
No vacuum passes through the vacuum boost so it is not being called (new one, old was same). Is it possible 1 faulty component is able to create all of the above?
If so has anyone any idea of the start of the chain.

Having read the other JTD power post, cured with a new MAP, is it possible this causes the EGR and Throttle faults.

Anyone any ideas. Any input appreciated.

Multihull
 
multihull said:
Having read the other JTD power post, cured with a new MAP, is it possible this causes the EGR and Throttle faults.

Anyone any ideas. Any input appreciated.
Click to expand...
I'd say it's very likely and if so then that's pretty weird to have the first 2 reports of MAP sensor problems within just days of each other (never heard of one failing before).

Be good idea to clean the gunge out of it first though and check connections are good before buying a new one.

Would seem the issue with the 'collapsed' VGT tubing was a red herring then :chin:
 
hey, I have a similar problem with Stilo JTD, in my case at the moment FIAT told meto change EGR to new one so I did, but after 70km the problem started again, now they know that there is a problem with steering signals to EGR (basically EGR is stuck open) but they don`t know why and what`s the cause. Maybye some of you had a same problem?
 
coguar18 said:
hey, I have a similar problem with Stilo JTD, in my case at the moment FIAT told meto change EGR to new one so I did, but after 70km the problem started again, now they know that there is a problem with steering signals to EGR (basically EGR is stuck open) but they don`t know why and what`s the cause. Maybye some of you had a same problem?
Click to expand...
Symptoms should be quite different for a stuck EGR valve as you should should be able to drive through it at high revs (biggest problems will be at low revs).

It's a common issue but very easily proven by simply blocking the valve (Use Search and you should find many threads on this)
 
I have exacly what you are saying, big problems in the low rpm, no problems iwhen high revs.

But I don`t want to block the valve, I want to find a cause of this problem, does anyone has any idea?
 
Argonought said:
It's a common issue but very easily proven by simply blocking the valve (Use Search and you should find many threads on this)
Click to expand...

coguar18 said:
I have exacly what you are saying, big problems in the low rpm, no problems iwhen high revs.

But I don`t want to block the valve, I want to find a cause of this problem, does anyone has any idea?
Click to expand...
No; blocking the valve only proves that the EGR is the problem - it's very bad practice to leave it blocked.

Was the EGR properly diagnosed this way before it was replaced because I've never heard of issues with EGR electronics but stuck valves are extremely common :confused:
 
I hope that FIAT knows what they are doing, they exchange the valve to the new one and the symptoms are the same, it is impossible that two valves (on btand new one) are stocked. I will give you an answer when I will take my car form service.
 
coguar18 said:
I hope that FIAT knows what they are doing, they exchange the valve to the new one and the symptoms are the same, it is impossible that two valves (on btand new one) are stocked. I will give you an answer when I will take my car form service.
Click to expand...
To put this another way.

If you block the (new) EGR valve and the symptoms remain then clearly the valve is not the problem - in which case I'd ask for a refund.

Blocking the valve is fairly easy to do and can be done without removing it.
 
This problem is now resolved.
The problem was a stuck closed EGR Valve.
Used Gendans ELM327 USB PC based diagnostic tool to read the faults, there were 4 - Turbo Boost valve, EGR valve, Throttle potentiometer and Mass Air Volume.
The EGR valve and solenoid assembly were removed, have provided a guide with pictures for this, and the valve when inspected was absolutely solid / jammed / immoveable. With hammer and special block tapped until valve would move and allow access to the inner chamber Cleared out the mass of soot and left the valve soaking in a mix of turps and carburretor cleaner. Was then able to use wet and dry to clean the whole inner bit.
Reassembled the valve and refitted. Still had the same problem on the diagnostic tester. This is how it looked: Ignition on only 4 faults as above, cleared them 2 came back on refresh - EGR valve and Turbo boost. Started engine and got all 4 back.
Checked with Gendan as my Stilo is Jan 04 and the EOBD code was for diesels from Jan 04. They checed that I could read engine revs and battery check. This confirmed a correct EOBD system, so the fault had to be electrical, connectors, wiring, relays, fuses, ecu(m).
Fuse F11 controls secondary injection functions (?) and was blown. Replaced fuse, cleared faults (all gone), started car it revvved to 5000revs for the first time since Spain.
My conclusion, the EGR valve stuck closed, we had stopped for fuel and then went off, very shortly after engine light came on and we lost accelerating power. The solenoid must have tried to open the EGR but as it was solidly blocked took the fuse out.
If you have loss of power check Fuse F11, if it is blown there is a fault probably with a solenoid. Sort the solenoid / valves out and replace fuse.
Without the Gendan I would still have been there trying to sort out the problem.

Thanks to all who have contributed to this post, with the knowledge that someone there could help made the job much easier.
 
Last edited by a moderator:
You must log in or register to reply here.

Similar threads

A
General 1.9 jtd weird electrical power loss
Replies
2
Views
586
ad777
A
A
General 04 1.9 jtd power steering gone
Replies
8
Views
823
ad777
A
A
General Thinking of getting a JTD
Replies
3
Views
75
cris1117
C
T
General Stilo Dynamic 1.9 JTD 2005 Parts
Replies
1
Views
280
Tristram
T
Fewas123
Technical 1.9 JTD oil pan / sump removing
Replies
3
Views
364
Ralf S.
Ralf S.
Back
Top