area310dude

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Everything posted by area310dude

  1. Hi cadillac guys I thought about this subject searching for a replacement EGR valve on my '92 Eldorado. Since GM went bust some time ago and took a government bailout, there's been a rumor on the internet that ACDelco parts are not really original GM / ACDelco any more. The parts seem to all be made in either mainland China or Mexico, with plenty of complaints about the functionality of these latest offerings. My question is, which is better to buy: A New Old Stock (NOS) EGR valve from the 1990s that actually has GM and Rochester stamps on it or A New 2017 Chinese ACDelco EGR valve that has a Part Number stamped on it that doesn't even match the Part Number on the box it came in? At first this may seem like a No-Brainer question since the NOS GM / ACDelco parts almost always work better than Chinese stuff, but . . . . . Is the diaphragm in a positive back-pressure EGR valve actually made of rubber or plastic that could become brittle with age and prematurely fail? In that case a new Chinese ACDelco may be the way to go.
  2. Slow but steady progress! It will get done, eventually. Thanks buddy. maybe it's a weak excuse, but I find it hard to find fix-it time for my car with a full-time job and other responsibilities. So a NOS EGR valve that could be 25 years old just sitting on a shelf would not have much degradation of whatever plastic / rubber seals or diaphragms exist inside it?
  3. Hi cadillac guys I thought about this subject searching for a replacement EGR valve on my '92 Eldorado. Since GM went bust some time ago and took a government bailout, there's been a rumor on the internet that ACDelco parts are not really original GM / ACDelco any more. The parts seem to all be made in either mainland China or Mexico, with plenty of complaints about the functionality of these latest offerings. My question is, which is better to buy: A New Old Stock (NOS) EGR valve from the 1990s that actually has GM and Rochester stamps on it or A New 2017 Chinese ACDelco EGR valve that has a Part Number stamped on it that doesn't even match the Part Number on the box it came in? At first this may seem like a No-Brainer question since the NOS GM / ACDelco parts almost always work better than Chinese stuff, but . . . . . Is the diaphragm in a positive back-pressure EGR valve actually made of rubber or plastic that could become brittle with age and prematurely fail? In that case a new Chinese ACDelco may be the way to go.
  4. Could use some help/advice on diagnosing an E046 trouble code for a '92 Eldorado with the 4.9 liter engine. I also failed my last smog check because of excessive NOx, btw. I'm thinking the two things are related. E046 is the the 'Left to Right Bank Fueling Difference' that will produce a Service Engine Soon light. My E046 is the single current code but the SES only comes on intermittently. My due diligence of Googling other people's experience with the E046 on this and other forums has been a bit disappointing. Many of the E046 complainers don't seem to use a Factory Service Manual for diagnosis, and most of the E046 threads I've seen have the guys replacing O2 sensors and fuel injection parts without really taking a more scientific approach (i.e. not throwing parts at the problem and hoping it will go away). Apparently the O2 sensors can be bad and produce an E046 without spitting out a more O2-specific trouble code. Anyway, the fault tree for E046 can be found on my attachment IMG_0379.jpg with some more info on E046 found in attachment IMG_0385.jpg Going through the steps of the tree, I am witnessing the ED35 (Right O2 sensor cross count) bouncing around from 0 to a high of 34, while the ED34 (Left O2 sensor cross count) varying between 0 to a high of about 24. These values do not seem to linearly increase as the car accelerates or travels at a higher rate of speed. Even just idling in Park in my driveway can produce non-zero cross counts. What should I do now? I have seen previous posts with differing opinions, e.g. the actual numerical value doesn't matter, it's the frequency of the numbers changing, the 0 value is no good, a high number is better, etc. and so forth. Some previous posters don't seem to have a really good grasp of what 'cross count' really means (me included). I'm taking an educated guess that if the cross count reading is '5' as an example, this means the O2 sensor is dictating 5 changes per second from a rich to a lean burn. Is that correct? So I have many more questions than answers, is there somebody out there that can help me with this dilemma? I feel that just blindly replacing O2 sensors as historically been done might be my last resort otherwise. Thanks, cadillac fellas.
  5. Ok thanks, fellas. I have a lot of work to do in the next week or two, I guess. I will let you all know if I am able to get rid of the E046 code and also pass the smog test. I think threads posted here are much more useful when we can read about how to successfully solve particular problems and trouble codes seen on the cars. If the original posters just disappear at the end of a thread, we never know if a certain approach was successful or not.
  6. Okay, I can see that a complete EGR system check is really essential to passing a smog test with low NOx. I will definitely put that on the agenda, and check if the EGR solenoid is working well too. As well as cleaning out the throttle body and the EGR tubes. Since the previous vacuum gauge testing seemed to eliminate a fuel injector problem or a vacuum leak, should I also plan to replace the two O2 sensors in order to eliminate the E046 code and help improve my chances of passing the smog test? Remember I was getting some extended lengths of time with zero (0) cross count readings on the right and left O2 sensors? I got a lot of things on my plate with the old Eldorado I plan to take care of, but for the immediate future I think I had best try to pass that darned smog test first and make my car street-legal ! thanks very much for your great advice so far, OldCadTech
  7. Hi, I am able to squeeze up the diaphrapgm on the EGR, but the engine keeps running with only a slight reduction in speed. I'm thinking this EGR is no good and needs replacement (together with a new gasket).
  8. At idle, there is some rapid waver that is plus or minus maybe 0.20 " Hg about the 18.5 " Hg reading. The wavering is less than a quarter inch in either direction, in other words. If that waver is acceptable, the Normal engine picture seems to be what I'm seeing.
  9. it took a while to locate the right attachment for the big nipple # 91 (brake booster hose fitting) but I finally did it, and here are the results: At a coolant temperature of 207 deg F, after 20 minutes of warming up 1) Vacuum at idle (650 rpm) was a fairly steady 18.5 " Hg 2) Vacuum at 2000 rpm was 21.5 " Hg 3) Vacuum with snapping throttle to about 2000 rpm caused the needle to fall to zero, then quickly jump up to 23 " Hg then go back to the idle vacuum of 18.5" Hg
  10. Would connecting the vacuum gauge to the # 91 fitting also require a 'T' connection to tap into the line? sorry for the rookie questions
  11. Hi, I dug around in the garage and discovered I have a Sun brand vacuum gauge that looks very similar to the black one in your picture. Is it okay to simply push the end of the rubber vacuum hose onto the nipple located at 102 ? The hose isn't threaded, it looks like yours.
  12. Sounds like a good comprehensive plan! So it looks like I should start with checking the vacuum in the throttle body first, correct? I'm almost sure the end of my vacuum gauge is threaded. Is using a 'T' connection my only option? How would I block off the open end of the T, please?
  13. ok 'scuse my ignorance, I have a vacuum gauge in my toolbox, where would I attach it on the 4.9 liter? And which vacuum condition would indicate a fuel injector problem?
  14. great information all around! i'm certainly learning something beyond what I got just from flipping through the service manual. So to answer the previous question, the PCM is showing 'Closed Loop' running and the Auto icon is lit up. Assuming that the "Likely causes of an E046" is ruled out (which I intend to double check) wouldn't the fault tree still indicate bad or lazy O2 sensors because both the right and left sensors had stretches of zero value cross counts during my test drives?
  15. hello and thanks, I really appreciate you smart and experienced folks here on the forums. I will double check the Auto light tonight. I just realized there are two 'Auto' light icons on the A/C display! In the attachment below, the Service Manual shows an 'Auto' icon on the left side that indicates Closed or Open Loop Mode status. The right side has an 'Auto' icon that will say if the car is in Park/Neutral or not P/N, correct? Which one should I be focusing on? Doesn't Open or Closed also mean when the thermostat opens to let the hot coolant flow through the upper radiator hose too?