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Cadillac DeVille, Sedan
#2462 of 2635 Problem starting 1997 DeVille in morning
Apr 25, 2008 (6:07 am)
Hello, I'm new to this forum and new to Cadillac's. I recently purchased a used 1997 Cadillac DeVille. I have a problem starting my 1997 Cadillac DeVille (mileage approx 100,000) in the morning when the engine is cold and morning temperatures are around 50 degrees. (I don't have a problem starting the vehicle in the evening when outside temperatures are above 70 degrees.) Once started, the vehicle runs fine. The problem is getting it started. I took the vehicle to a local repair shop and they said no problems showed up on the computer. They indicated that pressure is lost overnight in the fuel line and they suggested replacing the fuel pump and fuel filter and clean injectors for $1100. Has anyone had similar problems? Will their recommended solutions solve my problem? By the way, this sounds a little expensive! Thanks in advance for all responses!
#2463 of 2635 Re: Problem starting 1997 DeVille in morning [railer]
Apr 26, 2008 (1:42 am)
It could be a leaking Fuel Pressure Regulator (FPR).
Are you somewhat 'handy' around the motor? It's pretty easy to check for a leak. The FPR is about $60, and can be replaced easily also.
#2464 of 2635 98 Deville Northstar octane additive
May 08, 2008 (11:39 am)
This is first time I'm on this forum. I inherited 98 deville northstar with 45,000 miles. Gas is killing me...17 mpg ave. What about regular gas and octane additive? I don't want to ruin the car. Like new. Should I even attempt it or just be safe and use high test???
#2465 of 2635 Re: 98 Deville Northstar octane additive [pagar]
Jun 03, 2008 (9:46 pm)
I also owned a 1998 Deville from 2001 to 2004. My 98
Deville got an average of about 20 MPG in the city and 27 on the highway. Think your car may need some fine tuning. If you have a dealership you trust take the car in for your next oil change and bring this up to the service department, suspect they can put the car on computer diagnostic system and find out why your fuel economy is below average for your car.
#2466 of 2635 Re: 98 Deville Northstar octane additive [pagar]
Jun 03, 2008 (9:51 pm)
Forgot to mention that i have used STP fuel injector cleaner fluid on my 1998 Deville. Never had any problems with the Northstar system using this product but can't say for sure that it helped. The cost is around 90 cents per container. The folks at STP claim that it helps fuel economy and keeps fuel injectors clean.
#2467 of 2635 Re: 98 Deville Northstar octane additive [pagar]
Jun 03, 2008 (11:03 pm)
A lot depends on how agressive you drive, or the conditions you drive. If you have an easy foot on the gas, I think you can drop to mid-grade without any problems. You could probably drop to regular, and will hear some pinging, but still have no problems.
But, it you accelerate quickly, or drive in mountainous roads, you may need to keep premium gas in to. When the motor is under heavy load is when premium is needed to eliminate pinging.
I think if you drop the grade, your milage will probably also drop.
And I agree, the 20mph should be what you can get with a mix of in-town and highway driving, and with constant highway driving, you should be able to get 25mgp or better. On premium.
#2468 of 2635 How to disable airbags - 1998 Cadillac Sedan deVille D'Elegance
Jun 28, 2008 (6:03 pm)
How do you disable side impact airbags in a 1998 Cadillac Sedan deVille D'Elegance safely? We had a collison in which the driver's door was damaged and we are currently attempting to change the driver's door?
#2469 of 2635 Additives to fuel stystem
Jun 30, 2008 (8:28 pm)
I have a 03 deville with 66000 miles on it. Im getting 21mpg on the highway and 19 in the city. I was wondering if I should add something to the fuel in hopes of cleaning the fuel injectors. Is this wise to do?
#2470 of 2635 Re: Additives to fuel stystem [onelord]
Jun 30, 2008 (10:19 pm)
I owned a 1998 Deville and later a 2004 Deville for three years each and always used STP fuel injector cleaner fluid with each fill up. never had any problems.
The 98 got about 27 MPG highway and around 20 in town. The 2004 around 29 MPG highway and 21 city.
You may have other issues and may want to try a complete fuel system cleaner (STP has one as do other additive companies). Have you checked your air filter or replaced recently. Your MPG stats sound low
so you may want to investigate further if my two suggestions don't improve your MPG performance. The 98 Deville had 39,000 miles on it at time of trade and the 2004 Deville had 36,000 miles on it. Both much lower mile cars than yours but still think you should be getting better results.
#2471 of 2635 Re: Additives to fuel stystem [onelord]
Jul 01, 2008 (11:10 pm)
Unless you have been using very cheap unbranded gasoline, I wouldn't think you have injector problems.
With that milage, i woujld be thinking about plug wires and plugs. Us only GM wires and the recommended plugs. The wires and plugs should be good up to 100,000, but expecially if you have had some mechanical work done near the wires, they could be messed up. If you live in extremely hot area, the wires might also have broked down early.