: So many questions, so little time

11-20-06, 08:39 AM
Hello everyone! I am the newest owner of a 1995 Cadillac Deville Concours. I purchased the car from a friend of the family because I needed wheels fast and payments low and infrequent. Whether or not I lucked into a good deal remains to be seen. Despite a multitude of problems, I really appreciate the engineering that has gone into this car and I'm definitly going to consider keeping this one long term or at least buying a similar model. Purchasing new might be an option, but I don't know if the newer models live up to the class that this car has.

I could use some help solving some problems at the moment. I haven't been able to purchase a set up factory manuals yet, and the off-the-shelf books available locally and in the public library are too vague and general in nature.

Question 1: I keep getting an intermittent CEL, decoding as left and right cylinder banks running too rich. The light comes on and stays on for a day or two, then goes out while driving and stays out for a day or two. The seller had just put in platinum plugs, and when I pulled them out to inspect them, six of the eight had the light black fluffy fouling on them. I pulled spark plug wires from the coils one at a time with the engine running, and I believe I have one weak coil but the rest are firing great. The engine burns a little oil, but not a significant amount... not enough to be seen in the exhaust when idleing. On to my question: I noted somewhere in the internet that the PCM has an octane selection. Without a manual I can't elaborate, just read that the octane level is either 87, 90 or 93. I'm wondering if this is selectable and if so maybe a previous owner had it 'detuned' for regular gas and since I'm putting in premium it is too rich of a mixture.

Question 2: I also get the message that the traction control is disabled, and again, it comes and goes but mostly stays on. Is the switch in the glove box supposed to be a momentary push button, or should it 'click' with a definitive on and off position? You can push on mine, but it has no effect on the message whether or not the traction control message has been displayed or not, leading me to believe that perhaps the button in the glove box is bad.

Question 3: The car surges at low or idle speeds, and this can cause quite a panic when pulling up behind someone at a stoplight and the car suddenly wants to speed up. It's as if the PCM is searching for a good idle speed or compensating for something to keep the engine from dying. The normal idle speed is adequate, probably around 700 to 800 rpm. I want to say that I suspect a bad idle control solenoid, but don't want to start throwing money into shadetree troubleshooting since money is scare at the moment. Could this be related to question #1?

Question 4: The left turn signal flashes extremely fast. All the bulbs in the circuit are functioning correctly, and I'm wondering if either one of the bulbs is of the wrong wattage rating, acting almost like a short, or if the flasher (or might it be flashers) is weak and needs replacment. As with most of the other problems I have been experiencing, this one fixed itself temporarily (for a few days) and then came back.

Question 5: When cold, the engine starts right up. When warm, it is hard to start about 3/4 of the time, taking up to 10 seconds of cranking to get going. It happend even after I cleaned all the plugs off. To date, I've changed the fuel filter and air filter, ran a couple of cans of fuel injector cleaner and gas dryer through the tank, and sprayed some carb cleaner down her throat. I gave the engine a good high pressure bath, and highly suspect that this caused a lot of my temporary problems although that was two weeks ago and some of them are still haunting me.

On the good side, according to the on board computer, I'm averaging 25 mpg when I drive carefully. Recently the engine started sputtering and even backfired a few times, and the mileage when south accordingly. I think I just got a bad tankful of gas, as it went away on its own and has been running smoothly for several days now.

So in a nutshell: Fouling plugs, hard warm starting, intermittent PCM code indicating rich fuel mixture, wandering low speed idle. Magic pill/sensor, or just needs a LOT of TLC.

BTW, if anyone has a set of factory manuals for a '95 Concours they'd wish to part with at a reasonable price, let me know. I had a set scoped out on eBay, but a sniper got them at the last possible second. I'm also in the market for a factory wheel for this car, apparently quite rare, for use as a spare tire which I do not have at the moment.

11-20-06, 04:12 PM
1. No. It is not adjustable. It will detect what it thinks the octane is and adjust accordingly. It also has a knock sensor to detect spark knoch and retard timing. It will run just fine on 87. Check for a leaky FPR. That would cause a rich condition as well as hard hot starts.

2. The glove box switch should disable T/C until it is pushed again. It also disables 1st gear with T/C disabled. A bad wheel speed sensor will also disable T/C and will set a DTC (Diagnostic Trouble Code). Pull the codes. Decode them here http://myweb.accessus.net/~090/dtcobd1.html

3. Surging may be a vacuum leak. Does the ISC motor ratchet and the pedal jump after shut down? That would indicate the ISC motor.

4. Usually means a bad buld. Perhaps a bad ground.

5. Suspicions confirmed. Refer to #1.

11-21-06, 06:57 AM
I confirmed last night that the FPR is indeed leaking. At least it is something on top of the engine that I can get to easily. That goes a long way into explaining the fouled plugs and hard starts.

Checked my gas mileage on paper (vs. the on board computer) for the first time last night... yikes! 17 mpg vs. the 25 that the car said I was getting. I'm hoping that it has a lot to do with the FPR being bad and that it really doesn't get 17 mpg. It is a daily driver to work every day @ 50 miles round trip, average speed of 40 mph. I was hoping to get her running good enough to use for long distance trips, because our other 'good' car gets 23 mpg but isn't as comfortable.

I'm going to recheck the transmission fluid level to make sure I didn't over fill it, because it didn't make any whining noise before I did. Maybe excess fluid is causing cavitation in the pump or something.

I've also got the tensioner pulley on the water pump going out. I removed it and packed it with grease, but that is just a stop gap until I can find a replacement.

Thanks for the reply!

11-21-06, 08:00 AM
Rager is always oin the button!

These FPRs always seem to cause little problems. So flimsy to me.

11-21-06, 10:41 AM
Replacing the FPR will guarantee an improvment in your fuel economy. Probably closer to the 25 mpg that the DIC is saying.

11-21-06, 10:56 AM
Well, my local auto parts dealer says the FPR will run me $75 and he has one in stock. Question for the day: Can these be rebuilt if all that needs replacing is the seal? I see seal kits sold for these as well for about $12, but no information as to whether or not this kit is just the seal for seating the FPR on the fuel rail or if they are for internal requilding as well. Anyone have any experience rebuilding one of these?



11-21-06, 02:30 PM
Put the new OEM FPR on. They are not rebuildable.

11-22-06, 09:07 AM
Well, first the good news: I located a FPR at a nearby salvage yard. $10 and they brought it out to me. Plugged it in (they refuse to do any "mechanic" work on site, closed the hood and started down the highway. Didn't get very far.

Now, the bad news: The top speed of the car was 15 mph after installing the used FPR. I got about a quarter mile down the road, hoping it would get better... maybe the fuel rail had an air bubble or something. Anything. Well, turned around and headed back to the salvage yard. Gotta get that $10 bill back! 15 mph the whole way. Pulled up in the parking lot, the engine idling just as smooth as can be. Revved it up a little, and not a miss. Figured it was just a fluke, so without turning the engine off I headed back down the highway. Same thing... 15 mph max. Went about 200 yards and turned around. Pulled in, turned off the engine and opened the hood. You'll just have to imagine the look on my face to see the engine compartment completely covered in gasoline. It was running in streams from the soaked blanket under the hood. I just knew I was a dead man, watching the smoke rising up from the exhaust manifold. And the 'funny' thing was, I didn't smell any gas from inside the car. Those cabins are air-tight.

I ran into the salvage yard office and told the guy I needed some help, fast! He looked right at me and told me that "we ain't got no mechanics workin' here". I explained (rapidly) what had happened, and he said I could use their garden hose around the corner. I gave the engine compartment a good soaking, and as you can tell I didn't die in a fiery explosion. :thumbsup:

As Paul Harvey would say, "And now... the rest of the story."

I had not pushed the FPR in far enough, despite the fact that the clip seemed to go on perfectly. I pushed it a fraction of an inch farther, started theh engine and it didn't leak (or catch fire). The car now runs perfectly. The new FPR fixed my intermittent 'mixture rich' codes, smoothed out my low idle and I don't get the big black cloud of smoke when I step on it, so I am going to assume that my spark plugs aren't fouling any more.

I still have a lot to fix on this one. Everytime I touch a plastic part it breaks because of age. Old Floridian car that is not used to the Arkansas cold. Wish me luck... and thanks for all the help so far!


11-22-06, 11:21 AM
You are indeed a lucky man.

11-22-06, 10:25 PM
I played in the salvage yard today! The local yard got in two 1996 Devilles, one of which they are selling whole as it runs and looks good, the other they are parting out as it was t-boned pretty badly. I managed to get the engine hood light cover, the dogbone torque mounts, the windshield washer fluid sensor, a cigarette lighter for the rear passenger door and a space saver spare tire. All for $35.

This guy has a complete set of factory wheels, in the same design as my Concours but they are chromed. They have a set of matched tires (my car has 3 brands) that probably have about half their tread life left. Unfortunately he won't budge off of the $400 price tag. Not ever for cash. They look much better than my stock alloy wheels, but call me cheap 'cause I can't part with $400 right now.

I only have two more messages left to fix: Traction disengaged (constant) and Service ride control (intermittent). She's purring like a kitten except for the buzz that appears to be coming from the transmission and varies with engine rpm. Lot so much loud but annoying. And the whining from the front end that somebody said could be a wheel bearing going out. Oh yeah, I almost forgot, I plugged the nail holes in each of the right side tires, so no more having to air them up every 4th day. Slow leaks, but annoying just the same.

The engine hasn't stalled since I put in the FPR. Keeping my fingers crossed. Going on my honeymooon tomorrow and won't be posting for a couple of weeks.


11-22-06, 11:52 PM
Congrats on the car and the wedding, Dave!