1999 Buick Century Start rough idle and misfire

Tiny
DLVAUGHN1963
  • MEMBER
  • 1999 BUICK CENTURY
  • 170,000 MILES
99 buick century, I've posted questions before. My problem I'm wondering if it can be placed on my ignition system, via ignition switch/key. The car recently began not starting, but battery is new, and all ignition components replaced. The security light does not come on except when all the warning lights come on.
The car does start but after about 5 min. Is the chip in the key problematic with this car? Or is my ignition switch bad?
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Saturday, June 8th, 2013 AT 5:33 AM

18 Replies

Tiny
HMAC300
  • EXPERT
Have the ignition switch checked
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Saturday, June 8th, 2013 AT 5:39 AM
Tiny
DLVAUGHN1963
  • MEMBER
Would the ignition switch cause all of my mentioned problems?
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Saturday, June 8th, 2013 AT 5:56 AM
Tiny
HMAC300
  • EXPERT
The switch won't cause the misfire but could cause the starting/not starting problem. Hav eit scanned for codes and check fuel pressure with a gauge
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Saturday, June 8th, 2013 AT 7:58 AM
Tiny
DLVAUGHN1963
  • MEMBER
If I change the ignition lock cylinder will I need to replace the key or will my current key work?
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Saturday, June 8th, 2013 AT 6:36 PM
Tiny
HMAC300
  • EXPERT
Your current key will work
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Sunday, June 9th, 2013 AT 5:25 AM
Tiny
DLVAUGHN1963
  • MEMBER
So the lock cylinder is by VIN? Then as long as the correct cyl is ordered it should not matter? I checked the resistance of the key and according to the number of resister ballasts (15) my key registered the last measures key, 15. If that is correct then when the dealer orders another cyl is it done by VIN or is it ordered willy nilly?
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Sunday, June 9th, 2013 AT 6:26 AM
Tiny
HMAC300
  • EXPERT
You are not removing the lock assy you are removing the switch which is down the column beneath multi function switch
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Sunday, June 9th, 2013 AT 8:31 AM
Tiny
DLVAUGHN1963
  • MEMBER
Sir I think you missed my question. We were talking about the lock cylinder. It's my understanding that my ignition lock cylinder is bad. The question is IF the cylinder is bad, would replacing the cylinder require a new key.

Let me give you the history if this problem. About a week now starting this car ha been a little difficult. It first would not crank when you turn the key. All of the dash lights would come on like normal, then go out. The first time you turn the key to start, nothing, no clicks no starter engagement. No. Indication of any other issues to include anything with the security indicator. Then a second or third turn and the car would start. This was an intermittent problem. Yesterday I went out to my car to start it early in the morning, and had the same issue, but then the car started on four occasions. Then later in the morning went out to start the car, I get a starter whine like it was starting the car, but obviously no ignition or spark. I am wondering though, if the ignition cylinder has two contacts that mate with the resister on the key because it looks like the lower contact in the key cylinder looks as if it may be stuck in the detent.

The reason I asked about the current key is will it work in the NEW lock cylinder or will the new cylinder have a new key and cutting template?
Also I've read that old fuel pumps have a pronounced whine as they age which would account for the sound I hear under my seat. Is replacing the lock cylinder as easy as I've seen on the Internet for this vehicle, or should intake it to the dealer to have this done? Thanks for your assistance with this maintenance issue.
Dennis
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Sunday, June 9th, 2013 AT 8:50 AM
Tiny
HMAC300
  • EXPERT
If you go to a dealer or locksmith they can key your new cylinder to your key. But the switch and lock cylinder are two different things. Replacing your cylinder wont' help your starting problem if it's the switch
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Sunday, June 9th, 2013 AT 8:54 AM
Tiny
DLVAUGHN1963
  • MEMBER
Ok so the switch is located near the multifunction switch?
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Sunday, June 9th, 2013 AT 8:59 AM
Tiny
HMAC300
  • EXPERT
Read the previous replies it states where it is. It's $170 through gm parts direct
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Sunday, June 9th, 2013 AT 9:00 AM
Tiny
DLVAUGHN1963
  • MEMBER
I did thanks. Just looks like I'd have to order the part no matter where I go :)
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Sunday, June 9th, 2013 AT 9:18 AM
Tiny
DLVAUGHN1963
  • MEMBER
Changed ignition switch, same results
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Sunday, June 9th, 2013 AT 12:41 PM
Tiny
HMAC300
  • EXPERT
Scan for codes and check fuel pressure first. I think this hasn't been a starting problem electrically and you diagnosing not knowing what it is has led everyone concerned down the wrong path. If it's a 3.1L it should have 41-47psi and a 3.8L 48-55 psi. If it's a misfire and fuel pressure isn't low then check plug, wires and dist cap if yo have one if not coil for that cylinder. Also check compression an dfor vacuum leak on offending cylinder if not that then have apro diagnose it as he is able to find out which cylinder it is.
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Sunday, June 9th, 2013 AT 12:47 PM
Tiny
DLVAUGHN1963
  • MEMBER
All of the ignition system has been replaced. Wires, plugs, coils, ignition control module, I've checked all the fuses, and relays. All I get is a random misfire code. I have also replaced the upstream O2 sensor. The starting issue like it is now has only been happening a week. Yesterday awacs the first time the vehicle would not start. And turning the key in the start position did not even get a crank. Now it cranks or I should say turns but nothing else.
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Sunday, June 9th, 2013 AT 1:03 PM
Tiny
DLVAUGHN1963
  • MEMBER
Initially this was a rough idle issue, then the idle was fixed, and found a misfire codes.
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Sunday, June 9th, 2013 AT 1:04 PM
Tiny
HMAC300
  • EXPERT
Do what I said in previous reply random misfires can be anything and if you don't have an fule pressure it won't start. I can offer no other suggestions.
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Sunday, June 9th, 2013 AT 1:05 PM
Tiny
DLVAUGHN1963
  • MEMBER
Will send car to buick thanks
Ill let you know what the issue is.
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Sunday, June 9th, 2013 AT 3:33 PM

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