getting bad gas mileage.
Hey,
I am getting 12-16 mpg in my 03 Cummins, just over 200k. I have changed the air and fuel filters, put fuel rail cleaner through it, cleaned off the ait and map sensors still got about 3k miles before i need to change the oil and im not getting any fault codes on the obd2. I dont know what to do at this point i do have access to my own obd2 so i need to take readings just let me know. Any help would be appreciated. Doc89holliay |
Please let us know if you have any mods or if the truck is stock.
thanks |
Have you lifted or added bigger tires:humm:
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Also could be where hes getting his fuel from too.
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The truck is bone stock. 2500, 265/70r17 tires. I have changed nothing in the past 6 months but oil and the above items. Thats when i bought the truck
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Any light smoke on start up?
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none
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just wondering if run have run the valves lately. boost leaks will hurt too. to many things like injectors etc to list:hellox:
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Originally Posted by diesel pap
(Post 1100509)
just wondering if run have run the valves lately. boost leaks will hurt too. to many things like injectors etc to list:hellox:
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by running the valves i mean check valve lash. the boost leaks i talked about can be intercooler or tubes leaking. injectors can get worn and cause problems too
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Originally Posted by diesel pap
(Post 1100557)
by running the valves i mean check valve lash. the boost leaks i talked about can be intercooler or tubes leaking. injectors can get worn and cause problems too
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Did the truck start running rough or anything? Paps right injectors are probably worn maybe boost is low.
Some easy stuff to check is the AIT Map sensor ( I see you already did this) The combination, dual function Intake Manifold Air Temperature Sensor/MAP Sensor is installed into the top of the intake manifold with the sensor element extending into the air stream. The IAT portion of the sensor provides an input voltage to the Engine Control Module (ECM) indicating intake manifold air temperature. The MAP portion of the sensor provides an input voltage to the ECM indicating turbocharger boost pressure. This in turn lets the ECM know how to tune the certain engine parameters. I have heard of these getting dirty and causing problems. Try removing it and clean it with some isopropyl alcohol and "lightly" blow it dry. It's really hard to tell without some baseline that having gauges in the truck can give you!! I would get some gauges as soon as you can afford it! |
Originally Posted by Jet A Fuel
(Post 1100676)
Did the truck start running rough or anything? Paps right injectors are probably worn maybe boost is low.
Some easy stuff to check is the AIT Map sensor ( I see you already did this) The combination, dual function Intake Manifold Air Temperature Sensor/MAP Sensor is installed into the top of the intake manifold with the sensor element extending into the air stream. The IAT portion of the sensor provides an input voltage to the Engine Control Module (ECM) indicating intake manifold air temperature. The MAP portion of the sensor provides an input voltage to the ECM indicating turbocharger boost pressure. This in turn lets the ECM know how to tune the certain engine parameters. I have heard of these getting dirty and causing problems. Try removing it and clean it with some isopropyl alcohol and "lightly" blow it dry. It's really hard to tell without some baseline that having gauges in the truck can give you!! I would get some gauges as soon as you can afford it! |
getting bad gas mileage.
The Ecm will monitor the boost, fuel rail pressure using the map, fuel rail,ait sensors ect. but won't give you actual boost, fuel psi, and unless you have a egt probe in the exhaust no temp readings.As far I know the obd2 will only show voltage thresholds for these sensors. What kind of computer program or app are you using that can read these sensors and convert them to real numbers?
Here's a real life scenario to help explain why gauges are important. If you have gauges in your truck and your towing the gooseneck trailer everyday you will notice that at 75 mph in OD going down the interstate you are pushing 10 to 12 psi boost and your egt's are around 900 degrees on level terrain. You will become accustomed to seeing these numbers just as you have probably already memorized what rpm the truck runs down the highway at a given speed. So When you notice one day that the boost is low and the egt is not where it should be you can say there is a problem see what I am getting at? |
I should first ask are you driving mostly city or mostly highway? 12-16 is pretty nornal for a stock truck. Pretty normal for a modded truck even. That is if it's mostly city driving. I've owned 2 cummins from stock to bombed and never got better than 16 city driving.
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