I Swapped out engine and went to get emission test. Failed with code P1445 which is Purge Flow Sensor Circuit High Input. This is a 1997 Ranger XLT 4.0L OHV Auto Trans 4WD. Any Ideas of what to check first. From what I have read it could be a bad ground or wiring problem or a bad sensor. Did not have this error code before swapping engine. I have 15 days to find and fix problem.
Tia
Mel

Solved the problem by installing the wiring harness from the old engine. It was electrical Like RonD said.

 

The only thing I could suggest is posting many detailed pictures of your engine bay perhaps we might spot a evaporative emissions line disconnected or plugged into the wrong spot.

Since the code was not present before the engine swap I am guessing you may have installed a used engine with some used components.

Your problem may be as simple as swapping some of these parts back over from the original engine.

If I had the truck at my house the first thing I would do is double then triple check my work, I would be looking for any loose fitting, disconnected, broken dry rotted, split vacuum or emissions lines.

I would also look for a pinched wire, or wiring harness not routed properly that may be laying across a hot manifold.

If you have done all this already and are absolutely sure everything is 100 percent correct, the only thing you could do is break out a factory service manual and follow the instructions for the pin point test for the code you have.

However going by the manual and factory test procedures may lead you down a path that may require test equipment not available because of cost to diy tech at home.

If you research YouTube and have some basic diagnostic equipment you will find some informative how to videos that may help diagnosing this problem without a smoke machine.

Here is a link to one video that may help yet I found the guy so annoying I couldn't sit through it.

 

P1445 is an electrical fault and not an EVAP flow issue.

Most likely cause is the larger square connector you needed to unplug and plug back in when swapping out the engine
Or could be you left off a Ground wire
Could be the sensor but as you said it didn't have that code before, so most likely cause is a wiring issue

Good read here: https://www.ranger-forums.com/4-0l-o...e-445-a-37919/

 

I think you are probably right RonD. The engine was from a 1997 Ford explorer and the engine already had the harness on it, so I did not change the harness. I assumed that the wiring harness would be the same, since the engines are the same. the old wiring harness on the old engine has some busted connectors so that is why I used the one that came with the Explorer engine. I guess I could take and splice connectors off of the Explorer harness to the original harness that has the broken connectors.

I have cleaned all of the connectors with Electronic cleaner and did the same with the big square connector on the engine. still have the error code P1445. I got a used purge sensor so will try that next. will have to check with ford to see if the wiring harness are different between the explorer and the ranger even though the engines are the same.
Mel

 

I installed the wiring harness from the old engine and that solved the problem of the P1445 fault code, but now I have a new problem I will post it in another thread. Thanks everyone for your help.
Mel

 

Help, I have replace purge solenoid valve and charcoal canister new Motor craft fuel cap! I get check engine light on and off! Cleared all codes ran truck 8 miles each way to work no code. I fueled up truck until pump stopped not topping off!! Drove 36 miles Check engine light back on. P1445. Drove three more days light goes out on its own not being reset. Drove 220 miles no light. Filled up and on day two this time 25 miles Light went on! What can the forum suggest?

 

I had this same issue but I just now fixed it, I hope this helps.

Does your ac also not work?

I had replaced everything, purge flow sensor and valve, charcoal cannister, vent valve gasket, even bought a new pcm, etc..

It ended up being that when I did my engine swap I switched the connectors for the purge flow sensor and the high side ac sensor. I feel so stupid but that's what fixed it for me.

Switched them back. Erased codes and it's not coming back :)

Hope this helps!