Cranks if I jump the relay but no spark after major engine work?

Hi,

It sounds like you have more than one issue. There are two fuses that can affect the ignition coils. (Fuse 6 and fuse 16) both are in the power distribution center under the hood. Additionally, there is a relay called the automatic shutdown (ASD) relay. If that isn't operating correctly, you won't have power to the fuel injectors and pump, so it sounds like it is. That leaves fuse 16 specifically.

Here is what I want you to try. At each coil, there will be a red wire with a tan tracer. With the key on, that wire should have power. Check that first. If it doesn't, check fuse 16 in the PDC. When you check the fuse, make sure there is power to it.

I attached the schematic below so that you have a reference. The first two pics are of the ignition system. The second two are the starter circuit. If the PCM isn't providing a ground path via pin 85 on the relay, the starter won't engage. Additionally, pin 86 is the power supply from the PCM to the relay. Both pins 85 and 86 need checked to see if we have what is needed. Note that both will require the key to be in the start position, so you will need a helper.

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

Take care,

Joe

See pics below.

Hi,

Thanks for the update. When you say jumper switch, what are you referring to? Also, if you hear a relay clicking, see if you can determine which one it is. You should be able to feel a vibration if you place a finger on the relay.

Let me know.

Joe

Hi,

You can have power at the relay, but for it to actuate, there needs to be a ground path supplied to the primary side of the relay. It will be either pin 85 or 86 on the relay.

Here is a link that explains how to test a relay and its circuit:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Let me know about the fuses. Based on your last description (power to coils), it may have something to do with the ignition switch. You should have power at all times when the key is in the start or run position. Also, the new findings regarding power loss is interesting. Let me know if cleaning things up makes a difference.

Take care,

Joe

Hi,

If the starter relay doesn't click when it's in the start position and it does have two power supplies (two different pins) either the primary side isn't getting a ground path, the relay is bad, or the starter motor is bad, or isn't getting power.

Try one of these tests. At the starter motor is a yellow wire with a gray tracer. Have a helper turn the key to the start position while you check if the yellow/gray has power. It should only have power in the crank position. Also, the heavier gauge red wire has battery voltage at all times, so confirm that is the case.

Or remove the starter relay. You indicated it is getting power. Each of the 4 pins is numbered on the relay. Pins 85 and 86 are for the primary side. Confirm one of them has power. If it does, attach the alligator clip of the test light to the battery positive and probe the other connector. Have someone turn the key to the start position. In that position, your test light should turn on. If that doesn't happen, that is why the relay won't actuate.

Let me know what you find.

Joe

Hi,

It should have a connector schematic on the relay itself. As far as the yellow wire, if there is no power, check fuse 10 in the power distribution center under the hood. Also, check it for power. See pic below for the fuse location.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Keep in mind, the yellow/gray wire will only have power if the relay is working, and the key is in the start position. I'm assuming there is power from the ignition switch to pin 86 when in the start position and ground at pin 85 in the start position.

Let me know what you find. Also, I realize giving directions online are not the easiest to follow. Please let me know if you have questions or if I'm not making sense. LOL

Take care,

Joe

See pic below.

Hi,

To check pin 87, yes it needs to be connected. Use a thin paper clip or wire and push it in with the relay on pin 87.

As far as the ignition switch is concerned, don't worry about the switch at this point. When the key is in the start position, pin 86 should get power. If it does but pin 87 doesn't, then I need you to check pin 85 for continuity to ground when the key is in the start position.

The easiest way to check for a ground path at pin 85 is this. Take the alligator clip end of a test light and connect it to the battery positive. Probe pin 85 with the test light. When the key is placed in the start position, the test light should turn on if a ground is provided.

As for the Skim/Skreem circuits, we need to scan for B codes/can-bus system. Otherwise, if there is a problem within that circuit, it will be nothing but luck if we find it. A code such as B1A25 would be an example of a possibility.

Let me know.

Joe

Billy,

What are you referring to when you say communication? Do you mean there is no continuity to ground?

Let me know.

Joe