Troubleshooting PATS

[kythri]

Can someone point me in the direction of a good troubleshooting process for the PATS system on my '99?

I've been having intermittent fuel issues - specifically, the fuel pump not firing/priming on attempted startup.

I was suspecting the fuel pump going out, but now I'm thinking it might be the PATS ring in the ignition?

I've tried both of my keys. Both factory original. My regular use key (with most of the Explorer's 150K on it) and the other key, which was stored away and not used.

Neither changes the situation.

My last fuel pump troubleshooting attempt is going to be pulling the relay, and putting 12V to the pump at that point, and see if it fires.

If it does, then that would confirm my PATS theory.

Thank you for any help you can provide!

 

[410Fortune]

Does the theft light go out while cranking or flash rapidly?

Intermittent fuel pump power issues are usually the fuse or relay
Corrosion on fuse prongs
Or a failing fuel pump relay

It’s not very likely to be an issue with the inertia switch but it’s also worth a look to make sure the wiring plug is in good shape the button is pushed down fully, and the wires are not twisted or broken. No moisture under passenger carpet from a leaking windshield or heater core

Change the relay with the one next to it for testing

Before I drop a fuel tank on a gen ii explorer to change the pump I always apply 12v to the pump directly to see if it runs
If it does I then test for 12v on the truck side of the fuel tank harness

With the pass rear tire removed you can access that wire harness rather easily

 

[kythri]

Does the theft light go out while cranking or flash rapidly?

Intermittent fuel pump power issues are usually the fuse or relay
Corrosion on fuse prongs
Or a failing fuel pump relay

It’s not very likely to be an issue with the inertia switch but it’s also worth a look to make sure the wiring plug is in good shape the button is pushed down fully, and the wires are not twisted or broken. No moisture under passenger carpet from a leaking windshield or heater core

Change the relay with the one next to it for testing

Before I drop a fuel tank on a gen ii explorer to change the pump I always apply 12v to the pump directly to see if it runs
If it does I then test for 12v on the truck side of the fuel tank harness

With the pass rear tire removed you can access that wire harness rather easily

Theft light does go out.

Fuse is good, relay is good - tested/swapped with others, no change.

Prior to the past few days, it would fire the pump about 30%-40% of the time, and of course, once running, it never went out.

I was suspecting a dead spot on the pump rotor/stator.

I'll try putting power to the pump directly once the snow melts.

 

[CDW6212R]

All well said. My latest 98 has had prior body work, major R&R of interior I believe, and as a result the inertia switch wires are too tight, under tension and will rarely pull loose. Yours doesn't sound like that, but there is many things that can be an issue to cause all kinds of stuff. Most begin with past owners and mechanics.

Watch the THEFT light every time you start the engine, it should never flash, that tells you the key code failed to be confirmed by the PATS. My Mercury did that occasionally about 15 years ago, the blue connector on the key cylinder was broken and fallen away. Most things once you find them are straight forward to fix. I've had the THEFT light flash with my other two 98's rarely also, and when I see it, I stop cranking the starter, and turn the key off, and on again etc.

If you change the pump, use a top brand like Bosch, and skip the low end stuff which are mostly junk.

 

[410Fortune]

Pats is working properly if the light goes out

That means the halo has read the chip key and transmitted the code to the pcm and all is well

Sounds
Like a failing fuel pump to me

Final check is the wiring at the tank
Make sure you have battery power at the fuel pump + and - wires coming from the truck side of things before you go through the trouble of dropping the tank

Has saved me from dropping many tanks by doing this first…
Learn the hard way

Bosch blue top
Pump is the only one I will install in stock explorer w new strainer and filter every time

 

[kythri]

Got a part number for that Bosch blue top?

Rock Auto lists a Bosch 66085, but from the (color) picture, it has a black top.

Is there not a Ford OEM/Motorcraft replacement for these?

 

[CDW6212R]

The last Bosch fuel pump I got was from eBay for about $45, before they began adding taxes. There used to be many of them for sale all the time. Check on Rock Auto for choices, and they often list both a Ford part and the number, plus others with their part numbers. You can compare those and other parts you find elsewhere like Amazon.

Ouch, prices have changed a bunch. For a 99+ 2nd gen Explorer, it calls for a BOSCH 66085 pump, which comes with a strainer also. It's $105 from RA, plus shipping and taxes, minus the 5% discount code. A strainer is often $10-$15, so that's about about a $95 pump now, or double what it was a couple years ago.

Here's a link to that pump on RA; More Information for BOSCH 66085

 

[kythri]

Thanks! That's the one I found, too, but was just curious, since it didn't appear to be a blue top as 410Fortune mentioned.

If that's good, I'll go for it.

If I'm going to be dropping the tank, is there any brand recommendation on a new tank and straps? I creased my existing tank something fierce a few years ago attempting off-road awesomeness, and figured it couldn't hurt to just put a new one in once I've got the thing already dropped.

 

[CDW6212R]

I saw that hunting the 99 up model was a different part number, the pre-99 pump is likely the same and blue still. My last two were that one for my two 98's(lower pressure than 99+).

The tank could be pushed out if the dent is where you can get to it from the opening. But a skid plate is a good idea if you ever get onto any objects, any 2nd gen from 95+ and same tank size will work. I'm not sure where others buy the straps, those you rarely need. The bolts and nut clips are the weakest links, take your time loosening those, and add anti-seize to them before putting the bolts back in.

 

[Sager]

Do you have a remote start or aftermarket alarm? If you do, they can get confused, if you use both remotes, if you have an aftermarket device, you should only use the aftermarket..

Can someone point me in the direction of a good troubleshooting process for the PATS system on my '99?

I've been having intermittent fuel issues - specifically, the fuel pump not firing/priming on attempted startup.

I was suspecting the fuel pump going out, but now I'm thinking it might be the PATS ring in the ignition?

I've tried both of my keys. Both factory original. My regular use key (with most of the Explorer's 150K on it) and the other key, which was stored away and not used.

Neither changes the situation.

My last fuel pump troubleshooting attempt is going to be pulling the relay, and putting 12V to the pump at that point, and see if it fires.

If it does, then that would confirm my PATS theory.

Thank you for any help you can provide!

 

[RangerNutt]

Curious whether anyone "creates" an inspection cover centered over the fuel pump by cutting a hole in the bed? Seems like that would be much easier than dropping the tank. Flush-mount the cutout using a weld ring on the bottom side (or a few tack welds) and a little sealant... maybe it works.

Popping the six bed bolts on the Ranger is much easier, must be some similar method for the Ex.

 

[kythri]

Do you have a remote start or aftermarket alarm? If you do, they can get confused, if you use both remotes, if you have an aftermarket device, you should only use the aftermarket..

No remote start or aftermarket alarm.

 

[kythri]

Curious whether anyone "creates" an inspection cover centered over the fuel pump by cutting a hole in the bed? Seems like that would be much easier than dropping the tank. Flush-mount the cutout using a weld ring on the bottom side (or a few tack welds) and a little sealant... maybe it works.

Popping the six bed bolts on the Ranger is much easier, must be some similar method for the Ex.

I've seen some videos where someone pulled the rear seat and cut through the floor to access the fuel pump.

Seems rather redneck Mickey Mouse. Not for me. I'll do it the right way, and drop the tank.

 

[kythri]

I saw that hunting the 99 up model was a different part number, the pre-99 pump is likely the same and blue still. My last two were that one for my two 98's(lower pressure than 99+).

The tank could be pushed out if the dent is where you can get to it from the opening. But a skid plate is a good idea if you ever get onto any objects, any 2nd gen from 95+ and same tank size will work. I'm not sure where others buy the straps, those you rarely need. The bolts and nut clips are the weakest links, take your time loosening those, and add anti-seize to them before putting the bolts back in.

Any leads on a skid plate for a '99 4-door? Apparently, they're obsolute/discontinued, and my parts people can't locate one.