bil.dun

OK! So, here's the deal....I am quite ecstatic, because, I checked the engine temp while cruising, level ground, and up a few steep hills, and discovered the engine temp WAS in fact running cool. (Although the heater SEEMED to be OK, in the cold weather). So I installed a new 195 degree thermostat, and WOW! The temp is back up to normal, the exhaust is no longer chokingly rich smelling, the engine runs and idles smoother than ever, and best of all, the OD works properly and my fuel mileage is back to normal. SERIOUSLY. I am totally shocked that such a simple remedy could fix all these issues. And of course, I realize I am REALLY lucky, thanks to your help. I hope anybody else who may experience this problem reads this and is as fortunate. Thanks Rockfangd! And Sonjaab too..... Bill in VT PS I still have the '99 Deville as well

Thanks. I'm getting it out on the road again this week, and will check the temp via the OBD. I hadn't thought of, or considered the engine temp being a factor, as the heater is working fine, and the temp is displayed via the OBD in Celsius. I found the Celsius range should be 93-100 degrees. I'll let you know! It could be a faulty thermostat, causing it to run rich as well. Bill in VT

This is my 1990 Deville, 51k miles. There are no codes stored, and the RPM's at 55mph are 2000, it will shift into 4th gear as it should, just not OD. Although it did shift fine for the 1st 3000 miles or so. This car is a creampuff, and well worth fixing. Is it difficult (and might it help) to change the trans filter and gasket? I can get the tranny to shift into OD manually by using the OBD and in the correct mode, push in the "warmer" button. Any suggestions?

Hi Rockfanged, it was "decreasing fuel economy-trans not shifting into overdrive". I seem to have difficulty in searching for this and many other subjects, it seems the Caddyinfo site has changed. Let me know if I posted it in the wrong place.....thanks Bill in VT

It seems no one has any advice for my inquiry. Thanks anyways, guys

My 1990 Sedan Deville is not shifting from 4th gear into overdrive anymore, thereby dramatically reducing my fuel mileage at higher speeds. No codes on computer. But, I can manually make it shift into OD by utilizing the self diagnostics mode on the cooling/ heating control unit. I wasn't aware of how many different diagnostics and readings can be gleaned from this procedure (engine temp, RPM, etc.) Any advice would be appreciated, it seems not too much advice is offered on this site anymore, and a lot of advertising instead....HELP! Thanks Bill in VT

Hey Travis! Just my two cents worth....At one time or another, we all have been in your exact same situation. I still pour thru TONS of ads, for all kinds of vintage cars, but particularly vintage Cadillacs, just like yours. I am addicted to seeing what's out there, looking for that "creampuff", or "must have". My two cents worth is this- run away as fast as you can, when you see a car "being sold for my friend"....it's a ton of crap, more than likely! SERIOUSLY. These a- holes have a car that they want to sell, they know there is something wrong with it, and feel they can take advantage of someone new, or inexperienced, so when something goes wrong, they don't need to be responsible or feel guilty. Another RED FLAG, is when a seller bought the car, intended on "fixing it up", or bought it for a family member, and then never bothered to register the vehicle, and it just sits in their back yard. Don't lose hope, it sounds like you may have a decent car to work with, there will be others! Keep us posted, on your progress. Good luck- and don't give up! Bill in VT PS- for what it's worth, nearly all the low mileage vintage Cads I've bought needed TIRES. Many of them came with the original tires, or tires that looked like new, but were 20 years old....

Hi, I posted this previously, but perhaps in the wrong forum....I own a 1990 Deville, 51k miles, great condition. Can you guys tell me, is it a difficult job to replace the o2 sensor in these? The tranny seems to not want to shift into overdrive, either, although previously it was operating normally. These two problems seem to provide me with terrible gas mileage, the exhaust smells "rich", but it idles smooth. Any suggestions?

I seem to be having trouble finding this exact topic, so I'll try here....I have a 1990 Sedan DeVille with the 4.5L V-8, have owned for about a year. Bought it with 47k original miles, it had been well maintained and garaged. So my fuel economy has been as expected about 18 city, maybe 25 highway. Idles nice and smooth. PLENTY of power! It now has 51k miles. Over the past few months, the exhaust smells rich, and my mileage has decreased about 20-25%. Another symptom is, it seems it just doesn't want to shift into overdrive, which would explain bad mileage, and then at idle, it has the rich smelling exhaust. The car idles nice and smooth, so I think leaking injectors are not an issue (I think they may have been replaced, somewhere in the past). I just wondered if you guys had any thoughts, maybe the Oxygen sensor is defective? There are no warning lights, and no codes "thrown", but if I monitor the OBD it does seem to indicate a rich fuel mixture, and I can observe the OD not engaging properly, at times. Any thoughts? Thanks in advance for your help!

Thank you. So, what happened was the glue holding the mirror to the backing plate was very dry, and the mirror easily separated from the backing. So, I cleaned up the surfaces, installed the backing plate to the motor, with several loud clicks (glad the mirror wasn't attached) and checked for proper movement, looked good, then connected the two spade lugs, and dimmer plug, reattached the mirror with silicone glue, and it works perfect! So thanks much for your help, I just wonder now that these dimming mirrors are no longer made, and are hard to find in good shape- should I buy another for a future replacement? Who knows....thanks again, you guys are a great help! Bill in VT

Rockfangd, I just rec'd my replacement driver's side mirror- hard to find. So I can use the same method to install it as the pass side, but I need to be a lot more careful, so as not to mess up the liquid inside the dimming mirror- any hints? I read somewhere about using a block of wood to push the mirror back into place....again, any hints? Thank you! Bill

Got it!!! You are extremely helpful....I can't thank you enough. Now that it's reinstalled, I need to tackle the driver's side, with a heated and darkening mirror, as mine is almost black. It should work out fine, I'll keep you posted. Thanks again! Bill in VT

rockfangd, got the assembly apart, nothing broken, I really need your help in reinstallation.....see if this works * As it happens, it won't allow me to upload just 1 pic....I don't know what to do now.....it won't snap back into place. Bill in VT

Yes, it does have memory, and tilt on backup. I'm a little more confident now, so today I'm going to give it a try, will keep you posted. Thanks!

Thanks, rockfangd....I can't post a pic until I get the assembly removed from the housing. My main concern is, if I "pull" out the mirror and backing with some force, but carefully, as shown in some videos, (of 2000 and later models) will I risk breaking any mechanical parts? Then once it IS out, I think I can figure out the rest....or, if I can't figure it out, I'll post the pic of the unit. Have you tilted the mirror, and then pulled out the unit? Thanks! Bill in VT

I know this question has been raised before...however I cannot seem to find a clear answer, so here goes. On my 1999 Deville, the passenger side mirror has broken, and can still be used, but the backing plate has become detached from the motor ( 2 shafts ). It is still connected at the pivot point, however. So, my question is, is it possible to force the backing plate assembly off, without breaking any attachments? There are NO clear illustrations of what the unit looks like, when disassembled....only 2000 and later. and how can I "refasten" the mirror assembly to the motor? Any help or redirecting would be appreciated! Thanks Bill in VT

Hey guys, interesting topic....I wondered if you guys could give some input on a 1984 Seville, in near mint condition, but in need of an engine upgrade. What, if anything, can be done to boost the power of the old 4.1l, or can it be replaced with a much better 4.5l, 4.9l, or a 307 Olds engine? Any input would be helpful, if this needs to be reposted somewhere else, great, but I'd like some help! Thanks Bill in VT

Thanks guys. I know it doesn't make a lot of sense ( the spray ) but it did work sometimes for a few hours, sometimes overnight. Rockfangd, yes even when the doors were opened, the accessories would still work. But oddly, and truthfully, the condition has stopped for several weeks now. My son wanted to mention, that he did use the car often to jumpstart his '85 Corvette ( another project ). Thanks for all your help everybody! I do have another question, about replacing a 4.1l in a Seville, with a different engine, will post soon. Bill

Just a very late update....we have disconnected the remote start, and still have problems with the ignition remaining in the "ACC" mode, even with no key present. So, my son would disconnect the battery overnight (I know, not good) Just another note, we did spray some CDC electrical cleaner into the ignition cylinder, which seemed to help, temporarily. But somehow, the condition has "fixed itself", now the car seems to start and run as normal...(yikes!) Thanks for all your help, guys...

OK, thanks guys, that could be the problem....so, we'll try to figure out how to disconnect the remote start system, and see what happens. Of course I'll keep y'all posted on what we find. Thanks!!! Bill in VT

Thanks you guys...to be more specific 1) The car has an aftermarket remote start; seems to work fine up to this point. 2) Oddly, 2 nights ago, the car started ITSELF twice during the night! The next morning the battery was flat DEAD. 3) We jump started the car, drove for an hour, and when we returned home, it started fine. 4) HOWEVER, I did notice the radio stayed ON, even after turning off the ignition, AND removing the key, and yes, also after opening the doors! So, I found that with no key, the windows operate, W/S wipers, radio, but NOT the dash, or blower fan, so basically it acts as if it's stuck in the accessory position. Does it sound like a ( key/mechanical ) ignition switch, or the relay further down the column, as shown by Logan? Thanks, you guys are really helpful! Bill in VT

Can you guys please direct me to ignition switch problems? My problem is suddenly all my accessories work with the key in run/start position, but ALSO when the ignition is OFF and the key is removed, and yes, even after the doors are opened...! Thanks for any help, or redirection, if necessary Bill in VT