4.0L with OHV and random misfires on all cylinders

[2000StreetRod]

Half tank of fuel

. . . As far as the injector cleaner....can you add it any time to the fuel or should I wait to empty the tank and then add iot prior to a fill??

I would add it if I had one half tank or more.

With the fuel pump test...is it safe to be driving with the gauge connected?

It should be OK as long as the line is well secured and doesn't leak. One member had crud in his tank and drove for a long time with the gauge connected. When the fuel pressure started to drop he would change his filter.

 

[Sndsational]

Ok....I will look into that.....Thank you, I will keep you advised.

 

[Sndsational]

Oh. BTW.....what do I need to get to do the compression test and where should I get it?

 

[2000StreetRod]

compression gauge source

Oh. BTW.....what do I need to get to do the compression test and where should I get it?

I purchased an inexpensive one from Harbor Freight Tools but haven't used it yet.

 

[Sndsational]

I looked on line, but i only saw a diesel one. I think I can rent one from autozone.

 

[2000StreetRod]

cheap tester

This one should work fine for $10.

Flex Drive Compression Tester

 

[Sndsational]

Ok, so this is where I stand on the continuing saga that is my 2000 Explorer Sport. I changed the fuel filter for sake of doing it again. It had been a long time from since I bought the truck and then changed it....unknown the history before that. The fuel was coming out very dirty, so not a bad move. Also, changed the PCV valve....figured that would not hurt either. I added the Techron and drove it today....ran "ok", but still think there may be more. Was not able to put a ton of miles on it though. No compression test yet....gonna get there soon.

Now, fill you in a bit more, it was raw and rainy today....about 50 degrees. Doe sthat make a difference? Also, I cannot seem to get my truck to get over 13MPH......with significant highway miles.

Let me know what you think. And as always, thanks you for the help.

 

[Sndsational]

and then tonight, right back to the truck driving like crap. Seemed like it was having a hard time getting powerand to speed. I did notice that on start up it took a bit to get running. but the whole ride home it was not running well. Also, seemed at though it was really reving high to get to speed, not a smooth acceleration. Should I really start looking into the fuel pump possibly being bad?

Also, is there a way to determing the fuel pump I need without pulling it? I looked online and see there are "several" that are available.....help?

 

[2000StreetRod]

fuel pump and fuel economy

A faulty fuel pump does not explain only getting 13 mpg. Replacing the fuel pump is an unpleasant task. I wouldn't replace it unless I knew it was bad.

 

[hoss_hanna]

i agree with streetrod, i dont think its the pump...

 

[alohamonte]

I had idle issues (no misfiring) without a CEL on my OHV due to the air charge temperature sensor being bad. Just something to look at, it's only a $20 part.

 

[REDDY]

Only took a year for me to figure out, but yeah, u had to change fuel filter and found out it was dirty, still ran not so good, bad gas mileage, no hp at 55mph,......your gas tank is F'ed, replacing mine next weekend, hopefully my new fuel injectors arent f'ed already, rockauto $200 gas tank, probably going to order the whole assembly of fuel pump also.

 

[REDDY]

i read a few threads here recently but couldnt sign in, their problems were also gas tank probs., seems to be happening to alot of people now

 

[Sndsational]

are you guys saying it is a lot of junk in the tank? I do have to say, I drove the truck this AM and it ran well....still seemed to be a bit off, but not like last night. Seems to be the trend, good...bad, good, bad....I do not know what to make. I do know I am running out of options. I did read that there was one member who had an issue with a chaffed wire in the harness causing shifting problems. I had some top end work done a while back....possible that is the reason? Only thing is that the more I change and investigate....things seems to SLOOOWWWWWLY improve.

How would I determine if it is the gas tank?

Additionally, I have noticed that at about 65-70 MPH, I feel steady and consistant vibration in the gas pedal. Not sure if it is the front end vibrating, but it kinda feels like someone is pulsating air next to the pedal and I am getting the residual feeling.

Also, on a different note. When I am crawling to a stop or just rolling it feels as though i am on oval wheels....any reason?


Continued thanks!!

 

[ranger7ltr]

2 Questions; Gas tank and camshaft synchronizer...

When did the truck start running rough and throwing codes? Did the replacement of the chirping camshaft synchronizer have any bearing to this? If the camshaft synchronizer is a tooth off, the injectors will not fire at the proper time in the crankshaft rotation and this will cause the engine to run like crap...
Just a thought...

The other item is a dirty gas tank...If the inlet side of the fuel filter is looking like rust/dirty water/fuel the tank is what is causing that...I had my tank boiled out by a radiator shop then lined but it was apparent that the liner did not completely cover the tank because within 2 months I was back changing fuel filters because my fuel pressure was dropping...There is rust in the tank and, unless you can keep the tank full at all times, rust will continue to grow even in a cleaned out tank...And the clogged/dirty fuel filter will cause a leanout condition under load and this will cause misfires depending on which cylinder gets a lower amount of fuel from the injector...

The final straw was when the fuel filter died while driving away from home...The "filter" on the fuel pump doesn't filter out small particulate; that is why you see it suspended in the fuel at the inlet of the filter...But the pump does not like to pump solids and this will eventually kill the pump...So I bought a new tank and got the pump replaced under warranty...

This is what the inside of the tank looked like...And this is the inside of the new tank...

 

[Sndsational]

Cool, thank you for the info and the pics. Right now, I am not going to go that deep...only because it is intermittent and there are no codes...being thrown. Also, because it seems like it could be a temperature issue, I like the idea of the intake air sensor mentioned earlier. For the cost of th epart I would like to try that first.

Does anyone have a picture of the location on the 4.0L OHV?

 

[ranger7ltr]

Is your trucks year model a 2000?

If so, or actually whatever year model it is, look at the MAF plug and count the wires... If you have 4 wires there, look in the air tube going from the MAF to the Tb for the IAT...

If the plug has 6 wires, the IAT is part of the MAF unit...

 

[Sndsational]

my 2000 has 6 wires, so the IAT sensor is integrated in the MAF. The last diagnostic I had done said the MAF was fine....I assume that if the IAT part of it was bad that they would have been able to tell?

What else do you think....any other sensors? Or are you leaning to the fuel tank again?

One more thing....when I changed the coolant temperature sensor, I never disconnected the battery.....therefore a reset was never done. Again, no CEL, but do you think this may be an issue?

 

[Trader007]

I know it's a little late... but I found this thread off google.

I have a 1999 4.0L ranger that I went through these EXACT problems.

exact in the fact that the motor runs totally random. It's not weather, gas, air, anything related. I replaced every single sensor on the motor, fuel pump, coil pack, all filters... nothing helped. And no codes ever either, the motor would just randomly miss and lose ALL power (you have to smash the pedal to the floor just to get up to 40mph). Then, out of the blue, some days, some afternoons it would just run AMAZING. so much power you could smoke the tires. So i knew it wasnt compression related...

NO fix worked. Went on like this for two years just throwing parts at it. You couldn't imagine how frustrating it was. Until I finally figured it out.

What worked? Replacing the capacitors in the engine computer (pcm). Completely changed everything, truck ran great for 6 months.

Now I am starting to get the same problems coming back... but at least I know what it is. I just wanted to share. I think there were a batch of these PCM's that were built with subpar parts. Mainly the main power filter cap inside the computer.. mine was completely dead and once I replaced it the whole motor ran like new.

Now that mine is going bad again, I feel it's time to just get a new computer... problem is i have that stupid PATS system that wont allow me to change computers without a key-reflash. Problem is you need two chip keys to do that, and I only have one. Ford wants $300 for new keys and programming... screw that.

So for now I am going to just rebuild the computer again. I am guessing there are more components in there going bad than just the power caps, because those shouldnt be failing so quickly... but its easy to replace them and if it keeps buying me time so be it. 260k miles on this thing and its a rusty bucket of crap. Love it though.

 

[Runnin'OnEmpty]

Where exactly are these capacitors in the PCM?
Do you have to solder them in?