2000 2.7 L M/T engine bay ground locations

Hello again friends

My truck is throwing the AM2 fuse as soon as I turn the motor over. I have already looked for loose and damaged wires and haven't had much luck finding anything obvious. My next move is to check ground wires all throughout the engine bay. Does anyone have a diagram? I have had one ground wire by the engine bay fuse box that has been cut since the before I bought the truck about two years ago. Where is that one supposed to go? Negative terminal of the battery?

Thanks in advance!

 

It should have coming off the Negative Battery Terminal 1 wire going to the engine block 1 wire going to the inner fender.

The main ECM ground is near the throttle body

Check your ignition circuit . The coils

The switch as well

The fuse is tight in the block?

 

I have one Terminal in the block that has back and forth play. I know it doesn't help, but have you ever heard of this being the main cause? Any idea how to reduce the play in it?

There is also a severed ground cable right by my Negative Terminal on my battery. But, it's been like this since I bought the truck three years ago.




Hard to see, but if you look close, you can see the play of the Terminal

 

That could be your whole problem!! As it is the only ground from the battery .

If the bolt attaching the ground is to long see if you can find a shorter one if not clean things real good and add some washers till it is tight .

Yes you should also have another cable to the bolt you have circled in red from the negative battery terminal

 

Gotcha. Thanks brother! I'll be back and let you know how it went sometime this week!

 

New 8 GA ground to the battery, cleaned the ground from the valve cover to the firewall and no luck.

As soon as I turned the key on, she popped again. Didn't even try to turn it over.

 

When did this problem start ??

You have checked everything on the ignition circuit and the ECM ??

Ignition Switch Igniters/ Coils and the ECM and all the circuits between.

Unless someone has added extras off the AM2 fuse .

All connections good and tight ? Fuse tight in the socket?

 

Fuse is tight in the socket. I just tried to plug in my scanner and it's showing a link error. Maybe that helps? I'm trying to avoid tracing every wire, but it's appearing that I may not have a choice.

I've put on hands on o2 sensors, coil pack harnesses, ignition harnesses in the cab, I've physically put hands on everything I could touch.

I've owned this truck for three years and the only electrical mod I've made is an amp/ sub combo but that's been in for like 2 years without issue. It's never had that battery ground until I just put it in a few minutes ago.

The problem started last week. I made it about 300 years from work and it popped. Put a new one in, drive it for about 10 minutes before it popped again. I figured the slushy snow might have had something to do with it, so I let it sit for about 4 days. Put a new fuse in, popped immediately. It sat for 3 more days, and I put that new ground wire and fuse in a few minutes ago, and it still immediately popped.

I know prior to this, I had been throwing a cel for either an o2 sensor, or catalytic but I never did troubleshoot it. I think I was getting low voltage at the downstream sensor, and upon inspection, the harness looks a little burned, but nothing that intrudes into the harness itself. Just the exterior.

 

Here's what my downstream o2 sensor harness looks like:

 

Go through the Ignition Circuit disconnecting things till the fuse does not open that should lead you closer to the problem.

you can make a jumper and use a regular 30 amp blade fuse

With the fuse open of Course the OBII system will not connect

If the O2 sensor Shorted and caused damage to the ECM Rare but it could have happened.

Any other fuses open?? A short is easier to find then a open circuit

Electrical problems are much easier up close and in person. If I was close I would be glad to help.

If you need to test things make jumpers to use with your meter leads .

Only as a very last resort start pulling the harness apart .

 

I sincerely appreciate the offer to help. That's a pretty stand up move!

Of course, I'm posting in a couple threads here trying to hopefully catch the attention of someone who has already dealt with this exact thing. Even if it off sheer laziness (but mostly panic hahahah)

here's what I just posted on another thread, if this helps. I'm really hoping that I may have answered my own problem:



Thanks for the reply! My ignition fuse is good. All fuses are good other than the AM2. I attempted to plug in my scanner, and it is saying that it can't link. I'm assuming losing power to the ecu as well? Come to think of it, I sometimes have been having issues starting my truck. I thought it was the starter getting hung up, but maybe it actually was the ignition switch?. And being that it's a time delay fuse, it's finally failed to the point now where it blows as soon as I turn the key on? (Not even trying to crank the motor).

Seem like a legit point to start?

Thanks again for your help! I'm a bit perplexed here.

 

There is the key cylinder the mechanical part of the ignition switch.

Then there is the electrical part of the switch that is moved by the back of the mechanical switch.

It is a royal pain to get to because of the location.

If the ignition switch is shorted there should be physical marks arc marks burnt and melted wires .

No shorts cuts if anyone has a problem even close the odds it being the same are higher then powerball.

 

Thanks!

I bought an ignition switch and will be putting it in this weekend. If that don't work, then I guess I'm gonna have to man up and try to trace this dang thing :-/

 

Unplug every thing you can in the ignition circuit see if the fuse still opens that points to the ignition switch.

When you get things apart plug the new switch in see if it works then button things up.

Good luck

 

Well, there goes a waste of 65 bucks lol. Replacing the ignition switch didn't work.

suggestions for making a jumper? I'm tired of experimenting with 6 dollar fuses lol.

I have some confusion with the "ignitors". Are those my coil packs? (2 of them).

Should I get the battery tested? I know that's an expensive part to jump to (even the switch was too expensive to jump to, but the link between the fuse and a potentially faulty switch seemed to coincidental). Would a crap battery or terminals be a potential fault?

Someone shared the wiring diagram with me in another thread, but they kinda don't make sense. And if I can't push anything through that fuse without it blowing, how do I check the harnesses, wires, etc for voltage?

Thanks again

 

Yes with your Engine the igniters are in in the coil packs.

Just get some wire some male spade terminals a inline fuse holder for a blade fuse 30 amp fuses .

Sorry the ignition switch did not cure your problem.

If your battery was shorted it would be dead and not take a charge.

A positive battery terminal would need to have the cable to the starter short or the cable to the fuse block. Shorted .

Have you unbolted the fuse block and looked for problems under there.

You have either a dead Short or that circuit is drawing to much current .

If your meter has a audible mode you can ring out the circuits not being energized .

Battery is being Charged with a charger during all this testing ??

best of luck

 

That cable is also severed on my truck, but it runs fine. Should I replace it?

 

It ended up being a shortcut the shitty mechanic took when routing the wiring harness back to the MAF after a head gasket replacement. Found it grounding out on the hook attached to the motor.

 

I hadn't had any issues with electrical up until this point, and it wasn't related to that severed cable. Its probably in my head, but I feel like the motor is running smoother since I re-attached that ground with an 8ga wire. It was also cut on another buddy's truck when he bought it, so he just put in a new one. I wonder why this was such a common thing?

I'm no vehicle electrical wizard, but I would think the more grounds, the merrier?

 

I am so glad you found the problem causing open the fuse to open.

When negative Battery terminals /Cables are replaced people tend to get the wrong type or the counter person gives them the wrong one.

Yes more Grounds are better within reason.