Hard Start when Cold...2 dealers can't even figure it out!! Help!!

[BigTex123]

We have a 1998 Deville with only 46k orig miles. The car is very difficult to get started when cold (i.e. sitting overnight). I've searched a lot and done most of the recommended repairs but the problem still remains. Here's what I've done: new GM fuel pressure regulator, new fuel filter, new GM fuel pump relay, tested fuel pump pressure on start up (48 psi), and had a professional fuel rail injector clean completed. I don't know what else to do! The car runs beautifuly otherwise and has show no other symptoms.

When I replaced the fuel pressure regulator I went out the very next morning and the car started instantly. 1 day later, back to hard starts. Should I recheck the brand new fuel pressure regulator? I guess it could have been faulty and/or sitting on the shelf for the last 11 years and be defective. Two repair shops have now looked at it and can't figure out the issue.

Please advise!!

[antdeville79]

i have a 96 that was doing the same thing and it was the battery...when i tried to start it, it seemed like gas had to get back up to the throttle body to start, and the battery i had in there had juice to crank it over no problem...but i changed it and it starts perfectly fine even after sitting for weeks....sounds funny but true

[Ranger]

There is no gas in the TB, but try giving it a good cleaning. Have you tried starting it with the throttle just slightly depressed? If that helps, the TB needs a good cleaning.

[BigTex123]

So when you say with the throttle body slightly open, you are suggesting that I should have someone under the hood holding it open a little while someone else turns the key??

I don't get the comment regarding the battery being the problem....seems like if there's enough juice to turn the engine over, everything should be fine. It is an older battery, but it's never struggled to get the car started. It would be great if it was the battery as that is an easy fix! It could have been that the computer was cleared out when you disconnected the battery????

[Ranger]

Originally Posted by BigTex123

So when you say with the throttle body slightly open, you are suggesting that I should have someone under the hood holding it open a little while someone else turns the key??

I don't get the comment regarding the battery being the problem....seems like if there's enough juice to turn the engine over, everything should be fine. It is an older battery, but it's never struggled to get the car started. It would be great if it was the battery as that is an easy fix! It could have been that the computer was cleared out when you disconnected the battery????

No, just use your foot.

[sharpcar69]

you said you only have this problem in the morning...did you check your fuel pressure before you crank away trying to start her...it sounds like a fuel pump thats loseing pressure.and since it only happens overnite first crank in the morning...if fuel pump is loseing pressure it would take way longer to start your building the pressure while your cranking away...eventully it will start...in the morning before you start to crank to start open switch and you should hear something from the fuel pump,if you do leave switch open until that hummimg sound stops do this 6-7 times if it starts right up bad fuel pump loseing pressure,if you hear no noise and still after 6-7 switch cycles and still hard start,when you changed fuel pump did you change fuel pump pigtail its a big problem in g.m cars they short out in the pigtail with no visable signs of faliure and way to often mechanics even great ones dont change pigtail...some fuel pumps like carter come with that pigtail in box orignal acdelco does not. pigtail is sold seperately...hope info helps you..good luck.....

[Ranger]

The pump should build pressure almost immediately even if it bleeds down overnight. I really don't think that would cause a longer crank time.

[sharpcar69]

i had a 99 deville and it had those same issues i put fuel guage one morning before starting and it had pressure but way to low when i would crank it would build but with out cranking and opening and closeing switch it would get pressure much quiker and after 6-7 switch cycles vrooooom turns over like a kitty and drive all day no issues i could let her sit for couple hours no problem but if it say for more that 7-8 hours loses fuel pressure...the open switch cycles cured me for a bit then it finally went out .

[Ranger]

Yeah, your pump was weak as evidenced by it's eventual failure and what you describe is a sign of it, but if it is a good pump, and his appears to be by his pressure, it should build pressure very quickly even if it starts at zero I believe.

[BigTex123]

Yes, the dealer mechanic let it sit all night, put a gauge on it, and then looked at pressure at immed. start up.....pump pressure was there and was 48 psi. We have tried holding the pedal down a bit and it does not start any better. I will say that I did the "pedal to the metal" trick when I first found out about the FPregulator and that seemed to help. Again, after replacing the FP regulator, the very next morning the car cranked instantly. A day later back to the same problem. The FP regulator is an easy install so I don't think I could have messed it up, but I guess there's always a chance that the regulator I picked up from the dealer had been sitting on the shelf for 11 years and could have dry rotted some thus causing it to fail after a short period of use. I've had other "new" parts fail on me shortly after installs before.

I just can't get over how great the car runs all the time....it's just this darn hard starting problem in the mornings. The car is averaging 24 mpg on the highway so that seems to be in order too.

[Ranger]

I will say that I did the "pedal to the metal" trick when I first found out about the FPregulator and that seemed to help.

This would put it in clear flood mode and shut off the injectors. Try it again. If it helps, then I'd say you have a stuck open or leaky injector (if we assume that the FPR is good). The good fuel mileage would tend to rule that out though, the stuck opened anyway.

[antdeville79]

what i meant by the battery? my car suddenly had a hard time startin after the car sat 7+ hours...i mean i would crank the car for a good minute before it started....after a couple pops and sounding like it wanted to start....(which for it to crank for a minute it obviouslythe battery had juice)...that problem went on for like 6 months...then over the winter the battery i had in there shit the bed....it wouldnt even hold a charge....i bought a brand new battery and now it starts all the time...its my second car so i dont drive it all the time...sometimes i let it sit for a week or so....but it still starts without hesitation.....i think the battery that was in there didnt have enough power to simply power the pump right....call it a coincidence but it was deff the problem....thats why i say try it...for 40 bucs how can u go wrong

[99bluedville]

I would guess that it is a couple or more of the injectors leaking down putting to much fuel in the cylinders. Check the tailpipe for black smoke after startup or a buildup of soot indicating a rich mixture.
I have a 99 deville and depending on how I drive will get 25-27 MPG on the highway.
That being said do check battery voltage before you start the engine and after, these cars are very dependant on the proper voltage.

[antdeville79]

how did u make out with the problem? did u fix it? what was it