I need help/advice...I am stumped. Truck was running fine, then one morning it started acting up on me..cranked over and over and over 30+ seconds at least before starting. Once warmed up ran fine re-started fine, but if it sits over night it would have a really hard time starting. Changed fuel filter, went to start and just turned. Went to prime system and found lift pump went out. Replaced pump, reprimed, turned and got nothing. Checked fuel to injector pump, tried to bleed prime at the injectors....little to no fuel. Disconnected intake heater, reluctently gave it a shot of ether, fired up and ran fine. Shut down re connected intake heater, went on a test drive seemed fine. Figured maybe I was air locked in the injector pump. Parked truck, tried to start it this morning and it just turned. Pretty cold out, maybe 40 or so. Tried it again this afternoon, maybe 75-80 out, fired right up no problem. Tried it again tonight, down to maybe 55, struggled a little but started. I have been hoping it's not my pump starting to go...also found this evening that my intake heater isn't heating up. Checked voltage at intake...0. Checked voltage at power center, measured low..checked at heater relays found them to have it on the battery side, but dead on the heater side. Going to get new relays tomorrow and hopefully it fixes some of my problems. Anybody out there have any tips for me. I haven't ever experienced the hard to start issue with the truck, normally turns a few times and fire right up. Had it for about 4 years or so, has around 300K. I think it is the original injector pump, or at least thats what the guy I bought it from told me. Any advice is greatly appreciated!!

 

You should have a fuel pressure gauge, a temporary one will do. Is the truck level when it's hard to start? Go by autozone and check on any codes.

 

before replacing grid relays, how did you check them? they are controlled by ecm and I dont believe its cold enough for them to even cycle.

if you suddenly started getting hard starts but no drivability issues I'd suspect a air leak on the return side of the fuel system. as tank vacuum will haul the fuel from the VP back to the tank, to test park nose down hill or leave the fuel cap loose, it it fires right up after sitting for 7-8hrs. it will be a fuel problem or faulty fuel cap/tank vent

 

codes P1693 and P1689, believe they are due to me trying to figure out if I had a bad relay or not...pulled the fuel relay and the heater relay a couple times checking if I had power to them or not. Next step will be a fuel pressure test. Really hoping its a simple fix and not he pump.

 

just checked the grid relays with a tester. mechanic buddy was helping me...relays won't activate over 60 F is what he told me. Here's the kicker though...yesterday it wouldn't heat up at all and now today it is heating up. Didn't do anything to it, just kind of comes and goes. Both checks were in the 45-50 F morning weather. Should have been cold enough for the intake to heat.....still stumped. No check engine light on, and only those two codes present.