Scotty Posted February 2, 2005 Report Share Posted February 2, 2005 As for the low oil pressure message, I think I might just go pick up a new one just to be on the safe side. Since you guys said that they do fail quite regularly, I'll go pick one up later today and see what happens. I am reading something about the oil pressure switch, do you have 4 wires on your oil pressure switch? read this, this is news to me! The oil pressure side of your switich is normally open (see diagram below for the 4.9), when the oil pressure comes up, it forces the switch on, if you jump the plug you will simulate normal oil pressure. Try that and see if your light goes off, its possible that your problem is in the wiring, just a thought... Mike Link to comment Share on other sites More sharing options...
Scotty Posted February 2, 2005 Report Share Posted February 2, 2005 Is there a place (such as where the oil pressure sending unit attaches to the engine) that a pressure gage can be attached and actually display the oil pressure? Jim Yes, you could attach it to that port where the oil pressure switch is, with an adapter. Link to comment Share on other sites More sharing options...
Scotty Posted February 2, 2005 Report Share Posted February 2, 2005 See this schematic, the oil pressure switch is normally open and closed with normal oil pressure...If you jump it, your light should go off if I am reading this correct, that would prove that your wiring is functioning correct... Link to comment Share on other sites More sharing options...
caddy_man2132 Posted February 2, 2005 Report Share Posted February 2, 2005 Holy smokes I am new here and I cant beilieve the posts you have Scotty! You must be on here alot! Link to comment Share on other sites More sharing options...
northstar101 Posted February 2, 2005 Author Report Share Posted February 2, 2005 Hmmmm. That's really interesting since my fuel pump is starting to fail as well. When I'm low on fuel you can hear the fuel pump howling. I believe that I do have 4 wires on the oil pressure switch. So how do I jump the plug so I could stimulate normal oil pressure? Just discconect it and then reconnect it again? Link to comment Share on other sites More sharing options...
Scotty Posted February 2, 2005 Report Share Posted February 2, 2005 Holy smokes I am new here and I cant beilieve the posts you have Scotty! You must be on here alot! I get paid big money for this, so its no big deal! In reality I need to get a life! All kidding aside, I love Cadillacs they are in my blood! Given how much I hate what I do for a living, I am seriously considering becoming a Cadillac tech/specialist/mechanic on Long Island and advertise in the local penny savers and make a little extra cash on the weekend, I think I could get quite a following! This is what I love! Welcome to the site, Mike (hopefully I am helping out a few fellow Caddy owners) Link to comment Share on other sites More sharing options...
Scotty Posted February 2, 2005 Report Share Posted February 2, 2005 Hmmmm. That's really interesting since my fuel pump is starting to fail as well. When I'm low on fuel you can hear the fuel pump howling. I believe that I do have 4 wires on the oil pressure switch. So how do I jump the plug so I could stimulate normal oil pressure? Just discconect it and then reconnect it again? It appears that both sides of this switch are normally open, so if you jump one side and nothing happens, then jump the other side to stimulate oil pressure. DO NOT however mix the sides...... it should be obvious (i think) the different sides.....if you have four... am I making sense? IF YOU CAN'T DETERMINE THE SIDES ASSUMING YOU HAVE 4 WIRES, DO NOT EXPERIMENT Link to comment Share on other sites More sharing options...
northstar101 Posted February 2, 2005 Author Report Share Posted February 2, 2005 Yeah Mike you are definately very knowledgeable about cadillacs. I cant thank you enough for going through everything step by step and helping me out on this. Thanks again, Phil Link to comment Share on other sites More sharing options...
Scotty Posted February 2, 2005 Report Share Posted February 2, 2005 Yeah Mike you are definately very knowledgeable about cadillacs. I cant thank you enough for going through everything step by step and helping me out on this. Thanks again, Phil You are welcome and Thanks its fun One more thing, assuming that the sides of the oil sender are isolated, you could determine the sides by using a cheap continuity tester (with a battery and bulb get one from radio shack or home depot), so that when you start the car, the oil pressure will close the contacts, and you touch the prongs on the sender, and when you light the tester you will have the "sides" Am I Making sense? If you have an OHM meter that would work also, mine actually beeps when it reads continuity Link to comment Share on other sites More sharing options...
northstar101 Posted February 2, 2005 Author Report Share Posted February 2, 2005 I am totally confused about what you are saying there about jumping the switch. How exactly do I this? Sorry if I seem kind of stupid but you have to remember that I am only 17 and all of this is fairly new to me. Link to comment Share on other sites More sharing options...
Scotty Posted February 2, 2005 Report Share Posted February 2, 2005 I am totally confused about what you are saying there about jumping the switch. How exactly do I this? Sorry if I seem kind of stupid but you have to remember that I am only 17 and all of this is fairly new to me. Try reading what I wrote again just above your post, 17? you are doing great! Link to comment Share on other sites More sharing options...
northstar101 Posted February 3, 2005 Author Report Share Posted February 3, 2005 Oh alright I get it now. I have one of those tester lights somewhere in my garage. Do I have to get the motor to a cartain temperature before attempting this or does it not matter. I'll try what you said tomorrow and hopefully it will fix that message. Thanks, Phil Link to comment Share on other sites More sharing options...
Scotty Posted February 3, 2005 Report Share Posted February 3, 2005 Oh alright I get it now. I have one of those tester lights somewhere in my garage. Do I have to get the motor to a cartain temperature before attempting this or does it not matter. I'll try what you said tomorrow and hopefully it will fix that message. Thanks, Phil NOPE as soon as she starts OIL pressure is up, in reality I think you can do it with the engine off, but, im not 100% sure about that.....given the computer involvement (the computer might say, HEY how could we have OIL PRESSURE and NO RPM?) Remember its not a voltage tester, its a continuity tester when you touch the leads together the light lights, use it to find the sides of the oil sender, then jump the sides with a jumper.... Link to comment Share on other sites More sharing options...
32v_dohc Posted February 3, 2005 Report Share Posted February 3, 2005 It only happens at idle and when the motor warms up. Honestly I can't believe I missed this. It is not the switch. The switch has no idea when idle is and if two switches display the same behavior then it is not the heat. Hate to tell you this but you have low oil pressure. I beleive this because raising the engine speed will raise the pressure even in a worn system. This closes the switch and the message goes away. Check and make sure the oil is full. If it is then I would guess it is time for an oil pump. John Link to comment Share on other sites More sharing options...
Scotty Posted February 3, 2005 Report Share Posted February 3, 2005 It only happens at idle and when the motor warms up. Honestly I can't believe I missed this. It is not the switch. The switch has no idea when idle is and if two switches display the same behavior then it is not the heat. Hate to tell you this but you have low oil pressure. I beleive this because raising the engine speed will raise the pressure even in a worn system. This closes the switch and the message goes away. Check and make sure the oil is full. If it is then I would guess it is time for an oil pump. John If the oil pressure sender/switch is defective it will not make contact and turn off the light, if the switch is fine, he could have an open in the wiring and the system is not 'seeing' pressure. The 'switch' or sender is normally open oil pressure closes the switch.. IF he had an oil pressure problem he would be hearing his lifters I believe.. Although you raise a good point, it only happens at idle when the engine is warm.... he may have a pump problem at idle, good catch.... John What do you think of him using a higher viscosity oil? I fell into this as his oil pressure sender was leaking Link to comment Share on other sites More sharing options...
32v_dohc Posted February 3, 2005 Report Share Posted February 3, 2005 I don't think the system sees pressure. Doesn't it see whether the switch is closed or not? Again I have a hard time wrapping my brain around how the rest of the wiring would know the engine is above idle. I find it more likely that the minimum pressure to close the switch is more than the minimum to pump up the lifters and that idle pressure is somewhere in between. John Link to comment Share on other sites More sharing options...
Scotty Posted February 3, 2005 Report Share Posted February 3, 2005 I don't think the system sees pressure. Doesn't it see whether the switch is closed or not? Again I have a hard time wrapping my brain around how the rest of the wiring would know the engine is above idle. I find it more likely that the minimum pressure to close the switch is more than the minimum to pump up the lifters and that idle pressure is somewhere in between. John Yes you are correct, the system only sees ON or OFF from the sender. You can see that from the schematic on the prior page.. The minimum pressure that the sender is on I think is like 6 psi... So at idle his pressure is dropping low enough to let the switch OPEN.... I had the impression the LIGHT was on ALL THE TIME.... DUH... This mode of communication can be frustrating.. Link to comment Share on other sites More sharing options...
32v_dohc Posted February 3, 2005 Report Share Posted February 3, 2005 I know what you mean. Time lag on answers and having to read between the lines makes getting the right answer elusive sometimes. John Link to comment Share on other sites More sharing options...
Scotty Posted February 3, 2005 Report Share Posted February 3, 2005 I know what you mean. Time lag on answers and having to read between the lines makes getting the right answer elusive sometimes. John So John, what do you think about him using 10W40 and helping his idle oil pressure? I don't believe the pan is too hard to drop on the 4.9s to change the pump.. Link to comment Share on other sites More sharing options...
32v_dohc Posted February 3, 2005 Report Share Posted February 3, 2005 The heavier oil is alright as a stop gap but I would change the pump if it persists. One thing that hasn't been considered is what will happen when he gets rid of the pinging. Detonation can add quite a bit of heat to the pistons due to abnormal combustion distrubing the boundary layer that protects them from high heat. A good deal of this heat will transmit to the piston bottoms and into the oil. The oil may just be really hot. The pressure may come up a few psi when the pinging is cured. I think I would try 10w40 to see if it cleared the message and then address the detonation. Then at oil change time try going back and see what happens. If the meassage comes back then change the pump. John Link to comment Share on other sites More sharing options...
northstar101 Posted February 3, 2005 Author Report Share Posted February 3, 2005 Alright you guys I drove a good distance today and everything seems to run fine. I didn't get the message at all today so I'm happy. I'm pretty positive that the problem was with the plug from the sender since it was drenched in oil yesterday. Today it must have dried up and made a proper connection to the DIC so the oil pressure is fine. AS for the pinging, I'm almost positive it's the EGR valve so i'll pick up a new one and see what happens. Thanks you guys for helping me out on this one! Phil Link to comment Share on other sites More sharing options...
Scotty Posted February 3, 2005 Report Share Posted February 3, 2005 Alright you guys I drove a good distance today and everything seems to run fine. I didn't get the message at all today so I'm happy. I'm pretty positive that the problem was with the plug from the sender since it was drenched in oil yesterday. Today it must have dried up and made a proper connection to the DIC so the oil pressure is fine. AS for the pinging, I'm almost positive it's the EGR valve so i'll pick up a new one and see what happens. Thanks you guys for helping me out on this one! Phil Good let us know how the ping works out, Mike Link to comment Share on other sites More sharing options...
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