I've had the cold start blues for two years now - white smoke and rough idle on cold starts - even at 40F. It's worse the colder the temp is, and plugging in the block heater helps dramatically. Here's what's been done:

1. GPR checks out fine. Just replaced with a Stancor unit, and I've verified proper operation. I see 11.7V going to the glow plugs. The relay shuts off after an appropriate time (less than two minutes).
2. I have the 50 cent mod in place at the UVCHs.
3. Unplug the UVCH, terminals look good, nothing burned. Metering each glow plug returns .8 or .9 ohms. Bosch glow plugs are in there, replaced them a year or two ago.
4. I've metered each glow plug wire in the harness, from the UVCH connector to the out feed on the GPR, and all return .3 or .4 ohms.
5. New 175/146 injectors from Swamps, with tuning to match.

When we replaced the injectors (last week), one had a disintegrated lower o-ring. There was a piece of o-ring in the bottom of the cup, which we extracted during cleaning. I thought for sure that was my issue, but even after injector replacement, I'm still having the same cold starts. Yes, I know a little smoke is expected, but I'm having the toxic cloud that neighbors just love, with a bit of rough idle, the duration of which depends on temperature.

So, where to next? Is this a sign of a failing HPOP? Any other "easy" things to check prior to making a bigger, more expensive trial and error part replacement (Tugly Buckszooka-style)?

Thanks guys.

 

Also, note that compression shouldn't be an issue. I haven't actually performed a compression test, but the smoke issue clears after driving. A true compression issue would continue to smoke after engine warm-up, as I've been told by numerous sources.

And I run 5W-40 synthetic, year-round. Used to be Rotella T6, this time i went to Delo synthetic.

 

Without a scan tool or Torque, you might as well whip out the dart board, a blindfold, and your Buck$Zooka rounds.

Not to be contrary, but just being informative for the readers: Each of my Buck$Zooka blasts hit the mark... because I have a scan tool and plenty of input from FTE before I load a clip. It may seem like I went on a wild spending spree... but it was more like a carefully planned campaign against Stinky's fail spree.

 

That's not entirely true. I would check compression and also verify that the glow plugs actually heat up.

 

Bosch would seem to be good but there's lots of problems with anything other then motorcraft. You only need two to be none functioning correctly to have this problem. Use a heat gun on the exhaust manifolds to see what cyclinders are the coldest during warm up. That should tell you something. Like said by Tugly, a good scan gauge or AE would tell the story.

 

Just for the record, what would you be looking for from an AE/Scan tool to help diagnose this situation? Just trying to learn a bit more here as I plan on getting a scan tool in the next month and have similar type issues on cold start ups.

Thx

 

These are the big five. They all have to reach minimum values before the injectors will even fire. If these are all above the minimum and the truck still doesn't start, then it comes down to compression, fuel/quality, and heat.

 

Thanks Rich, you know the next question right? What are the accepted minimums for each of those as I see the in your visual you have maxiums depicted but the mins are all 0......

This is the type of stuff that really helps us figure these things out.

Also, I have read a bunch of threads where people claim their tach will show X rpm while cranking and if it doesn't hit X then injectors won't fire etc. In four different 7.3ls I've tried I have never ever seen a tachometer so much as move a wink during cranking.....so what is the truth on this?

Thx

 

The thing is, according to his description, he's not necesarrily having hard cold starts, he's just having rough idle with lots of smoke after starting. All the usual suspects seem to have been addressed.

 

Good point; I wonder if he has tried starting it in a stock tune or can he with 175/146s.......

 

All the minimums are covered in the last link in my signature, but going off memory:
ICP - 500
ICP DC (IPR) - Not really a set minimum, but it indicates the workload on the HPOP to achieve ICP. I would expect to see 14% KOEO and 31% while cranking.
Battery Volts - 10.5 is the common thinking, but I've seen trucks start with less.
RPM - the book says 150, but this is another fuzzy one
FIPW - 0.6 confirms the IDM is "ready". If that 0.6 isn't there, the show's over before cranking. Minimum while cranking is 1, but you won't see that low of a number when firing. It should be noted this is the last "stage"... the IDM doesn't fire until all the other criteria are above minimums.

As for the confusion on the tach... it depends on pre-2002 or post. Ford radically change the electronics for the 2002 model year, so the tach will behave differently for 2002/2003 trucks. I forgot which way it switched - tach or no tach while cranking.


You are right... I'm so wrapped up in no-start threads that I'm starting to zombie replies on this. Glow Plug system is highly suspect. That being said, I have no clue what the ICP is, and we all know that's not going to happen without a scan tool. And to "validate" the ICP reading, I would want to see the IPR signal... another scan tool exclusive.

It will actually fire up a little aggressively on stock tune. The Hydra has the zero setting that bypasses all tuning and puts it back to stock. My truck fired up with 160/100s on a stock tune and I drove 400 miles to get home with it like that. People talk about a touchy throttle on a DP 80E tune... that's nothing compared to this. Imagine removing the bottom part of this picture:

 

Steve, what altitude are you at?

 

how many miles on the truck?
dose it start fine or do you have to run the starter to get it going?
dose the smoke have a smell?
11.7v to the gp sounds low, i might check the battery clamps, as low volts will make the gp not get good hot.

 

Hey guys, a few answers for you and an update...

River19 - the 175/146 (175/0 for layman terms) injectors are single shot, so starting/running with the stock PCM isn't good. When done, it lopes like a gasser with a monster cam.

White Buffalo Rich - I'm in Bozeman, just shy of 5000'. Currently snowing.

Matt - 167k on the truck. Just switched to these injectors last weekend. Yep, starts quick with minimal cranking - like two seconds quick. Oh yes, that smoke has a nasty smell that just loves to hang around, especially if you walk through it. It's the typical white smoke cold start partially burned fuel smell. The 11.7V was at initial load of the glow plugs. Still after startup, they should be seeing the full voltage from the alternator, and I'd expect the smoking to quit pretty quick if that was the issue. It continues for a bit until the oil temp starts to rise.

Update - I talked to Dave at Swamps about this. Pre-injector swap, I was having this same issue. Because of the behavior and the age/mileage of the injectors, I was convinced it was worn out poppets on the factory injectors (or maybe it's tax refund season and I wanted an excuse to go new injectors). I still think that was the case. And the #6 injector had a shredded o-ring. However, that's obviously not the cause now. Dave directed me to a thread on Powerstroke Army. I'm not the only one with a ZF-6 tranny that sees this same issue. Quoting what I found today:

"What I'm getting at is when you go to different injectors the timing adder needs to be changed. That's what got rid of the smoke for me. You don't eliminate it, you simply modify it to account for the injectors. The smoke is unburnt fuel and the table just needs minor tweaks. For me lowering it by 35% did the trick. You'll probably only need to lower it by 10-15% and it'll get rid of the smoke but still act as designed.

What I meant by taching it out is with an auto trans you can adjust shift points to account for the cold oil, trans, and motor. With a manual there is no transmission tuning, so from my understanding they did it through this soi adder. Basically makes the truck a slow turd when cold so you bring cylinder pressures down and don't hurt anything when cold. Side effect is a little extra haze when cold. Bring this table inline with your base timing table and it goes back to working like it was intended and acting stock on cold start ups."

So, I talked with Dave a bit, and he's going to tweak the tunes to see if it's truly a tuning-related issue, which is typically isolated to us control freaks with manual transmissions. I'm really hoping that could be the issue here. The truck runs wonderfully besides the smoke at start-up. We'll see what Dave can come up with tomorrow. I'll keep everyone posted.

 

Good to know Steve. Thanks.