Car Struggles to Turn On.....

[AmericanZ28]

After I got back from Vegas last weekend, I noticed that my car turns too many times before it actually turns on when I crank it. Sometimes it takes as long as 3-4 seconds to start, or a couple of tries. It happens almost every time I try to start the car whether the engine is warm or cold. There are no SES lights or codes. I thought maybe the fuel system but after a filter change, it still has trouble. The wires are pretty new and the coil and MSD 6A is new as well. Everythings looks fine. A Tech 2 scanner test showed no DTC, and turning off the injectors one by one showed that they were all working as well as the EGR. O2 sensors showed the following:
Bank 1 Sensor 1 80-833mV
1 2 230 mV (constant)
2 1 70-820mV
2 2 180 mV (constant)
IAT 114 F
Ignition 13 degrees (Idle)

No Misfire data. What could it be? Opti has 82K miles, car has 108K

[Joe 1320]

Are you for the fuel system to pressurize before trying to fire it? Have you checked the fuel pressure? Checked for vacuum leaks?

[MN6WS6]

Sounds like a fuel pump to me. My car did the same thing, and two months later left me stranded. I don't drive it much, so that actually equates to about a week in daily driver terms. Big PITA, but not worth the $500 the dealer wants to do it. I will post details if you need it. You really need to get a fuel pressure gauge on there and see what it's doing.

[AmericanZ28]

Ill have a mechanic check it out today at the dealer. Do the O2 readings look ok? So its not likely to be the opti? Car runs fine once on, and I did try to let the system pressurise before starting and no luck.

[96TAragtop]

Start with the cheap stuff. Replace your fuel filter- $7. Could be a pressure problem, spawned by a clogged filter.

Just because there isnt a light, doesnt mean that there isnt a code somewhere. See if you can get it scanned somewhere.

[AmericanZ28]

MN6WS6 Could you please post the details? I will be doing a fuel pressure check tommorow, what PSI should I expect? A mechanic at work told me that it was likely that the Opti could be going bad. I mean, 82K for an Opti sounds like a lot. But ill post tommorow with regards to the fuel pressure.

[96TAragtop]

Originally posted by AmericanZ28
MN6WS6 Could you please post the details? I will be doing a fuel pressure check tommorow, what PSI should I expect? A mechanic at work told me that it was likely that the Opti could be going bad. I mean, 82K for an Opti sounds like a lot. But ill post tommorow with regards to the fuel pressure.

40-45 PSI is optimal.

[MN6WS6]

Mine started out doing the hard start stuff, anywhere from 5-7 seconds before it would crank. I put a gauge on it, and the line was not pressurizing when you turned the key on. You could hear the pump run, but no pressure. The line would not start pressurizing until you actually started turning over the car, and it took the 5-7 seconds to get enough pressure to actually crank it. I posted on here, bunch of people said fuel pressure regulator. So I got that, put it on (MAJOR PITA), and the car still did it, just not as much.

Right after that, and I mean like the following weekend, the sucker left me stranded. It did that same hard start thing, then the next time I cranked it it wouldn't run at all. Watched the gauge, turn key, no pressure. Start cranking car, never got any pressure. New fuel pump, and it fired up on the first hit of the key, like the car was brand new.

If you want the details as to how to swap out the fuel pump, my story would take up a few pages. Let's just say it involved jackstands on hot pavement, a sawzall, and a whole lot of cussing.

[96TAragtop]

The fuel pump itself, has a pressure valve in it, to allow constant pressure to stay in the line when sitting, for these very start up reasons. I believe the FPR keeps pressure in check when the car is RUNNING, not when it is starting. Anyone who has replaced a fuel filter knows that there is a ton of fuel pressure in the line even when the car is off. This is all thanks to the pump, believe it or not.

Anyhow, little or NO fuel pressure with car off, is a sign of the fuel pump going out, for sure... that valve in there (that I referred to above) goes out shortly before the pump itself does, about 95% of the time.

With the car sitting for a couple hours, safe zone FP should be above 35 psi still. Running, I believe 40-45 is the majic # for a stock unit.

Additionally, our pumps (being semi-high volume), do NOT like to get hot. This means, NO running your tank almost empty. It only takes the gas running out ONCE, for the pump to burn out, if you're one of those people that runs the gas all the way down to almost E all the time. That will kill our pumps.

Between our touchy pumps, and our crappy EVAP systems, it seems you cant ful fill our cars, OR run them very empty (mostly for us LT1 folks). Plus, getting 15mpg (sometimes less) makes it tough to keep up with the gas gauge. One of the many idiosynchrocies in our cars

-G

[AmericanZ28]

The Results Are In.....

I did a fuel pressure check just now and with the ignition switch on, im getting about 25 psi of pressure. With the car on, Im getting about 33.5 PSI of pressure. Its been going on now for about 1 and half weeks with daily driving. So could this be the fuel pressure regulator, or the fuel pump? Ill admit, I drive the car down to almost E all time. But Why is changing the fuel pump on these cars such a PITA? Ive heard people complain about it, but are not sure why. What do you guys think?

[PiercedJD]

GM is notorious for bad fuel pumps.

on the bright side it gives you a reason to upgrade.

[AmericanZ28]

Correction!

I forgot to pull the vacumm hose from the Regulator before taking the reading. Im getting 41 PSI with the FPR vac. disconnected and 33 PSI with the hose connected. I take it its not the fuel pump thats bad.....

[96TAragtop]

Re: Correction!

Originally posted by AmericanZ28
I forgot to pull the vacumm hose from the Regulator before taking the reading. Im getting 41 PSI with the FPR vac. disconnected and 33 PSI with the hose connected. I take it its not the fuel pump thats bad.....

Ya, your pressure looks good man.

is it RUNNING ok? how is it running once it is started?

And not that it matters now, but our pumps are a PITA because 1) theyre expensive ($500 give or take), 2) the exhaust has to come down 3) The tank has to come down too
Mine went out a while back- Luckily, the warranty covered it
-G

[MN6WS6]

With the switch on, you should be getting 40+ PSI of pressure. If the FPR is bad, you will smell gas in the vaccuum line for it. If you take the vaccuum line off with the engine running, it's a high possibility gas will leak out of the vaccuum hole on the FPR, which is a 100% sign of a ruptured diaphragm.

With that low of fuel pressure with just the key on, it screams fuel pump. You might as well start budgeting for one. If you're gonna change it out, go aftermarket, like a Walbro. You can pick one up for ~200 bucks.

To get the pump out, you have to remove the exhaust, which means you have to practically take the whole rearend out of the car. The car has to be high in the air to get the exhaust to clear the rearend if you don't remove the rearend. I just cut my exhaust off at the axle since I'm redoing it anyway. I cheated and it still took me almost the whole day, and I was working with a hurt back and had to do it all by myself. The absolute hardest part is getting the tank physically in and out of the car after you have everything disconnected. GM in their infinite wisdom decided to make the filler neck all one piece, solid steel. That means you have to bend, pry, and kick (literally) to get it out of the car. Getting it back in is even harder. So be prepared to do some "metal contortion", which for all of us in the know, that means get out the bigger hammer.

The 01-02 guys have it made, their tanks are plastic with flexible necks

[AmericanZ28]

Thanks for the posts guys!

The car runs good once started. And I agree that the low PSI with just the switch on is a good indication of pump malfunction. Are there other pumps that you recomend? The ones mentioned seemed pricey. Thunder racing sells a Holley for $80 good for up to 490HP, is this a good choice?