[mitlar37]

OK - I have a fuel pressure problem with my 99 Deville. After sitting overnight or more than 12 hours all my fuel pressure bleeds off the rail. I have to turn the key off and on about 6-8 times to cycle the pump and get it started. I've ordered a fuel pressure tester but haven't got it yet. This morning before I cranked it I checked the schrader valve and not a drop of fuel came out when I pressed it in. Once I got vehicle started I pressed it again and had fuel spray out like it should. I've already replaced the fuel pump and the FPR and no luck. I can't smell any fuel when running or not. I'm leaning towards replacing the injector O-rings next. Has anyone had similar problems? The car runs and cranks perfectly after the initial morning start. Any suggestions would be appreciated.
Also I got a Fram G7315 fuel filter that is supposed to be for the 99 Deville but the threaded side is too big - what's the deal with that?
Oh - and there are no codes being triggered either.

 

[Submariner409]

You may have a stuck/sticky fuel injector - before you start replacing parts and pumps, get a 20 oz. bottle of Chevron TECHRON and dump it in the gas tank with a fill-up of Shell, Chevron, EXXON or other Top Tier gasoline. Take a 100 mile drive - to exercise the engine and to pump a LOT of gasoline around the fuel system - the fuel pump moves a LOT of fuel around from the tank to the rail and back again. TECHRON is a powerfule fuel system cleaner - only once in 5,000 miles.

If that doesn't help, you're in the fuel injector removal and cleaning business - not easy or cheap.

"top tier gasoline" ??? Google it.

 

[mitlar37]

You may have a stuck/sticky fuel injector - before you start replacing parts and pumps, get a 20 oz. bottle of Chevron TECHRON and dump it in the gas tank with a fill-up of Shell, Chevron, EXXON or other Top Tier gasoline. Take a 100 mile drive - to exercise the engine and to pump a LOT of gasoline around the fuel system - the fuel pump moves a LOT of fuel around from the tank to the rail and back again. TECHRON is a powerfule fuel system cleaner - only once in 5,000 miles.

If that doesn't help, you're in the fuel injector removal and cleaning business - not easy or cheap.

"top tier gasoline" ??? Google it.

My wife dumped some fuel injector cleaner in it a few weeks ago - but she got it from Autozone and probably got their "recommended " brand and have put a 1000 miles on it since. I always buy my fuel from Exxon because they have the cheapest Supreme in town. Since she already put some in there will it hurt to run a bottle of Techron thru it so soon? Also I read somewhere that you can pressurize the rail and with the engine off pull the injectors and see if any are leaking - is this a PITA to do? Also the car runs like a new one with no hesitations or misses - it purrs like a kitten - wouldn't a bad fuel injector cause some hesitation or miss?

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Also thanks for the tip on "top tier gasoline". Didn't know that, I thought all gas sold today had detergents in them. Will definitely stick to Exxon or Chevron from now on as I have at times went to the cheap stations when out of town.

 

[MoistCabbage]

All gas does have detergents,it's an EPA regulation. Top tier fuels just exceed that.

 

[mitlar37]

All gas does have detergents,it's an EPA regulation. Top tier fuels just exceed that.

Thanks - good to know. I quit using injector cleaners a few years back because I thought if the gas had detergent in it I was wasting my money.

 

[Ranger]

Is the car hard to start? If an injector is leaking down, it will flood the cylinder and I would expect a hard start and rough initial idle.

It's not terribly difficult to pull the fuel rail to check the injectors if necessary.

Theoretically the system should hold fuel pressure forever, but my understanding it that it is not uncommon for the system pressure to leak down overnight via the check valve in the pump. Once the pump is energized when you crank the engine, it should pressurize the system almost immediately, so if that is the case and it's leaking back into the tank and causing no problem, I'd ignore it.

 

[mitlar37]

Is the car hard to start? If an injector is leaking down, it will flood the cylinder and I would expect a hard start and rough initial idle.

It's not terribly difficult to pull the fuel rail to check the injectors if necessary.

Theoretically the system should hold fuel pressure forever, but my understanding it that it is not uncommon for the system pressure to leak down overnight via the check valve in the pump. Once the pump is energized when you crank the engine, it should pressurize the system almost immediately, so if that is the case and it's leaking back into the tank and causing no problem, I'd ignore it.

Yes it's hard to start. I turn the key on and off 6-8 times to build up pressure then it'll turn over 4-5 times and start sputtering and finally start and idles and runs normally. It does act like it is kind of flooded as I have to keep starter engaged while it's sputtering before it cranks. And sometimes when it does catch and start I'll hear a backfire from the intake.

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Also if it is an injector leaking down (which is what it looks like) is this from bad O-rings on the injector or the injector itself?

 

[Ranger]

I'd go ahead and check the injectors. Sounds like that's what the problem is.

It's not the O ring. It's the injector.

 

[mitlar37]

I'd go ahead and check the injectors. Sounds like that's what the problem is.

It's not the O ring. It's the injector.

Great - Thanks Ranger. I'm going to go ahead and get o-ring kit and replace all of them while I'm at it and hopefully just have to buy 1 injector -$45 on ebay for AC/Delco.

 

[rodnok01]

I bought reconditioned injectors off ebay for 100ish for a couple cars(6 cylinders so prob more).
They flush(clean) them until the flow the same and provide new orings... just something to consider.

 

[92 4.9 Deville]

I have this same issue with my 92. Its more noticeable since it got colder outside. I had a tank of bad gas a few weeks ago that clogged up an injector and caused it to stick open. I replaced it and pressurized the rail with the injectors lifted from the intake and saw no leaky ones but I still have the cold start problem with no pressure. I only have to cycle mine 2-3 times usually though.
Im leaning towards the check ball in the pump. A friend of mine has a shop and says he has installed cheaper aftermarket pumps in different vehicles and run into the same problem. Including his own Subaru. But never when installing the higher end oem replacements.
Maybe a quality issue with tolerances internally?

 

[mitlar37]

Well I got a FP tester and found that when I turn the key on and the pump does it's 2 second cycle the rail pressure immediately goes up to 45-50 psi then it takes about 3 seconds to drop back to 0 psi. Hadn't thought about checking the pressure after engine is at operating temp since it starts fine the rest of the day. Got a new injector and will pull the rail off tomorrow and see which is bleeding off (hopefully it's just one!). I've ran 2 tanks of Exxon gas and 2 bottles of Techron injector cleaner ( Autozone had a bogo free sale!) through it and still no change. Will post again after checking the injectors.

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I bought a cheap after market replacement pump and hope to god it isn't the problem. Replacing that fp was a royal pita.

 

[Eninety2]

Well I got a FP tester and found that when I turn the key on and the pump does it's 2 second cycle the rail pressure immediately goes up to 45-50 psi then it takes about 3 seconds to drop back to 0 psi. Hadn't thought about checking the pressure after engine is at operating temp since it starts fine the rest of the day. Got a new injector and will pull the rail off tomorrow and see which is bleeding off (hopefully it's just one!). I've ran 2 tanks of Exxon gas and 2 bottles of Techron injector cleaner ( Autozone had a bogo free sale!) through it and still no change. Will post again after checking the injectors.

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I bought a cheap after market replacement pump and hope to god it isn't the problem. Replacing that fp was a royal pita.

Reviving this old thread to confirm how exactly does one determine WHICH injector is bad? I'm having this exact same issue. It rang true when you mention the long crank AND the backfire.

 

[Submariner409]

Lift the entire fuel rail intact and turn the Key: ON. The fuel pump will do its prime and you'll see any leaking injector(s).

 

[Eninety2]

Lift the entire fuel rail intact and turn the Key: ON. The fuel pump will do its prime and you'll see any leaking injector(s).

Thank you.