2000 Explorer XLT intermittent loss of power CURED

[Montana Daze]

Hey gents

About a week ago I was driving the old exploder when all of a sudden it started to snort, buck and sputter. Made it home with a top speed of about 25 mph, the next day it ran fine. Figured there was probably a water issue so drygas and seafoam were put in the tank.

Ran fine yesterday but last night it started said antics again so I got out the OBD reader that informed me there were no stored or pending codes. The way it was acting said "Starved for fuel" to me so out came the fuel pressure gauges, hooked it up and started it. Fuel pressure 62 psi, and it all seemed well 'till I shut the engine off at which point the fuel pressure dropped immediatley to 0.

I think I got a bad pump or pressure regulator. Since they're both in the tank I'll replace both as a matter of course just wanted to see what you guys think. This is the same vehicle I put the 4L SOHC salvage engine in last summer, I've grown to like it alot. Hope I can keep it alive

Regards,
Mar,

 

[donalds]

Hey gents

About a week ago I was driving the old exploder when all of a sudden it started to snort, buck and sputter. Made it home with a top speed of about 25 mph, the next day it ran fine. Figured there was probably a water issue so drygas and seafoam were put in the tank.

Ran fine yesterday but last night it started said antics again so I got out the OBD reader that informed me there were no stored or pending codes. The way it was acting said "Starved for fuel" to me so out came the fuel pressure gauges, hooked it up and started it. Fuel pressure 62 psi, and it all seemed well 'till I shut the engine off at which point the fuel pressure dropped immediatley to 0.

I think I got a bad pump or pressure regulator. Since they're both in the tank I'll replace both as a matter of course just wanted to see what you guys think. This is the same vehicle I put the 4L SOHC salvage engine in last summer, I've grown to like it alot. Hope I can keep it alive

Regards,
Mar,

Sounds like you're on track

Sometimes these pumps just get hot and cut out

The whole unit WITH A NEW NAME BRAND UNIT not a cheap one very important

 

[Montana Daze]

I will do that I only wanna do this once

 

[Exploder321]

Before installing the new pump, clean the interior of the tank so there is no sediment or grit, consider treating and painting any exterior rust while the tank is out. Hopefully you didn't just fill up, if so defuel to get the weight out of the tank. Have the fuel disconnect tool handy, spray the connectors on the tank liberally with WD-40, this will flush allot of the accumulated dirt out, those connectors can be challenging. Going forward, don't go under 1/4 tank if possible. This will keep the pump immersed, cool and lubricated. I've been running with Lucas Fuel Treatment, get a couple small bottles and the gallon jug, refill the single treatment bottles, much more cost effective. Lucas not as aggressive as SF, cleans and lubes. I like that it is an upper cylinder lube, as well. Good stuff.

 

[Exploder321]

Wouldn't hurt to replace the fuel filter while you're at it. Second the motion on a good quality pump, I got one that was wired wrong. When assembled it pushed the fuel gage down, had to drop the tank a second time to replace it. The second time went much faster than the first. This post from the 'vacuum diagram is unobtainium' thread; I'm on my third fuel pump... Post in thread '2001 5.0 Eddie Bauer Vacuum Diagram is Unobtanium!' 2001 5.0 Eddie Bauer Vacuum Diagram is Unobtanium!

 

[Montana Daze]

Good advice and thanks. Naturally, the tank's almost full...these troubles never show up when they're close to empty. The fuel filter was exchanged with a new one when the salvage engine was installed about 1500 miles ago, and I don't run cheap gas (like there's such a thing these days).

I have not acted on this as of yet; here in Montana winter has arrived. Today it's 0 F with a 21 mph wind which makes it a touch uncomfortable in the garage. This may not be a bad thing as it gives me more time to think and diagnose. I go out every five days or so to start it and let it run for awhile (it will idle) and now I'm getting preliminary codes claiming it's rich on both banks, something the short term fuel trim readings seem to comfirm on live data. This makes me wonder if the problem is on the other end such as stuck/leaky injectors since there's no indication of a line leak which would not make it run rich anyway.

Injectors are an easy swap out and I just happen to have a full set on hand that have been professionaly tested and cleaned. I'm more inclined to do this since tangling with the fuel tank on the ground is a miserable job that I'm very much not looking forward to especially given the time of year. I'm gonna wait 'till it's bearable in the garage before I get into this I am such a pussy.

In any event once I do the job I will get back to the forum here with the results good or bad

Regards,
Mark

 

[Exploder321]

While it's in the garage, give all the vacuum lines a good once over, including the fuel vapor system, I had several breaks that weren't visible and caused the running rich codes, all in the thread at the link. Good luck.

 

[J_C]

I would wait till it runs poorly again and plug in a code reader capable of live data, for example I keep a BAFX in my glovebox, that bluetooth links to my phone. Look at long term fuel trim.

When you put the *new* engine in, did you reuse the spark plug wires? Route them away from exhaust? Sometimes disturbing, previously working/good but old wires, can cause a fault when they shift (or damp/wet) just the right amount to get a misfire.

 

[Montana Daze]

This afternoon it was 33 degrees so I decided to at least start it and let it run awhile. It sputtered, evened out, and idled fine. I dropped it in gear, it moved as it should. Got it to the open road, gave it some throttle and the bucking snorts started. 300 yards of this and with a surge it ran fine. Drove it about 50 miles and it never skipped a beat. Too weird.

JC I used all new ignition components when I installed the salvage engine but this doesn't mean something's not bad. I now hope that the seafoam and alchohol finally cleaned out stuck injectors or it sucked the last of the water out the tank or someone's lost their voodo doll or whatever. It's supposed to be close to 40 tomorrow I'll run it again and test the fuel pressure again but I'll wait for a string of warmer days before I actually tear into it

 

[Montana Daze]

Right then

Having decided to wait and study this problem before going off half ****ed and spending a bunch on parts that may not fix the problem, the sum of my observations is this: If it's above 32 degrees it starts and runs fine. If it's below 32 degrees it starts and, above 2000 RPM or under load the misfiring starts. Perhaps it just hates the cold.

There's a spate of warmer weather coming on here and I'll be engaging this problem again soon's the garage is habitable. As promised, I'll relate what I find and what I do about it.

 

[C420sailor]

Colder air is more dense. More fuel required. Higher RPM/load, more fuel required.

Data is life. I’d love to see what your trims are doing when the problem rears its ugly head.

That pump may be providing good volume and pressure at idle, but trailing off as the demand increases. The cold weather may demand that extra bit of fuel that pushes the engine over the edge, and you’re then noticing the rough running.

If she is high mileage and on the original pump, she’s due anyway. I always say, there are parts that you want to change on YOUR terms, not on their terms—like on the side of the interstate at 2am when it’s snowing.

 

[donalds]

$25 or less
Elm327. Great investment
Forscan best scanner software you can get For any ford
Finding your problem in minutes priceless

 

[Montana Daze]

I did pick up a scanner last year when I got the old beast, it's made by an outfit called Innovia. Seems to tell me what I need to know.

Anyhow I picked up a complete Delphi pump from NAPA last week and installed it today. The one that came out looks to be the original so as I originally thought and 420 sez it sure can't hurt and was likely to be the problem anyway, and the job was not as bad to do as I remember it being. It hold pressure >50 psi for 20 minutes and the old exploder purrs like a kitten. Next cold snap we'll see for sure but I think this problem's solved.

Thanks much for those of you who paid attention to this

Regards,
Mark