2000 3.0 ohv problems for sure

[mfre1111]

I just installed a new engine in my 2000 Taurus. It is a 3.0 OHV non flex fuel. It was overheated and didn't have enough compression to run. I checked and it was about 20 to 30 psi per cyl. It had spark! I checked that as well. Now the engine will turn over by the starter (spin) but it has no spark for some (must be simple) reason. I put a new radiator in as well as a wrecking yard low mileage engine. I did a continuity check on all the wires to the pcm and they are all good. I took extra care to check the wires to the coil pack, they are all good. When I test the coil pack wires, the red (hot wire) is hot. When I test the reference wires at the coil pack they have power until the ign is put in start position. Then all power goes away (no flashing light on test light connected to positive on the battery) I know how to check it. What I don't get is why would it all of a sudden not have a reference signal from the pcm, Coincidence! I installed a new crank position sensor, thinking that had to be the problem. NOT! I triple checked all the ground wires from the pcm with an ohm meter. All good! My question is, is there anything in the security system that could cause this to happen? I did have to remove the battery. Is there anything that anyone can think of that would cause the pcm to not send the reference signal (Ground pulse) to the coil, other than the crank sensor or a bad pcm? Any help would be greatly appreciated. Thank you in advance for any help you may be able to give me. By the way, I am a pretty good wrench and have installed lots of engines. I always get it done and correctly. This baby just has me stumped.

[shorod]

Did you swap PCMs along with the engine, or just the engine? The VATS system is programmed to the PCM so if you swapped PCMs, that would be a problem. If not, then I'll have to dig in to the service manual.

-Rod

[mfre1111]

Thanks for the response. It seems this one has everyone stumped from the lack of responses. No I did not swap the PCM. Just the engine along with the wiring harness that came with the new engine. I am going to swap the wiring harness today. I don't think it will work, but it is worth a try. I did have my brother helping me and I was trying to keep an eye on his quality of work, but I was under the car connecting the exhaust and motor mounts and stuff for a while. I checked the harnesses side by side and they are the same. The donor vehicle was a clone of the wagon I have. Same everything! As I stated before, I am not a rookie at this stuff. Just every now and then we all run in to a head scratcher. This is mine for the year, lol. Thanks again.

[mfre1111]

I forgot to mention something. When checking the pulse wires from the PCM to the coil. When I connect the test light to the positive on the battery, There is a ground (the test light comes on) when the key is in the on position. Upon turning the ignition to the start position, the light goes off and there is no pulse signal. I am thinking this is not normal. because the ground would make the coil fire to the plugs. That to be means that when the ign is in the on position, the coil would be firing. Am I wrong in my thinking? would it be when the ground is broken it would fire? Another thing is that, according to the wiring diagram, there are 6 grounds that come from the PCM. 3 that connect next to the PCM on the fire wall and I am not sure where the other 3 ground. I disconnected the PCM main wiring harness plug (the one with the 10 mm bolt that holds it to the PCM) I checked the 6 grounds with a multimeter and they all show good grounds. The numbers do vari though. Like 3 are at 2 and 3 are at 6. As I stated, I am going over it all today. If I find a problem and get it working, I will post what I found to help anyone that needs it in future endeavors. Thank you, again.

[mfre1111]

Well after extensive continuity checks on the engine wiring harness, I found a broken wire in the circuit for the crank position sensor. One of the wires had a value on both contacts on the end closest to the Crank position sensor. The other wire had no reading at all on the same end. I yanked that harness off and put the old harness back on and it fired right up and ran like a dream. I said I was a pretty good wrench. I do have about 40 years experience and about another 6 to 7 in school, including all the seminars that the Ford dealership sent me to. I haven't work at Ford for like 30 years though. Just my own shops and mobile stuff. Anyhow, I am happy to say the least. Thank you to all that even contemplated trying to help.

[shorod]

I'm glad to hear you found the issue and got it resolved! Congratulations, and thank you for following up with what you found! It's too bad everyone doesn't follow-up....

-Rod