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Gas in Oil

Jeeplife7926

NAXJA Forum User
Location
NJ
1998 XJ Sport I6 4.0

HELP

I can smell gas in my oil.
It smells like there is a lot and it may be thinning my oil.
I noticed this a few weeks back and started with an oil change.
The gas smell came back immediately and seemed to get stronger after some light use.
Online research points to injectors leaking.
Fuel injectors were one of the many projects I recently completed.
I purchased the Bosch Upgrade injectors. The were re-manufactured and ultrasonic cleaned. They looked great and were packaged great. So i'm reluctant to believe they are leaking.
As my next step I did a Fuel Pressure test.
Turned the ignition to on twice and got 40PSI at the gauge, However
It dropped in pressure very quickly once switched off.
This confirmed loss of pressure in fuel system
While doing the Fuel pressure test I did not pinch of gas lines in order to verify if pressure loss was at injectors or the check valve into gas tank.
I pulled the fuel rail and the injectors and turned the ignition on. the fuel pressurized but did not leak out any of the injectors.
I did not crank the engine to see how fuel sprays from injectors

What should I test next?
Would fuel have leaked out of the injectors from just turning ignition on and pressurizing fuel rail, if they were bad.

Could a spark plug not be firing and fuel pass into oil that way?
The engine does not sound like its misfiring. It sounds normal.

I have also seen very little online about, ground short wiring on injector harnesses causing the injector to stay open.
I do see excessive wear on one of my fuel injector wiring connector harnesses. I can see the copper wire right before it plugs into fuel injector, Used electrical tape to keep the wires from touching. I also have a new set of wiring connectors for all the injectors if i need to cut and splice them in.

How can I tell if it is an electrical short keeping a fuel injector open.

If it is just a leaking injector what is my next step how can i tell if the injectors leaking?
Did I have to crank the engine over with the rail disconnected to find out more?
"I know there is a safer method of removing injectors and sending them out to be tested by machine." It is not reccomended to pull a fuel rail and visually observe its operation.

I dont want to contact the company that sold me the fuel injectors without knowing for sure if there leaking first, how many and which ones.
 
Pull the plugs and see what they look like. However, if a plug isn't firing you would notice it in the way the engine runs as well as a MIL.

Fuel smell isn't uncommon in oil especially if driven on short trips or immediately after a short trip. Blow by gasses also add to this. If you think your oil is contaminated take a sample and send it to an oil analysis company.
 
How far do you drive it on average?
If you aren't making half-hour or longer trips very often, the engine oil probably isn't getting hot enough to boil out the regular / healthy amount of gas that will blow past the rings during regular / healthy engine operation.
 
Talyn-
I pulled the spark plugs tonight and found them to be in normal condition using the chart in my haynes manual. I used a spark plug gauge to check gap and found all to be gapped at .035 see image










yossarian19-
Lately I typically drive my XJ less then 5 miles daily.

"the engine oil probably isn't getting hot enough to boil out the regular / healthy amount of gas that will blow past the rings during regular / healthy engine operation"

I think my engine warms up quickly and would not imagine that. I can notice even after a short trip the engine is hot and takes a long time to cool.
I've never noticed this gas smell in oil before.
Perhaps the injector upgrade spray pattern or flow allows more fuel to pass rings

But that would be nice if it was "regular / healthy engine operation"
I'll need to be more convinced.
 
Talyn-
I pulled the spark plugs tonight and found them to be in normal condition using the chart in my haynes manual. I used a spark plug gauge to check gap and found all to be gapped at .035 see image
They look good, a bit worn though. However, depending on the plug that may be the design that is making it look like that. How many miles on them?
I think my engine warms up quickly and would not imagine that.
The coolant warms up fast. The oil takes a much longer time than the coolant. 5 miles isn't even close to getting the oil up to temp. See this post for an example: http://www.naxja.org/forum/showpost.php?p=246118421&postcount=15 and http://www.naxja.org/forum/showpost.php?p=246118645&postcount=20 Notice that that coolant is up to temp after 8 to 10 minutes. While the oil isn't fully up to temp until around 25 minutes.
I'll need to be more convinced.
Get an oil analysis done to see if the oil is contaminates with gas and how much. www.blackstone-labs.com and www.wearcheck.com are two good companies.
 
Update
I have stopped driving the jeep. I am worried having gas in the oil will cause engine failure / damage.

There has been no CEL

Jeep has always had a hard start and takes turning the key twice when first starting.
If I start it shortly after driving, jeep starts instantly.


I ordered the test kit from www.blackstone-labs.com
I'm going to have to put my XJ back together and do some driving.
The first thing I did was change my oil when I noticed the gas.
I want to send a good sample

I am still suspicious of the wear on the fuel injector wiring harness.
I can see the cooper wires in areas that have no jacket near the connectors.
This might be cause a ground short and it may be intermittent
Causing the injector to send fuel while the engine is running?
I need to know more about "ground shorting" fuel injectors.


Here's some of what I have gathered on electrical fuel injector failures.

http://troubleshootmyvehicle.com/gm/4.3L-5.0L-5.7L/spider-fuel-injector-misfire-case-study-3 -Best information on ground short.

http://www.autodiagnosticsandpublishing.com/feature/fuel-injector-testing.htm -operation and drivers

http://www.youtube.com/watch?v=jsl531-6q-A -Ground short video




Hey yossarian19,
It would be nice to find out there is nothing wrong at all. Do you have any information on fuel in the oil being normal and healthy engine operation.
 
http://performancetrends.com/Definitions/Blow-By.htm

It's just combustion gases (with some unburnt fuel) making their way past the rings. This same thing is why frequent short trips qualify a vehicle for the "severe" service schedule in the Jeep FSM. 7500 miles between oil changes in regular use, frequent short trips down to 3000. The oil doesn't get hot enough to boil out all the crap that made it past the rings. Once the oil is up to temp the crud in it will mostly boil out & the crankcase breather system will suck it into the engine at a measured pace & re-burn it.

I suspect all or part of your issue is that you aren't driving it far enough often enough to let the oil self-clean in this way.

If you can see the copper in your injector wiring harness, either replace the harness or peel back the wire wrap & apply liquid electrical tape, then re-wrap the whole mess.
A ground short would indeed cause the injector to dump fuel, though I "think" this would trip a code. A lot of running time under this condition would produce a fair amount of soot in the tail pipe (running rich) but that may be difficult to tell on an older vehicle. In any case, I'd expect one or more cylinders to be running poorly with a ground short injector.
 
I need to know more about "ground shorting" fuel injectors.
When the key is turned on and engine started the ASD relay is activated which sends +12 volt to the injectors. The firing is done by the PCM via a negative 12 volt signal. If the wires coming from the PCM were to be shorted to ground the injector would fire when this happens. However you would notice this because your engine would run like crap. Stumbling, bucking, misfiring, popping, etc. You gave no indication that your engine has a problem running.
 
Do you have any information on fuel in the oil being normal and healthy engine operation.

Large amounts of fuel in the oil is not normal. Less than 0.5% is normal. However, there will be some from the blow by gases. Not much though. What is normal is those bypass gases to enter the crank case and cause the smell.
 
change your oil and drive the jeep longer. Make sure all grounds are good and consider testing the o2 sensor.
 
Update:

Today I received the test kit from Blackstone.
I put the jeep back together, running strong.
I patched up the exposed wires on the fuel injector connectors.

I'm going to need some time to put some miles on my XJ
I want to send a good sample, The first thing I did when I noticed the gas in oil was changing the oil.

No CEL and engine sounds smooth.
Maybe there is no fault in the fuel injector system.

My XJ went from DD to WW a few years back.
I have had my XJ for 10 years,
Recently my XJ has been garage kept, driven rarely for a short amount of time and distances.
Thankyou,
Talyn and yossarian19. I'm starting to think your right.
It might be normal blow-by due to short driving mileage.

I recently did a lot of projecting on the jeep. My XJ was apart for 7 months. Just got it running in July. I did intake and exhaust manifolds, fuel injectors, a custom exhaust, and more. Noticing gas in oil for the first time has me second guessing everything I have touched and it might be nothing. My XJ does seem to be running stronger then ever and with no CEL.



It will probably be a few weeks but I will post the findings of the oil sample from Blackstone Laboratories.
 
I'm sorry to hear that. Hopefully you weren't hurt bad. Is it repairable? If so, are you going to buy it back? Mine was totalled about 5 weeks ago, and I bought it back. Sometimes insurance companies do that because of repair costs versus what they think value is. Mine wasn't really hurt that bad but shop cost of the repair was almost $3,600, they had a hard time determining value of mine because it's a clean 86 2 door with very low miles. They gave me just under $3,600 and let me keep it for that price... Cheap excuse to do a 2000 nose on it and long arm, which is what I'm in the middle of...
 
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