EGR valve advice
23-05-2013, 06:16 PM
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EGR valve advice
I own a Mondeo 2.2 155 TDCI.
I had to call out the AA this morning, turns out the EGR valve needs replacing. The AA chap cleaned the valve, sprayed some cleaner into it. Cleared the fault code, runs not well, but runs. Read on a previous thread about blanking the EGR valve. Advice please.
I had to call out the AA this morning, turns out the EGR valve needs replacing. The AA chap cleaned the valve, sprayed some cleaner into it. Cleared the fault code, runs not well, but runs. Read on a previous thread about blanking the EGR valve. Advice please.
24-05-2013, 10:47 AM
#3
You can blank it on the 2.2 but you will get the EML coming on after a while. It won't do any harm, or cause any problems, but you'll be wise to check the fault codes every so often to clear it, and see if there are any more codes stored.
Remove it and clean it properly, give it a good soak to make sure that the valve isn't stuck open.
Some people drill a hole in the plate to stop the EML coming on, but in reality the hole needs to be so big that it renders the blanking plate useless.
Remove it and clean it properly, give it a good soak to make sure that the valve isn't stuck open.
Some people drill a hole in the plate to stop the EML coming on, but in reality the hole needs to be so big that it renders the blanking plate useless.
Last edited by DanW@FastFord; 24-05-2013 at 10:49 AM.
24-05-2013, 11:41 AM
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Did this on mine, bought blanking plate of eBay and made a difference to performance and mpg, no issues with MOT either.
Depends which engine you have as to whether you need the plate with or without the hole in, if I remember the euro 4 doesn't need the hole at all. May be wrong but a quick search on flea bay will confirm
Depends which engine you have as to whether you need the plate with or without the hole in, if I remember the euro 4 doesn't need the hole at all. May be wrong but a quick search on flea bay will confirm
24-05-2013, 12:38 PM
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24-05-2013, 02:01 PM
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Did this on mine, bought blanking plate of eBay and made a difference to performance and mpg, no issues with MOT either.
Depends which engine you have as to whether you need the plate with or without the hole in, if I remember the euro 4 doesn't need the hole at all. May be wrong but a quick search on flea bay will confirm
Depends which engine you have as to whether you need the plate with or without the hole in, if I remember the euro 4 doesn't need the hole at all. May be wrong but a quick search on flea bay will confirm
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25-05-2013, 12:07 PM
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New EGR Valve fitted. Bought from a jaguar spares on-line, 10 minutes to fit just the code to be removed.
Will be looking at a later date about blanking off.
Will be looking at a later date about blanking off.
17-06-2013, 10:17 AM
#10
EML = Engine Management Light, when a euro4 mk3 Mondeo has the EGR (Exhaust Gas Recirculation) valve blanked with a solid plate, the EML may go on, (because the ECU (Engine Conlrol Unit) detects lack of flow ard thinks the EGR is faulty) but it can be reset with a OBD11 fault code reader (about Ł22 online)
And euro 3 Mondeos can have EGR blanking plates fitted with no problem
Plates with holes in them are a waste of time (defeats the purpose)
A solid blanking plare can "fix" a faulty / jammed EGR valve, (becauese it disables it) the EGR valve must be working properly to fit one with a hole
And euro 3 Mondeos can have EGR blanking plates fitted with no problem
Plates with holes in them are a waste of time (defeats the purpose)
A solid blanking plare can "fix" a faulty / jammed EGR valve, (becauese it disables it) the EGR valve must be working properly to fit one with a hole
Last edited by black_jack; 17-06-2013 at 10:22 AM. Reason: typo
09-08-2013, 07:12 PM
#12
When mine stopped working I took it apart and found this broken
Orders some 3.5 mm silver steel IIRC and made 2 new dowel pins.
Still working couple thousand k later
When I had it apart I unplugged the egr while I waiting on the steel bar, I don't think the car drove as smooth (when unplugged its closed all time like when blanked) so I'm not convinced blanking it is the best option. Apart from in euro 4 the EML comes on also
Orders some 3.5 mm silver steel IIRC and made 2 new dowel pins.
Still working couple thousand k later
When I had it apart I unplugged the egr while I waiting on the steel bar, I don't think the car drove as smooth (when unplugged its closed all time like when blanked) so I'm not convinced blanking it is the best option. Apart from in euro 4 the EML comes on also
10-08-2013, 11:48 AM
#13
When mine stopped working I took it apart and found this broken
Orders some 3.5 mm silver steel IIRC and made 2 new dowel pins.
Still working couple thousand k later
When I had it apart I unplugged the egr while I waiting on the steel bar, I don't think the car drove as smooth (when unplugged its closed all time like when blanked) so I'm not convinced blanking it is the best option. Apart from in euro 4 the EML comes on also
Orders some 3.5 mm silver steel IIRC and made 2 new dowel pins.
Still working couple thousand k later
When I had it apart I unplugged the egr while I waiting on the steel bar, I don't think the car drove as smooth (when unplugged its closed all time like when blanked) so I'm not convinced blanking it is the best option. Apart from in euro 4 the EML comes on also
If its a Euro4 the EML can be reset regularily with a code reader
Last edited by black_jack; 10-08-2013 at 11:52 AM. Reason: Euro4
10-08-2013, 03:29 PM
#14
Its always better with the EGR blanked with a solid plate - turbo spools up quicker, eliminates the "EGR flat spot" and the inlet does not get contaminated/ choked with carbon/ crud - more reliable too (EGR valve cannot fail if it is blanked/ disabled)
If its a Euro4 the EML can be reset regularily with a code reader
If its a Euro4 the EML can be reset regularily with a code reader
I'd rather have it working that reset EML light all the time
01-09-2014, 09:04 PM
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EGR valve blanks and EML clearing
Am I right in assuming then, that if on a Euro4 you blank the EGR with a solid plate, and then you clear the EML when it appears using an OB2 fault reader, the light will just come back on next time you run the engine?
02-09-2014, 09:37 AM
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Thanks for the quick response. Sounds like there is no way round this then apart from continuously resetting or leaving the light on (in which case might it eventually go into limp-home mode?). Does anyone know in detail how this valve is controlled on the TDCi? I am guessing mechanically its opened pneumatically by the diaphragm unit but what role do the electrics perform? Are the three wires just for sensing whether its open or shut, thereby telling the ECU, or do they actually participate in triggering the actuation as well?
02-09-2014, 05:11 PM
#18
PassionFord Post Whore!!
Just to clarify, the Euro4 is a motor driven EGR, if you have the vac operated one it is not Euro 4, the electrics on the vac operated EGR is just a position sensor giving feedback to the PCM (Powertrain Control Module, Ford speak for ECU). The position sensor sends 5 volt reference 0.3 volts (closed) - 5 volts (open) back to PCM
As you say, the actual valve is operated by vacuum by a solenoid that is PCM controlled, the PCM will send a PWM voltage to the solenoid to operate the EGR.
As you say, the actual valve is operated by vacuum by a solenoid that is PCM controlled, the PCM will send a PWM voltage to the solenoid to operate the EGR.
Last edited by GVK.; 02-09-2014 at 05:36 PM.
02-09-2014, 06:03 PM
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Thanks again GVK. What a level of service! Very impressive and sounds like good news. I assume that the three wires are, respectively, power feed & return/earth and valve-position? (will these be 5v or 12v?). So as long as the valve moves from time to time (which it will presumably,even though the blank is in there) the ECU should not detect any apparent problems. Does this sound correct?
Now I realise what is going on here I really really dislike the idea of pushing hot, dirty exhaust gas back into the intake so think I will fit the blank on my 2 litre TDi Mondeo anyway (even though everything seems ok at present). Its actually a friend's car which put up a fault light so I need to check his EGR type as its a 2.2TDi (also a 2007 mk3) but hopefully it too is vac operated.
Thanks again for the advice. Much appreciated.
Just out of interest, do you know which of the 3 wires is which? Also, under what conditions does the valve open on a TDi? i.e which sensors are involved in compiling the info that tells the ECU when to open the solenoid controlling the vacuum actuator; and what engine conditions trigger them?
Now I realise what is going on here I really really dislike the idea of pushing hot, dirty exhaust gas back into the intake so think I will fit the blank on my 2 litre TDi Mondeo anyway (even though everything seems ok at present). Its actually a friend's car which put up a fault light so I need to check his EGR type as its a 2.2TDi (also a 2007 mk3) but hopefully it too is vac operated.
Thanks again for the advice. Much appreciated.
Just out of interest, do you know which of the 3 wires is which? Also, under what conditions does the valve open on a TDi? i.e which sensors are involved in compiling the info that tells the ECU when to open the solenoid controlling the vacuum actuator; and what engine conditions trigger them?
02-09-2014, 07:54 PM
#21
PassionFord Post Whore!!
3 wires will be 5v+, a ground and then signal which is the 0-5v depending on the position of the valve, I can check the pinouts and post up.
The joys of Ford wiring diagrams...and wiring codes/description
EVP sensor.. all 3 wires go to/from PCM
pin 1 yellow/blue 5 volt from PCM
pin 2 brown/blue signal return/ground to PCM
pin 3 white/violet signal 'forward/upward' to PCM
It's really only the motor type Euro4s that give EML light problems as they have feedback to the PCM for EGR flow. Hence you see blanking plates for sale with a hole in....
EDIT- It does appear actually that blanked off vac type EGR can put EML light on for lack of flow also!!
I know a lot of people blank off their EGRs but we (dealership) only do it during diagnosis to prove an EGR issue.
My argument is that yes blanking off EGR can give performance advantage,but, all the miles of running EGR has already clogged up the head/intake manifold etc etc....
2.2 2007 I would expect to be the Euro4 (but have a look!) as the Transits of that age had the motor type EGR which we changed hundreds of back then.
The joys of Ford wiring diagrams...and wiring codes/description
EVP sensor.. all 3 wires go to/from PCM
pin 1 yellow/blue 5 volt from PCM
pin 2 brown/blue signal return/ground to PCM
pin 3 white/violet signal 'forward/upward' to PCM
It's really only the motor type Euro4s that give EML light problems as they have feedback to the PCM for EGR flow. Hence you see blanking plates for sale with a hole in....
EDIT- It does appear actually that blanked off vac type EGR can put EML light on for lack of flow also!!
I know a lot of people blank off their EGRs but we (dealership) only do it during diagnosis to prove an EGR issue.
My argument is that yes blanking off EGR can give performance advantage,but, all the miles of running EGR has already clogged up the head/intake manifold etc etc....
2.2 2007 I would expect to be the Euro4 (but have a look!) as the Transits of that age had the motor type EGR which we changed hundreds of back then.
Last edited by GVK.; 02-09-2014 at 08:49 PM.
02-09-2014, 08:05 PM
#22
PassionFord Post Whore!!
Some generic Ford training EGR info (motor type)
Vac type must be old hat as can't find anything for it...
Principles the same though.
By using turbochargers, the temperatures in the engine's combustion chambers rise with the torque and output.
This increases the formation of NOX in the exhaust gas. In order to keep this NOX content in the exhaust gas within required limits, the EGR system is becoming increasingly important.
In the partial load range, exhaust gas recirculation is achieved by mixing the exhaust gases with the intake air. This reduces the oxygen concentration in the intake air. In addition, exhaust gas has a higher specific heat capacity than air. The proportion of water in the recirculated exhaust gas also reduces the combustion temperatures.
These effects lower the proportion of NOX and also reduce the amount of exhaust gas emitted.
The quantity of exhaust gas to be recirculated is accurately determined by the PCM.
An excessive EGR rate would lead to an increase in diesel particulate, CO (carbon monoxide) and HC emissions due to lack of air. Furthermore, combustion would become unstable due to a lack of O2 (oxygen).
Modern EGR systems consist of the following components:
MAF sensor,
Actuator motor-controlled EGR valve with
integrated position sensor.
Actuator motor
The actuator motor itself is actuated by the PCM as required. The opening cross-section of the EGR valve depends on the PCM control current (PWM).
MAF Sensor
The quantity of exhaust gas recirculated when the EGR valve opens has a direct influence on the MAF sensor measurement.
During exhaust gas recirculation, the reduced air mass measured by the MAF sensor corresponds to the value of the recirculated exhaust gases. If the quantity of recirculated exhaust gas is too high, the intake air mass drops to a specific limit. The PCM then reduces the proportion of recirculated exhaust gas. It is therefore a closed loop.
Position sensor
In the face of increasingly stringent emission standards, EGR control via the MAF sensor alone is reaching its limits.
The position sensor in the EGR valve actuator motor unit supplies a further signal to the PCM for calculating the EGR rate.
This signal also allows light soiling on the EGR valve seat to be compensated. An accurate EGR rate, close to the limit of running smoothness, is therefore guaranteed.
Intake manifold flap
NOTE: Throttling of the intake air is only supported with certain versions.
A further step towards minimising NOX is the restriction of intake air via the intake air valve.
By partial closing of the intake manifold flap a vacuum is generated behind the intake manifold flap. The vacuum results in the exhaust gases being drawn in more efficiently by the engine via the EGR valve, enabling the EGR rate to be metered more effectively.
Effects of faults
The majority of malfunctions in the EGR system are barely perceived by the driver. The only thing that can happen is increased combustion noise during idling.
If, however, the EGR valve jams open or if excessive metering by the PCM takes place, the following symptoms can occur:
rough engine running,
poor engine performance,
increased emissions of black smoke.
Diagnosis
Regulation of the EGR works as a system. The interaction of individual components is monitored.
Malfunctions lead to increased exhaust emissions which exceed the EOBD limits. Serious faults will also lead to the EGR system being switched off.
Since this is an emissions-related system, malfunctions are indicated by the MIL (malfunction indicator lamp).
Vac type must be old hat as can't find anything for it...
Principles the same though.
By using turbochargers, the temperatures in the engine's combustion chambers rise with the torque and output.
This increases the formation of NOX in the exhaust gas. In order to keep this NOX content in the exhaust gas within required limits, the EGR system is becoming increasingly important.
In the partial load range, exhaust gas recirculation is achieved by mixing the exhaust gases with the intake air. This reduces the oxygen concentration in the intake air. In addition, exhaust gas has a higher specific heat capacity than air. The proportion of water in the recirculated exhaust gas also reduces the combustion temperatures.
These effects lower the proportion of NOX and also reduce the amount of exhaust gas emitted.
The quantity of exhaust gas to be recirculated is accurately determined by the PCM.
An excessive EGR rate would lead to an increase in diesel particulate, CO (carbon monoxide) and HC emissions due to lack of air. Furthermore, combustion would become unstable due to a lack of O2 (oxygen).
Modern EGR systems consist of the following components:
MAF sensor,
Actuator motor-controlled EGR valve with
integrated position sensor.
Actuator motor
The actuator motor itself is actuated by the PCM as required. The opening cross-section of the EGR valve depends on the PCM control current (PWM).
MAF Sensor
The quantity of exhaust gas recirculated when the EGR valve opens has a direct influence on the MAF sensor measurement.
During exhaust gas recirculation, the reduced air mass measured by the MAF sensor corresponds to the value of the recirculated exhaust gases. If the quantity of recirculated exhaust gas is too high, the intake air mass drops to a specific limit. The PCM then reduces the proportion of recirculated exhaust gas. It is therefore a closed loop.
Position sensor
In the face of increasingly stringent emission standards, EGR control via the MAF sensor alone is reaching its limits.
The position sensor in the EGR valve actuator motor unit supplies a further signal to the PCM for calculating the EGR rate.
This signal also allows light soiling on the EGR valve seat to be compensated. An accurate EGR rate, close to the limit of running smoothness, is therefore guaranteed.
Intake manifold flap
NOTE: Throttling of the intake air is only supported with certain versions.
A further step towards minimising NOX is the restriction of intake air via the intake air valve.
By partial closing of the intake manifold flap a vacuum is generated behind the intake manifold flap. The vacuum results in the exhaust gases being drawn in more efficiently by the engine via the EGR valve, enabling the EGR rate to be metered more effectively.
Effects of faults
The majority of malfunctions in the EGR system are barely perceived by the driver. The only thing that can happen is increased combustion noise during idling.
If, however, the EGR valve jams open or if excessive metering by the PCM takes place, the following symptoms can occur:
rough engine running,
poor engine performance,
increased emissions of black smoke.
Diagnosis
Regulation of the EGR works as a system. The interaction of individual components is monitored.
Malfunctions lead to increased exhaust emissions which exceed the EOBD limits. Serious faults will also lead to the EGR system being switched off.
Since this is an emissions-related system, malfunctions are indicated by the MIL (malfunction indicator lamp).
Last edited by GVK.; 02-09-2014 at 08:07 PM.
02-09-2014, 08:43 PM
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Thanks yet again GVK.
I will have to look at that 2.2 ASAP to see which type of EGR it has and hope that just maybe, its not the motorised type with gas-flow sensing. When they fail, is it due to mechanical sticking again or is it the electrics sometimes? Pity there is no way to 'fiddle' the feedback signal somehow.
If you can post any pin data for these then that would be much appreciated. I would guess that on the motorised version there will be a motor drive wire (maybe 12v?), a ground, 2 for the flow sensor and maybe a valve-position sensor wire again (or perhaps a +5v).
Thanks also GVK for the edits which answered my question about the roles played by the various sensors, thereby answering the final question in my previous contribution (these systems certainly seem to be getting frighteningly complex and expensive). It looks as though perhaps with a blanking plate fitted, the 3 pin vac type can still recognise that maf flow does not change when the egr valve position signal is saying that the valve has opened and perhaps this is what turns the eml on, after all. What a pain! Does this sound right to you?
I will have to look at that 2.2 ASAP to see which type of EGR it has and hope that just maybe, its not the motorised type with gas-flow sensing. When they fail, is it due to mechanical sticking again or is it the electrics sometimes? Pity there is no way to 'fiddle' the feedback signal somehow.
If you can post any pin data for these then that would be much appreciated. I would guess that on the motorised version there will be a motor drive wire (maybe 12v?), a ground, 2 for the flow sensor and maybe a valve-position sensor wire again (or perhaps a +5v).
Thanks also GVK for the edits which answered my question about the roles played by the various sensors, thereby answering the final question in my previous contribution (these systems certainly seem to be getting frighteningly complex and expensive). It looks as though perhaps with a blanking plate fitted, the 3 pin vac type can still recognise that maf flow does not change when the egr valve position signal is saying that the valve has opened and perhaps this is what turns the eml on, after all. What a pain! Does this sound right to you?
Last edited by AlanFowler; 02-09-2014 at 09:24 PM. Reason: Saw more data
02-09-2014, 08:56 PM
#24
PassionFord Post Whore!!
Most common cause for the motor type failing was the gears stripping the teeth or the drive dowels as shown above, they were that bad they eventually bought out a warranty kit to repair them, as the complete EGR was on back-order constantly so were lots of vehicles off-the-road.
I will find the pin outs for the motor type, think they have 5-6 wires from memory..
I will have another look if there are more detailed EGR strategy info available...
I will find the pin outs for the motor type, think they have 5-6 wires from memory..
I will have another look if there are more detailed EGR strategy info available...
03-09-2014, 11:34 AM
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Most common cause for the motor type failing was the gears stripping the teeth or the drive dowels as shown above, they were that bad they eventually bought out a warranty kit to repair them, as the complete EGR was on back-order constantly so were lots of vehicles off-the-road.
I will find the pin outs for the motor type, think they have 5-6 wires from memory..
I will have another look if there are more detailed EGR strategy info available...
I will find the pin outs for the motor type, think they have 5-6 wires from memory..
I will have another look if there are more detailed EGR strategy info available...
In what follows I am presenting my guess at the basic strategy which I am posting here for discussion/critique as I am by no means certain if this is correct. Apologies in advance for long-windedness but if interest and patience suffice, your views would be much appreciated.
In effect, it seems the system is fundamentally trying to keep the fuel to oxygen ratio in the cylinder to within certain limits as with high temperature and rich oxygen concentrations, more nox tends to form. Since the PCM knows how much fuel is flowing and it also knows the intake air (21% oxygen) massflow from the MAF, it has an idea of the oxygen/fuel ratio (OFR). By controlling the exhaust gas recirculation flow it can vary this OFR so it sends a signal to the EGR seeking to achieve this.
On simpler systems this would be basically a form of open loop control telling the EGR valve what position to move to. But on more sophisticated systems, an additional feedback signal is required to monitor how much exhaust gas is actually being recirculated. I suspect that this is what pin 3 (white and violet) is providing on the 3 pin plug. However, rather than an actual mass flowrate, as is produced by a MAF, this one is, in effect, a 'proxy' measure since it is actually the valve position that is being monitored.
On the motorised 5/6 pin plug something similar is presumably happening. EDIT. Incidentally I have now checked and my mate's 2.2 does have the motorised valve and it does have 5 terminals as GVK predicted.
If all this seems true so far, then we can start speculating about the EML. If the PCM sends an actuation signal to the EGR valve but it does not actually move (due to mechanical sticking, broken drive etc) clearly the anticipated position feedback signal will not correspond so it is logical that the fault light will come on. Furthermore, this will happen with either a 3 pin/vac EGR or a 5 pin motorised one. So if the EGR is faulty, we will get a light even if we blank the recirculation port.
The question now arises what happens if we insert a blanking plate on a system where the EGR valve is working freely? Since the position feedback signal to the PCM should now balance with the control/command signal from the PCM, then the PCM might 'think' everything is normal, so it will not put up a fault or corresponding warning light. However, if the PCW is 'cleverer' than this it might recognise that the OFR is probably still high, as there will have been no corresponding reduction in MAF output when the EGR opened (due to the presence of the blank). Hence it may still flag a fault on the system.
So I wonder which of these scenarios it is (if either)? Maybe only the system designers know for sure? I hope this makes sense and would welcome any further thoughts on this.
Last edited by AlanFowler; 06-09-2014 at 10:43 PM. Reason: New info
06-09-2014, 10:51 PM
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Some Info from another site
Still not resolved this issue of how to prevent an eml light when blanking the EGR on a Euro 4 but found the following quotation on another site from 2012. He seems to be thinking along the same line that I was but this thread did not seem to come to a definite conclusion either.
"When the egr opens and under certain circumstances (I suspect maybe on the overrun at particular revs) the ECU expects the MAF sensor to show a drop in air flow. This is because some exhaust gas is now flowing through the EGR so there is a corresponding reduction of fresh air drawn flowing past the MAF sensor. This drop in airflow should manifest itself to the ECU by a drop in MAF output voltage (picture with colour codes based on my vehicle posted elsewhere).
With the EGR blanked there is no reduced airflow across the MAF but the engine knows the EGR valve is open because of the position sensor on the EGR itself. The answer is to introduce a voltage drop from the MAF when the EGR is open. This could be done by using a couple of op amps in a fairly simple circuit. But it may also be possible to make it even simpler by driving a small relay from the vacuum solenoid and using that to introduce a volt drop".
"When the egr opens and under certain circumstances (I suspect maybe on the overrun at particular revs) the ECU expects the MAF sensor to show a drop in air flow. This is because some exhaust gas is now flowing through the EGR so there is a corresponding reduction of fresh air drawn flowing past the MAF sensor. This drop in airflow should manifest itself to the ECU by a drop in MAF output voltage (picture with colour codes based on my vehicle posted elsewhere).
With the EGR blanked there is no reduced airflow across the MAF but the engine knows the EGR valve is open because of the position sensor on the EGR itself. The answer is to introduce a voltage drop from the MAF when the EGR is open. This could be done by using a couple of op amps in a fairly simple circuit. But it may also be possible to make it even simpler by driving a small relay from the vacuum solenoid and using that to introduce a volt drop".
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