Engine re-install: no start
 

1986 3.2 with all stock injection, etc. I removed the engine and transmission to have the transmission re-built. I have re-installed everything but it won't start. I have spark. The fuel pump sounds like it is working. It cranks just fine, but never fires. I have triple-checked all the connections and (except for as noted below) am pretty sure that I plugged everything in that I unplugged to remove it. (I did not plug the speedo wiring back in or the back-up light wires, because I don't have a speedo or back-up lights (it is a race car)).

Any suggestions on what to check for?

Ground strap?

Double check that you reconnected the fuel injector wire harness. It's a rectangular plug that you plug in behind the engine on top of the shock tower.

Are you sure you plugged in the speed/reference sensors to the correct locations? These are often plugged in wrong. Switch them around and see if it'll start.

+1, easily overlooked. Spray some starter fluid to see if she will try to start.

I had the exact same problem when I reinstalled my engine and trans in December. Remove the air filter and spray starter fluid into the airbox and see if it bucks and snorts when you try to start it. Mine did. It wanted to start when I did that. Let's you know it's a fuel issue. Ultimately what I had to do was prime the fuel pump and lines, changing the angle of the car to let gravity help get fuel from the front of the car to the back. I could hear the change in the sound of the fuel pump when it was ready to go. I also had to prime the fuel injectors by lifting the intake flap on the CIS, but I think your EFI 3.2 is more advanced than that. Good luck!

Thanks. The ground strap is attached and so is the fuel injector wiring harness. I will try some starter fluid.

Did you by any chance disconnect the DME relay under the seat before removing your engine or disable the fuel relay on the fuse panel :)

Cheers !
Phil

Do you smell fuel? Plugs wet? Can you disconnect a fuel line to confirm fuel pressure?

You shouldn't need to use starter fluid.
Check the following:
The crank sensors are plugged in correctly.
The wire harness at the fire wall.
Wire harness on the left side fender well.
Ground wires at the front left intake runner.
Wire harness' for the MAF, idle switch, and the idle control valve.

This next one is a strange one, but it happened to me.
Next to the ignition switch, up/under the dash there are 3 (2 or 3) small wire harness plugs. if for some reason you inadvertantly unplugged one of those, the engine will crank but not start.
Good luck.

Missing the fuel injector plug was my bone-headed move. Starter fluid had the car running so I knew all else was working and connected. If it gets to it, carefully check all the sensors using a multimeter per the check-list in the bentley. Its a great learning experience.

Thanks everyone. I have my to-do list for tonight after dinner. Wish me luck.

And the winner is . . . Harness that plugs in to the firewall! I went through everything methodically, as well as looked at pictures I took of the engine bay and engine before and during removal, and found that this one wasn't plugged in. I plugged it in and I am up and running.

Just out of curiosity (I haven't looked it up in the manual yet), what does that harness control?

Good, you'll never forget that one again ;)

Controls the fuel injectors- it's the harness that provides power to all six of them!

Credit goes to rsscotty at Rothsport. I know the connectors of the 3.2 engines pretty well but the injector harness is not one that always comes to mind for me.

http://forums.pelicanparts.com/porsche-911-technical-forum/654331-87-motronic-no-start.html

Thats the one that I missed per KTL's earlier and my "bone headed" miss. Its the only plug back at the firewall to attach. The 6 pin that fires the injectors. Near as I can tell from the wiring diagram, it actually fires 3 units at a time and doesn't actually fire the 6 individually by the way. Kinda interesting.