I have a need for help and guidance. I recently put in a new 7.3L in my 1996 F350. I had seven cracked and one broken piston, hence the engine change at Thanksgiving time.


I have the engine in the truck. When I took out the engine, I unplugged the wiring harness from within the engine compartment. It is reinstalled with no pinches. Everything is hooked up correctly. My tach does not work, and therefore, I have no fire for my engine!


Because the tach was not working, I put in a new PCM, as I have had this issue in the past (no tach = bad PCM). With a new computer in it, I still have no tach and still no fire. Can somebody point me in the right direction with this POS truck. I am getting so angry and frustrated.


Thank you.

 

I have some similar, but not identical frustrations going on. Sucks doesn't it! All that work and no satisfaction.

Do you get a Wait to start light with he key in run? If not you have no power to the PCM. Did you check your fuses in the engine box? Specifically 9 and 22 for the PCM. Make sure your PCM grounds (on the upper left rad support) or reconnected as well.

Good luck!

 

No tach usually mean bad CPS.

 

Thank you very much! And yes, it really sucks with the huge dollar signs and no payback!


I do get my WTS every time. Fuse 22 is good, but I couldn't remember the fuse to check.

 

Thank you for the reply!


In the past, I had no tach and replaced the PCM. That fixed it. This time, no change, but I am beginning to lean towards the CPS, as that is about all I keep reading across google today. What is weird however, this CPS was purchased from the Ford stealer at about $30. It has maybe 5,000 miles on it. I left it in the old engine until I had the new one up on the stand and began assembly. The other alternative is I hit it when I yanked the engine, as I did not take the front clip off as I did when I dropped it back in.

 

Check the all the wiring going down to the CPS all the way to the plug. check real good at the plug too. Move the wires around a bit and try it.

 

I will check the wires tomorrow. I did however, on an earlier repair, replace that entire pigtail. I know it works as the truck ran after that! Im probably going to buy a new CPS just for the sake of doing it.

 

that's not a bad idea. It good to carry a spare with you. Did you solder the connections.

 

Hi JP. I was reading through your other thread about the rebuild of your engine. Quite interesting and a wealth of information. I am curious however of a couple things, not that it will make any difference to my engine at this juncture, how much did you pay for your head studs. I wanted to go that route but they were $2000 for the cheapest set I found. Also, are there aftermarket cams we can put in these engines - you know, something like an RV cam if you will? I looked and looked but couldn't find one.


Doing my engine, I almost felt like an idiot. What began my engine swap process was I thought blew a head gasket and having oil blow up the dipstick tube. It was mess! I yanked the heads after running a compression check. Three cylinders on the passenger side was around 265 psi, which is quite low and the one cylinder with the hole in the piston, obviously had no compression. Got my heads done and put them back on. Still the same problem, but my truck ran a little better at times; it was as if was missing on occasion, but still got up and moved. Ran another compression check, and now had lower compression in the three cylinders and still nothing in the other.


Long story short, when I pulled the heads the first time, I saw the cracks in all four pistons, but what was strange, those cracks were in the same spots on all four pistons. So I just dismissed them as casting seams. And the hole, you actually couldn't see it as it was in the valve recess spot on the piston.


I completely assembled my engine on the stand, pulled off my front clip and dropped it in. Timing, took just over an hour to get it in. So, I am under my truck pulling the torque converter forward to put the nuts on the studs. I was getting irritated because that converter kept stopping. The studs would come just up to the flex plate and that was it. Finally, I decided it had to be something retarded and therefore googled a picture of a flex plate installed. I had that dumb thing on backwards. Yanked the engine again, turned it around, bolted the tranny back up inside an hour.


This truck has been a nightmare. Darin answered several of my original posts on this truck in 2012 when I started working on it. The entire engine is new. New computer, FICM, all the sensors, and a whole lot of headaches along the way too! I bought this truck at 319k miles thinking it would drive a long while before I had to do anything major on it. My truck now has 330,972.2 and I have pumped tremendous amount of money in it. I should have bought a new truck for what I now have in this one!


I love the color of your engine however. My block came back from the machine shop black so I just left it that way. For good reason however, my truck is red and black and the only chrome on it is the front bumper. So I decided to keep it that way!


As for the oil dipstick adapter, if you have a design and you are selling them, I would be greatly interested. Before I yanked that engine, I had to make that repair. We were coming home from a trip with my toy hauler. We stopped for something and I noticed this ridiculous puddle of oil under my truck. From the one stop, we zipped over the to auto parts store and left the truck running to check to see if that oil was actually mine from the previous parking lot. OMG, the amount of oil coming out was crazy and I still had another 40 miles to get home. SO I bought many gallons of oil and took a side mountain road home so I could keep stopping to add oil! I cant remember how much oil I used getting home but it was a lot! In effect, I bought the tools to hold that adapter. It took about an hour to change the o-ring and put a gasket on the outside. The hardest part was getting the o-ring to fit into the groove. It never leaked again though.

 

Wires soldered!

 

I tried twice and never could get that O ring in the grove. Get one side in and the other pops out!

 

Yes you can get a cam for these motors. But unless your doing some serious mods I don't think it's worth it. The head studs can be purchased through riff raff and there is a few other companies as well. Whoever quoted you 2000 was after your wallet. You should be able to get arp studs for around 650 ish. I know what you mean about input costs. I just finished building a motor for mine and now just doing the final touches to put it on the road.

 

I was just thinking about your colors. You may like mine then lol

 

I do like your colors! I didn't glass bead my brackets for my alternators or powersteering/AC, but getting all the crud and grease off was a challenge! The cool thing is, my truck is red. that would have been a good combo for mine, but I just left it black.


Also, like the ear plugs on the wiper cowling! But more seriously, was are the red tubes for? It looks like you have the stock garrett turbo and whats all the other stuff in front of the turbo? once I get my fired for the first time, I would like to do other stuff to it to get my EGTs down and get more power from it. I have a stock motor.

 

One trick that works is applying a coating of grease on it to help hold it. That's what I did. from start to finish, it only took about an hour to do. when I had the tool to hold the adapter from going into the pan, the other end has a big loop end, and I just zipped tied it to the tranny lines. piece of cake repair, but a pain in the butt! I was also willing to spend the money from the ford stealer and bought their gray gasket sealer and made a gasket for the outside nut. It never leaked after that. but I do like the idea of having a piece that can be welded to the pan.