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Ask Chad Farhat Your Own Question
Chad Farhat
Chad Farhat, ASE Certified Technician A6 - Electrical / Electronic systems A7 Heating / Air conditioning systems
Category: GMC
Satisfied Customers: 3644
Experience:  Owner at Carolina Auto Service &Sales , 20 years Experience in Foreign & Domestic vehicles
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Crank no start and low pressure in intake 11 GMC Acadia. Yes

Customer Question

Crank no start and low pressure in intake 11 GMC Acadia.
JA: Will the headlights turn on? Is the battery fully charged?
Customer: Yes all lights work even tried to jump it
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: originally had 2, 4, 6 misfires but I've replaced all 6 spark plugs and all 6 coils it was a catalytic converter code and the 3 misfires. and one day car shut off and hasn't started since
JA: Anything else you think the mechanic should know?
Customer: nothing other than the original codes were catalytic converter and misfire on the 2,4,6 car was running then shut off at a stop light, car started then shut off as it was only running on three cylinders and then has not started since even with replacing the 6 coils and plugs
Submitted: 1 year ago.
Category: GMC
Customer: replied 1 year ago.
is there a safety switch something that'll resemble a circuit breaker protecting/ blocking the engine from starting?
Expert:  Chad Farhat replied 1 year ago.

Hi, I'm Chad ,Welcome To JustAnswer, I'm reviewing your question and I will be posting a reply ASAP

Customer: replied 1 year ago.
Awesome, thank you.
Expert:  Chad Farhat replied 1 year ago.

is there a check engine light on ?

is there a red security light flashing on the dash while you are trying to start it?

have you had a diagnostic scan and retrieved the fault codes ? and what were they, you mentioned catalytic fault codes ?
We need Fuel & Spark for the engine to start ?

Do you have a test light so we can check for spark ?

Do you have fuel pressure tester to check for fuel ?

are you looking at fixing this yourself or looking to know the most possible cause of this issue and taking it to repair shop for the work ?

Do you have any prior experience in electrical troubleshooting and testing with a test light for power & ground ?

Please let me know

Chad Farhat
ASE Certified technician

Customer: replied 1 year ago.
to the engine light, but I am not a mechanic I will be taking it to a mechanic and just want verify the work that might possibly be done on the vehicle to avoid any extra charges. Does this vehicle have a inertia fuel pump relay cut off?
Customer: replied 1 year ago.
it seems the engine is not receiving the proper amount of fuel
Expert:  Chad Farhat replied 1 year ago.

there is no inertia fuel pump switch it is controlled by ecm

Fuel Shut-Off Mode The ECM has the ability to completely turn OFF all of the injectors or selectively turn OFF some of the injectors when certain conditions are met. These fuel shut-off modes allow the ECM to protect the engine from damage and also to improve the vehicles driveability. The ECM will disable all of the six injectors under the following conditions: * Ignition OFF-Prevents engine run-on * Ignition ON but no CKP signal-Prevents flooding or backfiring * A high engine speed-Above the red line * A high vehicle speed-Above the rated tire speed * Closed throttle cast down-Reduces the emissions and increases engine braking. The ECM will selectively disable the injectors under the following conditions: * The torque management enabled-Transmission shifts or abusive maneuvers. * The traction control enabled-In conjunction with the front brakes applying

Customer: replied 1 year ago.
Does the ECM need to be reset to rerun computer to determine new codes. does the ECM need to be replaced.
Expert:  Chad Farhat replied 1 year ago.

is there a security light flashing on dash ?

do you have 1 or 2 keys ?and have you tried starting with the other

in case the alarm is triggered the fuel and starter will cut off by ecm ?

do yiu hear the fuel pump running when you open switch to on, the fuel pump will run for few seconds do yiu hear it

Expert:  Chad Farhat replied 1 year ago.

lets try this reset procedure in case that is the case

Master reset Procedure

1- Disconnect Battery Cables ( Negative & Positive Cables )

2- Wait 10 minutes

3- Make sure all doors are closed

4- Reconnect battery Cables

5- Lock & unlock the vehicles using the key from driver door side (if you have a key fob with no blade key, just lock & unlock using the key fob buttons)

6- Enter the vehicle and attempt to start

Expert:  Chad Farhat replied 1 year ago.

well if the battery died the fault codes will be lost , but attempting to start it again , it will throw fault codes again in the memory of the pcm

a proper diagnostic scan is imperative to know what is going on ? so if you can get me fault codes again will be very helpful ?

Customer: replied 1 year ago.
I will do the master reset and then attempt to start. I will run the Computer and see the codes and relay them to you.
Expert:  Chad Farhat replied 1 year ago.

ok sounds great

I m online from 9 am till 12 pm today

Please let me know

Thank You

Chad Farhat

ASE Certified Technician

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