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Bainer
July 29th, 2006, 10:30
Jeep Specs: 1992, AW4, 4.0, 210,000 miles

I was checking my oil level when I noticed a very strong gas smell coming from the oil. I know this is bad, so I decided to first check the spark plugs for signs of gas fouling or excessive carbon deposits. All 6 spark plugs show signs of ash depositing and are over gapped to about .058” but no signs of excessive gas washing in the cylinders. My jeep has started over the last year to get progressively bad gas mileage from 18mpg to about 14mpg, but still runs relatively well. My question is do you think that my spark plugs could be the cause of the fuel in the oil or is it something more like my MAP, O2, Fuel Pressure Regulator, or just shot rings?
jeepdude10000
July 29th, 2006, 13:12
most of the time it is a fuel injector problem, but i would replace spark plugs, check compression, and wet compression, and when it is running touch each injector to see if is clicking nice, or there is a tool to check injectors.
MogifiedXJ
July 29th, 2006, 14:01
It sounds like your fuel pressure regulator's diaphram could be busted and is dumping straight gas into your intake manifold. Pull the vacum line off you regulator and if gas comes out it needs to be replaced. Mine did what you are describing, it started to run bad, the mileage went to the shitter, and there was a slight hint of gas in the oil. I caught it earlier and changed my oil and filter so I don't think it affected it...
Bainer
July 29th, 2006, 18:48
Thank you for the responses. I changed the plugs, wires, cap & rotor since it needed to be done anyway. It does run noticeably better. I unplugged the fuel regulator there was no fuel leaking into the vacuum line and the engine rpm changed so I think that the regulator is doing its job. I also unplugged the MAP sensor vacuum line and engine almost died so I believe it is also working. I have not checked compression yet, because I do not have the test kit yet. I also felt each fuel injector and to best I can tell each one seems to be working. I plan to change the oil and filter and wait to see if the problem returns. Any other advice would be appreciated.
SLAYER
July 30th, 2006, 05:29
Can i do the same test on the fuel pressure regulator diaphram on my 97 XJ?
I have a similer problem with mine.
jeepdude10000
July 30th, 2006, 07:43
Can i do the same test on the fuel pressure regulator diaphram on my 97 XJ?
I have a similer problem with mine.

ya works same.
SLAYER
July 30th, 2006, 18:16
Where is the fuel pressure regulator located at?
Sorry i dont have a book.
jeepdude10000
July 30th, 2006, 19:13
at the end of the fuel rail, most times at the front. and it has a vacuum line hooked to it.
JEEPTUBE
July 30th, 2006, 21:07
pictures?
JEEPTUBE
July 30th, 2006, 21:11
I just tried looking for pictures of the fuel pressure regulator but could not find any, not even at the online parts stores, (image not available).
Bainer
July 30th, 2006, 21:33
Go jeep has a write up on his website with lots of pictures of the fuel pressure regulator. http://www.go.jeep-xj.info/HowtoAFPR.htm
jeepdude10000
July 30th, 2006, 21:33
http://members.shaw.ca/heavyd10000/pics/cover1.jpg
SLAYER
July 30th, 2006, 22:31
My 97 does not have one there.
It must be on the fuel pump and filter inside the gas tank.
Or is it?
Bainer
July 31st, 2006, 07:06
Your 97's is located in the gas tank a pre 96 will look like the one on go jeep's write-up and the on in the photo is from a pre 92 Jeep.