Bad gas

Anyone ever get some bad gas in their tank? How did you end up determining that it was bad gas?

Here's a short version with the problem I have...

Coming home from a trip near Chi town. filled up one last time about an hour away from home. Rig running just fine all weekend. About 15 minutes from home it started idling like it was dropping spark in 1 cyl. When getting on the gas it runs fine. Made it home but it was idling like that every time I was at a stop sign.

Next day, I drive it to work about 10 miles each way. Idled rough like it wasn't getting spark in 1 cyl on the way into work. On the way home it started getting worse. Now I'm losing power like it's only running on 4 or 5 cylinders. By the time I pulled it into the driveway, it just barely made it. If I get it to start it runs like at least one or two dead cyls and it gets worse as I try to keep it running.

Codes I got were for both O2 sensors and heating circuit plus multiple miss fires codes.(I knew the O2 sensor problem 'cause I ripped the wire off on the down stream one at McCaslin) Took care of the O2 sensors, replaced the blown heater circuit fuse. Still runs like crap!

Plugs, wires cap and rotor is all new. I've got spark at all 6 plugs.

WTF? My wife keeps asking me if it could be bad gas...I blew her off in the beginning (she refers to specific parts as 'thingies')

Now I'm starting to wonder. In the olden days, I'd just pull the fuel line off the fuel pump that was right on the engine and stick the line in a can of gas but obviously you can't do that with a fuel injected system.

:repair: :dunno: Oh yeah, it's a '98

Pull the fuel hose back by the tank and run some fuel into a container so you can check it.

It sounds like contaminated fuel, water to be exact. Mom and Pop/off brand/older station?

You might have gotten E85 by mistake.

Got the gas at the Mobil Oasis in Belvadere Il. It's been there a while but it's not a mom and pop.

I wondered about that e85 or even diesel? Wouldn't that 'cause the rig to smoke a lot? I'm pretty sure I grabbed the correct nozzle but to tell you the truth, I was returning from my nephew funeral and I wasn't in the best of mind.

I'm heading up north this Wednesday for hunting season so I'll pull that line when I return and see what comes out...

Thanks Joe!

ps. My wife deals w/a lot if inspectors. They just had a complaint they dealt with that the guy put e85 in his car and I guess it must have run like crap. It wasn't the station. They figure he picked up the wrong nozzle.


If my wife is correct there will be no living with her!!!:smootch:

Flowers and dinner, man, flowers and dinner!

My Wife is always right, even when she is wrong, she is still right! :doh:

(Took me eight years and half of everything I owned to learn that lesson!)

Did you check the oxygen sensor heater fuse AGAIN? The fact that it blew once is suspect and repeats of blown fuses is not at all uncommon if a shorting condition exists.

Gotta ensure that the heater circuit is working properly before moving onto other things. If O2 checks out, I'd check fuel pressure at the schrader valve on the fuel rail. Easy to do and important in "process of elimination".

Good luck and let us know what you find!

Yeah, I checked it again. The reason the fuse blew the first time was because the wires for the down stream O2 sensor were damaged when they were ripped from the sensor. I fixed the bare wire short and the fuse survived.

I was planning on checking the fuel pressure. Just haven't had a chance to.

I will post how it goes. It will be after next week though. I have plans on taking my rifle for a nature walk from Wednesday thru the following Monday.

if you really think it may be the fuel you may want to try and call up that gas station. other people would have had issues also and the station may admit that something was wrong. i'm saying this because last year my gf ended up getting diesel put in her liberty. the fuel delivery guy apparently put the diesel in the wrong storage tank and the station was pumping diesel instead of regular for an hour or so. the station ended up paying for whatever was fouled up from the diesel

When was the last time the fuel filter was replaced?

I'd at least pull the filter, shake it up really good and dump the crap out.
Or replace it if it has been a while.

How long did you go with the messed up O2?
You could have fouled the cat and plugged the exhaust.
If the computer doesn't read the O2 sensor it will stay in "Open Loop"
Unbolt exhaust before the cat and drive around the block.
It'll be loud and mean and may piss off the neighbors, but it's fun.

Just a few thoughts off the top

Came across this and though I would pass it along since you repaired the O2 sensor wiring.

From the 00 FSM:

or pack the connector with grease.

Not sure how the repair was done or how the outside oxygen supply goes through the harness. Maybe someone can chime in on how this outside oxygen supply physically gets to the sensor.

OK, get a glass jar. Pump some fuel into it, off the fuel rail test port is the easiest way. Then add some water into the jar. Exact amounts don't matter. With a Sharpie put a mark at the line between water and fuel. Let it sit a couple hours and see if the water has grown while the fuel shrunk.

Why would you add water to the jar to begin with?

I imagine to get the line between the two to be in a more easily observed location of the jar, and also so that the tiny suspended droplets of water have something to combine back into to speed the separation up.

WI88XJ said:

Got the gas at the Mobil Oasis in Belvadere Il. It's been there a while but it's not a mom and pop.

I wondered about that e85 or even diesel? Wouldn't that 'cause the rig to smoke a lot? I'm pretty sure I grabbed the correct nozzle but to tell you the truth, I was returning from my nephew funeral and I wasn't in the best of mind.

I'm heading up north this Wednesday for hunting season so I'll pull that line when I return and see what comes out...

Thanks Joe!

ps. My wife deals w/a lot if inspectors. They just had a complaint they dealt with that the guy put e85 in his car and I guess it must have run like crap. It wasn't the station. They figure he picked up the wrong nozzle.


If my wife is correct there will be no living with her!!!:smootch:

Click to expand...

Around where im from the diesel comes from a larger hose, so that it wont fit down the hole of gasoline vehicles. So I dont think that would be likely that YOU did that. Maybe the station did...
E85 should run in your Jeep. It is bad for alot of the fuel system components, but it should run.

Sounds like water got in the tank somehow.

Good Luck.

It could be bad gas. I would also check your fuel pressure. If you got e85 It will eat the rubber fuel lines and maybe some plastic parts. I would try the glass jar trick, mentioned above..

To clarify my post, if the fuel has excessive alcohol content the fuel will absorb some of the water.

Hey guys. Sorry it took a bit to get back to this thread. I plan on doing a number of the suggestions here. I'm figuring on changing the filter and having the pump squirt out about a quart of gas to check. I've had the rig for a couple of years and I'm sure the PO didn't change it either. Cheap enough not to change.

I don't think it's the cat. I hope not 'cause I have a borla system from header to tailpipe and it's all welded. (fingers crossed)

Greenz, I know you're reading from the FSM but that doesn't make any sense. There is no way the O2 sensor gets any oxygen thru the wires. The sensor screws into the pipe up top and behind the cat and the only thing the sensor can 'sniff' has to come thru the pipe. Now just because it a FSM doesn't mean it's totally correct. I have a friend that faxed me what the manual has about the O2 sensor and no where did it tell me where the heater circuit fuse was. I found out about that here on .

From what I've been told by some folks I have talked to about the e85 is that it will make your junk run like junk if it isn't set up to run e85. So maybe...

I'm going to find out where I can get the fuel analized to find out what's really in the gas. I could try and call the station I got the fuel from and ask them. I'm not sure they will be straight about it.

But as much as I really need to get this figured out I have a week set aside to walk around the woods armed and scare nature and the general population. Nothing ever gets hurt but I feel pretty manly afterward. :laugh3:

Oh, Joe. A big 10-4 on the flowers. A few decades of matrimonial bliss has taught me that. It's just I know how long I'll have to grovel to break even on this one. :heart:

Um yeah, I didn't know how that was possible either but out of curiosity I looked it up.

Found multiple sources, here is one: http://www.aa1car.com/library/o2sensor.htm

"The outside of the bulb is exposed to the hot gases in the exhaust while the inside of the bulb is vented internally through the sensor body to the outside atmosphere. Older style oxygen sensors actually have a small hole in the body shell so air can enter the sensor, but newer style O2 sensors "breathe" through their wire connectors and have no vent hole. It is hard to believe, but the tiny amount of space between the insulation and wire provides enough room for air to seep into the sensor (for this reason, grease should never be used on O2 sensor connectors because it can block the flow of air). Venting the sensor through the wires rather than with a hole in the body reduces the risk of dirt or water contamination that could foul the sensor from the inside and cause it to fail."

From what I can find, the only thing that can bugger up that "breath path" would be solder and grease. I guess it depends on how you made the repair. I also imagine a repair like a butt splice wrapped in electrical tape or shrink tubbing could also close off the "breath path". :dunno: Just offering possibilities to help you troubleshoot.

One more thing, looking at a 99 & 97 FSM I couldn't find that warning. But a cross reference check of the O2 sensor part numbers between mine an 01 and yours 98 are the same indicating yours breaths through the wiring as well.

Yes FSM's can be wrong and it's good to come to a forum like this to figure them out. eace:

-Drain tank
-add a gallon of new gas, rock Jeep
-drain that- eyeballing for junk
-add 2-3 gallons fresh gas
-test run
-if ok, add more gas and buy lots of flowers.

Good Luck,
Orange

This problem could be "coincidental" and have nothing to do with your fill of gas. Not saying that it is, but be careful not to get tunnel vision.

If it were mine, I'd sure test fuel pressure. You can rent a fuel pressure gauge from many parts stores and it takes about 15 minutes start to finish. If you had brought this vehicle to a shop, they would have verified correct fuel pressure as one of the first things they did. "Basics first" and adequate fuel pressure falls under that category.

Well it isn't the gas.
My wife is IT for the state patroleum inspectors and she had them talk with me. I opened the valve on the fuel rail and turned the key on and got about a quart for them to check. couple hrs later and I get a call and it's clean gas w/10% ethanol.

Sooooooo
I wasn't impressed with how the fuel trickled out with that valve opened. I'm picking up a gauge after work Friday. Too many irons in the fire. Darn deer aren't cooperating either!

Thanks Joe!

Everyone else too. Stay tuned!!