Oil Pressure?
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New User
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Oil Pressure?
Hi all,
This is my first posting to this forum. I have a 1992 F-150 4x4 Off Road with a 302 engine. Just recently I put it in the garage for some maintenance. I changed to oil, filter and greased the chassis. In addition, I replaced the spark pluges and wires. When I took it out, I noticed a small knock on start up which goes away rather quickly and then I noticed that when the engine is hot the oil pressure gauge goes to "0" at idel. Could be be a result of a bad plug or improper spark plug wires. I purchased the plugs and wires at a local retailer, who suggested that all 302 wires for 1992 were the same. I was later infomed by another retailer that 1992 302 engines with EEC require different wires. Could this be my problem?
Any suggestions would help!
This is my first posting to this forum. I have a 1992 F-150 4x4 Off Road with a 302 engine. Just recently I put it in the garage for some maintenance. I changed to oil, filter and greased the chassis. In addition, I replaced the spark pluges and wires. When I took it out, I noticed a small knock on start up which goes away rather quickly and then I noticed that when the engine is hot the oil pressure gauge goes to "0" at idel. Could be be a result of a bad plug or improper spark plug wires. I purchased the plugs and wires at a local retailer, who suggested that all 302 wires for 1992 were the same. I was later infomed by another retailer that 1992 302 engines with EEC require different wires. Could this be my problem?
Any suggestions would help!
Senior User
Joined: May 2003
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From: San Diego
Oil Pressure?
Spark plug wires will not affect your oil pressure. The oil press guage is no more than a glorified idiot lite which switches at around six psi, then the guage goes from zero to about 2/3 scale.
First, replace the "sender" (only a switch with 20ohm resistor), or, if you have a mechanical guage, check the oil pressure with that first(then you'll replace the "sender"!).
Regards, Robert.
First, replace the "sender" (only a switch with 20ohm resistor), or, if you have a mechanical guage, check the oil pressure with that first(then you'll replace the "sender"!).
Regards, Robert.
Postmaster
Joined: Mar 2001
Posts: 4,968
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From: So Cal
Oil Pressure?
Spark plugs and plug wires would have no effecrt on oil pressure unless they were disconnected and the engine couldn't run.
Something else is wrong.
A slight knock during startup is usually a symptom of an oil filter that does not have oil in it during startup, usually because it doesn't have an anti drain back valve, as recommended by Ford. I forget which ones have it and which don't. This becomes an issue for engines where the filter is not hanging down from the engine but rather is on it's side or worse standing up, thus allowing oil to drain out.
Another possibility is that during the engine work, someone knocked the sender guage wire loose. I kind of doubt this one since I assume that you have oil pressure on startup and then it goes to 0 when warmed up.
The gauge on most of our trucks is really an idiot light. It runs in about the middle if you have pressure, it goes to 0 when you don't and there is no in between. I would recommend using a shop gauge to check if you really do have 0 when wamred up.
You might have a bad sender or a bad gauge or you might really have low pressure.
Low pressure may be caused by engine wear(bearings, lifters etc) or a worn oil pump or broken oil pump pressure spring. Could also be a bad head gasket or a bad internal seal.
Good Luck,
Jim Henderson
Something else is wrong.
A slight knock during startup is usually a symptom of an oil filter that does not have oil in it during startup, usually because it doesn't have an anti drain back valve, as recommended by Ford. I forget which ones have it and which don't. This becomes an issue for engines where the filter is not hanging down from the engine but rather is on it's side or worse standing up, thus allowing oil to drain out.
Another possibility is that during the engine work, someone knocked the sender guage wire loose. I kind of doubt this one since I assume that you have oil pressure on startup and then it goes to 0 when warmed up.
The gauge on most of our trucks is really an idiot light. It runs in about the middle if you have pressure, it goes to 0 when you don't and there is no in between. I would recommend using a shop gauge to check if you really do have 0 when wamred up.
You might have a bad sender or a bad gauge or you might really have low pressure.
Low pressure may be caused by engine wear(bearings, lifters etc) or a worn oil pump or broken oil pump pressure spring. Could also be a bad head gasket or a bad internal seal.
Good Luck,
Jim Henderson
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Oil Pressure?
Hi guys,
I really appreciate your responses. I just want to add a couple of things for clarification. First of all, the sending unit wire is fine. I have already checked that.
I find it extremely interesting that you metioned the oil filter. I have read a lot about Fram filters in this forum aprticularly that they should not be used on this engine. Unfortunately, that is what I put on my truck during my last oil change. I will change the filter and see what happens.
Thanks!
I really appreciate your responses. I just want to add a couple of things for clarification. First of all, the sending unit wire is fine. I have already checked that.
I find it extremely interesting that you metioned the oil filter. I have read a lot about Fram filters in this forum aprticularly that they should not be used on this engine. Unfortunately, that is what I put on my truck during my last oil change. I will change the filter and see what happens.
Thanks!
Elder User
Joined: Jul 2003
Posts: 870
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From: Upstate NY Rochester
Oil Pressure?
PLEASE READ. I used Fram on my new truck for many oil changes.
Once I spun a bearing, that all changed. When my oil pres. dropped to zero, I was doing 60 mph on a 4 lane x-way. By the time I pulled over, the damage was done. Fram oil filters will never belong on any of my vehicles ever again. I received a memo from Desert Racer, John Baker, which quoted Fram as saying that their filters were NOT up to the industry standards and should NOT be used in any modified engine. Mine was bone stock. They admitted that their oil filters are free flowing and do not build up pressure enough in most engines from idle to 10k rpm. Fram refused to help pay for my rebuild. They aren't worth the toilet paper they're made from.... Sorry for Rambling On guys.
Once I spun a bearing, that all changed. When my oil pres. dropped to zero, I was doing 60 mph on a 4 lane x-way. By the time I pulled over, the damage was done. Fram oil filters will never belong on any of my vehicles ever again. I received a memo from Desert Racer, John Baker, which quoted Fram as saying that their filters were NOT up to the industry standards and should NOT be used in any modified engine. Mine was bone stock. They admitted that their oil filters are free flowing and do not build up pressure enough in most engines from idle to 10k rpm. Fram refused to help pay for my rebuild. They aren't worth the toilet paper they're made from.... Sorry for Rambling On guys.
