1989 Sedan Cold Start Issues

[Dennis J. DiNorcia]

On my 1989 Sedan it recently developed a problem with cold starting. I was always able to start her up, and after a minute or two, drive off without a problem. Now when cold starting, I notice it idles rough and if I take off after only a few minutes as I have in the past it also bucks and misses when accelerating. It starts up without any hesitation. It has 116,000 miles and has always been properly maintained. I know this could be a world of things such as wires, plugs, injectors, fuel pump, etc. But before i go to my shop, I was wondering if anyone out there experienced the same issues and had it fixed without doing a trial and error diagnosis. Thanks.

["Cadillac Kid" Greg Surfas 15364]

Dennis,
How cold is it and when did you get the last tank of gas?
Greg

[Jim Sparrow]

Sounds like an overly rich air/fuel mixture (too much gas). Does the problem go away once it warms up? Is this car your daily driver or does it sit sometimes? Do you see black smoke out the tail pipe while this is going on? First thing I'd do is pull the spark plugs & check for carbon fouling or gas fouling. Carbon fouling is evidenced by black fluffy sooty deposits on the electrode. Gas fouled plugs will be wet or damp with a fuel odor. Also look for oil fouling if the car sits awhile between drive times. Oil fouling under these conditions could point to weak valve guide seals that allow oil to seep past them, down into the combustion chamber, & onto your plug(s). If you discover an overly rich condition, check for bad coolant temperature sensor, leaking injector(s), a fuel pressure regulator problem, or excessive fuel pressure being developed by your fuel pump. If you discover that you have a rich condition that resolves itself after the engine warms up, check the coolant temperature sensor. A last suggestion is to check your EGR valve. If it is stuck even a little open it will cause driveability issues, warm or cold. Hope that helps!    -Jim

[Dennis J. DiNorcia]

The car is my daily driver but I only drive it a few miles a day to and from the train station. I do sometimes notice a strong fuel odor when I start it up but then it goes away. I've only noticed the problem when the temperature is in the 30's or less. There is no black smoke and after the car warms it drives fine. I noticed also a big drop in gas mileage according to the digital monitor. i am getting under 10 MPG or less lately.

[Dave Shepherd]

I'd suggest going into self diagnostics and looking at the air temp sensor and coolant temp sensor inputs, for what you describe that's where I would start.

[Chris Short CLC 18814]

Well what I would do is just do a good tune up on it.  I drive a 89 Fleetwood for my every day car.  And even with 309K on it it still runs great.  For years my car has always gotten poorer gas mileage in cold weather when it gets below 25F for daily highs.  In the summer it gets wonderful mileage.  But untill it warms up it really chugs the gas.  It usualy takes about 1.5-2 miles of road to get better..  You can just watch the MPG number on the dash go up as it warms up.  It never misses or anything like that tho..  A friend of mine told me that I should put new oxygen sensors in it.  And that might help.  If the o2 sensors don't warm up fast enuff the computer doesnt use them to make the correct fuel mixture untill they are warm and sending a readable signal.  Thats what I've heard..

Good luck.. 

[CEC #20099]

Dennis; Do you have a 4.5 FWD car or a 5.0/5.7 RWD car ?? Do you have a shop manual ??
This thread is ambling without specifics.
c chleboun #20099

[TJ Hopland]

Good thought about the 5.0 (brougham) vs the 4.5's.     The 5.0's have a carb and I have seen a lot of those motors with choke issues.   The 4.5 are EFI and it could be something simple like a temp sensor telling the car its 90*F out, or perhaps its telling the car its -30*F even after it starts to warm up.  Its sending information so it wont trip a code but its giving bad information.

[Chris Short CLC 18814]

Just giving this  a bump up to the top..   And did you ever fix your car?  Let us know what u find..

Chris