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AZ_HUNTER, GM World Class Tech
Category: Cadillac
Satisfied Customers: 401
Experience:  16 years GM Tech, ASE Master Certified
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1997 Deville: cold mornings..I replaced the plugs/wires..same problem

Resolved Question:

I have a 1997 Deville that is really hard to start on cold mornings. I replaced the plugs/wires, thinking that might be the problem. They weren't in great shape, but even when replaced I still have the same problem. It's not a fuel problem, because you can smell the fuel, in fact it seems to be running really rich on fuel. Anym suggestions?
Submitted: 6 years ago.
Category: Cadillac
Expert:  AZ_HUNTER replied 6 years ago.

Hello and welcome to Just Answer!


The problem may be with the fuel pressure regulator located on the fuel rail. I have replaced many on the Northstar engine. Inspect the regulator by first removing the

engine cover. Then remove the vacuum line that plugs onto the fuel pressure regulator.

Inspect for fuel comming out of the vacuum line. If there is fuel in this vacuum line, then the rubber diaphram located in the regulator is split and excess fuel is being sucked into the intake through this line. This will also explain the hard start. If the regulator is faulty, the fuel rail pressure will bleed off when the pump is not running causing a hard start condition. Replacement of the regulator is pretty easy. Remove the retaining clip that holds the regulator in place. remove the old regulator and make sure all o-ring seals are

also removed. The install the new regulator. Good luck and please let me know what you find. Thanks!

Customer: replied 6 years ago.
That makes sense, but if that were the problem , wouldn't it start hard all the time and not just in cold temperatures? The reason I ask this is, today for example, it was hard to start in the morning when the outside temp was around 40, however this afternoon temps were around 60 and the car started fine. Over the last couple weeks I have experienced the same problem. It seems like once the temp drops below 50 and the car has sat for 3-4 hours or more then it has the problem. If the temps outside are higher, the car can sit for any days(over the weekend) and still start just fine. Thanks for your help.
Expert:  AZ_HUNTER replied 6 years ago.

I will take more fuel to start the engine during colder temps and when the fuel pressure and fuel volumn isn't present, it makes for a harder start when cold.

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