Advice on gen 4 engine into gen 3

Swapping an engine is a lot of steps, with a lot of things unhooked and reconnected. We're all prone to assuming we did all of that perfectly and didn't miss anything, and can therefore go straight to making deductions about sensors and ECUs based on not having codes before the swap, etc.

But seeing (from one of your other threads) that there are things like comm network errors involved, if it were happening to me, I think I would be going back over all the ways I might be assuming I didn't miss something or mess something up.

 

So I used all sensors from the gen 4 engine on both swaps I just did. Both used gen 3 EGR and O2 sensors, and gen 3 intake so the sensors on that but everything else was gen 4 that came with it.
I agree with Chapman I think there may be something you missed or something simple like that. Unplug all the harness plugs and plug them back in and make sure they click. Disconnect the traction battery fuse and put it back in, bust out the multimeter and start verifying voltages if you have to.

 

Think you can take a picture of how it's cut or mated up for reference?

 

How do you verify voltages? I went through the wire harness again and still nothing. So at this point who knows ?

 

There's not one generic answer to that, it's just good honest work. The repair manual will show you various voltages that should be expected at certain points under certain conditions. Those you can check with a meter. The most useful information will likely be in the manual sections for the codes you have. Often, other information can be found in sections for related codes, or other codes involving the same systems. The wiring diagrams can allow you to work out what measurements you ought to see at other points that weren't directly mentioned in the troubleshooting steps.

Others can help you across the internet, but that kind of demands a lot of detail from you about exactly what you've checked, how you checked it, and what measurements you got. Just saying you checked things or went through things won't really give readers hundreds of miles away enough to build on.

 

… to go back to overheating risk. Is that known to be a continuing issue with the Gen4 swap and should we just be prepared to have the car run a little warmer than normal? I’m worried about the T-connector that’s needed for the correct routing. If I could find that reference again. I’m going to try to drive it back across the country after this..

 

It seems that removing the jiggle pin in the thermostat cured the overheating issue.

 

I can try but its kinda buried in there under the inverter.

I didnt do anything except use a new thermostat. i have driven 300ish miles including 2 80 mile highway trips and havent gone over 210 F. Most of the time I'm at 180ish.

 

Huh, they said less than 50,000 miles on this engine so, I wasn’t going to change it… maybe I should now?

 

Mine had 55k miles on the engine. I did change the thermostat and recommend doing it, especially if you don’t know how long the engine sat. It’s only 3 bolts and they are cheap.

 

There doesn’t look to be as much room for the air filter box?

 

The engine sits in the exact same spot. Using the gen 3 manifold it all goes back into the same spot.

 

What about the water pumps? Are the 3rd and 4th Generations the same?
Same hose fittings?

 

Physically they look like they interchange and have the same harness plug. I have read they are different and they have different part numbers so not sure. If you need one I would get a gen 4 one.

 

I was hoping someone who has installed a Gen4 block would answer.
Since the block "seems" to be the same, outwardly, it seems they are the same mount.

 

Yeah my third gen water pump will absolutely bolt up and plug in on my 4th gen motor but i have read there are changes maybe with the impeller or something. Since they are about the same price anyway just get a gen4 one if you have the gen 4 motor.

 

If you are using a Gen4 block in replacement for Gen 3, yea, use the 4th.
Just wondering if they are interchangable. If impeller size is different, or connector, or the
electronics inside are different, will the brain communicate with it correctly?

 

hmmm … the electronics “inside”

 

The electronics inside are the brushless motor drive to translate the duty cycle of the ECM's WPO signal into a motor speed, and the tachometer circuit that generates the WPI signal reporting the motor speed back to the ECM.

And those signals are specified the same way in Gen 3 and Gen 4 as far as I see, so I doubt the difference will turn out to be any of that. Full disclosure, Gen 3's the only one I've actually had an oscilloscope on.

 

Since no one posted in almost a month… as a head’s up, one difference I notice is that my speedometer now matches the speed on street radar. With other vehicles, it was 2 miles above. Not sure if that’s b/c of this State I’m in or if it new Highway regulation, or if can see, its something else …
FYI.. I don’t speed