Technical EGR Valve

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Technical EGR Valve

I believe there is information on the alfa156 forum about this.
I have my local FIAT specialist garage clean mine out when i had a problem with the EGR valve while there where fixing my broken driver side door handle.
 
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Just had egr problem. Followed advice on pdf file and this cured the problem completely. Many thanks.
As a follow up, I found that touching a 12 volt supply to the contacts on the solenoid connector will prove whether it is working or not, also inserting a blanking plate on the egr intake proved mine was faulty as the car was fine as soon as the blank was in place.
 
Did your Croma go to see Barry and Paul recently? :D

How's the EGR valve now?

Hi Hellcat - Sorry for not getting back to you on this, but I somehow missed it. Yes indeed it did go see Barry and Paul and has run fine since. Although it is now due an annual service, and low and behold it is starting to get a bit tempremental and sluggish at pulling away.

Seems like this is an annual job - I think I am going to ask them to blank it off this time.
 
I think I am going to ask them to blank it off this time.

I don't think anybody has actually tried this on a Croma without an associated ECU reprogram/mod.

I think the ECU may eventially throw a warning light on the dash, such as EGR recirculate too low.

If you do fully blank off please keep us all posted on what happens over time.
 
That could be a bit tricky, as it doesn't have one. You only have to worry about Lambda sensors and catalytic convertors instead.

Yes i heard that on my local fiat dealer. No faulty codes. Maybe air sensor fault, but no faulty code.
 
Hi gys after trying to get the car running after the last episode it played up again, (see my thread more croma woes).

Ok so the AA chappy came out and plugged her in and confirmed EGR.

Removed and cleaned, replaced and worked for about 2 miles and then failed again. Luckily the AA chap stuck about and waited for test drive results.

Had a chat with him and obviously he knows the probs this engine has had in vauxhalls and saabs, he also said he has had a lot of Vag products and their dpf in the exhaust causing lots of grief.

Anyway, basically the chap said he woud just run it with it blanked off, he made us a gasket and fitted it and said he wouldn't bother replacing it.

Subsequntly the car ran brilliantly, throttle response on and off turbo is the best it has EVER been. Downside it has thrown a "CHECK ENGINE", warning.

Now the car is standard and i am slightly worried incase it would have any lasting effects, i have read many posts from various sites from various manufacturers, seems there are mostly " it wil be fine " posts out there.

Any other opinions out there?May ask on the punto forum as they prob have a few more ppl having tried it
 
Firstly the AA man was almost certainly not able to drill and strip the solenoid down and probably was only able to clean the valve chamber. So a full EGR strip down and clean seems in order.

There a four possible actions you can take.

1) fully strip and clean EGR
2) do 1) and fit a restricting "bullet hole" EGR plate
3) do 1) and re-plumb the EGR inlet to take filtered air either through a small cone filter or from the main filtered air inlet. To do this you will have to plumb into the air system post main air filter and pre air flow meter. You will also need to still blank off the exhaust EGR feed.
4) Fit a full EGR blanking plate and have the ECU programmed to remove EGR functions.

Note! Method 3) I claim full original rights to. I've seen no other person/group/etc suggest this other than me.

Personally at 37K miles my EGR is still ok. I have a bullet hole plate and gaskets in stock and also 75% prepared for implementing 3) above.

The problem with 3) is that I'm not sure (not having yet had to remove an EGR valve) how much play there is to allow the EGR inlet pipe to be disconnected and moved to one side and supported. The whole pipe assembly from exhaust could be removed but then the EGR cooler water feed will need replumbing requiring a coolant drain etc. etc.

Ideally I would like to keep that carbon poluted exhaust soot away from the inlet system but unless one goes for 4), which I've been quoted the same cost as a full performance ECU reprogram (£250+), one is left with option 3) or just average your time and losses and go with option 2).

Option 2) is the least invasive, will not result in insurance problems and should hopefully greatly increase the length of time before the EGR system get clogged up again.

What I would add is that EGR modification experience is new and there is little long term data available. (other than when I blanked to EGR off the car went like a rocket till the engine check light came on)
 
Cheers S130, they are definitely the most concise options i have seen noted, if i were to throw a swerveball in as to say...

What would happen if left in the current state, blanked off and no mods? Other than the obvious warning light, is it actually doing any harm to the car? ( i understand the emission side of the argument).

I've read people might say it might run warmer at times, but realistically, is the ecu jut thinking there is a problem, as obviously something has changed by blanking it?

The car has covered 35k and dissapointingly has suffered a fair few expensive probs recently.

The other thing we were considering, is just getting a new Part.

Does anyone have the part no.? The car is a 150 m/jet incase any different to the 120, i guess not but just in case.
 
Below is the full text from eLearn on the Croma EGR. (Sorry for no pictures).

This is what I think will happen/be going on with EGR mods. Anybody please feel free to correct me as I'm just working out/learning based on my basic engineering skills.

Having read the info below you will see that the EGR flow is NOT measured (unmetered). The ECU calculates how much the EGR flow is by noting the drop in air flow through the main aif flow sensor. If the ECU is telling the EGR to pass 10% then the ECU will expect a 10% reduction in the measured air flow. If you blank the EGR off then there will not be a reduction and this is how/when it decides to register the fault with the engine check light.

The reason (I think) there is a loss of power when EGR valves stick open is because if the EGR is supposed to be closed and is stuck open then loads of air/exhaust gas is sucked into the inlet manifold and this air is not metered. Meanwhile the main airflow sensor is only fueling for the low quantity of air it is measuring.

With me so far?

Now to answer your question. With the EGR blanked off in the short term (at least until the engine light comes on) then if the ECU is demanding 15% EGR then it will overfuel by say 15% compared to what it would normally do for the amount of air flowing through the main airflow meter.

So in the short term the engine will be running rich. Hence the noticable incease in engine response that people have talked about/experienced. The down side of this is that more soot will be generated which means the DPF will need to be regenerated more often. Also the inlet air temperature will be reduced as no hot exhaust gasses are getting into the inlet and this will increase "charge density" thus increasing engine power a little more.

Now when the ECU clocks the EGR fault then I have no idea what it does. IF I had programmed the ECU then I would just stop the overfueling compensation an turn the engine check light on. I see no reason the do anything else, e.g. limp home mods etc. as the EGR failure when blanked off is fully compensatable but just stopping the EGR overfuelling compenation. i.e. EGR = 0% exactly the same as when the EGR circuit is shut off by the ECU in normal running.

IF the ECU did nothing and kept the overfuelling in operation as though the EGR circuit was working normally then you may not see much of a reduction in overall fuel economy as modern engines tend to run leaner for emissions reasons. This is why most performance tuning ECU mappers claim more power, torque, driveability AND better fuel consumption.

On all the older diesel engines with EGR, like Stilo, Punto etc. (prior to DPF etc) I realiably told by a number of Fiat technicians the blanking off the EGR is a common last report practice, appears to do no harm and does not affect the emissions regarding offical MOT test measurements.

Personally I would not really like to drive round with the engine check light on as this would be masking and other more serious problem the ECU is trying to tell you about. Yes you can check and reset every week but if I had to go down this route the I would buy and fit one of those engine / driving monitors the plug into the EOBD socket, or a dirt cheap code reader/reseter and leave it permanently plugged in. (ScanGuage is one such monitoring device).

----------------------------------------------
CONSTRUCTION SPECIFICATIONS
This system makes it possible to send some (5 - 15%) of the exhaust gases to the intake in certain operating conditions.

This lowers the peak temperature in the combustion chamber restricting the formation of nitrogen oxides (NOx).

The E.G.R. solenoid valve (1) operated by the injection control unit (2) carries out the task of reintroducing some of the exhaust gases taken from the exhaust manifold (4) back into the engine intake.

A heat exchanger (3) makes it possible to partly cool the exhaust gases increasing the volumetric output of the engine.

1 - EGR solenoid
2 - Injection control unit
3 - Heat exchanger
4 - Exhaust manifold
5 - Intake chamber

OPERATION
At coolant temperatures of > 20°C with the engine speed between 800 and 3000 rpm, the injection control unit operates the E.G.R. solenoid valve with a square wave signal.

The variation in this signal allows the E.G.R. coil to move a shutter, thereby regulating the flow of exhaust gases from the exhaust manifold to the intake manifold; there are two results:

less air is introduced;

the combustion temperature is reduced (on account of the presence of inert gases) resulting in a decrease in the formation of NOx (nitrogen oxides).

The injection control unit is constantly informed of the quantity of gas recirculated through the information coming from the flow meter: in effect, if there is an intake of a certain quantity of air (Qam) for a given engine speed and the value sent by the flow meter (Qar) is lower, then the difference (Qgr) is the value for the quantity of gas recirculated

Qam - Qar = Qgr
Qam - Theoretical quantity of air memorized
Qar - Actual quantity of air
Qgr - Quantity of recirculated gas

The atmospheric pressure signal is used for the operation of the E.G.R. solenoid valve to recognize the condition of driving at altitude in order to reduce the quantity of gas recirculated and to prevent engine fumes.

DESCRIPTION OF COMPONENTS
E.G.R. SOLENOID VALVE
The Pierburg E.G.R. solenoid valve, fitted on the intake manifold, has the task of modulating the flow of exhaust gases to the intake according to the command from the injection control unit.

This modulation takes place by means of the internal solenoid, with PWM operation by the control unit, which activates the control rod via the internal valve.

1 - E.G.R. valve casing
2 - Internal valve
3 - Gas intake from exhaust manifold
4 - Gas outlet to intake manifold
 
Does anyone have the part no.? The car is a 150 m/jet incase any different to the 120, i guess not but just in case.

There is a difference. Check out ePer for: Exhaust Gas Control Device.

Or search some P/No.s e.g. 55204250, 55215031, 5520455, 55215032

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Nuova Croma 1.9/16v 150hp 55215031
 
I recently changed my '06 Croma 1.9 JTD EGR valve assembly and got very good service from emissioncontrols.co.uk. I quoted the Pierburg part number etched in the valve body to them and they duly obliged with a new part at about 2/3 of the price of a main dealer part. This included courier delivery and two gaskets with a 12 month guarantee. It's worth a look and will save you a few quid.
Incidentally, I will recondition the old unit myself using the excellent PDF 'How to' example shown on this forum recently.

Cheers Bob :D
 
I recently changed my '06 Croma 1.9 JTD EGR valve assembly and got very good service from emissioncontrols.co.uk. I quoted the Pierburg part number etched in the valve body to them and they duly obliged with a new part at about 2/3 of the price of a main dealer part. This included courier delivery and two gaskets with a 12 month guarantee. It's worth a look and will save you a few quid.
Incidentally, I will recondition the old unit myself using the excellent PDF 'How to' example shown on this forum recently.

Cheers Bob :D

(y) Good advice. Also, if you are in the market for an EGR, check out Vauxhall dealers. They are also doing the same part for a fraction of Fiats price. Part numbers will be identical too :)
 
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