Oil Pressure Gauge causes stalling?????

[barenfang]

Guys, I really need your help on this one. Here is the background. I have a 2000 Explorer XLS, 158,000 miles, 4.0 OHV with automatic transmission.

The SUV starts fine and runs fine as long as I do not go over 60MPH (please do not tell me the fix is to not go over 60MPH). I can drive at that speed for any distance or any length of time and it runs fine. However, if I go 70MPH for at least 10 minutes the next time I need to come to a stop the oil pressure gauge starts bouncing all over the place and then the Explorer stalls out. It starts right back up with no issue, but I need to rev the engine when I come to a stop. If I pull over and let it "rest" for 5 or 10 minutes it will run fine unless I go back up to 70MPH.

I have replaced the IAC valve, used heavier weight oil, used transmission fluid in the oil, and I have cleaned the PVC valve. I have searched the forums and I just cannot find a solution.

This forum has never let me down on any of the items I needed help with on my Old Explorer, so I am hoping someone has a fix. This one just has me stumped.

 

[my98nnj]

The oil isn't your problem, it's bouncing around as the engine starts to stall because of the idle speed. Heavier weight oil isn't doing you any good either.

The stalling is the issue.

Interesting that it stalls after a run at higher RPM's. When was the last time the engine was tuned up? Plugs, air & fuel filter etc???

 

[koda2000]

the oil pressure sender, or gauge, will not cause your vehicle to stall. low oil pressure may cause your vehicle to stall, but the gauge bouncing around may, or may not, be indicating low oil pressure. the gauge in Explorers isn't really telling you what your oil pressure is. there are no numbers on the gauge, the sending unit is either saying you have oil pressure or you don't. i'd start out by putting a real oil pressure gauge on your engine and see what it tells you. the rule of thumb is 10 psi for every 1000 rpm (when warm) up to about 45 psi. anything less than that you have an oil pressure problem. this can be caused by a worn oil pump, worn engine bearings or clogged oil pickup screen. it may be that pushing your engine more than 60 MPH is causung your oil temp to increase, thinning the oil. 10 MPH doesn't sound like much, but don't forget your truck has the aerodymanics of a barn door. good luck.

question - what weight oil are you using?

 

[barenfang]

Tune UP

My98nnj - I recently tuned up the Explorer August 2012. You have given me an idea though. We I performed the tune up I used E3 spark plugs. Wondering now if I should just replace with Motorcraft? I say this because right after I replaced with E3 plugs it ran a little rough, but then went away. To be honest they were not worth it anyway. I experienced no HP gain or MPG gain.

 

[barenfang]

Weight Oil

Koda2000 - I am using 10w30 and I am about to go up to 10w40. Along with the 10w40 I was thinking about using Seafoam in the hopes that if the screen is clogged it would clean it out.

 

[SoNic67]

Needle bouncing means that the oil pressure drops at around 5psi. It "rides" with the drops of pressure created by un-uniform wear in camshaft bearings (most likely). If you hear "deep" knocks in the bottom of engine, is too late.
Going to 10W40 or 5W40 (Shell Rotella T6) will help with the low oil pressure at idle. That's a way to stop accelerated wear on your bearings. Forget about 30, that's for a newer engine.
Going with higher rpm's (like over 60mph) causes oil to heat more, making it thinner, even if the engine coolant temperature remains the same.

Stalling at idle might be caused by defective IAC valve (those can 'bind' at higher temperatures inside engine bay). Check the rpm range at that point, slide the gear lever in 'N' to check...

 

[koda2000]

as it's getting warm out, try running straight 30 (or 40) for your next oil change and see if that helps. although multi viscosity oils (like a 10w30) are supposed to be 10 weight when cold and then 30 weight when hot, i always found they seem to be really thin when hot. i'm not a Seafoam believer, so that's up to you.

 

[boominXplorer]

Change those spark plugs out to Autolite copper plugs. I worked on a truck that drove like crap after a new tuneup and it turned out to be the plugs. For some reason it did not like double platinum motorcrafts. I think it just doesn't like the crazy E3 plugs.

 

[Styx]

I'm thinking a drain back problem??? all the oil is staying up at the top end and not draining back to the pan...???... Had this problem on a chev a bunch of years back (not mine) will it do it if you just keep it at higher rpm's sitting in one place for a time???

seafoam might help to clean it out but??? you need to find the blockage...

 

[koda2000]

Change those spark plugs out to Autolite copper plugs. I worked on a truck that drove like crap after a new tuneup and it turned out to be the plugs. For some reason it did not like double platinum motorcrafts. I think it just doesn't like the crazy E3 plugs.

the ignition system on this engine is not designed to use copper plugs. the minimum requirement would be platinum plugs. Autolite or Motorcraft plugs work best. i prefer double platinums. gap them to .054. if you install copper plugs, they will wear out very quickly due to the multiple spark the ignition system delivers. save your money and stay away from expensive "magic" plugs.

it might be an oil drain back problem if you've got a lot of sludge. i've experienced this problem on an old Chevy pickup (also not mine). remove a valve cover and see of the drain holes are clogged with sludge.

 

[barenfang]

Thanks for the ideas guys. I have tried running at higher RPM while parked to see if I could duplicate the issue in my driveway, but it worked fine.

I will try switching out the plugs first, then try the higher weight oil, and lastly remove the valve covers to check the drains.

It is just strange that as long as I stay below 60MPH I do not have this issue. I would think if I have sludge and the drains are plugged I would have this issue no matter the MPH.

 

[koda2000]

Thanks for the ideas guys. I have tried running at higher RPM while parked to see if I could duplicate the issue in my driveway, but it worked fine.

I will try switching out the plugs first, then try the higher weight oil, and lastly remove the valve covers to check the drains.

It is just strange that as long as I stay below 60MPH I do not have this issue. I would think if I have sludge and the drains are plugged I would have this issue no matter the MPH.

running it in you driveway doesn't exactly duplicate conditions on the highway (no wind resistance, so your oil may stay cooler/thicker). what if you turned off OD and drive it at say 50MPH?

 

[SoNic67]

If you had a drain-back issue, the symptoms would be WORSE at high rpm, pump would push all the oil up and it would not drain back, emptying the pan.
It's not the case here.

Go with higher (warm) viscosity oil as soon as you can.

 

[barenfang]

Update

Ok guys, I wanted to give an update.

I am not much on snake oil treatments, but after reading several other posts I decided to pour a half a can of Seafoam in my crankcase. The oil that was in the engine was changed about 1,000 miles ago, so I felt safe adding the Seafoam to this existing oil. I ran it for about 50 miles and then I changed the oil to 10w40 with the other half can of Seafoam. I was hoping it would clean out the return lines. I have ran the Exp for another 60 miles with no issues. I plan to run for another 40-50 miles and I will change the oil again with 10w40. I will let you know how it turns out.

Thanks to everyone for your recommendations!!

 

[barenfang]

Another update

Well I ran the new 10w40 w/filter and Seafoam for about 110miles. I drained the oil and it was clean as a whistle. I have owned the Exp since new and I always change the oil at 5,000 miles with Mobil 1 synthetic. Most of my used still looks pretty clean, so I am not sure I will see much difference with the Seafoam.

I put in brand new 10w40 w/filter. I started it up and the rattling that I normally hear was a little louder for about 1 minute. After that the old 4.0 quieted down even lower than normal. It has been running really good so far. In fact I think the old girl has a little more pep if that is even possible.

 

[Flash]

I had an old valiant that would do something like what you described.
The problem was a blocked muffler.

At high speed the blockage inhibited the exhaust flow causing the manifold to glow red.

 

[barenfang]

More Updates

OK guys. This winter something new started to happen with my stalling issue. Whenever I start the EX and let it idle for a period of time (10-15min), then got into the EX, and placed it into drive it would do one of two things:
1. Stall out immediately, but would start back up immediately and run perfect
or
2. It would go into drive and run for about a mile and then stall out. Again it would immediately start back up and run perfect.

This issue was really bugging me, so at a suggestion from a mechanic friend I checked my codes even though it never threw a check engine light. Sure enough it threw a P102 code which is MAF low output. I then remembered that before I moved from PA to VA I purchased a new MAF from Delphi. There was really nothing wrong with my old MAF, but I was worried that my K&N air filter got oil on the old one. Anyway I kept the old one, found it, cleaned it, and installed on the EX. The old girl has been running perfect even since. That is the second time I purchased an aftermarket part for the engine and it did not work. From now on I will only purchase Motorcraft.

Anyway, just wanted to post in case anyone else had similar issue and helps them out. Check codes even if it did not throw a check engine light and in my case it needed a Ford Motorcraft MAF.