96 2.2L Sonoma engine swap, no start

Hi, first time poster here. Recently I had to replace the engine in my '96 Sonoma with a working '97 S-10 engine I found at a junk yard. After having to swap old pieces onto the new engine to make everything fit, everything is finally plugged in and tightened up, unfortunately the engine isn't starting.

The starter seems to be working fine but the engine doesn't want to catch. I think I've narrowed the possible problems down a bit, or I might be completely off.

Possibility 1: The spark plug wires are plugged incorrectly.

I marked the wires correctly (I'm pretty sure) with 1 being at the front of the car and 4 at the firewall. I forget the order at the moment (2314 maybe?) but I followed my Haynes manual so that should be correct. Still, I am an amature so I may have gotten that wrong.

Possibility 2: A mystery sensor isn't seated correctly or is broken.

Because I have a '96 body and a '97 engine, there were a few part swaps I had to do to get everything to fit. One of these is a sensor found just underneath the ignition coils. I don't know what it is. I thought it was a knock sensor, but it's about finger length and it's slightly magnetic.

I would have just used the one on the '97 engine, but that plug has two prongs and my '96 harness has three prongs. I tracked down my old block to get the original sensor and used that, but the piece that screws down to the block is slightly different and I'm wondering if the whole situation would effect engine startup. It looks to be seated correctly.

Possibility 3: Something's wrong with the fuel lines.

When I was trying to start the engine, it was turning over but wasn't catching, so I gave it some gas. That didn't seem to help and I got a strong fuel smell in the cab. I went to check for leaks in the engine compartment, and not only did I not see any leaks, I didn't even smell any fuel (only very faintly). Did something break? Did I attach a fuel vacuum line to the A/C lines? Do I have to prime the new engine?

If anyone has some idea or word of advice, it would be greatly appreciated.

Most vehicles have the firing order stamped on the intake manifold. Second, Your Haynes manual should tell you which is number one cylinder and which position on the distributor is number one. Pull the spark plug out of the number one hole and place your thumb over the hole while someone cranks the engine. You will feel the puff of air when the piston is at top dead center. Stop cranking as soon as you feel the puff. It may take a couple of tries, but when the timing mark on the balancer is lined up on the timing pointer, you know that number 1 plug should be firing. At that point, remove your distributor cap make sure the pointer on the rotor is pointing towards the the number one wire. Also, make sure your distributor is rotating the right direction according to the Haynes manual. If the Haynes manual says clockwise, make sure the rotor is going clockwise. I have seen engine swaps where a counter clockwise engine was replaced with a clockwise engine and it will never start until you get the plug wires in the proper order.

Most vehicles have the firing order stamped on the intake manifold. Second, Your Haynes manual should tell you which is number one cylinder and which position on the distributor is number one. Pull the spark plug out of the number one hole and place your thumb over the hole while someone cranks the engine. You will feel the puff of air when the piston is at top dead center. Stop cranking as soon as you feel the puff. It may take a couple of tries, but when the timing mark on the balancer is lined up on the timing pointer, you know that number 1 plug should be firing. At that point, remove your distributor cap make sure the pointer on the rotor is pointing towards the the number one wire. Also, make sure your distributor is rotating the right direction according to the Haynes manual. If the Haynes manual says clockwise, make sure the rotor is going clockwise. I have seen engine swaps where a counter clockwise engine was replaced with a clockwise engine and it will never start until you get the plug wires in the proper order.

Good advice Rick, but my engine doesn't have a distributor cap, it has two fixed position ignition coils, so no rotating. From what I've been reading, it doesn't seem to matter so much what the firing order is as long as 4 and 1, and 2 and 3 are on the same coil. Thanks, and keep the ideas coming!

Update:

I've been checking the fuel lines and can't seem to find a leak or problem there. Anybody have any ideas?

The sensor beneath the coil packs should be the cam position sensor. That needs to be connected to time the ignition.