Hi everyone,
I have been troubleshooting an extended crank at startup on my 2002 Chevy Suburban 1500 with the 5.3.

Symptom: I can just hold the key in the start position and it will eventually start or I can just crank the engine for a split second and then on the next attempt is starts up instantly. This is regardless of if the vehicle is starting for the first time in the morning or it could be warmed up from a long drive.

180k on engine
Bought it used @ 168k
issue started right after an oil change following 950 mile return trip from Florida after Holidays.
Used Valvoline High Mileage synthetic blend (Can hardly find conventional oil these days) and an STP 3675 from autozone.
Accedentally over filled by about 1 quart during oil change by using multiple half jugs of this brand. (decided I can't just post this with the 1 quart over full because it would be a splinter in my mind)

Notes: I have put a large bottle of sea foam in the tank and then filled it up with premium and ran that through just incase it was a bad batch of gas. No idea if it is a gas pump or what.
(went out to driveway mid composition of this post and drop the filter a few times IOT bring the oil level to exactly where it should be)

***(Edit: I will add any new or relevant info below this line IOT present the most accurate picture)***
15 January 2023 The problem seems reduced but is still present

16 January 2023 I have turned the key on and kept it on for several seconds prior to starting to see if that makes any difference. The problem is still present. I am now leaning toward an electrical issue as the culprit, since I can crank the vehicle for about 5-7 seconds and it will start. I can also crank the vehicle for half a second and pause...then it starts with no issue on the second attempt.

16 January 2023 I have confimed that turning the key on and off prior to the first attempt to crank the engine does eliminate the extended crank symptom. Also there seemed to be no fuel pressure to be releived when I depressed the spring loaded check valve near the FPR.

16 January 2023 Checked fuel pressure and it is steady around 40PSI at idle and will go upto around 45 or more if given throttle.

17 January 2023 discoverd that my Suburban is indeed a flex fuel vehicle

22 January 2023 installed the new FPR and have been test driving it to see how it performs

23 &24 January 2023 There is marked improvement in the symptoms after the new FPR has been installed but if I pause too long after switching the ignition to the on position before cranking I will still get the extended crank on start or need to pause and crank the engine again.

**************************************NEWEST DEVELOPMENT WHILE TROUBLESHOOTING*********************************** ************
29 July 2023 I have determined that is may be an electrical issuse. I can cycle the ignition switch to the on position 3 times and to the off position 2 times in a slow, deliberate manner before cranking the engine. I starts within one second every time. The key fits loose in the ingnition switch since it is so old. I don't know if the problem is a worn out ignition switch or if there is another item that is not getting properly energized without fiddling with the ignition switch.

*SOLVED* It was the fuel pump. There is a check valve in the fuel pump that prevents the loss of fuel prime after shutting off the engine. This is why I could restart the engine right after shutting it off to go in a gas station really quick, but anything longer than that would often result in the delayed start or extended crank as I like to call it.

 

Could sure use some help with this...guess I thought it was fixed. It still acts up a little bit.

 

Try turning there key on for a few seconds before starting to see if that works. If it does, it might be the fuel pump.

 

I should have mentioned that I always turn the key on for a moment before cranking. I also did turn the key on for several seconds prior to cranking the vehicle to see if that made any difference. I'll be spending a little more time today experimenting with "what works" and so on. *edit* Thank you for replying and giving ideas.

 

Sounds like a fuel pressure regulator.
Try key on for a few seconds, off, on for a sec, and crank. I have to do this on my 06 Burb 5.3. Mine is a flex fuel so the FPR is located on the pump assembly in the tank.
I will keep doing this till my fuel pump need a replacement.
Gas FPR is easy to replace. Under the hood.
You could always rent a fuel pressure tester from one of the parts stores to test static and running fuel pressures.

 

Tried the key on twice before crank first thing this morning. The truck started in the proper amount of time. I'm going to see about replacing the FPR. Hope the parts store is open today, if not then it's going to be next weekend. Thanks for the insight.

***edit** I picked up a FPR from local parts store and was about to install it when I noticed that it was the wrong style and will have to order one. The thing I noticed when I attempted to release fuel pressure from the valve was that there was no pressure and I had just returned from the parts store. Does that indicate a fuel pump going out? The vehicle runs smooth at all RPM's after starting and runs smooth at all speeds with plenty of power and acceleration.

 

Just realized I was looking at the wrong valve. Bought a pressure tester and hooked it up. Pressure stays steady around 40 PSI after starting. The pressure will spike to 40 when I turn the key on and then drop after a moment when it's acting up or just not increase in pressure at all. Also when the engine is off the pressure drops back down to nearly 0. Is the pressure supposed to hold more than 5 seconds after the key is switched off?

Fuel pressure steady at 40

 

AFAIK, 40 psi seems a bit low. Key on static pressure should be between 50-60 psi. Running it should be around 50 psi.

Could mean a weak fuel pump.

Is this a gas or flex fuel 5.3? Flex fuel spec is a bit lower.
I think flex is 42psi at idle and 50psi with vacuum hose pulled off regulator

 

I guess the darn thing is a flex fuel. It has the E-85 lable inside the fuel door. The pressure will go past 45 and almost to 50 if I give it a little juice, but it will settle back down to 40 when idleing. I guess I can be safe and replace both the fuel pump and the FPR. I hope it is not the fuel pump. I now also understand why the parts store couldn't get the part right yesterday. I think I will be going with the FPR replacement next weekend unless someone has a strong belief that it is not the FPR.

 

Check the parts. My 06 Burb flex fuel engine has the FPR mounted on the fuel pump in the tank.
Looks like an 02 might be under the hood.

mine is like this