northstar101 Posted February 1, 2005 Report Share Posted February 1, 2005 Hey, I have a 1992 STS 4.9 and it's been showing me the low oil pressure message on and off for some time now. Now I'm getting the message everyday and it's really starting to annoy me. It only happens at idle and when the motor warms up. The car runs fine and nothing is out of the ordinary.What do you guys think would cause this and will it be an easy fix? Thanks in advance for any replies, Phil Link to comment Share on other sites More sharing options...
Scotty Posted February 1, 2005 Report Share Posted February 1, 2005 Assuming that you don't have low oil pressure, this may be an easy fix. I assume oil level is correct. Are you getting any lifter noise? Tapping? If not, you should check the oil pressure sender connection for looseness and corrosion and if that is ok, replace the sender. Here is a photo see pressure switch #1 Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life. Link to comment Share on other sites More sharing options...
GR8NSTAR Posted February 1, 2005 Report Share Posted February 1, 2005 Northstar101, Hopefully Scotty hit the nail on the head if that's not it It may be the oil pump. Link to comment Share on other sites More sharing options...
northstar101 Posted February 1, 2005 Author Report Share Posted February 1, 2005 Thanks for the quick reply. I'll go check the sender out right now. I believe it was covered in oil when I was last inspecting it so i'll go clean that up and see what happens. Link to comment Share on other sites More sharing options...
northstar101 Posted February 1, 2005 Author Report Share Posted February 1, 2005 Alright you guys, I went to go take another look and this time I took the whole airbox assembly off so I can get to the pressure switch. I just want to make one thing sure, the pressure switch is what you meant by the sender right? Anyways, I wiped everything clean and the wires seem to look fine. I put everything back together and took it out and the message still displays. If I were to change the pressure switch, How would I go about it. The wires seem to be soldered into the switch and the only thing I can think of is to splice them and resolder them. I'm going to a junk yard tomorrow morning and I'll see what I can find. I also need to get a new EGR valve since my motor pings like crazy. Man I hate when things start going wrong, especially when it's so cold outside. Phil. Link to comment Share on other sites More sharing options...
Scotty Posted February 1, 2005 Report Share Posted February 1, 2005 Alright you guys, I went to go take another look and this time I took the whole airbox assembly off so I can get to the pressure switch. I just want to make one thing sure, the pressure switch is what you meant by the sender right? Anyways, I wiped everything clean and the wires seem to look fine. I put everything back together and took it out and the message still displays. If I were to change the pressure switch, How would I go about it. The wires seem to be soldered into the switch and the only thing I can think of is to splice them and resolder them. I'm going to a junk yard tomorrow morning and I'll see what I can find. I also need to get a new EGR valve since my motor pings like crazy. Man I hate when things start going wrong, especially when it's so cold outside. Phil. Yes thats the sender, there is usually a plug there not usually a solder connection. can you see two blade type connectors? Its possible that someone soldered the two wires on.. If you have an ohm meter, you could connect it up to the two sender wires and see what you get. Anyway, the sender should screw out, in the old days they made an oil pressure sender socket, I imagine they still do. If you dont find the sender in the junk yard, its probably cheap to buy a new one. The pinging.... clean the egr tubes, look down the throttle body and you will see two tubes looking back at you, use a hanger and rod them out, i have used a gun cleaning round wire brush in the past, you might also want to remove the EGR and tap it with a hammer (on the cast frame part) and manipulate the pindle and diaphram to loosen up any dirt. If you can get some carb cleaner, clean only the pindle and seat, keep the cleaner off the diaphram. Check all of your vacuum hoses for cracks. Check for codes the egr sets an E048. Mike Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life. Link to comment Share on other sites More sharing options...
northstar101 Posted February 1, 2005 Author Report Share Posted February 1, 2005 Sorry for confusing you. I thought that the sender was the black plug that connects into the filter adapter. I just wanted to ask a quick question. Is there sapposed to be oil coming out when I remove the plug. It was soaked in oil and I found it hard to believe that the plug is sapposed to work when it's all filthy like that. I probobly sound like an idiot since this my first time dealing with this type of issue. So just to get things straight, the sender isn't the black connector but the piece that the connector plugs into right? About the pinging. I already cleaned my EGR tubes several times since everyone reccomended it and I tought that it was a possibility for my pinging. Afer that didnt help, I decided to do the test with the EGR valve where someone does a brake stand in Drive revving the motor up to about 2000 RPM. I placed my finger underneath the pintle to see if it does actually move up and down. Nothing. I then proceeded to lift it myself and the motor started hesitating and running rough so I quicky stopped. After that I decided to remove the EGR and clean the pintle. It still was pinging after I proceeded to put it back on. I always use premium fuel(94 octane) and the only thing I can think of is that stupid EGR valve. The pintle doesnt seem to lift up but vaccum is still running strong in the vaccum lines and no there aren't any leaks that I can detect. I get pinging at WOT and under a light load. The motor runs great at 168,000KM and the only issues I have is the pinging and the message. Thanks a lot Mike for your help. Phil Link to comment Share on other sites More sharing options...
32v_dohc Posted February 2, 2005 Report Share Posted February 2, 2005 The sender is the peice the connector plugs into. No oil should come out of the connection. Sounds like it needs to be replaced. On the pinging check your timing. It is adjustable so maybe it is misadjusted. HTH John Link to comment Share on other sites More sharing options...
Scotty Posted February 2, 2005 Report Share Posted February 2, 2005 Sorry for confusing you. I thought that the sender was the black plug that connects into the filter adapter. I just wanted to ask a quick question. Is there sapposed to be oil coming out when I remove the plug. It was soaked in oil and I found it hard to believe that the plug is sapposed to work when it's all filthy like that. I probobly sound like an idiot since this my first time dealing with this type of issue. So just to get things straight, the sender isn't the black connector but the piece that the connector plugs into right? About the pinging. I already cleaned my EGR tubes several times since everyone reccomended it and I tought that it was a possibility for my pinging. Afer that didnt help, I decided to do the test with the EGR valve where someone does a brake stand in Drive revving the motor up to about 2000 RPM. I placed my finger underneath the pintle to see if it does actually move up and down. Nothing. I then proceeded to lift it myself and the motor started hesitating and running rough so I quicky stopped. After that I decided to remove the EGR and clean the pintle. It still was pinging after I proceeded to put it back on. I always use premium fuel(94 octane) and the only thing I can think of is that stupid EGR valve. The pintle doesnt seem to lift up but vaccum is still running strong in the vaccum lines and no there aren't any leaks that I can detect. I get pinging at WOT and under a light load. The motor runs great at 168,000KM and the only issues I have is the pinging and the message. Thanks a lot Mike for your help. Phil I have to eat, so I will come back later on the pinging.. The oil pressure sender if it is leakng like that is bad and probably the source of your warning light issue, replace it and you should be fine, yes the plug comes off and you need to unscrew the sensor, see the pic I posted. Mike Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life. Link to comment Share on other sites More sharing options...
northstar101 Posted February 2, 2005 Author Report Share Posted February 2, 2005 Thanks guys for the replies. I guess I'll replace the sender tomorrow and see what happens. About the timing, I'll check that tomorrow as well. If someone can go through the proper procedure on how to do that then that would be great. Thank you, Phil Link to comment Share on other sites More sharing options...
Scotty Posted February 2, 2005 Report Share Posted February 2, 2005 Its probably not pinging but detonation. It occurs on light pedal not necessarily heavy pedal. Detonation occurs in the 4.9 because of poor or no EGR flow. If you said that your EGR diaphram did not move open it possible that either the EGR or the EGR solenoid or associated vacuum hoses are defective. You should be getting a code, have you tried dumping the codes? Check all vacuum hoses tomorrow, Mike Here is a photo of the TB hose routing, EGR solenoid, EGR, etc Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life. Link to comment Share on other sites More sharing options...
Scotty Posted February 2, 2005 Report Share Posted February 2, 2005 Here is a post from bbobynski on detonation in the 4.9: The other thing that you definitely want to check/service if you haven't already is to open the throttle blades and look down the throttle bores at the EGR tubes that are sticking up from the floor of the intake manifold. Those tubes are supposed to be clean...not clogged with carbon like they likely are after 12 years of operation. If the tubes are clogged/restricted then that will restrict the flow of EGR gases and cause detonation/spark knock despite the octane rating of the fuel you are running. If you notice detonation immediately on mid-grade or regular fuel I would be highly suspicious of the EGR tubes being plugged or partially plugged. You might check them and clean them out (rod them out with a stiff piece of coat hanger wire and carb cleaner) and then try the lower grade of fuel again. Loss of EGR flow will definitely cause detonation and make the engine much more sensitive to fuel octane rating than it would be normally. **************************************************************** When I cleaned mine, I removed the egr and sprayed carb cleaner down the EGR tubes, put a rag over the EGR port and blew the tubes out with compressed air. I am not 100% sure but I think you can test your EGR solenoid by jumping it, its sort of a vacuum switch, obviously if it is bad, the EGR will not open. Be patient with the @!#?% ping it drove me crazy before I got rid of it, I cleaned the hell out of everything, replaced all of the hoses and replaced my EGR... Mike Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life. Link to comment Share on other sites More sharing options...
northstar101 Posted February 2, 2005 Author Report Share Posted February 2, 2005 Thanks a lot Mike. You've been very helpful and I really appreciate it. I check the codes regularly and nothing ever pops up. I'll check everything tomorrow and I'll let you guys know what the deal is. Thanks, Phil Link to comment Share on other sites More sharing options...
jackc Posted February 2, 2005 Report Share Posted February 2, 2005 Did you say junkyard sending unit? Sending units are cheap and readily available at most parts stores. I'd be inclined to check on the price of a new one. They do tend to go bad and leak with age. We replaced 'em right and left back in my gas station days..... Just a suggestion. Link to comment Share on other sites More sharing options...
32v_dohc Posted February 2, 2005 Report Share Posted February 2, 2005 To set / check timing jumper pins a and b of the ALDL connector. This will eliminate the computer advance and allow you to set base timing. Since you have stated you get pinging at WOT I don't beleive EGR is the problem. EGR should not be commanded on at WOT. EGR problems will cause pinging at light to mid throttle and should have no pinging at WOT. HTH John Link to comment Share on other sites More sharing options...
Scotty Posted February 2, 2005 Report Share Posted February 2, 2005 He stated "I get pinging at WOT and under a light load." The 4.9 while a great engine, is known for the light pedal detonation and I have had a lot of experience with detonation in my own 4.9. If you can determine by doing your 'driveway" test with a helper that you have vacuum at the EGR vacuum hose, and the diaphram is not moving it may make sense to replace the EGR valve. I was told by a GM tech at my local dealer that its near impossible to clean the EGR valve but you can try. My detonation did not go away until I replaced my EGR. Whatever you do, if you can't find a shinny new one in the junkyard (since you get going there anyway) off the exact year, etc, buy a new OEM unit, do not buy a cheaper aftermarket unit, these things are calibrated for your engine. By all means check the timing but I think the majority of your trouble is the EGR system. Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life. Link to comment Share on other sites More sharing options...
Scotty Posted February 2, 2005 Report Share Posted February 2, 2005 Hook up a vacuum gauge to the EGR vacuum hose and tape it to your windshield to see if the system is commanding vacuum to the EGR while you drive. MAKE sure you don't pinch the hose coming under the hood, cover it with a 6 inch section of copper tubing. That will definitively tell you if you EGR solenoid/system is working! You may get a service engine code during this test (E048). If you DO get vacuum, clean the hell out of your EGR ports and EGR valve or replace the EGR. If you don't get vacuum, look to hoses (see picture) or the EGR solenoid for the trouble, Mike Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life. Link to comment Share on other sites More sharing options...
northstar101 Posted February 2, 2005 Author Report Share Posted February 2, 2005 Alright you guys, here's the deal. I went to the junk yard and picked up an egr solonoid and a new oil pressure sender. I've gotten them both from the same car. I replaced both parts and while I was at it I bought some carb cleaner and a wired brush to clean my egr tubes. After I completed everything I took it out for a test drive and I still get the stupid "low oil pressure" message. I'm pretty sure that the sender I got at the junk yard is good since it is in very good condition and looks like it was replaced already on the vehicle I acquired it from. I also replaced the egr solonoid and the motor unfortunately still pings/detonates . To add to my problems, my motor idles abnormally high now and takes a while for the idle to come down when I come to a stop. All in all I've had a pretty bad day due to all of my time going to waste trying to fix these problems. I just have a quick question about the egr solonoid. Is the hose that attaches from the egr valve to the egr solonoid sapposed to be attached to the first pintle closest to the egr valve or is it the second pintle further away. Thanks you guys, I really appreciate all of your help Phil Link to comment Share on other sites More sharing options...
Scotty Posted February 2, 2005 Report Share Posted February 2, 2005 Is the hose that attaches from the egr valve to the egr solonoid sapposed to be attached to the first pintle closest to the egr valve or is it the second pintle further away. That is confusing, what do you mean by pindle, pindle is the valve like mechanism that is inside the EGR.. Doesn't my diagram above help with your question? The idle problem will mostprobably stabilize, once you reset by disconnecting the battery. Its running FAST as you cleaned it good not doubt you cleaned the throttle body also! Disconnect the battery and let it do its learn procedure. Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life. Link to comment Share on other sites More sharing options...
northstar101 Posted February 2, 2005 Author Report Share Posted February 2, 2005 What I meant by pintle was the thing that the egr hose attaches to. I noticed that there where two of them underneath the solonoid so I just attached the hose to the one closest to the egr valve. I'll try attaching the hose to the one further away but I dont know wether it's the right thing to do. Sorry for confusing you. Phil Link to comment Share on other sites More sharing options...
Scotty Posted February 2, 2005 Report Share Posted February 2, 2005 Are there three vacuum ports on the EGR solenoid? Two on the bottom and one on the top? The EGR solenoid has electrical wires attached to it. I don't have my 91 anymore otherwise I would go out and look... The diagram show the photo of the EGR very clearly, but two on the bottom? Let me look at my manual be back shortly. Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life. Link to comment Share on other sites More sharing options...
northstar101 Posted February 2, 2005 Author Report Share Posted February 2, 2005 Yes exactly, there are two on the bottom and one on top that attaches to the throttle body. I'm not sure wether the other is a port or not but it has a brass cap and looks like the vaccum hose can attach to either one. Link to comment Share on other sites More sharing options...
northstar101 Posted February 2, 2005 Author 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. Link to comment Share on other sites More sharing options...
Scotty Posted February 2, 2005 Report Share Posted February 2, 2005 I think that one is an air bleed when partial EGR is commanded, if I am not mistaken, mine had a foam cover on one of them, look for foam residue, here is another view of your EGR / TB / vacuum system, notice that #15 the solenoid has one in and one out... Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life. Link to comment Share on other sites More sharing options...
tjtjwdad 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 Link to comment Share on other sites More sharing options...
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