Also, not everything is hooked up for the engine to run. I have an oxygen sensor and the coil pack not plugged in and the fuse for the fuel pump pulled. The reasoning was to crank and build oil pressure on the new assembly before putting the fire into it.

I'll need to find more wiring diagrams to better understand what's going on, but I tend to think the transmission range sensor would have nothing to do with other functions of the PCM and be mutually exclusive to the rest. Am I wrong? Perhaps there is a random fault in another part of the vehicle that is making the computer ignore the presence of the transmission?

FabricGATOR, responding to your earlier comment, I'm doing OK emotionally but it is definitely a disappointment to be this close to and yet so far from a good-as-new minivan. I really love this vehicle. I have personally put the last 120k miles on it and have used it for moving pianos, pulling trailers, and going between Pittsburgh and Dallas numerous times. It's gonna be sweet once it gets sorted... the suspension is all new and the new engine assembly is an extra-funky shade of purple in honor of Dr. John, Allen Toussaint, and the rest of the New Orleans musicians who are so important to me.

Thank you all for your help. I'm excited to have this baby back in operation!

 

Also, not everything is hooked up for the engine to run. I have an oxygen sensor and the coil pack not plugged in and the fuse for the fuel pump pulled. The reasoning was to crank and build oil pressure on the new assembly before putting the fire into it.

I'll need to find more wiring diagrams to better understand what's going on, but I tend to think the transmission range sensor would have nothing to do with other functions of the PCM and be mutually exclusive to the rest. Am I wrong?

Folks, Et al,
I believe that mattsblues was merely trying to crank the engine to prime the oil.
When it didn't crank as expected, I then think that he imagined all sorts of compatibility issues and other faults.
I bet that without the range sensor plugged in that a safety lockout stopped the ability to crank/start the engine (in gear) because the PCM was not sure if the engine was in either park or neutral.
Also from what I read, I believe he rebuilt and painted the original engine, got a low mile transmission from salvage.

 

Good morning! Thanks in no small part to your guidance, I recently completed an engine rebuild and transmission swap on my 3.8L 2006 Grand Caravan SXT. My problem now is that it won't start.

• Red dot on dash illuminates with key on
• Key fobs are black

All OE FOBiKs are black, all have Immob chips, and your "red dot" is telling you the system thinks you don't have a valid key (and is probably in "lockout" mode - more than 3 consecutive attempts to start without valid, paired key thus no crank)
This could be a problem with antenna, module (SKIM) or key - does keyless entry activate power locks with buttons?, have you tried the second key?

 

What was to operational condition of the vehicle before all this work?

1st 1st
If it don't crank we'll have a hard time figuring out if it'll run..

If you lie down under the front of the vehicle and touch the probe of a multimeter to the positive battery post on the starter, do you show voltage?

Please, I am not trying to be semantic, rather just trying to help you gather some baseline data. I can tell that you are quite capable and are pulling your hair out. I can only imagine how frustrating it must be to be doing all of this work, to the very best of your ability, only to be cheated of the purr of a warm engine idling and the growl of the exhaust as you stomp on the accelerator....

I get "Analysis Paralysis" sometimes and a mentor taught me how to calm the mind and be methodical in my troubleshooting.

 

If engine ran before you started this rebuild, then the problem should something you did or you didn't.

If you forgot to disconnect a wire when removing the engine or transmission (mainly transmission), and it was pulled along with transmission, chances are that a wire or two got loose from the connector.

Closely check your connectors.

 

Thanks for the replies!

FabricGATOR, yes, it cranks when the starter solenoid is jumped. I built 20psi of oil pressure this way with the spark plugs removed.

Before all of the work, the van ran well with the exception of a loud valve tap, multiple oil leaks, and an occasional hard shift. When the water pump blew, I decided to pull the engine and do a restoration. Since the van has 291k miles on the odometer, I opted for a newer transmission as well and found one from a recycler with only 30k.

LEVY, I agree with your thought process and have closely checked all the transmission connectors. Everything checked out. I even spent an evening diagramming the wiring harness between it and the PCM (see first attachment)

 

So Mattsblues, when you said you wanted a newer transmission and found one...
Did you integrate a different unit into working with your vehicle or did you simply swap in a salvage unit from the same year/make/model?

 

Is that the same engine from the van originally? I see early valve covers that would be plastic on later models (2003? or 2004 -up). I remember talking about swapping valve covers with someone in another thread. If this is an early engine in a later model, there will be problems...

 

Atoman, that's good to know. The keyless entry still works with both fobs but neither are much use in the steering column.

FabricGATOR, it's an identical unit from a salvage yard but with low mileage (so I'm told!)

Thanks for your help!

 

that is an absolutely killer colored engine, mark me down as jealous

it might be worth it to get the royal purple oil filter next time to make it all match ☺

hopefully you get it all working soon

 

OK, so you are not quite there yet. Still have wires to connect, sensors, etc....

You went to prime the oil system and the starter did not turn over?

I'd imagine that it the vehicle does not know the transmission is in either park or neutral... (transmission range switch) that for safety's sake, its not going to allow it to crank.

musicians...geeze.

Best of luck to you, looks good.
More pictures, get r done!

 

Love the paint! At the same time, it may be hindering a good ground connection somewhere. The alternator mounting points need to be bare metal, the starter mounting all metal, obviously any ground cables or wires, and sensors like temperature or other one-wire sensors that use the engine for ground.

I'm with Atoman in thinking it is security-related. You can try disconnecting the battery for a while to reset the system. That was probably why you were able to crank it to get oil pressure, and that used up your "free tries". The red security dot should not be on. Were any wires/connections in the steering column or down by the brake pedal/body control module disturbed?

 

Yes, there can be trouble brewing if correct cam & crank parts are not put on the motor (compatibility issues with SBEC vs NGC PCM)

However, even if the crank signal was absent (unplugged sensor) it would not prevent the engine from cranking over...