: Please help: 1996 deville hard starting ?



VIPERRACING
12-07-11, 01:19 AM
Hi guys, I have a 1996 deville with 98k miles that seems to have a periodic long starting issue. Doesnt matter if its cold or hot. It happens about every 4th or 5th cycle and in between those cycles it just starts up with no issues. Had the battery checked and they said it was bad so I changed it and still have the problem. Car also has a new fuel pump but has been reported to having this problem before the new pump went in. Dealership cant figure it out. Thought that maybe the fuel regulator was going bad but pulled the vacuum line to it and it was dry. I cant believe that Im the only one with this issue. Any help is greatfully appreciated. Thanks ahead of time, Tony.

maeng9981
12-07-11, 01:42 AM
Have you cleaned the throttle body?

VIPERRACING
12-07-11, 01:46 AM
No I havent. If it was dirty wouldnt that make the car hard to start all time and not periodicly? The car idles very smooth and never stalls.

maeng9981
12-07-11, 02:41 AM
My Deville used to fail at starting once in a while. Had to retry several times, it wouldn't start unless I pushed the gas pedal a little bit. Other times it started just like normal, turn the key and it starts. Then after a long time the gas pedal started sticking. Cleaned the TB, and all is gone.

VIPERRACING
12-07-11, 03:21 AM
Yes that is exactly what mine is doing minus the sticky pedal. I just thought that it might be a fuel issue or sensor issue causing the problem. Im not sure if the dealership replaced the fuel filter when they did the pump but I do know that this has been a issue with this car for a long time now after having the dealership pull the records for the car. What(how) did you clean the throttle bottle with? Thanks

maeng9981
12-07-11, 06:57 AM
People replace the fuel filter as a precaution but I never heard of any problems caused by fuel filters other than rusted out units.

To clean the TB: remove the intake ducting, remove the MAF sensor and screen unit. Open the throttle body butterfly by either pushing the accelerator pedal with a heavy object or get someone to push it down while you are cleaning. Spray a throttle body cleaner on the buildup on the butterfly and the throttle body itself; use an old toothbrush. There is a shiny side under all the buildup. Clean it through, try to remove buildup as much as possible. Don't let any unwanted objects like spray straw get into the intake. Reassemble everything, and test the car.

Ranger
12-07-11, 12:23 PM
FYI, there is a tutorial in the Tech Tips section on TB cleaning with pictures.

VIPERRACING
12-07-11, 07:33 PM
Guys, I cleaned the tb & maf and Im still having the same issue. Anything else that could be causing this issue?

89falcon
12-07-11, 08:15 PM
Guys, I cleaned the tb & maf and Im still having the same issue. Anything else that could be causing this issue?

Small headgasket leak.....

run a block test.

Ranger
12-07-11, 10:17 PM
No DTC's I presume?

VIPERRACING
12-08-11, 12:59 AM
Ive already been through the hg issue with my other cadillac and its not that. Car starts up and runs smoothly but sometimes its just hard to start exactly as stated in post #4. Im actually opening the tb slightly via foot pedal upon start up and so far its been firing up but Im going to continue this method for a day or so to make sure it does start up ever time. I will keep you all posted. Also do you guys know what the voltage is supposed to be on these cars? Mine ranges anywhere from 11v to 14v but never the same consistence. Also has anyone had any luck with the monroe 90008 & 90009 shock conversion? Thanks again for all the help.

iflipcars
12-08-11, 01:16 AM
When the throttle is closed, air is allowed into the engine via the IAC (Idle Air Control Valve). If it is sticking shut on occasion, its possible that it is your problem.
See this post here (http://www.cadillacforums.com/forums/cadillac-tech-tips/167181-tb-iac-idle-air-control-valve.html) and clean the IAC also.

89falcon
12-08-11, 01:56 AM
Ive already been through the hg issue with my other cadillac and its not that. Car starts up and runs smoothly but sometimes its just hard to start exactly as stated in post #4. Im actually opening the tb slightly via foot pedal upon start up and so far its been firing up but Im going to continue this method for a day or so to make sure it does start up ever time. I will keep you all posted. Also do you guys know what the voltage is supposed to be on these cars? Mine ranges anywhere from 11v to 14v but never the same consistence. Also has anyone had any luck with the monroe 90008 & 90009 shock conversion? Thanks again for all the help.

I do find that my STS can be "finicky" about battery voltage.....try hooking it to a charger when you start it.....just to troubleshoot.

VIPERRACING
12-08-11, 02:38 AM
Ill try cleaning the iac and let you knolw how it turns out. I thought that the iac only controlled idle and since I never had a problem with the car idling or stalling I never thought that would be the problem. Thanks

Ranger
12-08-11, 11:54 AM
Be sure to clean the TB first. It is more likely the problem. If that doesn't help, then do the IAC valve.

Voltage should be around 14v with the engine running.

turbonut
12-08-11, 12:23 PM
Possibly a bad or failing crank position sensor or wiring