What could it be? Flashing check engine w/o dtc
#11
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EGR beig stuck open a lil bit can make it idle like its cammed, so egr could be some of the problem. I guess it could be stock manifolds leaking, they're terrible about breaking the heads of the bolts and I guess after a while it could leak past stock manifold gasket. If he has a scan tool he could check the long tem & short term fuel trims that can be some indication of what the ecu is trying to do. but yeah usually flashing check engine light means random misfire. One question when do it do this? certain RPM, when engine is cold?
all the time, just trying to get more info.
all the time, just trying to get more info.
#12
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Ok guys.. so i took the truck to my tunner and he connected it and guess what... NO CODES and the engine check was blinking... the guy at the shop found a p1154 and we changed bank 2 1 O2 sensor and it got a little better but it still sounds wierd and smells like a lot of gas... plugs and wires were checeked and still the same.. it runs and my Stall wont lock up but as soon as e erases the check engine flashing it locks.. so i lean more into the electrical side than any mechanical thing... What do you all think help please
#13
11 Second Hall Moniter
iTrader: (22)
Your guy helping you needs to do more than just check for codes. He needs to scan live data while the engine is running. A flashing check engine light means that you have catalyst damaging misfires. Your tune (most likely) has the misfire count tables set very high, and that's why the DTC's are not being set.
With HPT, EFI Live, or many other quality scan tools, a tech can moniter current misfires for all cylinders, and history misfires for all cylinders. That will narrow down which cylinder is the problem in your case, and then the troubleshooting can begin.
With HPT, EFI Live, or many other quality scan tools, a tech can moniter current misfires for all cylinders, and history misfires for all cylinders. That will narrow down which cylinder is the problem in your case, and then the troubleshooting can begin.
#14
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EGR beig stuck open a lil bit can make it idle like its cammed, so egr could be some of the problem. I guess it could be stock manifolds leaking, they're terrible about breaking the heads of the bolts and I guess after a while it could leak past stock manifold gasket. If he has a scan tool he could check the long tem & short term fuel trims that can be some indication of what the ecu is trying to do. but yeah usually flashing check engine light means random misfire. One question when do it do this? certain RPM, when engine is cold?
all the time, just trying to get more info.
all the time, just trying to get more info.
#15
Staging Lane
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Your guy helping you needs to do more than just check for codes. He needs to scan live data while the engine is running. A flashing check engine light means that you have catalyst damaging misfires. Your tune (most likely) has the misfire count tables set very high, and that's why the DTC's are not being set.
With HPT, EFI Live, or many other quality scan tools, a tech can moniter current misfires for all cylinders, and history misfires for all cylinders. That will narrow down which cylinder is the problem in your case, and then the troubleshooting can begin.
With HPT, EFI Live, or many other quality scan tools, a tech can moniter current misfires for all cylinders, and history misfires for all cylinders. That will narrow down which cylinder is the problem in your case, and then the troubleshooting can begin.
#17
#18
FormerVendor
iTrader: (4)
Flashing MIL
I think it had to be a percentage over the FTP standard (over the 1.5 time listed below) to cause a flashing light. This would include Misfires as listed below
IMPORTANT
For the misfire diagnostic only: If a sufficiently high rate of misfire is detected within a speedlload window which could result in catalyst damage, the MIL will flash continuously until the vehicle is no longer in such an operating condition. It will then remain on.
MISFIRE MONITORING
Requirements
Failure criteria for the misfire diagnostic includes the following:
Both Current and History Misfire counts are viewed on Tech 2 Misfire Data List, under the Specific Engine Data Menu.
Under criteria 1 and 3 (above), a DTC will set and the malfunction indicator lamp (MIL) turns "on" when misfire is detected in a similar engine speed, load, and coolant temperature window for two consecutive trips. The MIL must also be turned "on" if there is a malfunction in two non-consecutive trips (not more than 80 trips apart) under similar engine speed, load, and coolant temperature conditions. If misfire is detected on two consecutive trips, the MIL will turn "on" regardless of engine speed, load, and coolant temperature.
Under criteria 2, the MIL must flash once per second if misfire is serious enough to result in catalyst damage. Catalyst damage can occur with misfire at high engine speeds and loads. Flashing the MIL is intended to discourage the driver from operating the vehicle in this condition (to ease off the throttle) before catalyst damage results. If criteria 2 has been met, the MIL must turn "on" within 200 engine revolutions of the onset of misfire. Further, the MIL must cease to flash and be steadily turned "on" when the vehicle is no longer in an operating condition where misfire will result in catalyst damage.
-NOTICE-"Similar engine speed" must be within 375 RPM, and calculated load must be within 10%.
I think it had to be a percentage over the FTP standard (over the 1.5 time listed below) to cause a flashing light. This would include Misfires as listed below
IMPORTANT
For the misfire diagnostic only: If a sufficiently high rate of misfire is detected within a speedlload window which could result in catalyst damage, the MIL will flash continuously until the vehicle is no longer in such an operating condition. It will then remain on.
MISFIRE MONITORING
Requirements
Failure criteria for the misfire diagnostic includes the following:
- A level of misfire sufficient to result in emission levels exceeding 1.5 times the FTP standard
- A level of misfire sufficient to result in catalyst damage at the current operating condition (engine speed, load and coolant temperature)
- A level of misfire sufficient to cause the vehicle to fail the California Inspection Maintenance (11M)test
Both Current and History Misfire counts are viewed on Tech 2 Misfire Data List, under the Specific Engine Data Menu.
Under criteria 1 and 3 (above), a DTC will set and the malfunction indicator lamp (MIL) turns "on" when misfire is detected in a similar engine speed, load, and coolant temperature window for two consecutive trips. The MIL must also be turned "on" if there is a malfunction in two non-consecutive trips (not more than 80 trips apart) under similar engine speed, load, and coolant temperature conditions. If misfire is detected on two consecutive trips, the MIL will turn "on" regardless of engine speed, load, and coolant temperature.
Under criteria 2, the MIL must flash once per second if misfire is serious enough to result in catalyst damage. Catalyst damage can occur with misfire at high engine speeds and loads. Flashing the MIL is intended to discourage the driver from operating the vehicle in this condition (to ease off the throttle) before catalyst damage results. If criteria 2 has been met, the MIL must turn "on" within 200 engine revolutions of the onset of misfire. Further, the MIL must cease to flash and be steadily turned "on" when the vehicle is no longer in an operating condition where misfire will result in catalyst damage.
-NOTICE-"Similar engine speed" must be within 375 RPM, and calculated load must be within 10%.
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