How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Pete Your Own Question
Pete
Pete, Pontiac Technician
Category: Pontiac
Satisfied Customers: 26307
Experience:  17 Years Pontiac Technician and training.
14928985
Type Your Pontiac Question Here...
Pete is online now
A new question is answered every 9 seconds

I have a 2004 Pontiac grand am 3.4 ltr motor. We have

Customer Question

I have a 2004 Pontiac grand am 3.4 ltr motor. We have replaced the cam shaft sensor, starter, rank sensor, ignition switch, ignition control module, plugs, wires, throttle control module, coils and fuel filter and serpentine belt. when cold car will start after it gets warm some times it will not crank, intermittently you will get it to crank and then will not fire and visea versa. We are at a loss, any ideas what we may be over looking, the care is not throwing any codes
Submitted: 7 months ago.
Category: Pontiac
Expert:  Pete replied 7 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 anything after market installed like a remote start or alarm system at all?

Have you had the fault codes checked to see what codes are set with this issue here at all with a scan tool that can communicate with the engine and body computer?

Let me know so we can continue,thanks Pete.

Customer: replied 7 months ago.
There are no after market parts installed or alarm systems, the only code it was throwing was the crank sensor and it has been replaced
Expert:  Pete replied 7 months ago.

Is it cranking with the starter now and not start or not cranking the starter over now at all?

Customer: replied 7 months ago.
most of the time the starter will not crank, and the starter is new
Expert:  Pete replied 7 months ago.

O.k.,do you know if it is acting up now and not cranking with the starter now and do you have any electrical test equipment like a test light or multi meter to test with at all so we can do some testing?

Let me know,thanks Pete

Customer: replied 7 months ago.
we have ran a scan on the car it is not throwing any codes at all. We have tested for spark with spark plug tester and the car is getting spark. we have tested fuel pressure and it is fine. The only thing that did not test good was that MAF Sensor it read 1.1
Expert:  Pete replied 7 months ago.

O.k.,try this.Unplug the mass air flow sensor with the key off.Then turn on the key and see if the engine starts then.If it does then the mass air flow sensor needs replaced as it is shorted internally.I have seen this sensor short out internally and cause this fault here needing replaced.

If this does not work remove the spark plugs and see if they are soaked with wet/raw fuel.If they are clean and dry them or replace them and see if it starts then just in case it was just flooded out.

If neither of these resolve the issue here 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 7 months ago.
the car started right up with the sensor unplugged and is running. turned car off and now will not crank with it plugged in or not plugged in. Does this after the car starts getting warm
Expert:  Pete replied 7 months ago.

O.k.,so to be sure it is not cranking now/starter is not engaging now?

Do you have a test light or multi meter to test electrical with right now?

Customer: replied 7 months ago.
I don't have the test equipment right now, its my brothers. The starter only cranks to 1 second and stops...
Expert:  Pete replied 7 months ago.

Without testing it can be difficult to pinpoint the fault from here.I will post the starting circuit diagram below if you or he gets a chance to do some testing when it will not crank over.What I can say here though is I have seen the starter relay fail in the under hood fuse box but this will only cause a no crank and since you sometimes have a crank but no start the other component that can fail after all that has already been replaced here is the PCM (engine and transmission computer).The circuits inside the PCM may be acting up/failing internally intermittently causing this fault here as the PCM is used to energize the starter relay as well as controls fuel and spark signals when the no start occurs.You would need to have the circuits tested below when it is acting up to pinpoint which component is at fault needing replaced to correct this issue.

With all that has been replaced and with what is occuring I am leaning towards a possible faulty PCM needing replaced.

https://www.dropbox.com/s/r60wfa78gugkx4a/stdia-08-08.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