Aaron Posted July 8, 2009 Share Posted July 8, 2009 I have a customer traveling a substantial distance for me to work on his truck, which he suspects is needing an EGR cooler and possibly head gaskets at this point. His local dealer has been feeding him poop for quite some time now and he is getting rather upset with it. They have repeatedly attempted to address his degas bottle blowing coolant out of it under load, and failed every time, he tells me. I pull a warranty history on this truck, and see this as the last warranty repair. TOPPED UP COOLANT AND CHECKED COOLING FAN OPERATION, AND CHECKED FOR LEAK, FAN WORK AND THE AND IS NO LEAKS,CHECKED EGR VALVE AND COOLER AS PER TSB 06 21 02 ITS OK, ,CHECKED AND FOUND INTAKE AIR TEMP SENSOR IS PLUGGED AND NOT READING CORRECTLY CAUSING THE EGR COOLER TO BOIL THE COOLANT INSIDE IT, REPLACED THE SENSOR AND RECHECKED TEMP SENSOR READING OK Labor Op Code Labor Op Description MT12A697 Causal Full Part Number Part Part Flag PREF BASE SUFF Description CPSC Quantity N DY 984 * 030008 1 N 3C3Z 9P455 AB SE E/G/R VLV 030008 1 Y * 12A697 * AIR CHARGE TEMP SENS 031403 0 Comments? Quote Link to comment Share on other sites More sharing options...
GregKneupper Posted July 8, 2009 Share Posted July 8, 2009 And to think this whole issue has been due to plugged IAT sensors. How come it took so long for someone to figure this out. Quote Link to comment Share on other sites More sharing options...
LARRY BRUDZYNSKI Posted July 8, 2009 Share Posted July 8, 2009 Aaron, Is the truck still under warranty??? If it is, do you have a loaner program with your dealership,maybe get the used car dept to pony up a loaner until repaired, talk with the D/P and explain the situation. He might be able to help you with this customer, maybe a new truck demo until the trucks fixed, I would start from scratch and be leary of anything that the other dealer did. Sounds to me like he has more problems than you have stated, get more info, how does he drive,whats the truck used for, how long has this been happening, is it still happening????? Ask ??????? Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted July 8, 2009 Share Posted July 8, 2009 CHECKED AND FOUND INTAKE AIR TEMP SENSOR IS PLUGGED AND NOT READING CORRECTLY CAUSING THE EGR COOLER TO BOIL THE COOLANT INSIDE IT Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted July 8, 2009 Share Posted July 8, 2009 Originally Posted By: Aaron CHECKED AND FOUND INTAKE AIR TEMP SENSOR IS PLUGGED AND NOT READING CORRECTLY CAUSING THE EGR COOLER TO BOIL THE COOLANT INSIDE IT Not all the pros work at dealer stores.... and not all the turds work at an independant... I'm pretty sure that if you put enough ketchup on road kill, it might come out tasting pretty good.... Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted July 8, 2009 Share Posted July 8, 2009 Horseradish will add some zing to just about anything. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted July 8, 2009 Share Posted July 8, 2009 Quote: TOPPED UP COOLANT AND CHECKED COOLING FAN OPERATION, AND CHECKED FOR LEAK, FAN WORK AND THE AND IS NO LEAKS,CHECKED EGR VALVE AND COOLER AS PER TSB 06 21 02 ITS OK, ,CHECKED AND FOUND INTAKE AIR TEMP SENSOR IS PLUGGED AND NOT READING CORRECTLY CAUSING THE EGR COOLER TO BOIL THE COOLANT INSIDE IT, REPLACED THE SENSOR AND RECHECKED TEMP SENSOR READING OK Sounds to me like their diesel guy is a bit gun shy and scared to get into it. Either that or he is a lot lazy and is just chuckin' parts to get out of any real work. Quote Link to comment Share on other sites More sharing options...
G. Bedford Posted July 8, 2009 Share Posted July 8, 2009 It's called "Greyhound Therapy". Do the cheapest part to get the claim paid so you can push the more expensive, correct repair claim onto the next dealers 126. If it ain't an IAT, it is a fan clutch, defective pressure cap or thermostat. But, it sure can't be head gaskets. We see far too much of this game. Quote Link to comment Share on other sites More sharing options...
Damon Posted July 8, 2009 Share Posted July 8, 2009 For the purpose of the discussion..... I understand the IAT2 sensor is used (in part) to detect EGR flow. Is this incorrect? If so, would it NOT stand to reason that a fouled IAT2 sensor might cause overactive EGR due to the slow response of the sensor due to the carbon buildup? Forgetting the BS of boiling coolant due to IAT2, there's at least the appearance of some merit to the theory that a lazy IAT2 might cause the EGR to be open longer than would be otherwise, thereby increasing the need for greater heat exchange in the cooler. That, combined with a clogged oil cooler, could cause the EGR cooler to fail. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted July 8, 2009 Share Posted July 8, 2009 I can see how you might come to that conclusion Clark however the IAT-2 sensor has no correlation with EGR operation other than it's reading "can" be used but a technician to verify that EGR is flowing during a road test. Under load with EGR flowing you could expect to see a 100* increase when the EGR valve is opened. According to the PCED the PCM uses the IAT-2 signal to control timing and fuel rate during cold starts and to provide an input to the cold idle kicker. I recall asking an engineer about this sensor back when we took note that these sensors coke up who confirmed this information. It's failure or contamination has no effect on EGR flow nor will it cause an EGR cooler to overheat or cause coolant to boil in the EGR cooler. Quote Link to comment Share on other sites More sharing options...
Aaron Posted July 8, 2009 Author Share Posted July 8, 2009 At Diavik, we'd pull the EGR valves out and weld them shut. EGR cooler failures - 0. (As an aside - we did that so they wouldn't carbon up, not to help the EGR cooler situation.) Quote Link to comment Share on other sites More sharing options...
Damon Posted July 8, 2009 Share Posted July 8, 2009 According to the PCED the PCM uses the IAT-2 signal to control timing and fuel rate during cold starts and to provide an input to the cold idle kicker. I recall asking an engineer about this sensor back when we took note that these sensors coke up who confirmed this information. So what's the other IAT used for then? I couldn't get accurate info through Ford about the theory behind the IAT2 sensor, but on the IH VT365, they call it the MAT (same sensor and location) and the IAT is the one in the MAF. So, IH says about the MAT: Originally Posted By: "IH VT365 service info" Manifold Air Temperature (MAT) The MAT sensor detects intake manifold air temperature. The MAT signal is monitored by the ECM for EGR operation. The MAT sensor is installed in the right front of the intake manifold. Quote Link to comment Share on other sites More sharing options...
DwayneGorniak Posted July 8, 2009 Share Posted July 8, 2009 What fuckin floors me is that this fuckin thing got paid through warranty and made it into the system. How the fuck does an illegitimate repair like this get paid for? And why the fuck can't we get legitimate repairs paid for? Oh, I know. The repair was below the group national average for repair costs and some monkey at the other end is thinking, We better pay this one because it's a cheap repair. Quote Link to comment Share on other sites More sharing options...
Aaron Posted July 9, 2009 Author Share Posted July 9, 2009 What fuckin floors me is that this fuckin thing got paid through warranty and made it into the system. How the fuck does an illegitimate repair like this get paid for? And why the fuck can't we get legitimate repairs paid for? I was wondering the same thing. Quote Link to comment Share on other sites More sharing options...
BrunoWilimek Posted July 9, 2009 Share Posted July 9, 2009 Originally Posted By: Keith Browning According to the PCED the PCM uses the IAT-2 signal to control timing and fuel rate during cold starts and to provide an input to the cold idle kicker. I recall asking an engineer about this sensor back when we took note that these sensors coke up who confirmed this information. So what's the other IAT used for then? To quote the coffee table book, "The IAT1 sensor's primary function is to measure intake air temperature to control the timing and fuel rate when cold starting. The continuous monitoring by the IAT1 sensor limits smoke emissions." "The primary function of the IAT2 sensor is to provide a feedback signal to the PCM indicating manifold air temperature." From my notes from the 6.0 diesel update course,"if the egr valve is leaking, the IAT2 will read higher than normal. IAT2 at 200 degrees when EGR is working properly. IAT2> 300 degrees or above 200degrees is too high." From the 6.0 Diesel Updates course book, "The IAT1 sensor on the 6.0 diesel engine performs the same function as the IAT on the 2003/2003 7.3L engine. The PCM uses the changes in IAT1 voltage to determine the current ambient air temperature. The IAT2 on the 6.0 diesel engine performs the same function as the manifold air temperature(MAT) sensor on the 7.3L engine. The PCM uses the IAT2 signal to measure manifold air temperature to help determine the proper fuel delivery." I hope this helps. Quote Link to comment Share on other sites More sharing options...
Damon Posted July 9, 2009 Share Posted July 9, 2009 Originally Posted By: Damon Originally Posted By: Keith Browning According to the PCED the PCM uses the IAT-2 signal to control timing and fuel rate during cold starts and to provide an input to the cold idle kicker. I recall asking an engineer about this sensor back when we took note that these sensors coke up who confirmed this information. So what's the other IAT used for then? To quote the coffee table book, "The IAT1 sensor's primary function is to measure intake air temperature to control the timing and fuel rate when cold starting. Which contradicts Keith's comments (he said this is the job of the IAT2 sensor, see quote above) and also directly contrdicts at least ONE other coffee table book that states that the IAT sensor in the MAF is used ONLY for fan operation and AC operation (see the 2004 coffee table book page 29) Originally Posted By: BrunoWilimek "The primary function of the IAT2 sensor is to provide a feedback signal to the PCM indicating manifold air temperature." It stands to reason it's part of the rationality check for setting EGR flow codes instead of sensor position codes. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted July 9, 2009 Share Posted July 9, 2009 My opinion is these parameters can change with every calibration flash level and arguing the point may be fruitless. Everyone could be right on this one, depending what flash it has in it..... Quote Link to comment Share on other sites More sharing options...
Damon Posted July 9, 2009 Share Posted July 9, 2009 Thanks for at least a partial vindication. I see all Ford's references to this sensor as being used to measure manifold air temp but it falls short of saying what for. IH makes no mistakes about it though. It still won't cause an EGR cooler to fail, but it is an integral part of the EGR system, IMHO. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted July 9, 2009 Share Posted July 9, 2009 And, don't forget how many errors there are in the PCED. Just because it's written doesn't mean God wrote it. Quote Link to comment Share on other sites More sharing options...
Shlep Posted July 9, 2009 Share Posted July 9, 2009 And, don't forget how many errors there are in the PCED. Just because it's written doesn't mean God wrote it. Now isn't that the TRUTH.... Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted July 9, 2009 Share Posted July 9, 2009 Cool! It has been a while since we have had a spirited technical discussion. It seems that there are indeed inconsistencies regarding descriptions of the function of the IAT2 sensor for 6.0L engines. I would even say there are some outright vague statements too. This supports Bruce's point about manuals. I have listed the most relevant ones I have found thus far. I am sure there are more. Only the OBD System Operation manual mentions EGR in relation to IAT2 - cooler efficiency to be exact. There are other monitors and sensor checks requiring a valid IAT2 signal however. Here are some printed statements regarding IAT2: 2003 PCED 6.0L [*]The IAT2 sensor is located in the intake manifold. The sensor provides a manifold air temperature signal to the powertrain control module (PCM). 2007 PCED 6.0L [*]The IAT2 sensor is located in the intake manifold. The sensor provides a manifold air temperature signal to the PCM. The PCM uses the IAT2 signal to control timing and fuel rate during cold starts and provide an input to the cold idle kicker. 2003 MY OBD System Operation Summary for 6.0L Diesel Engine [*]Typical Intake Air Temperature 2 Rationality Check Entry Conditions: P0096 - initial Oil Temperature (EOT) is less than 40 deg C. . [*]Typical Intake Air Temperature 2 Rationality Check Malfunctions Thresholds: P0096 - When the change in Intake Air Temperature 2 (IAT2) is less than specified (5 deg C), the drive cycle increment counter advances. 2007 MY OBD System Operation Summary for 6.0L Diesel Engine- [*]Typical Exhaust Gas Recirculation (EGR) Cooler Efficiency Monitor Thresholds: P2457 – Fault sets if IAT2 > 85 deg .C (F series), > 95 deg. C (E series) 2003.25 6.0L Coffee Table Book [*]The primary function of the IAT2 sensor is to provide a feedback signal to the PCM indicating manifold air temperature. . [*]The PCM monitors the IAT2 signal to determine if the temperature is satisfactory. . [*]During engine operation, if the PCM recognizes that the IAT2 signal is lower or higher than the expected value it will set a Diagnostic Trouble Code (DTC) and illuminate the amber malfunction indicator lamp on the dash. MY OPINION is that IAT2 has no direct role in EGR operation, control or (feedback relative to control.) You have an EGR position sensor providing direct EGR valve position feedback and the EBP, MAF and MAP sensors are used to calculate the EGR flow rate and for concern detection. MY EXPERIENCE has been that I have never had a concern with the IAT2 or and EGR concern where diagnostic tests so much as mention IAT2. As mentioned, I have been taught that using IAT2 data can help identify an EGR efficiency concern using data logger. In fact, I have diagnosed a few CLOGGED EGR cooler/ports that had no DTC's in memory and only one failed the IDS-EGR test because it was totally blocked. The others kept spitting pebble-sized pieces of carbon into the valve hanging them up. I am willing to learn more... Quote Link to comment Share on other sites More sharing options...
Damon Posted July 9, 2009 Share Posted July 9, 2009 Cool! It has been a while since we have had a spirited technical discussion. Well, cool. I do NOT profess to be a guru at 6.0's but anyone that knows me knows I'm rather famous for spirited technical discussion. Most of the time I haven't got a fucking clue what I'm talking about. This is another one of those times. Originally Posted By: Keith Browning Only the OBD System Operation manual mentions EGR in relation to IAT2 - cooler efficiency to be exact. There are other monitors and sensor checks requiring a valid IAT2 signal however. Which adds at least something important to this discussion. IAT2 IS or MAY BE at least responsible for managing some part of EGR operation. Originally Posted By: Keith Browning MY OPINION is that IAT2 has no direct role in EGR operation, control or (feedback relative to control.) You have an EGR position sensor providing direct EGR valve position feedback and the EBP, MAF and MAP sensors are used to calculate the EGR flow rate and for concern detection. I have no opinion, because I haven't tested it. It wouldn't be hard to do, and I assure you I will do so. I'll see how EGR operates when IAT2 matches IAT as an ambient temp sensor under identical driving conditions. Right now, all I have is IH saying it's important and Ford (belatedly admitting) it might play a role in EGR operation and fault detection. All the books I have show the same pictures when sdiscussing the sensor. They ALL seem to show IAT2 with EGR in the theory sections..... Then IH comes out and says things like this: Originally Posted By: IH service info The ECM calculates the appropriate desired EGR valve position in response to the changing engine speed, fuel desired, operator demand, engine operating temperatures, exhaust back pressure, boost pressure and altitude. Components involved with the control of the EGR include the following: Barometric Absolute Pressure (BAP) sensor Exhaust Back Pressure (EBP) sensor Manifold Air Temperature (MAT) sensor Manifold Air Pressure (MAP) sensor Accelerator Pedal Position Sensor (APS) Engine Coolant Temperature (ECT) sensor Engine Oil Temperature (EOT) sensor Electronic Variable Response Turbocharger (EVRT™) actuator The EGR actuator consists of two components, a valve with actuator (solenoid) and a position sensor to monitor valve movement. The EGR is at the front of the engine on top of the intake manifold. The EGR actuator is a variable position valve that controls the amount of exhaust that enters the intake system. The EGR valve is controlled by the ECM using a pulse width modulated signal. The system is closed loop using the EGRP as input. Other inputs that are used to calculate the desired position of the EGR valve include BAP, EBP, MAT, VGT control, MAP, APS, and EOT. IH isn't Ford, nor are they infallible in their service info either. But it appears that IH is clearer in their remarks about the role of IAT2 in the operation of the EGR valve. Originally Posted By: Keith Browning MY EXPERIENCE has been that I have never had a concern with the IAT2 or and EGR concern where diagnostic tests so much as mention IAT2. As mentioned, I have been taught that using IAT2 data can help identify an EGR efficiency concern using data logger. In fact, I have diagnosed a few CLOGGED EGR cooler/ports that had no DTC's in memory and only one failed the IDS-EGR test because it was totally blocked. The others kept spitting pebble-sized pieces of carbon into the valve hanging them up. I am willing to learn more... My experience matches yours here. We can agree on this. I can't say that based on this alone it stands to reason that IAT2 isn't partly responsible for fault detection though. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted July 9, 2009 Share Posted July 9, 2009 I can't say that based on this alone it stands to reason that IAT2 isn't partly responsible for fault detection though. It would be great to hear more on this from an engineer that actually has the answer. It seems the more I go looking for answers the more questions I have. I had one additional thought for us to chew on. I have yet to see an IAT2 sensor that didn't have carbon packed around the thermistor and I question the impact of that carbon on the sensor's ability to react to temperature changes quickly or it's accuracy for that matter. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted July 9, 2009 Share Posted July 9, 2009 I have no opinion, because I haven't tested it. It wouldn't be hard to do, and I assure you I will do so. I'll see how EGR operates when IAT2 matches IAT as an ambient temp sensor under identical driving conditions. I'm not following you here. Are you stating you are going to watch EGR command when IAT and IAT2 are the same temp? They almost never are, except at cold startup when the EGR won't be functioning because cold engines don't produce NOx (which is what an EGR is there to reduce). During driving conditions, IAT and IAT2 will never match. Or, are you stating you will modify the IAT2 signal via an external sensor or signal generator, to match the IAT's signal? PS IH calls IAT2 MAT, but I'm sure everyone figured that out by now. I've always felt the PCM was watching IAT2 to confirm EGR flow, as well as using it as a general input for fuel strategy, timing, idle speed, glow plug, and VGT, among other things.. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted July 9, 2009 Share Posted July 9, 2009 I was always under the impression that the two sensors also gave the PCM a good indication how well the intercooler was doing/how hot the charge air temp was. Quote Link to comment Share on other sites More sharing options...
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