Multiple misfires after rebuild ** FIXED **

In the pic below, notice pin 2purple wire, of relay coil goes thru Park/Neutral Pos Sw I mentioned earlier, it is pin 2’s path to gnd. Not saying it’s a Park/Neu Pos Sw problem but you mentioned ealier about no light imdicator for Park ? I’m out shopping, far as I can go.,..good luck

 

Sorry, trouble uploading from phone. That's what I was trying to explain above. Relay Gnd path is via Park/Neu Pos Sw.

 

I just drove it some more and now I am getting a P1780 - park/neutral switch malfunction. In addition to my misfire codes. I fixed the parking light issue and reseated the instrument cluster but still no speedo.

I just don’t see how all the sensors could just start failing.

 

No idea how to help you other than to again suggest some kind of common ground problem.

But man, credit for still being with it. I'm pretty sure I would have just shot myself by now.

 

Does anyone know of any other common grounding locations?

 

I know a bunch of things use the ground under the passenger side kick panel.

 

What’s really bugging me is that I didn’t do anything inside the car. The only wiring I messed with is the engine harness, which I have replaced.

Unless there is a ground in the engine bay that I am missing I don’t see how it can be anywhere else.

I did remove the ECU and all the wiring that goes into it, is there a ground near the ECU? Or is there a ground at the drivers side kick panel?

 

Can someone with a similar year truck as mine check something for me? I noticed this morning that when I turn the key to the on position there is a whining noise from the throttle body. When I unplug the connector at the top of the throttle body the whine goes away. Is that normal? I might just be more sensitive to electrical noises right now.

 

Just stepped out and checked mine, yes, its normal, or at least mine does it too.

 

There should be three grounds on the engine

 

One at the bottom of the block, and one each at the back of each head, correct?

 

I believe so.

 

I know that those are connected.

I think I am about at the end. I might have to give it to a mechanic to do some diagnosis. I hate admitting defeat, but I don't know what else I can do.

 

Well, I just drove my truck to the gym. I had my data logger on the whole time. There are no misfire when I’m driving. It seems to be only at idle. Which makes me wonder if I’m actually having misfires authors do something else going on. The truck drives just fine and feels good. I really don’t know what to make of it.

 

I mean, it's entirely possible it's something related to a/f ratio at idle. Could point to something with the throttle body assembly or any of its sensors/mechanics.

If it drives fine, there's no reason you couldn't drive over to a dealership for diags, but ... I dunno. You may just want to drive it until it completes a cycle and see if the wrinkles iron out on their own, but ...

So you're not getting any wacky shit, like no speedo, etc?

 

I actually put a brand new throttle body on it. My speedometer still does not work. I am getting some weird things there.

I think I am going to drive it more and see what happens. I have an appointment on Wednesday to look at the AC to see if they can get that working.

 

So I cleared the codes and drove to work. I am getting a cylinder 7 misfire and the Park/Neutral switch fault code. I am sure that it doesn't help that I have grounded the ground pin in the starter relay to the fender so that it will start.

Could the Park/neutral switch be causing my speedometer not to work? Also, I have an Autel scan tool and when I am looking at live data it shows the speed I am going, so does that mean that the ECU is seeing the speed and maybe the instrument cluster is to blame?

 

Just following up, I cleared the codes again and drove it home. I am still getting the misfire codes but when I am driving there are no misfires. Only when I stop do the misfires start.

Also, I checked my scan tool again for vehicle speed and there is one reading that is 0. So I assume the ECU is not reading the vehicle speed from the transmission even though I replaced both speed sensors and it didn’t fix the problem. So I am still at a loss for why the speedometer doesn’t work.

 

I don't have much to add other than that cluster failures are very uncommon on these trucks. I've seen one and I think it was somewhat self inflicted.

 

Well, some good news. After researching the speedometer issue I found someone that mentioned one of the connectors by the ECU has a dual lock on it. I went and checked and sure enough, it was not connected all the way. I connected and my Speedo and odometer work and my AC works now too. Unfortunately I still have the misfires, but I will take the win.

here it is in case anyone has the same issues:

 

It’s the little victories. Especially when they are free. That one bank of misfires stills has me leaning O2 sensor.

 

It’s funny You should say that. I just recently started getting a P0125 code. From my research it looks like it’s O2 sensor related.

 

I just drove to work after clearing the codes. I pulled the codes. The only code I have is the neutral safety switch fault.

 

I looked at the EWD and it looks like that is the IE2 connector. How do I find out what goes through that connector?

 

That's the fun of the EWDs. Just hitting CTRL + F (or CMD + F on Mac) will let you search for "IE2" and it'll put you on each page containing it.

The downsides are plenty:

• EWD isn't color-coded - at least the'06 one isn't, it's aggravating - so you need to pay attention to the capital letter abbreviations to know the wire color (there's a key code somewhere in the EWD)
• Some of the EWD actually have a weird space, so searching for "IE 2" may give different results from "IE2"
• The different cab types are in different sections and have different wiring, both colors and quantities, so you really need to watch the page title carefully!
• It's not remotely clear what the purpose of the wires are, whether they have voltage, etc. in many cases, you have to trace back to the origin
• Relays, switches and other things aren't remotely labeled clearly IMO

EWD are here if nobody linked already.

 

Oh, and in looking at the '02 EWD, I understand now why that connector being loose affects P/N switch and the tach/speedo.

You may just want to fully unseat then re-seat that connector and see if it subsides. Note the white boxes on the lines coming out of the top and/or bottom of the modules I circled showing "IE2". The number to the left or right of the white rectangle is the pin position inside the connector.

 

From my searching it appears that the P/N switch actually runs through the IE1 connector (the grey one in my picture). That one appears to be double locked but I am going to reseat it to see what happens.

 

It's also a connector that is part of the path for the gnd to pin 2 of starter relay that you've had problems with.


As shifty alluded to, EWD's can be daunting and makes good points about watching the headings.....2UZ vs 5VZ.
The upside is you only populate the IE2 connector with about a third of what it actually holds. Most that I checked deal with what you have had errors on.

The below is concerning colors....for example L is blue.

 

Yep. IE1 and IE2 appear to plug into each other. Look at the 2nd pic I posted with the purple wires. Note the arrow pointing to IE2. Note what IE2 is plugged into ... IE1.

 

WAIT - nix that. I just noticed there's an asterisk next to one of them. That usually is an indicator you need to look on that diagram page to see their footnote. It may be there's two diff't configs depending on model/engine/cab/whatever.