Ok, need a little advice before i go crazy over thinking this. i have a 1998 Ford Ranger, 3.0L v6,2wd auto. this is my personal truck. it threw a code for P0303 and P0300, upon diag found that i had a stuck open valve on cylinder 3, took the heads off sent them off to be rebuilt, got them back put the truck back together over a course of days ( Work schedule wouldn't permit to much time. ) so anyways after i get it back together, go to start the truck and it has a slow crank with no start. so i go to the basics and check my firing order, all is good there, check my wire harness found that the Cam sensor was unplugged, so plugged it up, go to start, sounds like it was starving for fuel, like fuel timing was off. so i plugged the Cam sync up tried to start, same issue, tried starter fluid and it back fired threw the intake (probably not the best idea.) so at this point im thinking timing is off but not really understand how being as i never messed with timing, so now i'm current awaiting for the alignment tool for the cam sync to show up, my question is, if this doesn't fix my problem, what else should i double check.. any help is appreciated . has anyone else ever ran into this issue? i also had the wire harness repaired by Ford and they checked each pin.

 

First thing I would do would be to crank engine, then pull a spark plug, it should have fuel on it, if not then you are not getting fuel.
Because of the back fire I would recheck firing order on coil pack
3 4
2 6
1 5
Front

Very easy to mess up cylinder wires on the 1, 2, 3 side, passenger side
And 5, 6, 4, jeeze I always get that one wrong, should be 4, 5, 6, lol, make it easy Ford

When you tightened up valve train did you rotate crank a few times to let push rods and rockers seat?
Slow cranking could be too much compression, check a few cylinders.
Also wrong firing order can slow the crank way down, as a cylinder can fire while piston is still going up.

Spark timing and fuel timing is done by the Crank sensor(CKP sensor)
If there is no pulse from CKP sensor then there is no spark or fuel.
You have spark or wouldn't have gotten a back fire.

CPS(cam position sensor) "fine tunes" fuel injectors.
I have read that the 3.0l won't run without CPS working, but find that hard to believe, could be true but just doesn't make much sense to me.
CPS was added for better MPG and better emission, if you can time the injector opening with intake valve opening less fuel is lost coating the inside of the intake, so less fuel can be used.
On other engines with CPS you would get a code number if CPS pulse was gone or if CPS and CKP sensor didn't match close enough, CKP sensor is primary sensor, CPS is secondary, i.e. engine will run on CKP only, or with working CKP and CPS, but won't run with no CKP and a working CPS.

Crank and valve timing is done by the timing chain, so it should be fine, because you didn't touch that.

 

Thanks Ron for a very insightful reply. I always have a hard time with ford engines. It's like 1am here so I'm half tempted to go check but either so I have to wait for the alignment tool so I can reinstall the cam sync.

When I installed the rockers I didn't read anything in alldata about turning the crank put I'm going to recheck them all when I reinstall the cam sync.

I checked my firing order before and seems about right. When I put the plugs oh I did number 6 first because I knew it was in the middle of the coil on the right side of the coil. I messed it up last time I changed out the coil lol. Once my tool arrives I'll report back thanks so much for all the information.

 

this maybe after the fact, but i figured out why my truck had a slow crank/no start condition. some how i mixed up the plug wires for 1 and 3 on the coil. must of had a confusing moment or something. although it wont be a quick fix now because i thought it was because of the cam sync so i decided to pull it and check the alignment of the timing chain, long story short, im glad that happened because my chain is loose as all hell. just got new parts in the mail so hopefully it will be running again shortly.