No power to coils and injectors?

Hi,

For the injectors to spray, they must be getting power and a ground path from the PCM.

When you turn the key to the run or start position, power should be present at each injector. To complete the circuit and actuate an injector, the powertrain control module (PCM) provides a brief ground path. If they are spraying all the time, power is present and it sounds like the PCM has failed and providing that ground at all times.

If you look at the pic below, it shows the injectors. Note that each injector has a brown wire with a white tracer. Once the key is on, there should be 12v present at each injector via those wires.

Let me know if that is what you have.

Take care,

joe

See pic below.

Hi,

Where was the short? Also, power shouldn't stop at the injectors. It is supplied by the automatic shutdown relay (ASD). It is located in the under-hood fuse box.

Here is a thought. If this just started since the transmission was replaced, inspect the connectors at the totally integrated power module (TIPM) which is basically the under hood fuse box. They may have had things unplugged and damaged pins when they reconnected things. The connector pins at the TIPM are many and very small. The ASD relay and fuel pump relay are both located there. However, the fuel pump relay is integral to a printed circuit board and not serviceable.

Let me know.

Joe

Hi,

I have a feeling I know what is happening. This vehicle has a totally integrated power module (TIPM). They have connectors that have (as far as I'm concerned) too many pins. As a result, the pins are small and prone to damage, corrosion, and breakage. I suspect that is where the short is.

The idea that you get power for a couple seconds and then lose it to the ASD is likely being caused by a poor connection that can't handle a load.

So, the TIPM is basically the power distribution box under the hood. Under the fuses are the modules. We need to check the connectors for damage or corrosion.

Before you start, disconnect the negative battery terminal. There are several different connectors. I attached several pics below. Primarily, we are looking for the connectors related to the ASD. I highlighted the connector numbers, the pin locations in the connectors, and a legend showing the purpose of the pin.

I suspect the TIPM is going to need to be replaced. A power supply that drops off is a common symptom with these when they fail. But the best thing to do is confirm there is an issue. It isn't a cheap part.

Let me know what you find.

Take care,

Joe

See pics below.

If there is a short to ground via the PCM, that could cause it as well. However, the PCM doesn't explain why you lose power to the ASD.

If possible, check the affected fuel injector wiring to see if there is constant continuity to ground when the key is on. Make sure the connector is disconnected to prevent the injector from actuating while the ASD powers on. If you have constant ground, then we need to check for a short in the wiring to ground or at the PCM connector. Also, the PCM may be shorted internally, so this technique will get us moving in the right direction.

Let me know.

Joe

Hi,

Absolutely! If you look below, the first two pics are for the crankshaft position sensor. The remaining pics are for the powertrain control module. (PCM)

There are 4 connectors at the PCM. Following the pics in order, I first attached the connector identification, the connector pinout, and then what each pin is for. Following them in order you will go each connector one at a time.

Let me know if this helps.

Take care,

Joe

See pics below.

Hi,

If the PCM isn't providing a ground path when the engine is cranking, yes, it is likely the problem. However, if you are checking it without cranking the engine, there will not be a ground path.

Keep in mind that the connector at the PCM may be a problem, so make sure you check that as well.

Let me know what you find.

Take care,

Joe

If you have a constant ground path at the PCM, it has an internal short. Just make sure the connector isn't the issue. If it isn't, replace the PCM.

If you look below, I provided the directions for the removal and replacement of the PCM.

Also, the new PCM will need to be programmed.

Let me know if this helps or if you have other questions.

Take care,

Joe

Hi,

We need to scan the computer (can-bus) to retrieve codes. The lightning bolt indicates an issue with the throttle control circuit. Could it be the throttle body? Anything is possible. However, it could be a throttle position sensor, wiring, accelerator position sensor, and so on.

When I say scan the can-bus, that refers to the Controller Area Network. Basically, the different modules are tied together via a few wires and communicate with each other. This type of scan will retrieve codes regardless of the module storing them. By doing this, it will help point us in the right direction. Otherwise, it will become a guessing game which can get expensive.

Here is a link that explains how it's done:

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Let me know if that is something you can do or have done.

Take care,

Joe

Hi,

The canister will cause evaporative emission system problems. Also, I suspect the vacuum hoses to it were melted as well, so that would have caused drivability issues as well.

The idea that the check engine light is on with no codes indicates either your scanner can't read the code type or there is a breakdown in communications between the modules and data link connector.

When the exhaust was modified, where was it cut? Are the catalytic converters still on the vehicle?

Let me know.

Joe