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GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 15133
Experience:  GM Grand Master Technician 2007. 14 years experience.
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Intermittently lot of blue smoke out tail pipe. when

Customer Question

intermittently lot of blue smoke out tail pipe. when smoking, sometime it does not to go and sometime it just takes off great.
Submitted: 4 months ago.
Category: Chevy
Expert:  Chad Farhat replied 4 months ago.

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

Expert:  Chad Farhat replied 4 months ago.

the blue smoke indication of excessive fuel .

what is the mileage on it ?

do you have a scanner that can read fuel trims ?

Please let me know

Thank You

Chad Farhat

ASE Certified Technician

Customer: replied 4 months ago.

thanks I check

Customer: replied 4 months ago.

93k is mileage.

no codes.

My Snap On does not show fuel trim.

I did notice when I accel on fuel peddle it wil start racing 4000 rpm but the APP % is around 4.

Expert:  Chad Farhat replied 4 months ago.

have you check the idle air control valve & throttle body itself .

a mass air flow sensor will cause that and dont throw codes , but if scanner cant read fuel trims i cant confirm it for you

get a mass air flow sensor cleaner and clean it or replace it .

Please let me know

Thank You

Chad Farhat

ASE Certfied Technician

Customer: replied 4 months ago.

you mean the injector pump

Expert:  Chad Farhat replied 4 months ago.

yes the injector pump called on yours

Customer: replied 4 months ago.

What are the readings on a mass air flow sensor supposed to be at on a scanner?

Expert:  Chad Farhat replied 4 months ago.

you need to see 5 g/s at idle and 340 at the change of gear from 2nd to 3rd gear if you doing a drive test on it

Customer: replied 4 months ago.

do you also check it for cal load being more that 85% on accel? is diesel different than gas

Expert:  Chad Farhat replied 4 months ago.

calculated load i m assuming you referring to , and yes you can check calculated load comparing to real engine load on any internal combustion engine ,so diesel and gas you can check

The fuel injection system uses this to calculate the correct amount of fuel delivery and also the correct ignition timing, variable-valve-timing actuation (where so equipped), etc.

Customer: replied 4 months ago.

I don't think the p30 has a mass air flow. It has a map sensor. Scanner did not give me those reading for MAF. Checked veh load Idle was 24-54 (which seems odd) and hard accel 99%. It stop smoking on the way back and at idle was 5% ( which I thought was normal. What do you think?

Expert:  Chad Farhat replied 4 months ago.

you have 6.5 diesel non turbo correct ? on this one no mass air flow sensor ,my bad but it does have map sensor , so your map sensor showed 5 % at idle

how long the blue smoke stayed coming out of tail pipe ?

does it do it more when cold ?

what is the mileage and have glow plugs been replaced

do you have any hard start when cold ?

Customer: replied 4 months ago.

how long the blue smoke stayed coming out of tail pipe ? Intermittently but when it does it it come out as long as you are in the pedal.

does it do it more when cold ? both

what is the mileage and have glow plugs been replaced. any speed even at idle with the rpm up.

do you have any hard start when cold ? no

what would make the vehicle load be so high at idle?

Expert:  Chad Farhat replied 4 months ago.

Characteristics of LOAD are: - Ranges from 0 to approximately 0.95 for naturally aspirated engines, 0 – 4 for boosted engines( diesel)

There isn't a single sensor it uses to figure this out. it utilizes, Manifold Absolute Pressure (MAP) sensor, Throttle Position Sensor (TPS), and Engine Coolant Temperature (ECT) sensor to do calculations and to see if the engine is at the ready point to make the calculations. compression ignition (diesel) system are required to maintain this.

so a combination of sensors output read by ecu is how the load is determined .

so any issues with these sensors will cause this if one or some are given ecu wrong values

Chad

Customer: replied 4 months ago.

With what I have told you what do you think the problem is or what is the next thing to do to find out whats wrong

Expert:  Chad Farhat replied 4 months ago.

TPS Throttle position sensor will cause this .That what i will check next .

Customer: replied 4 months ago.

New TPS but still same problem. Any other suggestions

Expert:  Chad Farhat replied 4 months ago.

wiring or computer , but at this point you need a diagnostic scanner specific to ford that can actually see live data on all sensors and run n test on pcm and all other modules available, if you are changing parts with no results, suspect wiring back to the ecm,

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