Thanks Everyone, but one more issue

[Oredigger97]

First of all, I want to thank everyone here for all of the valuable knowledge. Between here, TTS, and TDP, I have gained a wealth of knowledge about my new to me truck.
I recently bought my 94 as somewhat of a project truck, it needed new injectors and came to find out later it also had a piece broken out of an intake valve causing a miss. It recently got new heads before I bought it so that was strange. I tore the head off and fixed that and while I was there, did a ton of other work to try to make this thing as reliable as possible, its a long ways between towns here in montana.
I ended up putting all new exhaust on the truck, new injectors, new glow plugs, pmd relocate, lift pump relay, new lift pump and wix spin on prefilter, new harmonic balancers, and aftermarket braided oil cooler lines. I fell prey to the classic "while i'm here", but its done now and I'm pretty happy overall.

So now to the only problem I seem to have left. On startup it smokes really bad for about a minute, I searched the forum and found a few similar cases but nothing definative. I have been searching around and did the trick and unplugged the coolant temp sensor and started the truck, fired right up and no smoke, higher idle, everything was grand. I stuck a new CTS in it tonight and it still smokes like crazy so not the CTS. I am down to injection pump timing or possibly the intake air temp sensor. It did have a new IP put in about 20,000 miles ago by an independent shop, I'm thinking maybe he didn't do the relearn on the IP. Only other thing I can come up with is that air temp sensor. Any thoughts?
I'm thinking that it is definately one of the two because yesterday I started the truck, smoked like crazy, turned it off, unplugged the CTS, started back up and no smoke, idled like it should. Thanks everyone.

[DmaxMaverick]

If your only issue is the startup smoke, either change to quick-heat glow plugs or extend your glow plug cycle time. Simple as that. AC60G plugs are great, but they heat very slow.

[slicer89]

I know how you feel about the long drives in Montana.

I'm having the same issues, Only mine runs like crap for the first few seconds and smokes out the entire street in white smoke.

I'm narrowing it down to glow plugs not working right, or bad / worn injectors.

[Oredigger97]

If your only issue is the startup smoke, either change to quick-heat glow plugs or extend your glow plug cycle time. Simple as that. AC60G plugs are great, but they heat very slow.

If it was glow time, why would unplugging the cts make a night and day difference? I forgot to mention it stumbles a little and will pop in the exhaust a little when it smokes real bad until it has run for a minute or two. When i unplugged the cts the idle went up, no smoke at all, and smooth with no stumbling. This is why i think it is timing or sensors (already changed the cts, didnt help). Thanks for the help.

[Oredigger97]

Slicer, where are you at in our fine state? I thought my problem was glows and injectors too, they helped and it needed them anyway, but havent cured my woes.

[DmaxMaverick]

If it was glow time, why would unplugging the cts make a night and day difference? I forgot to mention it stumbles a little and will pop in the exhaust a little when it smokes real bad until it has run for a minute or two. When i unplugged the cts the idle went up, no smoke at all, and smooth with no stumbling. This is why i think it is timing or sensors (already changed the cts, didnt help). Thanks for the help.

Bingo!

Re-read my previous post. Unplugging the CTS creates a condition when the PCM "thinks" it's going to have to start at -40 (open circuit default). Result: maximum glow time and cycles (full tilt, give 'er all she's got!). If unplugging the CTS "cures" your issue, then your issue is cold plugs, for whatever reason. Either change to a hotter/faster plug, or extend the glow cycle time. Consider, it isn't even winter, yet.

[Oredigger97]

Thanks Mavrick, so I have been paying attention to the glow plug cycle. It only seems to provide about 8-10 seconds of glow plug time at cold start no matter if the CTS is plugged in or not, doesn't seem to change. It does start better when I get two full cycles of the plugs but my question is there a sensor that is possibly screwed up that is causing it to not vary the glow plug cycle? It also isn't doing any afterglow, which also seems strange. I put a new CTS in it and I ran it on a scanner tonight and it looked like the air intake temp sensor was working fine. I am planning on building a bypass relay so I can control the glows manually if that is all it is but if a sensor is bad somewhere I really want to track it down. Thanks for the help guys.

[rapidoxidationman]

Have you tested each glow plug to insure they're all getting power when they're supposed to? A broken wire could cause problems.
8-10 seconds of glow time sounds about right for a COLD start, like what you'd see in sub zero weather or with the CTS disconnected. The glow light on the dash won't indicate afterglow.

Have you done a compression check? A cylinder that doesn't compress well wouldn't ignite well at colder temps and if a piece of a valve got eaten then you may have a scratched cylinder wall somewhere. What happens when you take the oil fill cap off? Is there a ton of blowby?

[More Power]

Increasing glow time can mask the true cause of a hard starting problem.

As a fuel injection system ages, it becomes harder to properly atomize fuel at cranking speed. Poor fuel atomization can result in hard starting. www.thedieselpage.com

As an engine starting system ages, cranking speed slows. Batteries, cables and starters contribute to cranking speed. Slower cranking speed results in poorer fuel atomization and lower cylinder pressures/temperatures at cranking speed. Slow cranking speed can result in hard starting.

As an engine ages, piston ring wear can result in lower cylinder pressures at cranking speed. Worn engines can experience hard starting.

It's not always just a choice in glow plugs... but that's a good system to eliminate early-on in the troubleshooting process.