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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: 3412
Experience:  Owner at Carolina Auto Service &Sales , 20 years Experience in Foreign & Domestic vehicles
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I have a 2006 gmc envoy cl Denali v8 5.3 wen the car get

Customer Question

I have a 2006 gmc envoy cl Denali v8 5.3 wen the car get warm the engige stop working ... will crank but won't star... if we wait about 2 hours the car star normal ...
We replace the cranck sensor , the fuel pump, ecm, alternator, battery... clean the throttle body and the same thing happen
Submitted: 6 months ago.
Category: GMC
Expert:  Chad Farhat replied 6 months ago.

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

Expert:  Chad Farhat replied 6 months ago.

hey how are you

at the time of no start , what are you missing ?fuel or spark or both ?

are the fuel injectors pulsing sat the time of failure have you checked ?

when it want start ,if you spray starting fluid will it run ,if fuel is new but injector not opening it want start but when you spray starting fluid you bypassing the injectors

with a test light on ignition coils & injectors ,when it dies what are you missing there , ecm controlled , have you done a wiring wiggle test

inspected the ecm connectors for any backed out pins making poor or intermittent connection

We need correct Fuel pressuer & good Spark for the engine to run correctly ?

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

Thank You

Chad Farhat

ASE Certified Technician

Customer: replied 6 months ago.
If I use starter fluid will run
Customer: replied 6 months ago.
Ck and clean all the ecm connector
Customer: replied 6 months ago.
Wen goes out I notices that the throttle body wind work
Expert:  Chad Farhat replied 6 months ago.

okay ,is pump running does is buzz for 3 secs or so at ignition switch from off to on

Expert:  Chad Farhat replied 6 months ago.

new or used ecm ?

Customer: replied 6 months ago.
New at napa
Customer: replied 6 months ago.
Now does but after 1 to 2 hours idle the pump stop the throttle body stop
Expert:  Chad Farhat replied 6 months ago.

if pump running at time of failure and fluid will start it and u have pressure at rail

then ecm is not pulsing i know it is new but i bought new bad ones before when they heat up they act up

Expert:  Chad Farhat replied 6 months ago.

ECM OR ECM WIRING

it controls all these components , wiggle harness next time.

you can ohm out ever wire in the harness .

after 2 hours tells me heat or temp effecting something most likely the module if the harness it will be consistent ,i don't know what you think :)

Please let me know

Thank You

Chad Farhat

ASE Certified Technician

Customer: replied 6 months ago.
I just replace the fuse box with another original ... and a new ecm
Customer: replied 6 months ago.
Let see what happen next
Expert:  Chad Farhat replied 6 months ago.

ok sounds good

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Thank You
Chad Farhat
ASE Certified Technician

Customer: replied 6 months ago.
I just replace the fuse box and give a try ... the car is on for the past 2 hours and did not turn off ..... I can turn off and on with no problem ....
seams like I had a bad fuse box
Expert:  Chad Farhat replied 6 months ago.

Awesome news man I m glad ,but test more :)

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Thank You

Chad Farhat

ASE Certified Technician