1998 STS

[pats37]

I wonder if anyone else has this problem.

While driving on highway the car just cuts out! Sometimes you get an air bag indicator, sometimes not. It's just like someone turned off the ignition switch.

It's been on computer several times, no error codes. Cam sensor replaced, same problem. Sometimes it wont start unless you turn off ignition, wait 15 sec., press accelerator to floor and release, then start.

Stalling occurs below 50 mph.

All I'm doing is piling up charges with no repair. Have had car since new, only 24,906 miles on it, garage kept.

Any help/guidance will be appreciated.

[tjtjwdad]

When it dies does the instrument panel go dark ... the same look as when you turn the key off? If so, your could be suffering from an electrical short. When it occurs did the car just go over a bump, in a curve with body roll...?

Tough to diagnose these over the net.

Jim

[bigfoo]

Man that's a weird one.. I get some stalling when I go around a corner fast and hit the gas hard but i think that might be the t/c. Why do you have to press the accelerator down and release before you start? that's very odd.. also very odd if your whole display goes out but you didn't mention that.. if the engine simply stalls but your gauges and everything are still online then it must throw up a code somewhere. You can check them yourself on the DIC

[pats37]

Yes, instrument panel goes dark, then lights up again. Also occasionally resets display panel (e.g. av mpg, range, gallons/gas used,etc.) but not always. Seems to happen more frequently going up or down an incline.

We suspect a short or bad ground. But where? Both fuse and relay boxes checked, all battery terminals (under rear seat checked) the mystery is why an "air bag" warning? (Only occasionally).

The car is like new except for this problem.

[tjtjwdad]

It sounds like the main power is grounding out somewhere. These issues can be associated with the main power to the following components. Alternator, Starte, Ignition switch, the bulkhead (compartment connector) between the engine compartment and the passenger compartment. Other areas (someone else with Cadillac experience) the coil pack.

You're going to have to try and determine what sets it off, up/down hill, curves etc ... and go from there. In these cases often a "good" visual inspection is your best tool.

I've had to chase this problem on other more simplistic cars but not a late model STS.

Jim

[pats37]

Jim,

Thanks for the info. The mechanic tried all day today to duplicate the problem with the computer connected by driving over different terrains. The only problem he could duplicate was the starting problem once. At one point he tried to start it and it just kept cranking. He had computer connected and no error codes. Finally he turned it off, waited 15 seconds (per manual) moved to pre-ignition position, depressed pedal to floor and released,(it wont start if pedal is kept to floor) turned it on and it started.

He is keeping it another day because now he is determined (pissed!) to find the problem. I reminded him that one month after I got the car I hit a deer, $7000.00 in damge on front end in Nov.'98. Since car is garage kept and low mileage he thinks there may be a frayed wire or cracked connecter that may be turning into a resistor.

I will phone him tomorrow with your suggestions and hope that he will find it. The problem that still puzzles me is "Can the starting problem be part of the stalling problem or are they two separate problems'?

I appreciate your help and was thinking along those lines today as was he.

As an aside, I called three different Caddy dealers and inquired if they had come across these problems. As for stalling, all said no. As for starting, yes. They claim that problem was solved by replacing the cam sensor. Well we already replaced the cam sensor and it has no bearing on the starting problem.

The problem with these "intermittent" problems is you cant duplicate them when you want to. Truly frustrating. The car just turned 25,000 miles during road tests.

If and when the problem is resolved I will post the complete results of the troubleshooting so all can benefit from it.

Thanks again for your help.

Pat

[Ranger]

You said you replaced the cam "sensor". Isn't there two? Maybe you replaced the wrong one if my memory is correct.

[pats37]

Larry (and Jim)

There was an error in my previous detailed post. I stated that the "cam sensor" was replaced. It was the "crank sensor." There is only one crank sensor according to the mechanic. The other is the cam sensor which checked out OK.

LATE DEVELOPMENT

After a couple of hours of checking the wiring the mechanic "tapped" the key in the ignition switch while the car was running and it stalled. They are in the process of installing a new ignition switch. I hope this solves the problem.

At least this recent development comes after checking many wires and their connectors for deterioration (none found). All of the help from this board has been gratifying and I have sent all of the comments to my mechanic. He is independent but a good mechanic. Cadillac just kept charging me for diagnostics and could not solve the problem. My private opinion is that the dealers dont invest enough money in continuing education for the employees. When the dealer recommended replacing the EGR sensor for about $500.00 I decided to go to this mechanic who I heard good things about. He removed the EGR and cleaned it and it had no bearing on the problem. He will get my future business from here on.

This car was never back to Cadillac for anything other than routine service since I bought it. I have heard horror stories from other owners but never experienced any until now. At one time in the past I had my local dealer do an oil change and tire rotation. They charged me the sale price (for oil change) so when I got home I checked the oil. They put only five quarts of oil in. I had to add three quarts! I checked the filter and at least that was new. But they never rotated the tires. The rims were dirty from recent rains and there was not a "fingerprint" on them. I called them out on it and they refunded the entire bill and I haven't been back since. They charged $21.95 for the oil change and $32.00 for the rotation plus tax. I later had the rotation done for $12.00 (no rebalancing).

I dont mind paying the fair price for any service but I do expect results. This board is a valuable asset for any Caddy owner and I will visit it frequently and help when I can.

Thank you to all and I will post the complete analysis of my car when all is complete and the problem is resolved.

[JimD]

There are two crankshaft position sensors on your engine.

[pats37]

JimD,

Thanks, have faxed your message to him, he is out on a tow. His assistant is waiting for the ignition switch which they know is bad.

Thanks for your help. It is much appreciated.

Pat

[Ranger]

A bad ignition switch will definately cause the problems you discribed. Why didn't I think of that. They always seem so simple..... in hide sight.

[pats37]

Larry,

I agree. I kept telling everyone, (Cadillac dealers and mechanic) that it was like I had a passenger who just leaned over and turned off the key. But then there was the other problem (not starting until the pedal was fully depressed and released).

I'm sure this didn't help in trying to find the solution so I am not criticizing anyone. After all, I am not a mechanic, I can just report symptoms. I rely on others for the fix. My mechanic tells me that unfortunately on problems like this it is difficult because there are "parameters" on sensors and even though they are not bad yet where the computer can detect them, they are borderline bad.

He also stated that Corvette and Cadillac have the best ECM's in the industry. Usually most problems are discovered if it is a sensor. Intermittent problems are a nightmare, especially when the sensors are not involved.

I gave him the web address of this board who I thank for all of the input. Perhaps someday he (or I) can help another. People helping people, that's America. I love it!

Pat

[BSchlossmann]

On my 93 Eldo 150K the ignition lock was replaced twice before I purchased the car at 109k. I haven't had any problems but before every winter I do give it a squit of LPS or WD-40. This appears to be the weakest link in the chain.

[pats37]

Thanks, I'll remember that. WD-40 cant hurt.

Here's a couple of tricks I've learned over the years that some may not know.

For "pine pitch" or stubborn road stains (tar, etc.) use dry gas. It wont hurt the paint (at least on the Caddy or other GM cars)).

When the rubber gaskets (exterior) by the windows get that "old" look, water spots etc. that armor all wont remove, use paint thinner. This is also good for the stubborn dirt that collects on Toyotas or other SUV gasketing between the wheel opening exterior sash and the body.

Use a soft (jersey type) cloth with your fingertip in it and just moisten with paint thinner. When it loses effectiveness add a little more. Doesn't hurt the paint.

I hope this helps someone.

[pats37]

Latest Update !! 3:25PM

Mechanic decided not to change the ignition switch ! After he removed it he saw a clip was not on right causing the wires to move,which could cause intermittent operation. So he checked all contacts (clean and good connections) reinstalled the existing ignition switch, and used the same "tap" test. Everything worked fine. If the problem re-occurs he will replace the switch. The switch is really expensive (he didnt tell me the cost). He said he should have listened to me and gone there first but all protocalls told him to look elsewhere. He said he is not charging me for much of his time but I will see to it that he is properly compensated.

It's funny how things change as you get into a problem. At least I know I have found an honest and diligent mechanic (a rarity these days). He could have told me that he replaced the switch and I would not have known otherwise.

However, the real test will be if the problem is resolved. As I promised earlier I will post the entire history of this problem in one post in the hopes that many can benefit from this frustrating problem.

My thanks to all for your input.

Pat

[tjtjwdad]

Sounds like progress is being made. I do uderstand confidence in the car though. But, then again I've seen the biggest headaches solved by the simplist things.

I'm still baffled though with having to mash the gas pedal to the floor. I have to do that to my 1970 Pontiac, but it has a carburator and an automatic choke!

Jim

[pats37]

Jim

I have the same thought regarding the accelerator. Is this part of the ignition switch problem? I'm not sure but I seem to recall being told that the idle is controlled by a small motor or something to that effect. This problem has gone on for weeks and this was mentioned early in the problem.

Perhaps if it is, it is also controlled by the ignition switch and that wire was also loose. I picked the car up this evening and drove home (about 30 miles) without incident. But since this was an intermittent problem all along I will need more time to see if all of the problems were solved. Maybe someone with a good knowledge of these ignition switches will read this and comment.

I might add that it was very difficult to even access this switch. He had to remove the radio and console to get at it before he could see the problem of the loose clip and wires. He did not want to charge me for correcting the switch problem because he felt bad that he replaced a crank sensor that might not have been necessary. I made him take $150.00 because I know he spent quite a few hours on this problem over the last two days.

If any problems still exist they should show up within a week or so. After that if all is ok I'll let all of you know. I certainly hope it is fixed as it has been trying. Having your car die on you with other cars behind you tends to increase your pulse rate immediately particularly after losing your power steering.

Thanks again for your help and interest.

Pat

[cad98]

There is only one crankshaft sensor and 2 camshaft sensors

[pats37]

To All,

Well, I've had a week of driving over diverse terrains and not a problem. It seems the harness and clip jarring loose (from the ignition switch) was the problem all along. But what a "bear" to isolate. As for the hard starting, the idle has an electric motor also with a connection at the ignition switch. That wire must have been loose also. Both problems are gone.

My thanks to all who responded. Your recommendations and an intrepid mechanic helped bring this to a happy ending.

I really love this car and this is the first problem I have ever had. And as it turned out Cadillac could not be blamed. Hey, crap happens.

I've gotten a preview brochure on the new STS and I can't say I'm impressed. They shortened it and added those funny headlights. I think I'll wait for the body change on the 2006 DTS. I'm told they will still have front wheel drive. However I have no complaints on handling with the 1998 STS with Stabilitrak in deep snow and heavy rain.

If I do buy a 2006 DTS, I'll keep my 1998 STS. I just love the car and the way it responds, handles, sounds and acts. The color, moonstone, is also unique.

Thanks again to all for your help.

Pat