Check Engine Light still on

[dwpenney01]

I have read as much as I can on the check engine light problems related to my 1991 Explorer (111K miles). This weekend I changed the 02 Sensor (scraped knuckles and all). I have also cleaned the "Mass Air Flow" sensors with a electronics cleaning solution. We were only getting about 10 mpg before these changes. It is still to early to tell if this is making any difference, but I know it is not improving that much. When I drive for a little while (10-15 minutes), when I slow down to a stop the "Check Engine" light still comes on. I also changed the oil this weekend and noticed quite a bit of gasoline in the oil when I drained it. I have seen some people mention the "Fuel Pressure Regulator" in this form as going out as well. Obviously, something else is still wrong with the engine. It still runs okay, but the MPG is still looking bad as well as the check engine light. I replaced the altenator about 10 days ago, so the battery has been un-hooked long enough to clear the computer.

Questions:
Where is the "Fuel Pressure Regulator"?
Can I replace it myself?
Does the Haynes book show how to do this?
Why is there so much gas in my oil?
How much does the "Fuel Pressure Regulator" cost?

Try to do most of it myself if I can.

Any help would be greatly appreciated.

Thanks,

Donnie Penney
dwpenney@htcomp.net
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http://www.penneyspointers.com

 

[Robert]

Originally posted by dwpenney01
I have read as much as I can on the check engine light problems related to my 1991 Explorer (111K miles). This weekend I changed the 02 Sensor (scraped knuckles and all). I have also cleaned the "Mass Air Flow" sensors with a electronics cleaning solution. We were only getting about 10 mpg before these changes. It is still to early to tell if this is making any difference, but I know it is not improving that much. When I drive for a little while (10-15 minutes), when I slow down to a stop the "Check Engine" light still comes on. I also changed the oil this weekend and noticed quite a bit of gasoline in the oil when I drained it. I have seen some people mention the "Fuel Pressure Regulator" in this form as going out as well. Obviously, something else is still wrong with the engine. It still runs okay, but the MPG is still looking bad as well as the check engine light. I replaced the altenator about 10 days ago, so the battery has been un-hooked long enough to clear the computer.

Questions:
Where is the "Fuel Pressure Regulator"?
Can I replace it myself?
Does the Haynes book show how to do this?
Why is there so much gas in my oil?
How much does the "Fuel Pressure Regulator" cost?

Try to do most of it myself if I can.

Any help would be greatly appreciated.

Thanks,

Donnie Penney
dwpenney@htcomp.net
Subscribe to the Best Free Handicapping Newsletter
mailtoenneyspointers-subscribe@topica.com
http://www.penneyspointers.com

It sounds like you are just wasting a lot of money. Get ahold of a code reader for about $30 and read the codes. It will at least point you in the direction of what is causing the light. Post your codes here and I'm sure someone can help. There is an alternate way of reading the codes by jumping a copule of pins on your EEC-IV connector and counting your check engine light flashes. Im not sure how to do it though. Someone here probably does.

 

[Boneil1964]

I had the same problem about a year ago. Went through every part in the emission system and nothing seemed to help. I finally decided to ask for some help and 8 out of 10 people said to check the fuel pressure because there is a known problem with them going bad. Since this was the answer that a majority had recomended I just replaced the fuel regulator. It is located on the fuel rail next to the valve cover on the passenger side. It is very easy to change. Just remember to pull the fuse for the fuel pump and run the engine until it stops to releave the fuel pressure. The one I bought was from NAPA and cost $117 but I have seen posts that say you can get it a lot cheaper. I was in a hurry and NAPA could get it the same day. Also you will need the part number that is stamped on the side of the regulator as it appears that there are 2 different ones that could be on a 91. Mine was the more expensive of the 2.

Hope this helps.

P.S. Reading codes didn't do me much good. Mine had a stored code of being rich and a running test code of being lean.