Ok, that's good feedback, don't get discouraged, that's a good find.

Now at KOEO, use your multi-meter to check for B+ at the coil pack electrical connector again.
If you don't have B+ to the coil pack at KOEO, back up to the computer firewall electrical connector & check/back probe the coil pack B+ feed wire there. If no B+ there, look to a connector/pin/socket problem, or computer problem, or ECM power relay feed problem. When you don't have spark, are the dash warning lights coming on for their self test at KOEO?

EDIT: If you have B+ at the computer firewall electrical connector at KOEO, but not at the coil pack, look to a wiring run break, or pin/socket electrical connection problem.

If you have B+ at the coil pack, look to a computer ground switching problem. Like an intermittent crank sensor feed to the computer, or an internal computer problem.

Maybe try thumping the computer, or wiggle the wiring harness & see if you can wake it up & let us know what you find.

 

ok so with KOEO i have power to B+ at the coil pack tested with a continuity tester wiggled the wire harness and tried again. no luck on the spark to the plugs. the truck still acts like the timing is off which iI suspect is the dieseling effect of turning the engine over and no spark? then when wiggling the wires i relieved the pressure to the fuel rail and then turned the key off when i turned the key back on i noticed the fuel pressure was only 30 psi. I turned the key a couple of times to check and it went right up to 55+ lbs most of the time with an occasional stop at 30 don't know if this makes a difference but thought i would mention it
So i guess tomorrow i will check the Ground voltage to the coil pack and see what other advice i get
Thanks for the help

 

Ok good trouble shooting & feedback. SO, you have 12 volts B+ to the coil pack at KOEO as you should, but still no spark when cranking the engine, so that suggests that you aren't getting a crank sensor output signal to the ECM, or the ECM has an intermittent internal problem that's preventing it from ground switching the coil pack to make spark.

While your helper cranks the engine, you can back probe the crank sensor signal at the computer firewall electrical connector, to see if it's output is making it that far.

Seeing as how things suddenly woke up after messing with the battery, & now the fuel pressure seems to be jumping around, kinda makes me want to suggest a wiggle test of Both battery cables on Both ends. Maybe perform a under load voltage drop test across the battery posts when cranking the engine & across each battery cable end connector to the battery posts with your DVM, to see if you might have unseen wire strand to cable lug connection problems, or cable clamp to battery post, or cable wire strand to
lug connection problems on the other end of both the B+ & B- cables.

We only have 12 volts to work with, so any resistance in either of those cables, their end lug connectors, or the connection those cable ends make, to the battery posts, engine or body grounds, or the B+ connection to the under hood power distribution center, all should be on the suspect list for voltage drop testing. All connections need to be clean, bright & tight.
If the battery voltage is dropping below 9 volts when cranking the engine, it has internal problems, like plate sulfation, that's making the battery unable to take a heavy electrical load without excessive voltage drop.

If all that checks out ok, then put the ECM on the suspect list & the only thing I can think of to quickly check it is to swap in a like known good computer from a friends or salvage yard vehicle & see how it goes.
OR, remove & open up the suspect computer & look for cold solder connections, solder splashes moving around & causing mischief, or signs of overheated components, or connections.
Let us know what you find.

 

.
Woops I forgot the "i have power to B+ at the coil pack tested with a continuity tester", part. If you measured B+ to the coil pack with a 12 volt test light, that's not good enough. Perform the test with a DVM at KOEO & while cranking the engine, to make sure you don't have a bad under load voltage drop To the coilpack.

 

Happy Fathers Day Ok here we go again, voltage across bat 12.35 then 10.95 - 11.18, voltage B+ at coil pack 12.25 KOEO then 10.95 during cranking, Voltage B+ to neg side of coil pack 0.10-0.25 all connections are good to bat and starter and neg at engine, grounds at firewall good. Now what?
Thanks again for all the encouragement and help

 

I think you said in another post that you had another Ranger that would not start,,,was wondering if your computer is bad and maybe swap it with the other just to see if it will start then,,,of course this will be putting on the wrong computer on but if it will start then you know your computer is not firing the coil pack,,,will run ruff with wrong computer,,,just a quick try to see if it is your computer,,,of course disconnect battery before changing and make sure not to get them mixed up !!!!!!

 

Of course this is a waist of time if your unlucky enough to have 2 bad computers !!!!

 

OK, that's good trouble shooting feedback. The battery output seems to be ok under load when cranking, the 12.25 volts at the coil pack is enough for it to make spark if the computer would ground switch the sucker.

The no load 12.35 reading across the battery posts says it's only at about a 70% SOC, so put it back on the smart charger overnight at a slow rate of charge, like 2-6 amps & let it sloooowly come back up to a full SOC until the smart charger turns off, so it doesn't sulfate while your trouble shooting the no start condition.

SO, that leaves you looking at Why the computer isn't ground switching the coil pack to make spark?

When cranking the engine for a start, if you can read/back probe the crank sensor output at the computer firewall electrical connector, then it seems it would leave you looking at a intermittent computer problem.

Thinking about this some more I can't understand why replacing the battery last time woke things up so it would start, if all you did was disconnect & reconnect the battery cables at the battery posts. Did you mess with any other under hood wiring while swapping the battery out?

With the B+ being ok under load/while cranking the engine, the fuel pressure shouldn't be jumping around like you measured, unless the fuel pump has an electrical feed problem, or it's internal fuel pressure regulator is acting out.
So right now it seems you have at least two problems to wrestle with.

If you don't have spark, the ECM should be setting a trouble code for that.
With your multi-meter, you can easily measure the voltage & current to the fuel pump to try & get a grip on what's going on there. If it's unclear, try & swap the fuel pump power relay for a like known good one & see how steady fuel pressure is.

Once you get fuel pressure steady I suppose you could try spooktn's computer swap idea to see if spark shows up with another computer & see if it'll try & run.

You might also consider trying swapping the ECM power relay for a like known
good one not needed to crank, or run the engine, in case you have faulty ECM power relay contacts.
I think your about to zero in on the problem/s. Let us know what you try & how it goes.

 

would a 1999 ranger 4.0 ECM work in this 2001 3.0 L 2WD automatic or would bee better to use my 1999 ranger 3.0L 4 WD manual trans bee better
Or should I just try to find one on line? my closest junkyard doesn't hsve that one

 

I dont think it would make any difference which one you used,,, ( but I would use the 3.0 one if you know it is good ) this is only to do a short test to see if it will run,,,if it does start and run remove the donor computer put it back where it came from and let us know,,,I can point you to where I got mine if yours is bad,,,,if it does not start then it is not a computer problem,,,assuming donor computer is known to be good !!!!

 

That didn't go so good as i wanted it to :-(( it kicked the anti theft system on any way to fix that without taking it to the dealer to get it flashed?
all help is immensely appreciated

 

Opps my bad you need a loaner or donor computer from a 98 or older to get around the PATS issue,,,i think 99 was the first year of PATS so try and find a loaner just to see if that is the problem,,,and of course if it does start it will run ruff and not be drivable but it will tell you what the problem is or should i say is not if it does not start,,,if it does not start then it is not a computer problem and more troubleshooting will be the only way to solve your problem,,,,see if you can borrow one from a friend or get a cheap junk yard one just to troubleshoot with,,,i keep a old 95 one just for that reason,,,,thats how i knew mine was bad,,,ordered one from Newyork that solved all my problems,,,it was the best price and came with a lifetime warrenty !!!!!

 

Just a shout out to say thank-you for a great suggestion. Of course any suggestion which helps solve a problem is a great one, but if you can do it without a bunch of parts swapping and so on, it is even better. pawpaw suggested checking the PCM relay, which was exactly the faulty part. In my case, the relay did nothing, so no CEL at KOEO and no power to my OBD2 port. The PATS was flashing a 1-6 which indicated it couldn't communicate with the PCM (duh, PCM had no power?) This on a 1999 2wd 3.0 Ranger. I swapped one of the other relays and voila! Life! Then I replaced the dead relay with one from my 2003 Taurus (awaiting a second head job). Thanks! I got to look like a hero this weekend, fixing a great low-mileage truck I got for my daughter because neither the owner nor the mechanic I bought it from wanted to deal with it. And, I got it for a very reasonable price. Add in a nearly zero-dollar repair and ... hero sauce. Can't have done it without everyone's help on the board.

 

OK, you get an Attaboy for a good trouble shooting find, thrifty fix, feedback & to hear all seems well & your on the road again!!!!
Yup, those danged power relays are a common problem part & are often the problem on power feed woes.
Any time at KOER we can't see the dash warning lights light up for their self check, that's a clue for us to check/swap the computer power relay. Some members with vintage rides carry a spare or two in the glove box like fuses!!! lol