CEL fiasco, on-off-on-off (Read More)

[Nvy]

Ok so as some of ya know that I have talked to concerning my (new to me) 1992 MGM I bought off a private seller, I knew there was gonna be some lil' issues here n there to deal w/. No big deal. Well the CEL comes on & again, no biggie (most times), i find out from a lil' garage here in town that still uses the old scanner systems as every other shop i called said nope, we only do 96 and newer, the shop tells me theres a code of (121-TPS, 124-TPS, 336-EGR). My engine does idle a lil' funny, sitting in the drive it will raise and lower raise and lower not extreme or anything but noticeable enough.

So I say ok, erase the codes im gonna go buy a tps and put it on and take out the easy part of the equasion that I personally can fix myself out, 2 minute job really, done! Drive a day or so still idling funny up n down like it was and the CEL is on again grrrr, so i then say screw it and dealer it, i take it in long story short, they tell me the only code that is coming up for them is a TPS code!?!?? Ok so now being confused, i replaced the tps, a 2yr old could do it, sooooo how is it still a tps? Maybe cuz i bought the tps from auto zone and its junk? possibility i guess. Then the next question, where did my egr code go and why was it there a day or two ago and now its gone not to be seen, was it an old code lingering that maybe the previous owner didnt erase? So many questions too little patience i tell ya,lol.

So there ya have it, as of rite now the dealership is installing an OE TPS and supposedly they will have it done and fixed by tomorrow am. ill keep ya posted and please do chime in, as im sure this story is gonna get better by tomorrow,lol.

[sly]

check the wiring for issues going to the TPS... then with the TPS plugged in, and the key on (engine off) back probe the TPS to make sure it's got a good sweep of voltage on the green wire. One wire should be 5V (about) and the other ground with the green being variable between about 0.9 closed and 4.5 or so open.

[1990LTD]

a voltmeter is cheaper than a throttle position sensor.



just sayin.

[Nvy]

told ya the story would get better folk's, so i get a call to come get my car, shes fixed and all ready to go!! (Yay!) I rush w/ excitement to get my car back home from the dealership smilin ear to ear like a kid in a candy store w/ permission to grab at will!! So i leave the dealer & get about 2 miles from home &.......

[pantera77]

Well take it back and complain it ain't fixed. And don't pay a penny more until it is.

[1990LTD]

Do you have any interest in learning how to fix this yourself?

Did you go to the dealer and tell them to install a TPS or did you have them diagnose and repair whatever issue is causing your check engine light? Was any diagnosis done by the dealer?

Did anyone actually run these codes to see what they mean?

121 - Throttle Position (TP) sensor out of range - TPS

124 - TP voltage was higher than expected - Fuel control

336 - PFE sensor signal is/was was high - PFE


You need someone who is capable of proper diagnosis and not just a parts hanger.

[Nvy]

Do you have any interest in learning how to fix this yourself? I did fix it myself once already (i thought?), cel came back on after i replaced the TPS myself, so i was at a loss, took it to the dealer and they said it was the tps again. I can do minor things to cars but im no master mechanic.

Did you go to the dealer and tell them to install a TPS or did you have them diagnose and repair whatever issue is causing your check engine light? Was any diagnosis done by the dealer? yes they diagnosed it and said it was the tps, no egr codes were found just a tps code to which they did not give me the EXACT code it fired off. I explained i just replaced it how could that be, he continues to tell me if i installed it and put it even a fraction of a centimeter off it would and will throw a tps code.

Did anyone actually run these codes to see what they mean? did they run it? i dont know, i just know they told me it was (THE TPS), so they replaced it. (AGAIN)

121 - Throttle Position (TP) sensor out of range - TPS

124 - TP voltage was higher than expected - Fuel control

336 - PFE sensor signal is/was was high - PFE


You need someone who is capable of proper diagnosis and not just a parts hanger.

I answered your questions within your quote above. And YES by the way i WANT to learn all i can to fix my own vehicle yes sir, i dont wanna pawn off what i can do myself i just thought this was getting away from me and out of my knowledge base or capabilities as i am not stock piled w/ tools here ya know. But in a nut shell yes i am VERY interested in learning from yall, thats why i signed up to this forum. Well i thought a dealer would be a VERY GOOD place to get reliable work done altho VERY expensive i felt safe w/ them but am finding out quickly i am no more safe w/ them than any other joe schmo shop round here.

[SVT98t]

2 bad TPS sensors?
You might want to inpsect the wiring and the connector. 20+ year old cars have this habit of cracking, corroding, breaking, chafing, loosening, and causing all sorts of mayhem on wiring.
They might be a bit brittle. If the tabs on the TPS connector are broken, it may not seat propperly and get the correct connection.
I have a few spare DPFE (Differential Pressure Feedback EGR) sensors if they come into play. Which now thinking about it, might be causing some issue.

-ryan s.

[Nvy]

Well the thing that gets me is, before all this started my idle would raise up n down check engine light would sparatically come off and on for 10-20 seconds then go off, now when i replaced the tps sensor the idle still went up n down so i beleive mine may have been junk? BUT, the one THEY put in has fixed the crazy up n down idle i had, it purrs like a kitten now but the check engine light temporarily came on as i was bringing it home from the dealer and again it only stayed on like 10 seconds then went rite off, no noticeable mechanical issue such as engine spitting or fluctuating idle or anything this time just a CEL breifly came on. I'm taking it back to the dealer tomorrow at 8 AM b4 i go to work so i hopefully will have an answer sometime thruout my workday tomorrow what they find. ill keep ya posted.

[jaywish]

That is actually great news that your idle stabilized. perhaps it is a different code now.

[miamibob]

See what the code(s) is/are. On those engines, I have seen the CEL come on (especially during highway driving) and the EGR ports needed a REAL GOOD cleaning and that fixes the issue. Again, the codes should tell the tale! Bobby

[SVT98t]

Time to clean out the EGR passages.
Which means it's time for me to make that F'n write up!

-ryan s

[Nvy]

Time to clean out the EGR passages.
Which means it's time for me to make that F'n write up!

-ryan s

yes as i been patiently waiting for it as well, no matter if that was my issue or not i am gonna do it,lol!!! So my question to you guys mechanically inclined walking a person thru it is this, When/if the dealer tells me tomorrow that it is indeed my egr, i have the money if need be to have them do it, but should i have them do it, or is it something yall can walk me thru or is this a little too detailed for the AVERAGE joe like me? to save myself a little money, if its worth it i would like to try but i have searched the net and seen a video or two and or folks describing how to do it and it seems a bit difficult to change these particular egr's and or tubes. Understanding ill be doing this from lying on my back or w/ a floor jack etc. No special equipment stuff here,lol.....

[sly]

it's real simple on the 92-95 intake of suck.

take the EGR valve off... then take the 4 bolts that hold the intake elbow off (have replacement gaskets on hand just in case the old ones shred like they did on my 93 at the time I did this) and just flip it over as the throttle cables allow. scrape carbon build up out. put back together. (do remove the large plastic intake part first though. If it's in good condition, it'll still have the original bolts holding it in place that you'll need to find and remove before yanking on it).

Here's the pics of my EGR channel before and after cleaning.





There was a more in-depth how-to on this, but that user got banned and took all his images with him.

[Nvy]

thanx sly, ill give it a go but you werent real detailed in how to take it off (egr) i mean, when i open the hood it looks as if i need to have go go gadget twisty arms to get up under the egr to take it off, is this done from under the car, on top etc? Cuz from the top of the car i cant even see the bolts let alone take em off. And all the garbage in my way is yet another story, nehoo when i get her back ill take a closer look at it and take sum photos.

Onto the subject at hand, so the dealer calls me today Sly rite? lol, well, Tim we were unable to reenact the engine code that had come on for you, our lead tech. and shop supervisor have been working on your car all day and they cannot pull a code up, get the check engine light to come on what so ever and they have driven your car well over 15 miles today. Do you mind us keeping your vehicle overnight to do further tests to see if we can come up w/ why this is happening.

So when i originally picked my car up from the dealer saturday afternoon i drove it 3 miles and the CEL light came on for 30-60 seconds then went off, when i drove the car today for a grand total of 4-5 miles to the dealer from my house, the CEL came on again for about 60 seconds then went off on my way there. I told him this morning what im telling yall now. He states they arent pulling a past, present code up. All they are pulling up is a code of 1111 or maybe it was 111111, i forget exactly how many 1's it was but he said it that the 1's meant no codes or vehicle clear of all trouble codes. So whats yalls take on this, im really starting to get F'n pissed off. should i continue this BS non-sense relationship w/ the dealer or start troubleshooting this shit myself somehow with direction from you folks of course.? = )