Hard starting '01 8.1L
 

Didn't notice this much when I first got this truck, but now that I'm driving it a little more often, it seems to be a trend. Truck cranks and seldom starts on 1st try. Starts easily on 2nd try. No other issues at all. Anyone ever experience this? Normal weather conditions - doesn't matter if truck has been sitting or if I just shut it down 10 minutes ago.

Re: Hard starting '01 8.1L
 

When I first brought my 2005 home it would do this intermittently. It had some pending misfire codes after an extended cranking session... Extended being 5-8 seconds rather than instant fire.
I changed the spark plugs and wires with OEM Delphi wires and AC Delco platinum plugs.
I also changed the oil in the whole driveline along with the air and oil filters.
The oil pressure came up to the centre mark and stopped regardless of engine RPM. After the oil and filter was changed the gauge reacted to RPM changes and the pressure came up a bit faster.

For the 8.1L 496
I'd use the NGK TR55GP Platinum plugs or AC Delco 19299585 Platinum plugs. Delco plugs are still my first choice but NGK are high quality plugs as well. Iridium plugs aren't recommended for the engines in the GMT800 rigs.
Denso 6718064 plug wires. Delphi doesn't make 496 wire sets and the AC Delco wires are low quality made in China now.

Re: Hard starting '01 8.1L
 

Thanks Hatzie, very helpful info. I haven't set an codes yet, but that may be around the corner. I have been experimenting wihh how long I wait after moving the key to on. A good, honest 4 count seems to eliminate the issue - maybe I was just starting it too quickly, even thought that really shouldn't be a problem. My plugs are original, but only have 13K on them, they looked pretty good when I checked them - but haven't swapped any wires yet. I'd assume that if it were wires or plugs, it would be an issue no matter how long I waited to turn the key after switching the ignition to on. All the fluids are fresh throughout the truck. Thanks very much for the part numbers, I'll keep these on mind! Yes, AC Delco made in china just makes me kinda sad...

Re: Hard starting '01 8.1L
 

Waiting a few before cranking actually eliminating extended cranking sounds like fuel delivery.
Check valves?
Fuel filter?

Re: Hard starting '01 8.1L
 

An 01 has a return style fuel system. Check the fuel pressure regulator.

Re: Hard starting '01 8.1L
 

Thanks for the replies. I did replace the fuel filter about 150 miles ago, but it didn't solve the problem (I just changed it because I had no idea how long it had been on the truck - believe it was the original and the truck had been sitting for a long time, wasn't yet trying to solve this issue - but it was a little hard to start prior to and after the change, so don't think that was the issue). Will check press reg, thanks. Also noticed it sometime idles rough for a few seconds after start, kinda like it's learning.. ha. The weird thing about this issue is that it's intermittent - when I mentioned above that it seldom starts on the first try - that also means that SOMEtimes, it fires right away and runs great. Odd. Thanks again for the inputs.

Re: Hard starting '01 8.1L
 

Well.. no leaks on the vac side of the fpr, and I showed rock steady 45 psi with key on and rock solid 45 psi running (and, of course, it started right up... ha). But - I did notice that it bled down rather quickly after shutdown - but I didn’t really measure/time it either. So I went back to re-test and now all I get is zero psi... yet the truck runs perfect. Reattached to the Schrader valve several times, nothin. I think my gauge actually bit the dust, ha, perfect timing. Could still be the fpr, but troubleshooting came to a screeching halt when the gauge quit. Kinda hoping it’s not a leaky injector, but certainly possible - or the check valve, as has been mentioned. I’m gonna try my “bad” gauge on another truck just to make sure I’m not losing my mind. Once that is resolved, the troubleshooting can continue. Strange behavior.

Re: Hard starting '01 8.1L
 

Minimum fuel pressure spec is 58(engine not running). So I think your gauge was acting up.

Re: Hard starting '01 8.1L
 

Thanks for that additional info - assumed same but that pretty much clinches it. Getting a new one.

Re: Hard starting '01 8.1L
 

Sounds exactly like a failing check valve in the fuel pump.

Re: Hard starting '01 8.1L
 

Problem solved - pressure regulator.

Re: Hard starting '01 8.1L
 

At work I had a c6500. 8.1 that was always hard starting. 336,000 miles before they bought me a newer box truck. Anyways, some guys would get in it and couldn't get it to start. I got used to the drill when it was extra stubborn. Whirl it over awhile, then stop. Then turn the key back on and wait 5 seconds or so. Usually it would pop off then. If not whirl it over and try again. I always wanted the shop to put in a new fuel pressure regulator but they never did. There were a few times it backfired crazy loud. It sounded like a 12 gauge going off. I have never heard a backfire that loud before. That happened a couple times during the 5 years I had it. And lastly, those 8.1's sure are tough. I was never under 20,000 pounds with it and usually around 26,000 pounds. It burnt oil of course but it sure got abused and took it.