hard starts

[danzick]

This has been an issue for a couple years now, but it has gotten much worse. When I start the truck at 45 degrees or under, it knocks like crazy, idles like crap and smokes the shop completely out in a few seconds. Once It warms up for a minute or so, the idle smooths out and it runs fine. Truck runs great, balance rates when warm are all great, I just replaced all 8 glow plugs last year in hopes of solving the issue but it didn't help at all. When I replaced the glow plugs, I verified the relay was working via a test light. About 5 seconds after the light expires I can hear my lift pump ramp way up and the volt meter goes up, so I'm assuming the relay is still working.

 

[danzick]

My old rattly 94 12 valve cummins daily driver with 270,000 miles starts with ease, smooth and hardly smokes at 10 degrees. really confused why this common rail is so horrible.

 

[DAVe3283]

I have a 325,000 mile LB7 with lowered compression, no intake air heater, +75% race injectors, and mine starts clean at 13°F with no rattle or smoke.

I really don't know why these common rails are so horrible. LOL

There is clearly something wrong with your specific truck. What all has been done to the truck? If it is tuned, that's probably the issue.

Edit: signature says PPEI tuning. Try flashing it back to stock and try a cold start.

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[danzick]

I do have the intake heater deleted. I don't have the stock file for the truck anymore. Long story, but it involves my original ECM being bricked. running it on 1 or 5 on the dsp doesn't seem to make a difference. It has 81,000 on the clock. I believe I replaced the injectors at 68,000. It seems to start fine when its warm, so I don't think its a leaking injector.

 

[DAVe3283]

I bet it is tuning. If you know someone nearby that you could borrow a stock ECU from, you could do that. Just do the 30-minute anti-theft relearn, then let it get cold and see what happens.

You could also try and get a dealer to flash a stock file on, or find one online. This assumes you have the ability to put your PPEI tune back on. Also, you might be able to contact PPEI and see if they kept the stock tune.

 

[danzick]

I do still have the stock file, but I don't think it will work in the new ecm?

 

[DAVe3283]

I do still have the stock file, but I don't think it will work in the new ecm?

It should work just fine. Just do a full flash to remove the DSP5 code, or it will get angry. And do a full flash to put the DSP5 tune back when you're done testing.

 

[danzick]

thanks, I will give it a try. I also emailed Kory a copy of my dsp5 file to double check everything.

 

[Josh154]

What glow plugs did you use? I replaced mine with 8 Diesel rx plugs and didn’t get any codes for a couple weeks but truck was knocking and smoking and shaking real bad. The codes finally showed up and had 6 bad plugs. Replaced them all with 8 ac delcos and the truck fires right up now no smoke or nothing. This is how bad it was and still didn’t throw codes for 2 weeks lol.

[YOUTUBE]nGiKlchCGTI[/YOUTUBE]

 

[danzick]

All new acdelco

 

[danzick]

That video it's pretty dang accurate. But more on a colder say. Say 20 degrees or lower.

 

[TheBac]

Thats been my life for a long time. I joke that my truck acts like an old Detroit when the temps get below 35*. :roflmao: I know my problem stems from poor injectors.

 

[DAVe3283]

It could be injectors, but with how low the miles on them are, unless they were junk injectors, it is probably tuning. Not many tuners alter the cold start tables (and there are a lot of them), so it can get cranky as tunes get more aggressive. And honestly, even GM's stock cold start tuning was kind of crap. I made improvements to that when my motor was stock even.

With some effort (OK, a lot of effort), you can even have a built motor with big injectors start and run clean in the cold:
[YOUTUBE]vsn1Frr_was[/YOUTUBE]

 

[danzick]

interesting. I will have to see what Kory says. They were LDS injectors.

 

[danzick]

bringing this back up. I think this is from bad injectors. Ever since I put some garbage injectors from LDS in this thing a few years back it has never started right. I fired it up tonight after it has sat for 2 weeks. smoked like crazy and had a bad miss/knock. I started noticing it wasn't going away. One balance rate is at 15, and another one was at 5. it smoked like crazy driving until it hit around 140 on the ECT. Balance rates are ok when its at operating temp. I think these two injectors have been leaking into the cylinders since I installed them. This would explain why it always blows a ton of smoke at start up.

 

[Yngdmax92]

bringing this back up. I think this is from bad injectors. Ever since I put some garbage injectors from LDS in this thing a few years back it has never started right. I fired it up tonight after it has sat for 2 weeks. smoked like crazy and had a bad miss/knock. I started noticing it wasn't going away. One balance rate is at 15, and another one was at 5. it smoked like crazy driving until it hit around 140 on the ECT. Balance rates are ok when its at operating temp. I think these two injectors have been leaking into the cylinders since I installed them. This would explain why it always blows a ton of smoke at start up.

I'd make sure you diagnose that before going off on lds. I think they sell quality stuff as I've nvr had a problem with there stuff...but why don't you try killing some injectors during start up to make and see if smoke dissapates. Pretty simple, and sense you have it narrowed down to two it won't be that hard to make sure.

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[Yngdmax92]

Actually, didn't you have this problem a while back? You were asking about bent rods before I think?

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[danzick]

not going off on them. Just my opinion. and yes. Ive been having problems with starts ever since the day I installed these injectors. The problem has slowly gotten worst over the years though. It started doing it right after the injectors. I spent a lot of time on the phone with Brent at LDS but he kept saying it had to be something else. My balance rates have always been bad at the cold start, but he didn't seem to think that was a bad thing. If I'm not mistaken they have about 12k miles on them now.

 

[IOWA LLY]

If it happened right after you installed the injectors you probably got dirt in the lines or injectors. I promise you it isn’t the fault of LDS. Either you botched the injector install, or your motor has more serious issues.


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[danzick]

Good to know thanks.