96 K1500 Cranks but won't start
1996 Chevy Silverado K1500 4WD, 5.0 WILL crank, but will not start. No fuel pump noise when key turned on. Now I recognize a quick diagnosis would be that the fuel pump is the culprit, but keep reading. When key is turned on, none of the normal starting lights come on (check engine light, airbag, and batt). With the key in the "on" position, none of the gauges seemed to be powered -- fuel quantity, oil, and batt voltage (only the gear indicator is illuminated (P)). Though when key is moved to ignition, engine cranks normally -- won't start though. Radio, fans, windows, all accessories also work. When key is moved, no clicking is heard from any of relays under hood. All fuses checked good.
There is a history of the common fuel pump problem (engine quits unexpectedly -- 3X in two years), but problem seems to resolve itself in a 24 hour period (in one case after a tow), so I really question whether it is the fuel pump. Seems to be more inline with the starting sequence logic, perhaps VCM/PCM/ECM? Any help would be greatly appreciated
Problem solved for now...
Thanks guys excellent advise. After two days of research on the Internet, as well as your help (I really did not want to change a fuel pump), I traced the problem to the fuel pump relay (for now). Although, it wasn't as simple as just changing the relay. In fact, the first thing I did was to change the relay but remember that I mentioned that when I turned the key on, I would get no gauge lights (check engine, batt, etc.). So, with the key in the on position, I wiggled every connection under the hood. When I went back to look at the dash, bingo, I had gauge lights. So, I proceeded to start the vehicle. Around the third attempt it would start. Now I mention this because my research educated me on a few things. The best info is that when you turn the key on, although you should hear the fuel pump whine for 2 seconds, it's absence doesn't necessarily mean a bad fuel pump. There is a back up to the fuel pump, and that is the oil pressure switch. Initially during the start (again after I got the gauge lights back) the oil pressure was indicating zero. Around the third attempt, the oil pressure would raise, and the truck would start. I hope this helps those who have the "hard starting" issue, as well as those who don't hear the fuel pump when you first turn your key to on. To fix the hard starting issue (or starting after oil pressure build up), I went back to the fuel pump relay. I replaced it, and now everything works fine.
I honestly believe that a lot of people first change the fuel pump only to find that the fuel pump is not the culprit. I've also read posts where people have changed CPS's, and PCM's with no luck. Bypassing the fuel pump relay (I used a jumper over the relay early on) told me the fuel pump was good, and the lack of gauge lights led me to check all connections. So for me, it was a combo of loose connections (which I am not sure I've permanently solved), and the fuel pump relay.