94 Explorer. My baby hates hot weather

Marcsnothere · March 19, 2012

After reading dozens of threads on here, I have realized that this problem remains a mystery for many, much like myself.
Symptoms: Over 80 outside, Runs horrible- Sputters at a stop, dies, may or may not restart, depend on how long I drove it for.
Ran great all winter.
Sometime must sit for an hour for it to restart
Fuel pump relay is kicking in.
Fuel pump replaced 2 years ago.

Tested MAF. (Voltage at idea, and under load) OK
Tested TPS. (Voltage at idle, and under load) OK
Swapped IAC. No fix
Replaced Coolant Temp Sensor. No Fix
Replaced plugs (all the time). No fix.
Tightened up/low intake bolts. No fix.
Cleaned IAC. No fix.
No fuel smell.
No coolant loss.
Power (giving it gas) horrible, even when not sputtering.

Read an amazing post on here about reading CEL codes, received the following:
KOEO : 186 Injector Pulse width high
KOER : 172 R.S. Heated O2 Sensor (lean indication)
136 L.S. Heated O2 Sensor (Lean Indication)
167 Indufficient TPS Change during Dynamic response.

Im at a loss. weeks in, and my head is tired of being scratched. Has anyone actually fixed this problem???? If so, please, for the love of Explorer owners everywhere, tell us how? I know it can be a few things, but Ive been an explorer(s) owners for years, and I miss my baby running reliable enough to take my kids out in!
Thanks in advance friends.
Marc

mgmgmg · March 19, 2012

I have the same problem but only on very warm starts like temps above 80....but the problem is only on idle if i hit the gas i have no shutter after 30 seconds it goes away....one time i opened the gas cap and let the gases out it seemed to help somewhat...I wonder if it has to do with gases building up in the gas tank. I hope somebody can reply on this....

And no its not a bad IAC! or MAF!@

Jason94sport · March 19, 2012

Replace the coil pack & fuel filter. Both cheap & easy to eliminate. And the 02 sensors since you got codes for them. Could also be a clogged cat.

Happy Jack · March 19, 2012

Yup, me too. Replaced the O2's, coil pack, water pump, intake gasket, and IAS. New fuel filter and pump. Mine does fine around town except for hard starts but when it's over 90 and I'm loaded heavy with camping gear climbing the mountians it's a problem. Or on steep long off road trails where I work it really hard. And I get a bad cross between exhaust and fuel smell. Replaced EGR and Canister. Read somewhere about a valve in the return for the gas tank but is no longer avaialble? CPS out of adjustment? I had mine replace and was told it was adjusted. I checked for bad CAT by removing it and trying a test tube. :dunno:

MrShorty · March 19, 2012

Has anyone actually fixed this problem????

I can't speak for your specific problem, because I can't say for sure what your cause is. I had just about the exact same symptoms with a new fuel pump. Suspecting a fuel problem, I put a fuel pressure gauge on it when it was running rough, and saw that the system was dropping down to ~20 psi and below, when it wouldn't start, it wasn't generating enough pressure, and so on. Checked the regulator out and the wiring to the pump (I, too, had a new pump at the time), and eventually determined that my new pump was doing something funny when it got hot. Replaced the pump and all was well.

FWIW, those O2 sensor codes could be caused by low fuel pressure, too.

That said, the first thing I'd do in your situation would be to put a fuel pressure gauge on it the next time it acts up on you. If the pressure is normal, then go on to something else. If the fuel pressure is too low, then delve deeper into the fuel system to see why the pressure is too low.

Roadrunner777 · March 19, 2012

mgmgmg said:
I have the same problem but only on very warm starts like temps above 80....but the problem is only on idle if i hit the gas i have no shutter after 30 seconds it goes away....one time i opened the gas cap and let the gases out it seemed to help somewhat...I wonder if it has to do with gases building up in the gas tank. I hope somebody can reply on this....

And no its not a bad IAC! or MAF!@

Same thing here... it is very repeatable, so now that it's warmer, I'm going to throw the fuel pressure gauge in try to catch it. Someone else said it happens at Walmart... that's where I always have trouble too... there is some bracket of time, more than 10 minutes, less than an hour.

Anime · March 19, 2012

Keep the ECM/ECU in mind. The capacitors in the ECM eventually leak and cause problems that can't otherwise be explained. The only solution is a new/refurb ECM or replacing and cleaning up the capacitors on the current one.

Usually if you can read codes the ECM is still good, but I had some pretty erratic operation prior to that, replacing fuel/ECM relays helped, but by the time the codes can't be read, the engine randomly won't start, the caps have leaked all over and you better do something about it.

You may also want to check other sensors and battery related things (alternator/voltage regulator, starter cable, etc.), but the ECM is the big one.

Bruces expo · March 19, 2012

welcome to the site , i just drove my rig from poplar grove il ! thats weird , i have a Great mechanic friend that can help you and he is also in PG , here is his link to his Facebook http://www.facebook.com/GearHeadzMechanical give him some info im sure he can help you , make sure you tell him Bruce from Ga sent you his way !!

mgmgmg · March 20, 2012

Roadrunner777 said:
Same thing here... it is very repeatable, so now that it's warmer, I'm going to throw the fuel pressure gauge in try to catch it. Someone else said it happens at Walmart... that's where I always have trouble too... there is some bracket of time, more than 10 minutes, less than an hour.

Roadrunner keep me posted on that fix plz :thumbsup:

Marcsnothere · March 20, 2012

Thanks for every reply, I seriously do appreciate it everyone!
Ok, I really need to read the responses sooner. Drove ok yesterday, but today:
Started rough (parked in temp controlled garage. 75) cleared up after 5 minutes. drove great in heat for 40 minutes. sat for about an hour. Restarted, a little rough, but thendies 7 times on the way home. warmest day(ish) of the year so far. It refuses to stay on at a stop, give it gas, just sputters n dies, and now it smells like gas when dies. Its as if its not getting any air, but plenty of fuel.
Earlier I replaced the air intake temp sensor (also known as Air charge temp sensor)
and did an oil change.
So, providing I can get to autozone and back....:
Fuel pressure test?
Coil Pack?
ECM?
Clogged CAT?
Battery and Alternator are testing out fine.

Question tho... When I tested other sensors, it was running fairly well, What if the outside temp being warmer throws off one of the sensors, would it then, and only then, test out bad?? Ug, Im out of dough, and running out of options. The outside warmth is fighting something on the truck. There has to be an explanation as to why the truck runs great in cooler weather, but not in warm weather. This just does not make any sense, and many have/had this problem.

MrShorty · March 20, 2012

The gas smell suggests to me that it is running rich/flooding. Fuel pressure test still seems to me like the best first test. Be sure to pull the vacuum line off of the fuel pressure regulator (FPR) and check for gas (gas in that vacuum line = bad FPR), as this is a common failure mode on the FPR.

Question tho... When I tested other sensors, it was running fairly well, What if the outside temp being warmer throws off one of the sensors, would it then, and only then, test out bad??

As ahypothetical question, yes, a fault that is "intermittent" is harder to diagnose because you have to be looking at it when the fault occurs. If this proves to be true for your situation, you at least have the advantage of a condition (temperature) that seems correlated with the symptoms. With summer coming, this fault will only get more consistent and therefore easier to diagnose as summer approaches, if it is temperature related.

Marcsnothere · March 21, 2012

Ok. Yesterday, before I took off, I cleared the codes. Then drove it all around, it died 7 times, the last time being 2 doors downfrom my house. Each time, the explorer needed a few minute to cool (engine temp ok), and it would restart. the problem is so intermitent though. Gah- confusing..
I was able to limp it into the garage. This morning, I recvieved new codes. If I remember correctly, if the engine temp isnt warm, then I will get 2 codes that are irrelevant? Oh, and for the record, it did start, sounded rough, but it ran this morning non the less. Either or, I havent looked up the new codes yet, but here they are:

KOEO: 171
172
176
186
332

KOER: 116
332
After I let it warm up, I redid the KOER Test, and only came up with 1code 136...

I cant go anywhere until later, maybe tomorrow, so getting a fuel pressure tester is not currently an option. I did pull the tube from the FPR, and there was no sign of gas. I am thinking of pulling the PCM, and seeing if it has any of the blown capacitors in it like I have read on here.

I know this is a pain, but I think if we can come up with a solution, then many of us may save some stress, and dough. Thanks again for all of your help.

crazymind · March 21, 2012

When mine dies the fuel pressure drops to 2 psi. When I had my buddy last time it dies I had him turn the key on I could hear the field pump run but it sounded like is wasn't getting enough juice to spin or it was struggling. I changed both ect sensors it help but still dies.

Marcsnothere · March 21, 2012

I think I should change the title of this thread to :ON A MISSION:
lol
I pulled the PCM. Looks brand new. Capacitors are not blown or even bubbled in the least bit. Probly he cleanest part of the truck.
Reinstalled.
Decided to repull codes again.
koeo, all clear 111
koer
172 Heated O2 right side
136 Heated O2 left side
332 EGR Not opening
So, O2 or EGR? Is one setting off the other? Would warmer outside temp cause one of these to act likle a d-bag? Must learn how to test these. be back later!

MrShorty · March 21, 2012

To be more specific with your O2 sensor codes, 172 and 136 mean that the O2 sensors are indicating a lean mixture. Earlier you said it smelled like gas indicating a possible rich mixture. Not a final word on the diagnosis, but that suggests the possibility that the O2 sensors are not sending correct information to the PCM. How old are your O2 sensors?

I'd probably still wait for a good fuel pressure test. If the fuel pressure test looks normal, then it might be time to look at the O2 sensors more carefully.

crazymind · March 21, 2012

Sorry to thread Jack. How can you tell if the capacitors are leaking? Is there stuff that comes out of them or do they look burnt?

Marcsnothere · March 21, 2012

Maybe I should rename this thread Mission Impossible??

I agree, A FP test should help eliminate quite a bit. I 'm going to hit Autozone tonite or tomorrow and rent one.

I have only owned this explorer for about 3 years, and have never replaced the O2's. She wasnt well taken care of when I got her (200 bucks!) Been reviving her, but shes stubborn.

Is there 1 O2 sensor that goes bad often?

Crazy- If your capacitors are bad/going bad, then the tops will bubble up, kind of like a dome (supposed to be flat), sometimes they will form leaks, sometimes not. Google blown capacitors, and look at a few pics to help ya out.

X94 · July 29, 2012

not sure if anyone has solved this problem yet but you can put my explorer on the need help list for this one.

AussieMike · January 30, 2013

My explorer has started to do this as well, since I have moved to the heat in Northern Australia, I would love for a solution to be found as well

wood1 · January 30, 2013

Check your fuel pressure as Mr Shorty suggested. He knows his stuff.

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