View Full Version : 98 deville hard starting

09-07-05, 08:52 PM
okay, my dads caddy has been acting up lately. Once the car is cold. it cranks and cranks for a good 5 seconds before firing up. shutting the car off immediatly after and it starts right up. no real signs of power loss im thinking. but my dad is a grandpa driver so who knows. Personally I think the car should take off a lot faster on the freeway, the old man likes to say, oh its a heavy car, its not a race car. In response I reply with. IT's a heavy car with a high performance motor and the car should get up a lot faster. I'm thinking its a leaking injector, although, I havent got my n* yet to view all the posts and do a bunch of research on it and the different system implemented with it. What are the possible causes for the hard starts and were is a good place to start along with some good factors to evaluate. the car is getting decent gas mileage. 21.? mpg city/hwy and he really grandpa's the car.

There are no trouble lights coming on, all normal operation on the guages. also the car is running at approx 199 - 210 degrees farenheit. at what tempature is the stock thermostat suppose to open up at? 190?

Let me Know

09-07-05, 09:11 PM
How many miles are on the car? Before my misfire started, I was having problems with hard cold starts. New Delco 41-950 plugs and 748J wires fixed it and now it starts better than ever when it's cold. If it's over 100k, it's due for plugs and wires. Mine gave me problems before 100k. If it's a leaking injector, the exhaust should smell strongly of gas just after it's started cold. You might have to pluck them all out of there and pressurize the system to know for sure if that's what's going on. Have the throttle body bore and plate been cleaned lately? That's an easy chore, just remember to disconnect the battery for 60 seconds after you do it, then try a cold start and see what you get. Someone else may have better suggestions.

09-07-05, 09:50 PM
hmm.... well I don't have the manual in front of me to check, but if the cadillac is like 99% of the other GM cars, the fuel pump relay will only kick in on initial key on (for 2 seconds). When the oil pressure switch receives oil pressure, it bypasses the relay and keeps the fuel pump on as long as there is oil pressure (i.e. as long as the engine is running). In the event the relay dies, it will take a looooong time to crank before you get any oil pressure, which will turn on your fuel pump, and let your engine run.

So, with that in mind, do you hear the fuel pump come on when you put the key to "run" (but don't start it)?

Assuming you do, a leaking injector could be a possibility. As well as a bad fuel pressure regulator... You can check those two by putting a fuel gauge on, and seeing if the pressure starts dropping fast after the fuel pump prime I mentioned earlier... You can also check the regulator by pulling the vacuum line to it, and seeing if there is any liquid gas coming out.

Stock thermostat opens at 195 I believe.

98 Caddy
09-07-05, 10:14 PM
Probably fuel pressure regu;ator. Do a search. Testing it is very easy, just pull the hose off the regulator with the car running and see if you see any dampness around the diaphram. Good luck. By the way, it is a pretty common failure.

09-07-05, 10:54 PM
My understanding is that the FPR is more likely to cause hard hot starts. You might also try cleaning the TB.

Then go to the top of this page and click on Technical Archives and let dad read up on Full Throttle Acceleration.

09-08-05, 10:56 AM
car has 80,000 miles on it

09-08-05, 03:21 PM
Stat starts to open 192-199, fully open at 219.