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07-08-2019, 08:33 AM
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#1
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Senior Member
Fleetwood Owners Club
Join Date: May 2012
Posts: 181
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Check Engine / Engine Protect warnings
On a recent trip pulling a long grade at high altitude, my rig produced a "Check" light, followed shortly thereafter with a "Protect" light and then it derated. Ambient temp was around 90F, engine temp was not high (190 Max) boost was good at 27lbs, and no other anomalies noticed. I was pretty heavy on that trip and so I had pulled most of that grade in 3rd gear to keep the RPM up (around 1800-2000) and my speed was down to around 35mph. The fault would clear within 30 seconds or so of backing off on the throttle but would return when I pushed it back up again. I know about overheating problems with some of these rigs and I have my slobber tube extended out past the intake to the rear cooling fan. I am suspicious that the the manifold air temp sensor was out of limits since the coolant temp did not get high. How do I get the codes to read back?
2007 Freightliner Custom Chasis with 45000 miles
CAT C7 has had regular (5000 mile oil changes and fuel / air filter changes)
Thanks in advance for any help!
__________________
Jim Brinsfield
07 Fleetwood Excursion
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07-08-2019, 09:38 AM
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#2
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Senior Member
Join Date: Apr 2011
Location: Powell River, B.C.
Posts: 31,311
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You've extended the slobber tube ; how often do you clean the rad and CAC ?
Cummins says to clean both every 7,500 miles on rear rad coaches, and is a good idea , no mater what engine and rad location a coach has.
Procedure for codes I believe is covered in the " Sticky " posts , at the top of the post list here in the Caterpillar forum .
__________________
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.
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07-08-2019, 10:44 AM
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#3
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Senior Member
Fleetwood Owners Club
Join Date: May 2012
Posts: 181
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Further to my initial post, Freightliner has walked me through recovering any stored fault codes and there were none stored. Also I have noted previously on this forum, that my boost routinely max's out 1- 2 pounds higher at altitudes above about 2000 feet. At sea level I see 24 to 25 pounds max and at altitude I see 26 - 27 pounds max.
__________________
Jim Brinsfield
07 Fleetwood Excursion
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07-08-2019, 11:38 AM
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#4
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Senior Member
Monaco Owners Club
Join Date: Aug 2017
Location: Orlando, Florida
Posts: 5,819
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If you have a "derate" condition, there will be a fault code stored.
You may be doing something wrong trying to retrieve codes. I would take the coach to Freighter and let them check. Might be something important.
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07-08-2019, 12:36 PM
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#5
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Senior Member
Fleetwood Owners Club
Join Date: May 2012
Posts: 181
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Quote:
Originally Posted by CountryB
If you have a "derate" condition, there will be a fault code stored.
You may be doing something wrong trying to retrieve codes. I would take the coach to Freighter and let them check. Might be something important.
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Thanks for your response..... Followed Freightliners instructions and found the diagnostics menu on my digital display, the system showed that it was retrieving stored codes and that it found none. i will continue to diagnose this at home before taking to Freightliner. I suspect something in the charge air intake system. Either a clogged CAC which seems unlikely since the coolant temp is not high or a bad sensor.
__________________
Jim Brinsfield
07 Fleetwood Excursion
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07-09-2019, 10:42 AM
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#6
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Senior Member
Join Date: Mar 2018
Posts: 337
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Hello, Take the motorhome to a CAT service center and have a progress report run on your engine and you will find out what happened Thanks, Joe it show complete history
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07-12-2019, 10:24 PM
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#7
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Senior Member
Join Date: Jan 2005
Posts: 1,443
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Low coolant switch located in the surge tank can cause this. It also will not leave an event code or a diagnostic code. The switch is known to fail fairly often. Of course if your coolant is actually low then it will activate. If the engine ecm sees low coolant it will turn on the check engine light and derate the engine. Safe Travels
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07-13-2019, 07:20 AM
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#8
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Senior Member
Fleetwood Owners Club
Join Date: May 2012
Posts: 181
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Quote:
Originally Posted by Cat
Low coolant switch located in the surge tank can cause this. It also will not leave an event code or a diagnostic code. The switch is known to fail fairly often. Of course if your coolant is actually low then it will activate. If the engine ecm sees low coolant it will turn on the check engine light and derate the engine. Safe Travels
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Thanks for the response! Had the engine history downloaded by CAT yesterday. There were two relevant codes in there:
1. “Low Coolant” and “Very Low Coolant” This seems odd to me since I can see visually in the surge tank that the coolant level is at the “Cold Min” mark and I replaced the coolant level sensor a year ago when I replaced the surge tank. Furthermore, the coolant temp never got high. The CAT tech told me that they like to fill the surge tank all the way to the top of the neck to prevent the sensor from false readings when accelerating or going up or down hills. Seemed reasonable to me.
2. “High EGT” and “Very High EGT” Further research on the C7 indicates there there is no direct EGT probe measurement on this engine only indirect measurements of induction boost, atmospheric pressure, engine rpm and, intake manifold temperature which the ECM uses to calculate EGT and then issue power derate commands as necessary to bring the engine back to within limits. The amount of derate depends on how over limit the system is. If it's too far over limits or for some conditions, the ECM will actually issue a shut down command.
As I wrote in my initial post, I was at high altitude, pulling a fairly heavy tow, on a very long and steep grade and the OAT was around 90F. The CAT dealer and I are calling this one "operator error" (excessively heavy right foot)
I am thinking of installing a ScanD system to start monitoring Intake Air Temp. Does anyone know what the C7 limits for this parameter are where where I can find such data?
Thanks
Jim
__________________
Jim Brinsfield
07 Fleetwood Excursion
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07-13-2019, 07:51 AM
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#9
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Senior Member
Join Date: Oct 2012
Location: Foley AL
Posts: 7,138
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Quote:
Originally Posted by jbrinsfi
Thanks for the response! Had the engine history downloaded by CAT yesterday. There were two relevant codes in there:
1. “Low Coolant” and “Very Low Coolant” This seems odd to me since I can see visually in the surge tank that the coolant level is at the “Cold Min” mark and I replaced the coolant level sensor a year ago when I replaced the surge tank. Furthermore, the coolant temp never got high. The CAT tech told me that they like to fill the surge tank all the way to the top of the neck to prevent the sensor from false readings when accelerating or going up or down hills. Seemed reasonable to me.
2. “High EGT” and “Very High EGT” Further research on the C7 indicates there there is no direct EGT probe measurement on this engine only indirect measurements of induction boost, atmospheric pressure, engine rpm and, intake manifold temperature which the ECM uses to calculate EGT and then issue power derate commands as necessary to bring the engine back to within limits. The amount of derate depends on how over limit the system is. If it's too far over limits or for some conditions, the ECM will actually issue a shut down command.
As I wrote in my initial post, I was at high altitude, pulling a fairly heavy tow, on a very long and steep grade and the OAT was around 90F. The CAT dealer and I are calling this one "operator error" (excessively heavy right foot)
I am thinking of installing a ScanD system to start monitoring Intake Air Temp. Does anyone know what the C7 limits for this parameter are where where I can find such data?
Thanks
Jim
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I don't have a CAT (it's a 2005 ISM Cummins) but the "sweetspot" for EGT is around 135 degrees F. I throw a code at about 185. It logs but doesn't derate. Pretty sure I've got a failing Ambient Sensor and/or EGT sensor (replace next week). The chk eng appears to be some ECM combination of event/number of events/timeframe. If not helpful just ignore .... I have a ScanGaugeD.
__________________
2005 Newmar Essex 4502, 2013 Caddy SRX
1997 HR Endeavor 37, CAT, 1996 Geo Tracker
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07-13-2019, 03:44 PM
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#10
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Senior Member
Monaco Owners Club
Join Date: Aug 2017
Location: Orlando, Florida
Posts: 5,819
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Quote:
Originally Posted by bruceisla
I don't have a CAT (it's a 2005 ISM Cummins) but the "sweetspot" for EGT is around 135 degrees F. I throw a code at about 185. It logs but doesn't derate. Pretty sure I've got a failing Ambient Sensor and/or EGT sensor (replace next week). The chk eng appears to be some ECM combination of event/number of events/timeframe. If not helpful just ignore .... I have a ScanGaugeD.
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EGT is Exhaust Gas Temperature.
I think you mean ECT (engine coolant temperature).
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07-13-2019, 06:34 PM
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#11
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Senior Member
Join Date: Jan 2005
Posts: 1,443
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Quote:
Originally Posted by jbrinsfi
Thanks for the response! Had the engine history downloaded by CAT yesterday. There were two relevant codes in there:
1. “Low Coolant” and “Very Low Coolant” This seems odd to me since I can see visually in the surge tank that the coolant level is at the “Cold Min” mark and I replaced the coolant level sensor a year ago when I replaced the surge tank. Furthermore, the coolant temp never got high. The CAT tech told me that they like to fill the surge tank all the way to the top of the neck to prevent the sensor from false readings when accelerating or going up or down hills. Seemed reasonable to me.
2. “High EGT” and “Very High EGT” Further research on the C7 indicates there there is no direct EGT probe measurement on this engine only indirect measurements of induction boost, atmospheric pressure, engine rpm and, intake manifold temperature which the ECM uses to calculate EGT and then issue power derate commands as necessary to bring the engine back to within limits. The amount of derate depends on how over limit the system is. If it's too far over limits or for some conditions, the ECM will actually issue a shut down command.
As I wrote in my initial post, I was at high altitude, pulling a fairly heavy tow, on a very long and steep grade and the OAT was around 90F. The CAT dealer and I are calling this one "operator error" (excessively heavy right foot)
I am thinking of installing a ScanD system to start monitoring Intake Air Temp. Does anyone know what the C7 limits for this parameter are where where I can find such data?
Thanks
Jim
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Well at least your ECM logged event codes for the coolant many are not set up to log the low coolant events. If you continue to get alarm for high Egt, check your air inlet cooler for external plugging. Also keep those rpms up. Safe Travels
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07-14-2019, 05:35 AM
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#12
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Senior Member
Join Date: Oct 2012
Location: Foley AL
Posts: 7,138
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Quote:
Originally Posted by CountryB
EGT is Exhaust Gas Temperature.
I think you mean ECT (engine coolant temperature).
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Sorry, what I actually meant was FIA (Intake Manifold Air Temp F. from ScangaugeD) from which EGT is calculated. I should have been more careful with my abbreviations. The Cummins will log a high Intake Air Temp which will also result in a calculated high Exhaust Gas Temp.
__________________
2005 Newmar Essex 4502, 2013 Caddy SRX
1997 HR Endeavor 37, CAT, 1996 Geo Tracker
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