Common questions

Why does my PCM stall when I Turn on the engine?

Why does my PCM stall when I Turn on the engine?

The MAP sensor senses intake vacuum, which the PCM uses to estimate load so it can adjust the air/fuel mixture accordingly. If the MAP sensor isn’t reading right, the PCM will receive bad information and possibly add or subtract more fuel than it should causing the engine to stall.

What causes a car engine to stall after starting?

Engine stalling shortly after starting. The engine hesitates or drags while under load or idle. Hesitation and jerking during acceleration. The engine hiccups. Excessively rich or lean idling. A sensor that has been contaminated by fuel, varnish or dirt will under report airflow.

Can a faulty manifold sensor cause engine stall?

A faulty manifold pressure sensor has symptoms that closely resemble; a vehicle with injector problems or low compression problems. If the (MAP) sensor is not reading accurately; the (PCM) may add too much fuel or not enough. This again will cause engine stalling.

Why does my Saturn engine not start after Idle?

The engine ran great, idled smoothly (for a Saturn) and passed the state emissions test. But every now and then, the engine would not restart after a short trip. The engine would not stall, it just would not restart. It would crank normally but would not start until it sit for half an hour or so.

What causes a GM OBD trouble code 33?

Engine running rich (too much fuel, black smoke from exhaust) Due to erratic engine vacuum, other engine performance problems can cause a code 33 to set

What are the symptoms of an engine stall?

Here are some of the most common symptoms of, a faulty mass airflow (MAF) sensor; The engine is very hard to start or turn over. Engine stalling shortly after starting. The engine hesitates or drags while under load or idle. Hesitation and jerking during acceleration.

Why does my car stall when I start the car?

Engine stalling problems can be caused by, almost anything but, are usually sensor related. A cold engine needs a fairly rich fuel mixture to start, and to idle smoothly while it warms up. What do you look for when the car starts to shake and sputter eventually causing engine stalling.

A faulty manifold pressure sensor has symptoms that closely resemble; a vehicle with injector problems or low compression problems. If the (MAP) sensor is not reading accurately; the (PCM) may add too much fuel or not enough. This again will cause engine stalling.

What causes bad acceleration and bad hill starting?

A general lack of performance with poor acceleration and bad hill starting can be due to a fault in the torque convertor. With some models it is possible to check the convertor by carrying out a stall test, though this procedure is not suitable in all cases.

What makes an engine run and idle without stalling?

Every engine needs three things to run and idle smoothly without stalling: a correct air/fuel ratio, sufficient idle speed for the idle load, and a good spark. If any of these is lacking, the engine may stall. Cold stalling problems are the most common because the engine needs a richer fuel mixture to maintain idle speed until it warms up.

Why does the PCM think the engine is under a lesser load?

A faulty MAP sensor can sometimes mislead the PCM into thinking the engine is under a greater or lesser load than it actually is. The MAP sensor senses intake vacuum, which the PCM uses to estimate load so it can adjust the air/fuel mixture accordingly.

What causes a car to run lean on a hill?

If the fuel filter is not changed for a long time, eventually the particles and sediment from the gas tank will build up and clog the filter, restricting fuel flow. If the flow of fuel is restricted too much, not enough will be able to reach the fuel injectors and the car is likely to run lean.

How to disable Active Fuel Management on GM engine?

Should you delete Active Fuel Management on GM engine? There are two ways to disable active fuel management on a GM vehicle, but first you have to determine whether your engine is a candidate for the delete or disable procedure.

Why does my car struggle to go up hills?

Once you start experiencing low cylinder compression, your vehicle will always be struggling on an incline because the engine power won’t be strong enough to push it up there. If you start to have acceleration problems as you attempt to drive uphill, do not slam down on the gas pedal to try to get up the hill.

A general lack of performance with poor acceleration and bad hill starting can be due to a fault in the torque convertor. With some models it is possible to check the convertor by carrying out a stall test, though this procedure is not suitable in all cases.

When does a shorted sensor cause an engine to stall?

A shorted sensor doesn’t always set a check engine light or MIL (malfunction indicator light). The computer is programmed to trigger a “service engine soon light” when the sensor has failed for a predetermined amount of time, say one minute, it only takes an intermittent shorting sensor one second to stop the computer system (stall engine).

What kind of car stalls after engine heats up?

The Chevrolet Cavalier is a compact automobile produced from 1982 to 2005 by General Motors. car starts and runs fine until engine heats up to operating tempature, then it stalls, it will restart but keeps stalling until engine cools down. What can cause this? Answered!

Why does my ttora not start when hot?

If I start it when cold or not up to operating temp it fires right away. I’m just thinking that the coolant is leaking back from the hot head to the coolant temp sensor, heat soaking it and causing it to run a rich start up. I’ve checked the sensor and all the resistances seem to be within spec.

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Ruth Doyle