Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
OK I have read your compliant and I see you say the ECM fried?
Did you determine what caused an ECM failure?
If you feel the fuel pump is working, then after some basic checks, connect a quality scan tool, and check for any trouble codes that would lead you into the direction of a problem area.
Here's what I need to know.
Does the engine have Spark to the spark plugs.
Does the fuel pump run for about 2 seconds when you cycle the key to the on position.
And does the engine run and continue to run when you spray a starting fluid or carb spray down into the throttle body.
Now when you check the fuel pressure on this engine, you need to check to see that the fuel pressure regulator is not failing. If the fuel pressure gage does not hold the pressure at about 60 lbs after the 2 second fuel pump cycle, then you are going to need to get to fuel pressure regulator under the upper intake and replace it.
So basic checks first.
Fuel pressure gage holds at 60 lbs.
Engine has spark
Engine has compression.
And does engine continue to run while spraying starting fluid down the throttle body.
Sometimes just a bad fuel pressure regulator can flood an engine, and with wet spark plugs, the thing just will not start again.
I must not have received your reply correctly. It appears that your original statement about your blazer came through to me instead of a reply.
Please try again
You didn't explain why the ECM fried?
There is no question that a crankshaft position sensor could be causing your problem.
I was just curious about what happened there.
Was trying to figure out if that may have had anything to do with the problems you are experiencing right now.
If the computer is incapable of doing its part, the engine will not start.
The signals or inputs from the sensors on the engine tell the ECM how to control fuel and spark. If you are unable to retrieve data from the ECM, then that needs to be addressed.
All power and ground circuits must be functional at the ECM. And the ECM must function.
Have you removed the spark plugs to see if they are wet with fuel? Have you checked for a Good strong blue spark at the plug wires while someone cranks the engine? Do you have a Fuel pressure gage on the engine to verify it is holding pressure after key is cycled on for 2 seconds. Have you sprayed starting fluid down the intake to see if the vehicle runs and continues to run while spraying?
Please try to understand that we are not compensated in any way, shape or form until you are happy with our answers and you click the "ACCEPT" button from your end.
If we are asked to get into detailed long distance diagnosis that can take us hours and hours to help you with, it is customary that you follow closely the procedures we recommend, and use the tools and test procedures we offer along with being prepared to offer a little extra in the way of compensation for our work.
There are many situations where we don't just have a quick fix for a vehicle where the description is that ...."my car won't start"
It sounds as if you may have a very complicated and extensive bit of work to accomplish on your Blazer. This may be something that is way beyond trying to do via text with the vehicle there and me here.
When I say cycle the key to the on position, that is simply to on and not all the way to start.
If I ask to have the key bumped, I will say cycle the key to the start position.
The on position is just when the dash lights up but the engine is not cranking.
In the case of your Blazer, most of the sensors will provide a voltage value that is viewed via a quality scan tool. For instance, you would look at the parameters of a Throttle Position Sensor with a scan tool, and you would be able to see the voltage vary from about .54 volts at throttle closed to about 4.90 volts at wide open throttle.
Important inputs and outputs for fuel control and are IAC, Coolant Temperature and Crank and Cam position.
Yes, you can toss a crank sensor at this thing, but you need to know the ECM is working. One of the first steps in determining if the ECM functions is to view the Check Engine Light on the Dash. If that doesn't work, that needs to be the first step in your repair.
All of the inputs to the ECM are interpolated, and then the ECM decides the spark timing, the amount of Fuel to be delivered, and it looks at the RPM and Load all in an effort to make any necessary adjustments to the systems so that the drivabiility is best for the conditions.
I've been trying to tell you we use a scan tool. oOr Just install a new sensor and see what happens.Diagnostic Trouble Code (DTC) PO337 and DTC P0338 will set if there is a crank sensor malfunction. Refer to Diagnostic Trouble Code Charts .
CIRCUIT DESCRIPTION The Crankshaft Position (CKP) sensor sends a reference (0 volt/5 volt, "OFF," "ON") signal to the Vehicle Control Module-A (VCM-A) to indicate crankshaft position and RPM so that the VCM-A can determine when to pulse the ignition coil and control ignition timing. DTC P0337 is a type "B" DTC.DTC PO337 WILL SET WHEN
ACTION TAKEN (VCM-A WILL DEFAULT TO) The VCM-A will turn "ON" the Malfunction Indicator Lamp (MIL) (Service Engine Soon) after two consecutive driving cycles with the fault active.DTC P0337 WILL CLEAR WHEN The VCM-A will turn the MIL "OFF" after three consecutive trips without a fault condition present. A history DTC will be cleared if no fault conditions have been detected for forty warm-up cycles [coolant temperature has risen 22°C (40°F) from start-up coolant temperature and engine coolant temperature exceeds 71°C (160°F) that same ignition cycle] or the Tech 1 clearing feature has been used.DTC CHART TEST DESCRIPTION Number(s) below refer to circled number(s) on the diagnostic chart.
DIAGNOSTIC AIDS An "Intermittent" problem may be caused by a poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation.Any circuitry, that is suspected as causing the intermittent complaint, should be thoroughly checked for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wiring connections or physical damage to the wiring harness.
You may be able to check the crank sensor by putting your low AC volt meter on the wires with the sensor out of the car. Move the magnetic pickup near a large piece of steel an watch the meter to see if it fluctuates as you move the sensor close to and away from the steel.
I've heard of people checking them in that way.