Oil sending unit / Lean condition.........HELP
Thread Starter
Instructor
Joined: Jul 2003
Posts: 231
Likes: 0
From: fresno ca
Oil sending unit / Lean condition.........HELP
any advise would be greatly appreciated.
I have a 99 coupe with only 74k on it.
been getting black soot on the rear bumper along with missing oil.
I was told the black soot is actually fuel and the missing oil is due to too much fuel in the combustion chamber and washing it off the cylinder walls, this is all due to the engine getting a lean message and providing the extra fuel.
The mechanic said that because my oil sending unit is bad, and the engine thinks its getting 130lbs of pressure, that its trying to compensate by providing extra fuel???
My sending unit went out over 2 yrs ago, its run fine, passed smog etc.. but the missing oil/soot out the back problem is more recent.
My question is: With a bad fuel sending unit, would this make the computer send a lean signal , creating all these problems???
thanks in advance
I have a 99 coupe with only 74k on it.
been getting black soot on the rear bumper along with missing oil.
I was told the black soot is actually fuel and the missing oil is due to too much fuel in the combustion chamber and washing it off the cylinder walls, this is all due to the engine getting a lean message and providing the extra fuel.
The mechanic said that because my oil sending unit is bad, and the engine thinks its getting 130lbs of pressure, that its trying to compensate by providing extra fuel???
My sending unit went out over 2 yrs ago, its run fine, passed smog etc.. but the missing oil/soot out the back problem is more recent.
My question is: With a bad fuel sending unit, would this make the computer send a lean signal , creating all these problems???
thanks in advance
Drifting
Joined: Dec 2006
Posts: 1,523
Likes: 5
From: Holly, Michigan
Mine has been pegged at 130PSI for about two months now, as I haven't gotten around to replacing it yet. In any event, by the grace of God, I have not experienced any of the problems you are having. I thought that the engine used coolant temp as a factor in calculating air/fuel ratios?
Thread Starter
Instructor
Joined: Jul 2003
Posts: 231
Likes: 0
From: fresno ca
Anybody else out there have the sending unit go bad and didnt bother replacing it? if so how long ago did it go out, and did it create any other problems?
thanks
Tech Contributor
Joined: Jan 2007
Posts: 19,239
Likes: 1,091
From: Dyer, IN
I agree, and I dont know either. Thats just what the mechanic suggested. personally i'd rather not replace the sending unit, unless I was in that area for another reason. I can justify spending $350.00+ just so my pressure reads correctly.
Anybody else out there have the sending unit go bad and didnt bother replacing it? if so how long ago did it go out, and did it create any other problems?
thanks
Anybody else out there have the sending unit go bad and didnt bother replacing it? if so how long ago did it go out, and did it create any other problems?
thanks
Race Director
Joined: Jul 2004
Posts: 16,794
Likes: 62
From: Lake Havasu City, AZ
You can get the oil sending unit at most autoparts stores for under $50. It is about a 2 hour job to replace it. It you can turn a wrench and have or can borrow/ rent a torque wrench ANYONE can change it themselves. Seriously all you need is a good set of instructions....
which you can find here
http://forums.corvetteforum.com/showthread.php?t=958008
with additional info here
http://forums.corvetteforum.com/show...e+sending+unit
2 tips...
Don't overtighten the sensor 15 foot-lbs torque...
Meticulously clean the old connectors.... make sure there is no oil on them from the failed sensor.
12K miles on my replaced AC/Delco sensor
purchased from Gene Culley www.GPpartshouse.com
(under $40 delivered at the time)
which you can find here
http://forums.corvetteforum.com/showthread.php?t=958008
with additional info here
http://forums.corvetteforum.com/show...e+sending+unit
2 tips...
Don't overtighten the sensor 15 foot-lbs torque...
Meticulously clean the old connectors.... make sure there is no oil on them from the failed sensor.
12K miles on my replaced AC/Delco sensor
purchased from Gene Culley www.GPpartshouse.com
(under $40 delivered at the time)
Former Vendor
Joined: Feb 2004
Posts: 10,876
Likes: 8
From: Las Vegas NV
St. Jude Donor '06 & '12
When I had my motor out, I relocated it to the side of the block. The day before yesterday mine went out. It took me LESS than 5 minutes to have it swapped and running.
You can get the oil sending unit at most autoparts stores for under $50. It is about a 2 hour job to replace it. It you can turn a wrench and have or can borrow/ rent a torque wrench ANYONE can change it themselves. Seriously all you need is a good set of instructions....
which you can find here
http://forums.corvetteforum.com/showthread.php?t=958008
with additional info here
http://forums.corvetteforum.com/show...e+sending+unit
2 tips...
Don't overtighten the sensor 15 foot-lbs torque...
Meticulously clean the old connectors.... make sure there is no oil on them from the failed sensor.
12K miles on my replaced AC/Delco sensor
purchased from Gene Culley www.GPpartshouse.com
(under $40 delivered at the time)
which you can find here
http://forums.corvetteforum.com/showthread.php?t=958008
with additional info here
http://forums.corvetteforum.com/show...e+sending+unit
2 tips...
Don't overtighten the sensor 15 foot-lbs torque...
Meticulously clean the old connectors.... make sure there is no oil on them from the failed sensor.
12K miles on my replaced AC/Delco sensor
purchased from Gene Culley www.GPpartshouse.com
(under $40 delivered at the time)
Le Mans Master
Joined: Mar 2002
Posts: 8,466
Likes: 51
St. Jude Donor '17
any advise would be greatly appreciated.
I have a 99 coupe with only 74k on it.
been getting black soot on the rear bumper along with missing oil.
I was told the black soot is actually fuel and the missing oil is due to too much fuel in the combustion chamber and washing it off the cylinder walls, this is all due to the engine getting a lean message and providing the extra fuel.
The mechanic said that because my oil sending unit is bad, and the engine thinks its getting 130lbs of pressure, that its trying to compensate by providing extra fuel???
My sending unit went out over 2 yrs ago, its run fine, passed smog etc.. but the missing oil/soot out the back problem is more recent.
My question is: With a bad fuel sending unit, would this make the computer send a lean signal , creating all these problems???
thanks in advance
I have a 99 coupe with only 74k on it.
been getting black soot on the rear bumper along with missing oil.
I was told the black soot is actually fuel and the missing oil is due to too much fuel in the combustion chamber and washing it off the cylinder walls, this is all due to the engine getting a lean message and providing the extra fuel.
The mechanic said that because my oil sending unit is bad, and the engine thinks its getting 130lbs of pressure, that its trying to compensate by providing extra fuel???
My sending unit went out over 2 yrs ago, its run fine, passed smog etc.. but the missing oil/soot out the back problem is more recent.
My question is: With a bad fuel sending unit, would this make the computer send a lean signal , creating all these problems???
thanks in advance
I think the sensor just lets you know what the pressure sensor is "sensing" that is all.
The pressure is either there or it is not there regardless of what the sensor is reporting
I think our cars run rich normally and over time even more so. A reprogram will fix this.
Last edited by Got uid0; Oct 28, 2007 at 01:44 PM.
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Team Owner
Joined: May 2006
Posts: 21,473
Likes: 356
From: Palmdale, Ca----- 2009 Cyber Gray 4LT A6 F55 452 RWHP 422 RWTQ- RIP 1998 C5 734 RWHP & 585 RWTQ-----
That sounds like a bunch of BS!
You need to pull the codes on your Vette and see if it is running lean or rich!
An oil pressure sending or even a fuel sending unit will not make it run rich or get a lean condition!
If for some reason your fuel pressure drops it will run lean then you either have a bad fuel filter or fuel pump!
CHECK for CODES! Let us know what is stored!
Thanks,Matt
You need to pull the codes on your Vette and see if it is running lean or rich!
An oil pressure sending or even a fuel sending unit will not make it run rich or get a lean condition!
If for some reason your fuel pressure drops it will run lean then you either have a bad fuel filter or fuel pump!
CHECK for CODES! Let us know what is stored!
Thanks,Matt
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
I believe the only tie from oil pressure to fuel is the fuel pump needs to know there is oil pressure to run, at least that is the way my C4 was. Initial key was 2 second fuel pump run and then it runs when there is oil pressure.
Sound to me like the soot is oil. Have you had an oil analysis, with the much fuel in the oil it will readily show up. Have you looked into the intake, is there oil in there? The PCV valve may need replacement. Also, that much extra fuel will send the PCM out of its range for correcting long term fuel trims and I would think you would throw a code.
Sound to me like the soot is oil. Have you had an oil analysis, with the much fuel in the oil it will readily show up. Have you looked into the intake, is there oil in there? The PCV valve may need replacement. Also, that much extra fuel will send the PCM out of its range for correcting long term fuel trims and I would think you would throw a code.
Last edited by vettenuts; Oct 28, 2007 at 07:18 PM.
Thread Starter
Instructor
Joined: Jul 2003
Posts: 231
Likes: 0
From: fresno ca
There are no codes to pull, no codes have come up, no check engine light. on the hand held scope , the mechanic showed me where its running rich.
The black soot is fuel, not oil
will know more soon. possible vacuum leak,one of my vacuum line connectors didnt look too good, will look into PCV valve also
Le Mans Master
Joined: Mar 2002
Posts: 8,466
Likes: 51
St. Jude Donor '17
Thread Starter
Instructor
Joined: Jul 2003
Posts: 231
Likes: 0
From: fresno ca
I got in there and changed out the oil pressure sender unit (through the cowel area) its been a long time since that gauge read correct. And I have the hole in there , so when the mexican made GM replacement part goes bad, I can change it without a sweat.
Back to the Running rich problem: SOLVED
I replaced the PCV valve, replaced a broken vacuum line elbow and installed small hose clamps on all vacuum lines. Had the mechanic rescan it and its no longer running rich. Hopefully this was my problem and it will solve my burning/missing oil problem
Back to the Running rich problem: SOLVED
I replaced the PCV valve, replaced a broken vacuum line elbow and installed small hose clamps on all vacuum lines. Had the mechanic rescan it and its no longer running rich. Hopefully this was my problem and it will solve my burning/missing oil problem
