2000 Windstar intermittent won't start due to severe misfiring

[Windstartled]

Originally Posted by 12Ounce

The tank is huge

It is indeed, a mechanic buddy of mine says it's the largest he's ever seen on a minivan (dang thing costs a fortune to fill, but lasts a while), but also says it's a large minivan. Van ride is smoother with tank full, means it's a lot of fuel weight. Ride becomes noticeably harsher with less than half unless you put more heavy stuff or people inside.

[MrCreosote]

Maybe not fuel pump:

Decided to suck some gas out of the Schrader port on the injector rails using my MytiVac Evacuation gizmo. Had to give up because just couldn't get any gas to flow enough.


I don't know if it should be possible to suck gas here or whether there are check valves or whatever that would preclude this BUT it might be a clogged fuel filter (!)


So I changed it(!)


I cut it open and found no sludge in the can, however, when gas dripped out in the backwards direction, it was brown. Clogged with micro brown "rust?"


Put new one on and a new fuse, it started on 2nd try.

Took it for ride and seriously, it has a lot more mid range and top end HP.

Seriously.


Filter must have been clogged.


Of course now, I'll have to start the van repeatedly every day at home to establish statistically if the problem is gone.


Time will only tell.

[12Ounce]

Congratulations on repair! But you wonder where the "brown" came from ... and is there more to come?

[MrCreosote]

I hope it is in fact "repaired" but I won't trust it until I start it a couple of dozen times over the next week.

The brown stuff, well, it has 160k on it. There is always risk when you get gas and you notice the fuel flow is very slow because the filter at the gas station is plugged, or you are getting gas when the service station tank is nearly empty..

I know a lot of people replace the fuel filter when the replace the pump. I wonder how many fuel pumps have been replaced because the filter got plugged?

[MrCreosote]

Back to drawing board - it occasionally does not start.

I need to confirm that there is no fuel pressure when it does not start.

I was thinking I could get an injector manifold mini pressure gauge but the question is: Once the injector manifold is pressurized, engine running, when you turn engine off, does pressure remain in the manifold? Or do I need to monitor the gauge while it is cranking and NOT starting?

Next Step:

OK, its hasn't blown a fuse so far and does not start. Need to determine 12v is showing up at the fuel pump. Someone said there is a connector around the front of the tank. Need to get the pin outs and watch for voltage.

If I get voltage and no fuel pressure, then I replace pump.

The last thing I want to do is put the pump in and still have the problem (!)

[12Ounce]

On my '99, there is a strong residual pressure on the rail ... even overnight ... after the engine is shut down. But this depends on a number of things.

You could try "jumping" a 12v supply to the output receptacle at the fuel pump relay base. That would assure that 12v is at least headed for the fuel pump. Next is the inertia switch.

Yes, there is a pair (I believe) of connectors at the front edge of the fuel tank that you should be able to access.

[northern piper]

Just to quickly touch on the rust part of the filter removal. I changed my filter 2 days ago and too noticed a certain amount of rusty gas flow backwards from the front segment of tubing. In looking a bit closer, I believe this rust was from the exterior of the filter, dissolved by the gas, when the gas flowed backwards once the filter tube had been removed from the plastic coupling. I've had this happen each time I've replaced the filter so I don't believe it's reason to be concerned and does sound only coincidental and likely not a contributor to the OP's problem.

[12Ounce]

If I read the diagrams correctly, the pump motor is fed by a P/B conductor and B is ground. These are the colors at the "tank" connectors ... kinda near the fuel filter you changed out. Don't forget that unless you jumper the relay bases, you will only get a few seconds of fuel pump 12v feed before the electronics turns it off. Of course, you could have a helper switch the system on-off for you.

Ford had a number of truck inertia switches just disintegrate ...could not take the current without burning up ..... S's 2004 Ranger required an up-grade kit (plug and play).. I don't know if any Windstars were affected.

[MrCreosote]

I'm curious about the electronics powering pump a few seconds on start up.

Is that a fixed amount or do they determine that the system is pressurized?

Either way, it sounds like the pump cycles during driving and the logical choice would be to cycle according to rail pressure. I'm guess there is no electronic pressure gauge. So how would you measure this? Current draw on pump?

I think I also need to get a wiring diagram or at least one for the fuel pump and interlocks/relays. Any suggestion here?

Thanks
Tom

[MrCreosote]

I found a circuit diagram of a 2001 fuel pump: http://ww2.justanswer.com/uploads/fo...1_windstar.gif

The series current flows: 1) fuse, 2) relay, 3) inertia cutoff, and 4) fuel pump.

The PCM controls the relay.

I'll check for voltage at the inertia cutoff first since it is easy.

[12Ounce]

On the 2000, the pressure is controlled thru mechanical regulator. The fuel pump is given a few seconds run-time 'til the engine is proven to run ... then the pump runs full-time if the PCM sees the engine running.

Later systems operate somewhat differently.

[MrCreosote]

Diagnosing now done:

1) Jumpered inertia switch and measured 12v: It is present when it should be.

2) Plumbed pressure gauge to injector rail: Engine sputters to stop when no fuel pressure in rail. Rail pressure goes to zero while there is 12v at the inertia switch and hopefully the pump too.

That is about all I'm going to check. Time to drop the tank and replace the fuel pump.

If I knew where to cut an inspection hatch in the floor, I would do so. Its a Cargo van so that would probably be easy provided it wasn't under the front seat.

[12Ounce]

You need to drop the tank before cutting that floorpan ... as there is almost no clearance between the tank and the pan. Dropping the tank is a bad, not impossible, job!

[MrCreosote]

Today's effort: sucked 10 gallons of gas out with my MityVac Extractor Unit which is NOT SUPPOSED TO BE USED WITH FLAMMABLE LIQUIDS!!!!!!!

The only hose I could get down the spout was about 1/4" OD clear vinyl. Took almost 2 hours to get that done.

[12Ounce]

There's still about 3 or 4 gallons in there, I betja!

Funny how a fuel pump never gives up the ghost unless the tank is nearly full. LOL!

BTW, I have removed the core of the Schraeder valve, clamped on a vinyl tube there ... used the pump to prime hose ... and drained tank fairly well, thru pump. Even if pump is dead, you can usually pull fuel thru it with little problem.