So my 2001 1500 318 has always started quickly and easily. The idle was sometimes a bit choppy but always revved and drove smooth. The first cold mornings are hitting and I went to start it. I don’t recall how cold but somewhere from 35-45 degrees probably. It cranked and cranked and would fire sporadically, just enough to raise the rpm a bit. It started eventually with the help of pumping the gas pedal. It was very rough, then immediately smoothed out to normal.

Ive been reading the other posts about issues like this and I’ve tried priming the lines in case it had leaked down to the tank. That did not affect it, and yes I could hear the relay and the pump running. Today I pulled the throttle body off and cleaned it pretty good. I removed the IAC motor and cleaned out its bore and where the piston seats. I had cleaned the IAC motor some time back already. New gasket and some Hylomar blue on the TB side and put it back on. No change, but when I did get it going it blew some white/gray smoke. Again, really rough then smoothed right out. Warm idle has always been around 600 RPM just FYI. Don’t know if that has anything to do with it.

 

How's fuel pressure? You need to check it with a gauge.

 

Update, this weekend the truck sat for 2 full days. Wasn't too cold but it started right up. Otherwise I've been having luck with priming the system with 3 turns of the key. However, this morning it took me 10 minutes to get the truck started. Was probably 45-50 degrees out. Just like I described before, it cranked and cranked and hardly fired. Between each 5 seconds of cranking I primed it again. Really not sure what's going on because there's no way it didn't have fuel. Is it possible to over fuel it by doing that?

I'll have to check my fuel pressure this week, unfortunately the nearest parts store is an hour drive. When I check it I'm assuming I should just turn on the key, take a reading and see if it drops? What's the spec for pressure? Thanks

 

Check fuel pressure, and also check and see what tempt the PCM thinks the engine is when it is cooler out.

 

Ok, how can I check what the PCM is reading? Also I remember somebody saying if you pushed the plunger in on the IAC it messes it up. I might’ve done that but I don’t remember exactly, it was a while back when I first cleaned it.

 

Need a scan tool even a cheap one can read that data. That might mess up the idle but I doubt it would make it hard to start.

 

Ok good to know. Forgot I had a Napa in town, I'll be going there tomorrow. I'll check fuel pressure and depending on how that looks I'll do the coolant temp sensor too.

 

Check your distributor cap. Cold air can condense moisture in the cap and it will short out. This makes a no start problem. Look for any hair line cracks or burned electrodes. You may just need a new cap and rotor. Everybody has all sorts of uses for WD-40, but this is what it was originally designed for. Getting the moisture out.

 

Update again. I checked the fuel pressure, absolutely no problems there. Running pressure at operating temp was a steady 49 PSI. Shut the engine off and it held at 45 PSI for over 5 minutes, and didn't go below 40 for even longer. Since that was good I went ahead and replaced the coolant temp sensor. Some coolant found its way out of the hole so I topped it off at the cap. Afterwards it was running ~10-15 degrees hotter than normal, either that or the new sensor is reading different, whether it's accurate or not. The next morning it started fine if I remember.

I decided to bleed the coolant in case I got air in the system. I parked uphill and drove up a bank a little bit on the passenger side. Engine was cold and I let it run up to temp with the cap off and heater on. Didn't see much for bubbles so I called it good. That did not seem to make a difference, but I guess it doesn't matter because it's still under 210 degrees.

Now for the interesting part. Today I drove back to where I work, about 3 hours. Shortly after arriving I needed to make a run to the store. The truck was still plenty warm. I turned the key and it cranked with zero fire, sounded like it didn't have any fuel or spark. Few tries later it coughed to life and idled really rough. Got to the store, came out 10 minutes later and it did the same thing, cranked abnormally long but this time started on the first try. Hard starts always seem to happen immediately after long drives. They happened in the middle of the week too, though.

While bleeding the coolant I noticed the boot on the ignition coil was arcing to the top part of the coil. The truck doesn't misfire, and I figured a bad coil would cause an absolute no-start condition. Is that just a bad wire/boot or could it be the coil? Maybe the coil is causing the hard starting?

 

The different sensor reading may mean one or the other is off. The remote infrared thermometers are pretty handy to have and one will tell you what the engine is running at. As for the coil, it definitely should NOT be doing that. Since it is doing that and you have a hard start on when hot, I'd say you have a heat soak issue. It has a crack and as it heats up, the crack expands. Replace the coil and I'll bet that particular problem will go away.