Blazer takes long time to start HELP !!
#1
08-06-2011, 04:15 AM
Blazer takes long time to start HELP !!
ok so i just turned 16 yr old and my family passed down the 89 s10 blazer 4.3l v6 4x4 to me. now its a great truck but it takes time to start it. i have to press down the gas pedal and crank the truck while cranking it makes a popping sound like it back fired from the throttle body and then i have to pump the gas pedal and then it starts right up. its fuel injected so why do i have to press the gas pedal while starting it ? does any one know what could be wrong ?
ps. the truck has a new fuel pump and filter and the spark plugs have been replaced
ps. the truck has a new fuel pump and filter and the spark plugs have been replaced
#3
08-09-2011, 01:35 PM
Easy there Turbo!! Just wait and you will get responses.
Now, even though the fuel pump and filter are new does not mean that you have enough fuel pressure to the throttle body.
A couple of things could be wrong........Idle Air Control valve, lack of fuel pressure. Does it start up easier after it has been running for a while...or is it still hard to start??
If it is easier to start after it is warm I would be looking at the IAC valve...if not it could be a fuel delivery issue.
Do you have a fuel pressure tester?? If so hook it up and see what pressure you have with the key on and the engine not running.
Then after that let it sit for about 10-15 minutes with the gauge still attached and see how much pressure you have after that. It almost sounds like you might have a leaking fuel pressure regulator....
TESTING
Properly relieve the fuel system pressure.
If necessary for access, remove the air cleaner assembly and plug the vacuum port(s).
Disconnect the flexible fuel supply line, located in the engine compartment between the fuel filter and throttle body.
Install a fuel pressure gauge, such as J-29658 or equivalent, inline between the fuel filter and throttle body unit (between the steel line and flexible hose). If necessary, use an adapter or Tee fitting in order to connect the gauge and complete the fuel circuit.
A Tee fitting may be fabricated for this purpose. Depending on the fuel pressure gauge, short lengths of steel tubing, appropriately sized flare nuts and a flare nut adapter may be used.
If the engine will run, start the engine and allow it to run at normal idle speed. The fuel pressure should be 9-13 psi (62-90 kPa).
If the engine does not run, turn the ignition ON , but do not attempt to start the engine. Listen for the fuel pump to run. Within 2 seconds of turning the ignition ON , pressure should be 9-13 psi (62-90 kPa). If necessary, cycle the ignition OFF , then ON again, in order to build up system pressure.
If the fuel pump did not run or system pressure did not reach specification, locate the fuel pump test connector. The connector is usually found on the driver's side of the engine compartment (on or near the fender), with a single wire (usually red) leading from the relay to the connector. Using a jumper wire, apply battery voltage to the test connector in order to energize and run the fuel pump. The pump should run and produce fuel pressure of 9-33 psi (62-90 kPa). If the pump does not run, check the relay and fuel pump wiring.
If the pump pressure was lower than specification, first check for a restricted fuel line or filter and replace, as necessary. If no restrictions can be found, restrict the fuel supply line between the pressure gauge and the TBI unit (a flexible hose may be temporarily clamped to produce the restriction), then apply voltage to the test connector again. If pressure is now above 33 psi (90 kPa), replace the faulty pressure regulator. If pressure remains below 9 psi (62 kPa), then the problem is located in the fuel tank (the fuel pump, coupling hose or inlet filter).
If during Step 7, the pressure was higher than specification, disengage the injector connector, then disconnect the fuel return line flexible hose which connects the line from the throttle body to the tank line. Attach a 5 / 36 in. (8mm) ID flex hose to the fuel line from the throttle body and place the other end into an approved gasoline container. Cycle the ignition in order to energize the fuel pump and watch system pressure. If pressure is still higher, check for restrictions in the throttle body return line. Repair or replace the line if restrictions are found or replace the faulty pressure regulator if no other causes of high pressure are identified. If fuel pressure is normal only with the flexible hose-to-fuel tank line out of the circuit, check that line for restrictions and repair or replace, as necessary.
Once the test is completed, depressurize the fuel system and remove the gauge.
Secure the fuel lines and check for leaks.
If removed, install the air cleaner assembly.
Have you checked for any vacuum leaks?
Now, even though the fuel pump and filter are new does not mean that you have enough fuel pressure to the throttle body.
A couple of things could be wrong........Idle Air Control valve, lack of fuel pressure. Does it start up easier after it has been running for a while...or is it still hard to start??
If it is easier to start after it is warm I would be looking at the IAC valve...if not it could be a fuel delivery issue.
Do you have a fuel pressure tester?? If so hook it up and see what pressure you have with the key on and the engine not running.
Then after that let it sit for about 10-15 minutes with the gauge still attached and see how much pressure you have after that. It almost sounds like you might have a leaking fuel pressure regulator....
TESTING
Properly relieve the fuel system pressure.
If necessary for access, remove the air cleaner assembly and plug the vacuum port(s).
Disconnect the flexible fuel supply line, located in the engine compartment between the fuel filter and throttle body.
Install a fuel pressure gauge, such as J-29658 or equivalent, inline between the fuel filter and throttle body unit (between the steel line and flexible hose). If necessary, use an adapter or Tee fitting in order to connect the gauge and complete the fuel circuit.
A Tee fitting may be fabricated for this purpose. Depending on the fuel pressure gauge, short lengths of steel tubing, appropriately sized flare nuts and a flare nut adapter may be used.
If the engine will run, start the engine and allow it to run at normal idle speed. The fuel pressure should be 9-13 psi (62-90 kPa).
If the engine does not run, turn the ignition ON , but do not attempt to start the engine. Listen for the fuel pump to run. Within 2 seconds of turning the ignition ON , pressure should be 9-13 psi (62-90 kPa). If necessary, cycle the ignition OFF , then ON again, in order to build up system pressure.
If the fuel pump did not run or system pressure did not reach specification, locate the fuel pump test connector. The connector is usually found on the driver's side of the engine compartment (on or near the fender), with a single wire (usually red) leading from the relay to the connector. Using a jumper wire, apply battery voltage to the test connector in order to energize and run the fuel pump. The pump should run and produce fuel pressure of 9-33 psi (62-90 kPa). If the pump does not run, check the relay and fuel pump wiring.
If the pump pressure was lower than specification, first check for a restricted fuel line or filter and replace, as necessary. If no restrictions can be found, restrict the fuel supply line between the pressure gauge and the TBI unit (a flexible hose may be temporarily clamped to produce the restriction), then apply voltage to the test connector again. If pressure is now above 33 psi (90 kPa), replace the faulty pressure regulator. If pressure remains below 9 psi (62 kPa), then the problem is located in the fuel tank (the fuel pump, coupling hose or inlet filter).
If during Step 7, the pressure was higher than specification, disengage the injector connector, then disconnect the fuel return line flexible hose which connects the line from the throttle body to the tank line. Attach a 5 / 36 in. (8mm) ID flex hose to the fuel line from the throttle body and place the other end into an approved gasoline container. Cycle the ignition in order to energize the fuel pump and watch system pressure. If pressure is still higher, check for restrictions in the throttle body return line. Repair or replace the line if restrictions are found or replace the faulty pressure regulator if no other causes of high pressure are identified. If fuel pressure is normal only with the flexible hose-to-fuel tank line out of the circuit, check that line for restrictions and repair or replace, as necessary.
Once the test is completed, depressurize the fuel system and remove the gauge.
Secure the fuel lines and check for leaks.
If removed, install the air cleaner assembly.
Have you checked for any vacuum leaks?
Last edited by Frog; 08-09-2011 at 04:25 PM.
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