No injector pulse

SOURCE: 2000 chevy blazer, truck cranks

Does your battery go dead?

SOURCE: GM TBI low voltage at the injectors

sounds like a computer issue on the burb, but i would check the IAC(idle air control) valve and the TPS(throttle position sensor) first.
I would start with the IAC on the 93'.

Harvey N Tawatao

• 3854 Answers
• Posted on Jun 03, 2009

SOURCE: 1993 s10 2.8 tbi the fuel pump fails to pressurize

There needs to be 60 PSI of fuel pressure in the system to have the fuel injectors to work. There is also a fuel pump relay on the fire wall just left to the brake booster, There is two relays there, i just can not remember which relay is which but try switching the relays with one another. Also check the fuses to the fuel pump and ECM, and the fuel pressure from the shredder valve. Good luck and keep me posted, not a bad Idea to also replace the fuel filter, and that is located at the inside frame rail under the drivers side.

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.




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SOURCE: Chevy S-10 Start problems

If hall effect switch was bad you wouldn't get any spark.What year 2.5L is this?Is this a 2 injector Throttle Body? The pink wire on top of injectors comes thru a 20Amp fuse controlled by the Ignition switch you should have battery voltage with key on The dark green and dark blue wires come from the pcm which are called injector drivers the drivers supply a pulsating ground if you crank the engine with a test light between either pink/dk green or pink/dk blue test light should flash dimmlythat would mean injectors are being driven but there isn't any fuel at the injector or the injectors are bad no pulse means either a bad computer ( which these drivers are known for going bad)or the computer isn't being commanded to fire the injectors.