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Pete
Pete, Auto Service Technician
Category: Dodge
Satisfied Customers: 26308
Experience:  Over 17 years diagnosing and repairing automobiles various makes and models with some training and certifications.
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Cummins very hard to start when cool it does not have to be

Customer Question

Cummins very hard to start when cool it does not have to be cold even just a little cool its very hard to get started. Starts great when warm or hot out. No codes and wait to start light works ? Need some help Diag this one.
Submitted: 6 months ago.
Category: Dodge
Expert:  Pete replied 6 months ago.

Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.

Is this after the vehicle has sat a period of time or over night that it is difficult to start?

Let me know so we can continue,thanks Pete

Customer: replied 6 months ago.

No as long as its fairly warm out it starts right up ! But if it gets evenba little cool she's a bear to get started.

Customer: replied 6 months ago.

Just let it sit for four days and it fired right up 80 degrees here.

Expert:  Pete replied 6 months ago.

Is the starter engaging but the engine is not starting with this issue here when the fault occurs?

Customer: replied 6 months ago.

Yes turns over great just don't want to start.

Expert:  Pete replied 6 months ago.

Have you checked the engine coolant temp sensor signal to see if it is o.k.?I have seen issues with the engine coolant temp sensor that can cause this fault here needing replaced.In some cases when it acts up it can act up at certain outside temps sending an incorrect signal like the engine is warm when it isnt and cause a lean issue causing a hard start.This is usually checked with a compatible scan tool that can plug in and communicate with the engine computer to read the temp sensor signal.

If this is or was checked have you replaced the fuel filter at all as well as observed on a scan tool the data for actual and commanded fuel rail pressure.I have seen issues with the fuel filter in some cases as well as the injection pump.Usually these act up all of the time if this is the case but in some cases I have seen issues with the pump acting up at certain temps.

If all of these have been checked let me know so we can continue.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service,your 5 star rating is appreciated.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 6 months ago.

Fuel filter was replaced and is new. Let's start with checking coolant temp sensorand fuel rail pressure . I have scan tool (snap on MODIS ) shoot me info on checking temp sensor and rail pressure ?

Expert:  Pete replied 6 months ago.

O.k.,with the vehicle acting up check the data list on the scan tool for actual fuel rail pressure and desired fuel rail pressure when cranking the engine when it will not start.These numbers should be very close to each other.If they are not there is a good chance the injection pump is starting to fail.

If this is o.k. to check the coolant temp when it is acting up you would need something like a laser pointer temp gun to probe the engine to see what temp the engine is,then turn on the key and observe on the scan tool what the data shows in the engine data list for engine coolant temp.They should be close to the same.If the temp is way off on the data display compared to what you read with the temp gun then this can usually indicate a fault with the temp sensor.

Let me know if you need anything else and feel free to rate my help here as this is how I receive credit for my time.Your 5 star rating is appreciated

Thanks Pete

Customer: replied 6 months ago.

Great thanks gonna have to wait for a cool morning will hit ya back after I check.

Expert:  Pete replied 6 months ago.

Sounds good

Customer: replied 6 months ago.

Hey Pete coolant temp sensor reads -40 on scan tool and never changes all the way op temp. Is there two sensors one for gauge and one for computer or are they the same one ? Where is comp temp sensor located ?

Expert:  Pete replied 6 months ago.

I apologize for the delay as I had to step away with an emergency.

They are the same sensor and this does sound like the fault here.It looks like it is located on the side of one of the cylinder heads as shown below.Your model only uses one sensor.

https://www.dropbox.com/s/7s8lxekj10r0p73/ct-09-25.gif?dl=0

Let me know if you need anything else and feel free to rate my help here as this is how I receive credit for my time.Your 5 star rating is appreciated

Thanks Pete

Customer: replied 5 months ago.

Hey Pete pulled the coolantvtemp sensor out of the drivers side rear head got one ordered. The parts store tells me there is 2 one for the computer and one for the guage ? The one on the driversbside rear of head is expensive 140.00 but they say that is for the guage I'm replacing it anyway since I have it off. Canbyou double check and see if there is a second separate sensor for computer and where its located they are ordering both.

Customer: replied 5 months ago.

The one on the drivers side rear of head is a single wire connector and is like 3\4 diameter. Just an fyi

Expert:  Pete replied 5 months ago.

Let me take a look real quick

Expert:  Pete replied 5 months ago.

O.k.,I dont show a location other then the diagram above earlier and the diagram here.

https://www.dropbox.com/s/u1pn0kai4yzdear/co-09-29.gif?dl=0

I do show that there is a 2 wire sensor that leads direct to the gauge.It is a yellow wire and a wire that is black with white stripe.Diagram posted below.

https://www.dropbox.com/s/kbat20didc8bj8o/te-09-29.gif?dl=0

Customer: replied 5 months ago.

Let change out this single wire sensor and see if its the right one ! Hit ya back tomorrow and letbya know.

Expert:  Pete replied 5 months ago.

After re checking there is two sensors on this model although my first info only shows one.Here is the diagram of the second sensor that feeds the computer.It looks to have a tan wire with black stripe and a black wire with light green stripe.

https://www.dropbox.com/s/zghd5yy527syt9v/sen-09-29.gif?dl=0

Let me know if you need anything else and feel free to rate my help here as this is how I receive credit for my time.Your 5 star rating is appreciated

Thanks Pete

Customer: replied 5 months ago.

Pete I installed new sensor on drivers side back of head still reads -40. Any idea where 2nd sensor is located ?

Customer: replied 5 months ago.

I have sensor but have looked everywhere can't locate ect sensor for computer. ?

Expert:  Pete replied 5 months ago.

Are there any sensors on the sides of the cylinder head or around the thermostat or intake area that this sensor fits?