Code p0140 diagnostic

SOURCE: 1989 Chevy Truck 350 Stalled Wont Start After I filled Gas Fuel

You need to check the fuel pressure to the TBI. I just fought one which was doing the same thing. I pulled the fuel tank to replace the fuel pump. It turned out to be the short hose from the fuel pump to the steel line coming out of the tank. It had a split in it so I wasn't getting enough fuel pressure. Some places show two pumps available. One you can pull the unit and replace just the pump. The other the pump and sender are all one unit. Hopefully you have the first one. The second is around $300.

The easiest way to get to the top of the tank is to pull the front 6 bolts mounting the bed and loosen the back two. Take the three screws from the filler neck and unhook the rear axle vent tube. You can then take an engine hoist and lift the front of the box. You can get right to the pump and gauge assemble in the top of the tank. Most times, this works easier than emptying the fuel tank and removing it.

SOURCE: 2001 Chevy Malibu, 89,000 miles, 3.1 engine, won't start

CLICK HERE for the injector schematic.
CLICK HERE for the Ignition schematic.

Since the PCM uses info gatheres from the crank and cam sensors to calculate ignition - and there are no OBD codes - in all likelihood, the PCM itself is bad.

The Ignition Module, also transmits to the PCM.

It appears after all your testing - that the PCM is at fault.

It does not error report on itself (unfortunately).

The ignition timing is controlled by the Powertrain Control Module (PCM). No adjustment is necessary (distributorless ignition) or possible.

Please see the following....

The ignition timing is controlled by the Powertrain Control Module (PCM). No adjustment is necessary or possible.
The engines covered by this manual are equipped with distributorless ignitions, ignition timing is controlled by the Powertrain Control Module (PCM), as applicable. No adjustments are possible. If ignition timing is not within specification, there is a fault in the engine control system. Diagnose and repair the problem as necessary.
Ignition timing is the measurement, in degrees of crankshaft rotation, of the point at which the spark plugs fire in each of the cylinders. It is measured in degrees before or after Top Dead Center (TDC) of the compression stroke.
Ideally, the air/fuel mixture in the cylinder will be ignited by the spark plug just as the piston passes TDC of the compression stroke. If this happens, the piston will be at the beginning of the power stroke just as the compressed and ignited air/fuel mixture forces the piston down and turns the crankshaft. Because it takes a fraction of a second for the spark plug to ignite the mixture in the cylinder, the spark plug must fire a little before the piston reaches TDC. Otherwise, the mixture will not be completely ignited as the piston passes TDC and the full power of the explosion will not be used by the engine.
The timing measurement is given in degrees of crankshaft rotation before the piston reaches TDC (BTDC). If the setting for the ignition timing is 10 BTDC, each spark plug must fire 10 degrees before each piston reaches TDC. This only holds true, however, when the engine is at idle speed. The combustion process must be complete by 23° ATDC to maintain proper engine performance, fuel mileage, and low emissions.
As the engine speed increases, the pistons go faster. The spark plugs have to ignite the fuel even sooner if it is to be completely ignited when the piston reaches TDC. Spark timing changes are accomplished electronically by the engine and ignition control computers.
If the ignition is set too far advanced (BTDC), the ignition and expansion of the fuel in the cylinder will occur too soon and tend to force the piston down while it is still traveling up. This causes pre ignition or -knocking and pinging-. If the ignition spark is set too far retarded, or after TDC (ATDC), the piston will have already started on its way down when the fuel is ignited. The piston will be forced down for only a portion of its travel, resulting in poor engine performance and lack of power.
Timing marks or scales can be found on the rim of the crankshaft pulley and the timing cover. The marks on the pulley correspond to the position of the piston in the No. 1 cylinder. A stroboscopic (dynamic) timing light is hooked onto the No. 1 cylinder spark plug wire (2.2L engine only, on the 2.4L engines, special adapters are needed) . Every time the spark plug fires, the timing light flashes. By aiming the light at the timing marks while the engine is running, the exact position of the piston within the cylinder can be easily read (the flash of light makes the mark on the pulley appear to be standing still). Proper timing is indicated when the mark and scale are in specified alignment.


WARNING When checking timing with the engine running, take care not to get the timing light wires tangled in the fan blades and/or drive belts.

The engines covered by this manual are equipped with distributorless ignitions, ignition timing is controlled by the Powertrain Control Module (PCM), as applicable. No adjustments are possible. If ignition timing is not within specification, there is a fault in the engine control system. Diagnose and repair the problem as necessary.




Thanks for using FixYa!!

Ned C Cook

• 3433 Answers
• Posted on Sep 24, 2009

SOURCE: 2001 Chevy Cavalier won't start

MY turn! OK, Fuel system, supply and demand. Once upon a time, someone thought of a way to have a vehicle imitate a humanNow a car exchanges tons of information and the result is the same. the whole mass gets confused about the objective and that is to get moving.
A quick run down on efficiency. There are numerous sensors in a motor vehivcle but we will just touch may the five or six that count. Furst we have thefuel pimp. Supply only on demand. If the fuel syatem maintains a residual pressure in the fuel system it will no have reason to prime. The vapor recovery system and gas cap only recycles fumes that condense and gives the left overs to the engine.Hence hard starting because it screws up the air fuel ratio by bypassing thesystem fuel controls. Which are: The coolant temp and the intake air temp sensors. These two team up to function as the choke/cold start like in the good old cars,They enrich the fuel on startup.Once he engine and air temps are optimal, they allow the fuel mixture to be controlled bt the Mass air flow sensor. This sensoris mounted inside a rigid section of the intake ducting. Once it takes over, it starts reading the density, volume and velocty of yhe intake airand through the ranges meters the proper amount iof fuel in relation to the air being induced. The throttle positioning vavle simply lets the fuel get to the injectors according to how much ias requred to get the desired results.smoothly.. The air filter condition is critical because it impedes air flow and if in poor shape filtration wise, it allows dirt to accumulate on the MAF sensor sensing componants.In the event the MAF cannot read properly it affects the fuel supply directly by ling to the computer. A dirty sensor reads low air volume and velocity and cuts back on the fuel, leanning it out and the vehicle stalls, runs rough, hard starts, and surges. AND, we have arrived back at Dennis.and his dilemna. Vehicle unreliable.. As you can see, the other sensors are in the shadows right now. In the shadow of the MAF sensor. The MAF SENSOR CAN BE CLEANED using only CRC electrical spray cleaner. Thoroughly wasjing(rinsing) the sensor avoiding touching, rubbing, or brushing. The spray cleaner dries rapidly and compressed air must not be used.. Once cleaned, everyone should be "on the road again" I hope this info helps you dennis.. Good Luck-Ned

SOURCE: fuel pump not working

I am have the exact same problem but my ground seems to be intact and getting a good ground. Do you have any other ideas on what may be cause the Fuel pump not to kick on?

SOURCE: 1978 Chevy 1/2 ton Truck - fuel is not getting to

On the front of the carburetor where the fuel line comes in is the fuel filter.Did you change that?Take off that line and slip the end into a container,coffee can size.Have a friend turn over the motor,watch for fuel.If you get fuel your needle and seat have seized in the closed position.No fuel check the rubber lines that hook to the fuel pump.You replaced the pump,it's only $2 worth of rubber hoses.If they don't seal the pump can't pull the fuel,it's cheap insurance.