truck runs great for 54 miles

[richtrebraiden]

I have a 1992 explorer sport and when you first start it up it idles a little rough until it warms up. then it will run great for 54 miles then the engine studders and you can here it drop the clyinders after about 4 more miles it will clear up and run fine also i am only getting about 10 miles to the gallon when it spudders u can smeel raw fuel and see black smoke out of the exhaust check engine light comes on and then cuts off but it has been doing that sence i had the truck about a year and a half this problem just started any sugestions

 

[snoborder42]

Get the codes read and start from there.

Or do the basic tune up stuff. Plugs, wires, filters, fluids...

 

[richtrebraiden]

done all the tune up stuff still have prob cleaned maf, iac

 

[ma96782]

What have you done so far? Compression test, changed spark plug wires, changed plugs, spark tested, vacuum test, fuel pressure...........and, what were the codes?

You DO KNOW that just cleaning doesn’t ALWAYS fix it.


Aloha, Mark

 

[little x]

codes codes codes. They can help so much. If you don't have one any auto parts store will have a code reader for your truck for about $30. Well worth the investment.

 

[richtrebraiden]

ok have the codes
122 tps low
157 maf low
158 maf high
173 oxy sensor rich right side
now all of these were cont. mem codes
koeo was 111- ok
now before i pulled the codes trying to figure the problem while the engine was running i unpluged both the maf and tps would this be why 122, 157, 158 would show?? i cleared the codes and will check again tomorrow
i dont think the o2 sensor is bad i think its doing its job. any sugestions thanx

 

[richtrebraiden]

ok after clearing the the codes and driving again untill CEL came on again i repulled the codes and only have 173 o2 sensor rich.
but is this the problem?? or a result i did the koer test and still just 173
truck has 189,000 miles and i dont think they have ever been replaced
WHAT SHOULD I DO NEXT ?? again CEL is comes on and cuts off never steady on and it has been doing this sence i had the truck and problem just started

 

[Positive Vibes]

How are you clearing the codes?

Personally I like to disconnect the battery so the ECU has to re-learn everything.

 

[richtrebraiden]

you can clear the codes by disconecting the jumper wire while the codes are being out put

 

[Positive Vibes]

But does it reset the ECU?? Seem you know more than I.

 

[Nick Means]

hey man

Did you try the temp. sensor that sends a signal too the computer not the gauge temp sensor mine was doin the same thing and that cured my prob. Good luck

 

[MrShorty]

Clearing codes by pulling the jumper wire during code output only clears CM. KAM (Keep Alive Memory) is left intact. To clear CM and KAM, you have to disconnect the battery.

From the black smoke and the fuel smell, it would appear that the engine is indeed running rich as indicated by the O2 sensor. Suggesting that the O2 sensor could be good. Next thing I would do would be to check fuel delivery.

Two basic failure modes that I would be looking for: ruptured diaphragm in the FPR or high fuel pressure. A ruptured diaphragm will let fuel into the vacuum line to the FPR. In other cases (which seem similar to this case), the fuel pressure will be at spec KOEO and at initial startup. But, after a while, the FPR slams closed (or something else blocks the return flow to the tank), and fuel pressure will spike to 80 or 100 psi. Because you say it takes 50 miles bnefore the problem surfaces, this might be a case where you need to rig up your fuel pressure gauge in such a way that you can monitor fuel pressure while driving.

 

[richtrebraiden]

thanx mrshorty i have checked the vacuum line and it is dry as a bone
i was leanning to the fpr also only thing is ... it fixes itself like flipping a switch you can be driving and it will be jumping smell fuel and hear it drop the clys. then like a light switch its fine. every other weekend i drive about 4 hrs on the hwy to see my girl after it messes up (after a hour of driving) it will clear up in about 2 miles and then it wont do it again the rest of the 3 hours but after i cut it off let it sit the weekend it dose the same thin comming home like clockwork.

 

[ma96782]

richtrebraiden,

My hat is off to you.......you've come a long way, thus far.

OK......IF I'm reading you correctly, you got code 173.......oxy sensor rich right side. But, there is a QUESTION IF you have two O2 sensors or just one.

http://www.explorerforum.com/forums/showthread.php?t=176453

Read this too.

http://www.explorerforum.com/forums/showthread.php?t=121789&highlight=code+173


So, hey I'm for saving money. So, IF you have two O2 sensors………you could try switching the O2 sensors right for left......then logically the code should switch to the other side......correct. Cause, if it does......then the 02 sensor would be at fault......correct?

Now, If you get another code 173......then the sensor is OK.....and you still got the "problem." That side bank is rich......so, next.......perhaps it's a "problem" with fuel delivery or bad combustion on that side of the engine. So, the spark (wires/plugs/coil) on that side should be checked......or, there is something wrong w/ the delivery of the a/f mix on that side. So, could it be an intake leak? Though it usually reads "lean."

Or, perhaps the FPR is gone? Dumping fuel in there so it's reading "rich."

Or you could search and find something like this:

I have a 92 explorer XLT, 6 cyl 4 liter, 4WD, pushrod.

My car began to have trouble starting, it would take two turns of the key before it would crank. i gave it a tuneup with no changes.

Next my check engine light (cel) began to come on while I was driving. it would only come on after i had been driving for several minutes (after the car warmed up). The code was 173 "oxygen sensor reading rich". At the same time my gas mileage dropped from my standard 16 MPG to 12 MPG.
After seeing my MPG drop i believed teh code was correct and the O2 sensor was not the problem.
I checked the vaccume line conected to the fuel pressure regulator for leaking fuel and it was dry. I connected a fuel pressure guage to the fuel rail and the pressure dropped from 40 to 0 pretty quickly after the key was turned on but the engine was not started.

I also listened to the injectors with a piece of garden hose and all seemed to be clicking as they should be.

I decided to go ahead and change the fuel pressure regulator since I had already bought one. I disconnected the battery cable for several minutes to reset the computer and drove it to work the next day. The cel has not come back on since. Also my gas mileage has jumped back up to its normal awful self and now my car starts on the first try.

I hope this info will help someone else in the future.

And the next post was:

Well, It's awesome that you were able to figure that out on your own... quite impressive. I had that happen to my '92 ex about 4 years ago, and I even brought it to my dad (a mechanic at the dealer) and he suggested to change the o2 sensor. After we did that (and I was 4 hours away) it began happening again, and actually I was using about double the fuel, I came on here and read about this dreaded fuel pressure regulator. It cost me about $100, took me 1/2 hour to change, and the problem was solved. Glad you wasted less fuel than I did, LOL!

And IF you didn't read the thread above (like I said you should):

Problem solved!

I decided to change the FPR based on the comments about fuel pressure and also another thread where the truck was recently fixed after a 173 by changing the FPR and I reset the computer. I have run over 250 miles and much to my surprise-no check engine light. She is running great. No more rich smell and the power seems better on hills. Also, I noticed that the small amount of engine pingging that I used to get on uphills has returned. I think the rich condition eliminated the small amount of pinging.

I guess that the lack of fuel in the vacum side of the FPR was NOT a conclusive indicator that the FPR was good. If fuel was present, it would just be an indicator that the FPR was bad.

Anway, I sincerely appreciate everone's help.

Whatever you do or try......GOOD LUCK.

Aloha, Mark

 

[Tony H]

Nuts, I was betting on the FPR.

That is usually the cause of a rich condition IF the O2 sensor is functioning.

 

[richtrebraiden]

it only has 1 o2 sensor and ive done all of the ignition checks im betting on the fpr i have a long drive on sat and i will have a fuel press. gauge hooked up inside so i can see im pretty sure thats gonna be the culprit i will let you know thanks to all

 

[richtrebraiden]

ok explain this i drove 215 miles 2day to se my girl expectting it to mess up as it has been around 54 miles insted it made it the whole way and my gas milage is back. What gives all i have done is clean the maf and iac and the conectors with contact cleaner to those and the tps but its running great but i still have cel code o2 rich any advise ???????????

 

[MrShorty]

Do you get a KOER O2 rich code, or just a CM code? Did you clear the CM codes before this trip, so you'd know if the computer thought it saw a problem? I'm guessing your problem is intermittent, and Murphy doing what he does, decided that your problem shouldn't surface while you're in a position to see it.

 

[richtrebraiden]

both cm and koer and i did clear both the cm and kam but like i said b4 the cel has always come on since i had the truck about a year and 3 months this problem has been constant for about 8 months every time i drive more than an hour but now like you said Murphy is just toying with me but mabye when i cleaned the connector at the tps that was it . It was correded and when i unplugged it engine running it messed up like it did while driving i am going back home on tue. and will see if she is still running ok. as 4 the o2 i have a 93 mustang and according to advance auto the o2 sensors have the same part number so i will switch them to see if mabye that could be bad.