runs like crap...

[nothinglikeaford]

hey would anyone know whats wrong with my explorer?
first off it starts up fine and edles pretty good and i can slowly rev the engine around 5000rpm no problem...unless i give it to much throttle.
if i floor it, stays around 2000rpm sputting like crazy, if i was reving higher thn 2000 it drops with no sound almost till its around 2000rpm and then starts sputting.
when its cold i can sometimes floor it and have no problems once or twice but after that its back to sputtering.
and i changed alot of parts and checked everything.
new parts:
fuel filter, fuel pump, spark plugs(again) sparkplug wires(again), coilpack, MAF sensor as well as vacume sensores and temperture sensor.
check ups:
alternator is 14 plus volts, timing and chain are fine, no cracks or dirst in my air system,injector plugs seem all fine, vacume lines don't leak(tested under water), and nothing comes up on the computer.

i'm really running out of ideas, i got a hole other truck for parts, its a 96 limited edition but the engine and most of the parts are same as my 97 explorer.

any help would be awsome, thanks

 

[Macgiobuin]

Have you tried

doing a resistance test on the throttle position sensor? It should sweep steadily from high resistance to 0 ohms, from one end of travel to the other. You can test it with a multimeter set to ohms.

 

[nothinglikeaford]

swaped

i actually swaped it from my other explorer this morning and still no change, and the other explorer ran perfect besides the transmission so its probably not that, but thanks anyways

 

[joker1457]

Have you thought about a cracked head, I had a Bronco II do the same thing to me years ago, turned out it had a cracked head. Check your oil if it looks like something other then oil get it looked at. It will look like its curdled because radiator fluid has gotten into it, like the consistancy of cottage cheese. My second guess could be a clogged catalytic converter is there any rotten egg smell coming from the vehicle?

 

[2000StreetRod]

What engine?

What engine is in the vehicle? If you're using parts from a 96 then it must be either a 5.0 V8 or 4.0 OHV V6.

When the engine is cold started the fuel system runs open loop and rich based on preset values. Since your engine runs better when cold then I'd suspect it is running lean when warmed up. When you mash the throttle the MAF sensor and the TPS notify the action to the PCM. The PCM richens the mixture to support the rapidly increased load. The IAT sensor has very little effect on performance. I've experimented with varying the MAF sensor voltage to the PCM and learned that it has to be way off to set the CEL. Since you already have swapped the MAF, TPS, fuel filter and fuel pump and checked the injectors there is little left that affects the richness. Do you have access to a scanner?

If you had a SOHC then there's a possibility it could be the timing. The knock sensor could be faulty and radically changing the timing.

 

[Macgiobuin]

Next easiest step

Try taking the idle air control valve out and spraying engine cleaner or WD40 into the two holes to free up the plunger valve. Spray alot in there and move that plunger up and down as well as you can, it only moves about 3/16 of an inch to open up the orifice. Then put it back in check it out.

 

[nothinglikeaford]

replie

joker1457, its not the head or head gasket, oil is fine and its not burning oil or prestone but i was thinking about emptying the converters but i don`t know if i should. it has 2 one after the other and i just have a tube muffler after, and the only smell is from the gas burning late in my muffler when it sputters... found out its the paint off the muffler that was burning.

2000streetrod, i did plug the computer on my truck and i got the MAF sensor and got that fixed but now nothing comes up but it still runs like crap.
but i was planning on changing my crank shaft sensor, its nice and open for alot of wear and tear so it could be my problem. i should know today if its my problem. and yes its the 4.0L.

Macgiobuin, i already swaped the idle control but i will take it back off and clean it and make sure its working, wouldn`t hurt.

thanks for the replies guys

 

[2000StreetRod]

. . .
2000streetrod, i did plug the computer on my truck and i got the MAF sensor and got that fixed but now nothing comes up but it still runs like crap. . .

I assume that you meant that you read the diagnostic codes with a code reader and it reported the MAF sensor which you changed. I was asking if you have access to a scanner so you could tell if the PCM is reading the correct MAF and TPS values when you mash the throttle.

 

[nothinglikeaford]

more swaps

no i don`t got a scanner but i`ll look into it.

swaped the knock sensor and fuel pressure regulator today and guess what...still runs like crap... any more idea`s guys? i should be under the hood again tommorow. thanks again

 

[2000StreetRod]

Dpfe?

. . .swapped the knock sensor and fuel pressure regulator today and guess what...still runs like crap... any more ideas guys? I should be under the hood again tommorow. thanks again

I thought you indicated you had an OHV V6 but it was my understanding that only the SOHC V6 had a knock sensor.

Here's another idea. When the engine is idling or cold the Differential Pressure Feedback EGR (DPFE) is disabled. After the engine warms up, I believe its still disabled at idle but not at normal engine speeds and temperatures. If the DPFE is not working right the engine won't run right. If the EGR valve is stuck closed it can cause detonation which the knock sensor would correct for by retarding the timing. If the EGR valve is stuck open the engine can run rough at cruising. Make sure the two vacuum lines to the DPFE are connected and in good condition. Also check the vacuum line from the EGR vacuum regulator to the EGR valve.

 

[nothinglikeaford]

got a SOHC

i swaped the egr valve, the black plastic one.
the one mounted on my exhaust manifold is pretty stuff on there...same with my parts donner.
i`ll try shooting some air and maybe wd-40 in it to see if its jamed or not...maybe use a shop-vac also and see if it changes how the engine runs.
once its warm enough outside i`ll be under the hood again.

 

[nothinglikeaford]

update

i changed my egr valve mounted on my exhaust, i actually changed the hole tube...my valve was rusted right through it but even tho i changed it my truck still runs bad and even worst now...i grabed the spark plugs off my doner truck since i saw a spark from one of my NEW wires... i also drilled a hole in my catalic converter to see if it was blocked and i managed to poke a hole through both of them so they are not cloged up if they where before.
also scanned the computer again and no codes still....still got a coupple things on my to do list and one of them is to drop the gas tank and check my wires to the pump and make sure they are alright and i'll pull the spark plugs out to see if any are damaged or show any signs of bad spark.

anything you guys think i could check? i really don't want to have to send it to a garage cus i have a feeling its gonne stay there a while and cost me an arm and a leg :s.

 

[2000StreetRod]

Tough problem!

Here's another idea and since you have a doner vehicle it will only cost you time to check. If the PCM determines that the engine is not running when the ignition is ON, after a few seconds it will open the fuel pump relay. The PCM uses the camshaft position (CMP) sensor to determine if the engine is running. You may want to try swapping the CMP sensor to see if it makes a difference. You may have an erratic sensor. The previous owner of my Sport left it abandoned on the freeway because it stopped running. The only thing wrong was a bad CMP sensor.

 

[scsr_11]

Hello guy. Any update on your situation? Your situation sounds just like mine, but I don't have a parts truck to play with! I've swapped plugs, wires, and fixed vacuum leaks so far with some improvement, but still a baddd miss and bad performance.

 

[nothinglikeaford]

reply

hey sorry i still didn't get it up and runner and didn't get much time to do so.
but i got soem good suggestions if you want to check them on your own truck...maybe your problem is not quite like mine. best of luck.

oh and i had a question guys...its kinda hard to get to the sensor that replaced the timmer but if i do pull it out and swap it...does it effect any of the timing? don't wana screw up the timing if i swap sensores.

if it does effect the timing is it just like a normal timer and i jusy time the engine at top dead center or is this more gadjety???

thanks

 

[2000StreetRod]

OHV or SOHC?

. . .
oh and i had a question guys...its kinda hard to get to the sensor that replaced the timmer but if i do pull it out and swap it...does it effect any of the timing? don't wana screw up the timing if i swap sensores.

if it does effect the timing is it just like a normal timer and i jusy time the engine at top dead center or is this more gadjety???
thanks

I'm still not sure if you have an OHV or an SOHV.

To my knowledge there is no adjustment possible with the crankshaft position sensor (CKP) nor any way to "time" the engine. The CKP tells the PCM when the crankshaft is 60 degrees BTDC for cylinders 1 and 5. It's also used by the PCM to determine rpm.

I have another idea. The PCM relies substantially on the engine coolant temperature for richness. When the engine is cold it requires a much richer mixture to run right. As the engine warms up as reported by the ECT sensor the PCM decreases the richness. If the ECT sensor is bad and the PCM thinks the engine is still cold then it would run way rich after warmup. If that's the case, you should be able to detect black (unburned fuel) in your exhaust. If there is a poor electrical connection to the ECT sensor the PCM thinks the engine is cold. You may want to check the connection for looseness or corrosion. The ECT sensor can be tested with an ohmmeter and a pan of hot water. Or, you could swap with the one in your donor.

 

[quackattak]

I know you replaced everything with your fuel system but have had a fuel pressure gauge plumbed into it. I had a 99 f350 v10 and a 96 F350 460 have those exact same symptoms in the same week. One had a fairly new pump held 35psi idling and dropped a little with slow rev up, floor it and the pressure dropped to around 5psi and the thing fell flat on its face.

 

[nothinglikeaford]

reply

i did do a fuel pressure test but i had it done when the computer told me my mass air flow was bad....since then its possible and i was planning on doing an other test today.
so far now i"ll be checking fuel pressure, the eleictronic timer and tempurture sensor...hopefully its one of those and hopefully its not fuel pressure cus last time i changed the pump,tank,straps and filter at a garage and it cost me 1305$....pump was 400$ :S

 

[JDraper]

Is this problem occuring when you're driving the truck, or only when it's sittting still and you rev the engine?

 

[quackattak]

most the sensor stuff will set off a code, the 2 fords I mentioned earlier also had no codes.