Cold... Very cold

[AH64ID]

If it's cranking and not firing there should be white smoke if fuel is getting injected. No white smoke means no fuel. 

[kzimmer]

5 minutes ago, AH64ID said:

 

 

So you had the current pop pressure with different nozzles? And the issue started with new nozzles? 

 

That sounds like a nozzle issue and not a pop issue. 

 

I had cheap DSS 7x.014 injectors set at 340 bar with no issues of any kind. Actually improved cold starts. The DAP 7x.013's went straight in at 365 bar. All in the name of science and experimentation. No regrets! Well maybe a little...

3 minutes ago, AH64ID said:

If it's cranking and not firing there should be white smoke if fuel is getting injected. No white smoke means no fuel. 

 

Yep, agreed. And there is fuel when I crack the lines, cylinders 3, 4 and 5. Now, that doesn't mean the VP is building as much pressure as it should... but regardless, the problem is only below -20° C. And the truck drives great.

Edited December 28, 2017 by kzimmer

[TFaoro]

12 minutes ago, kzimmer said:

 

That's a very good question. I remember looking once and not seeing anything. Even when I finally get it running, there is very little smoke, at least no more than expected on an arctic temperature day.

 

Note: I did crack three injector lines on the 25th when I couldn't get it running. Plenty of fuel dumped out when I cranked. I don't think that fuel, or rather enough of it, is making it through the injectors.

 

You should have seen my 2003 Jetta TDI smoke when it started that morning. Made my dodge look like a prius.

In my experience, there's a pretty fine line between too much fuel and not enough fuel. 

When I had a VP and large injectors the truck would buck and knock blowing smoke everywhere until it hit 800rpms and was no longer calling for Chit loads of fuel. 

Now with a Ppump, I have to hit the throttle when it's cold to make it start (Otherwise it just turns over and no smoke out the pipe)

- BUT I can't give it too much or it won't even try to fire (just blows smoke)

Sounds like you're on the low side of fuel given the lack of smoke. Everything's too cold to get enough pressure built to fire the injectors.

[kzimmer]

1 minute ago, TFaoro said:

In my experience, there's a pretty fine line between too much fuel and not enough fuel. 

When I had a VP and large injectors the truck would buck and knock blowing smoke everywhere until it hit 800rpms and was no longer calling for Chit loads of fuel. 

Now with a Ppump, I have to hit the throttle when it's cold to make it start (Otherwise it just turns over and no smoke out the pipe)

- BUT I can't give it too much or it won't even try to fire (just blows smoke)

Sounds like you're on the low side of fuel given the lack of smoke. Everything's too cold to get enough pressure built to fire the injectors.

 

Good info and I agree 100%. I am really looking forward to finding out for sure.

[AH64ID]

16 minutes ago, kzimmer said:

 

I had cheap DSS 7x.014 injectors set at 340 bar with no issues of any kind. Actually improved cold starts. The DAP 7x.013's went straight in at 365 bar. All in the name of science and experimentation. No regrets! Well maybe a little...

 

Yep, agreed. And there is fuel when I crack the lines, cylinders 3, 4 and 5. Now, that doesn't mean the VP is building as much pressure as it should... but regardless, the problem is only below -20° C. And the truck drives great.

 

 

Ah, so replaced the entire injector. 

 

Watch it when it cranks, you should get white smoke if it's not firing. 

[kzimmer]

1 minute ago, AH64ID said:

 

 

Ah, so replaced the entire injector. 

 

Watch it when it cranks, you should get white smoke if it's not firing. 

 

Same bodies, I just swapped the nozzles and calibrated pop pressure.

[Me78569]

Yea that thing should be smoking like a freight train if it is getting fuel to the injectors.  

[kzimmer]

1 hour ago, Me78569 said:

What do it do on a no start?  Does it just crank at normal speed without a sputter?  Any smoke out of the tailpipe?   have you do the park nose downhill to verify it isn't a fuel leak issue.

 

Given the size of injector the cranking fueling command will be WAY moire than enough to fire.  The flow from the 7 x .013's should be roughly 2x that of stock injectors at a given duration command.

 

Sorry I missed this post. Cranks at normal speed with not so much as a sputter. The odd time i'll get one single fire, on one cylinder. That's it, but i'm talking once, at the start of a 30 second crank. No smoke that I've noticed.

 

I know with the size of the injector and commanded fuel there there should be more than enough. I just don't think the injectors are popping properly. Maybe there is an underlying condition amplifying the magnitude of this problem (like a weak VP44). Or maybe, just maybe, nobody else was (dumb? adventurous? ambitious?) enough to try a 365 bar pop pressure at -25 to -30 Celsius. Lol.

[Me78569]

I should be at 350 bar in a few weeks.  

 

However if you aren't getting any smoke then there is something else up.  The pump should be building a TON more pressure than 365 bar even during cranking.  I would expect white smoke and a lot of it.  

[kzimmer]

11 minutes ago, Me78569 said:

I should be at 350 bar in a few weeks.  

 

However if you aren't getting any smoke then there is something else up.  The pump should be building a TON more pressure than 365 bar even during cranking.  I would expect white smoke and a lot of it.  

 

It'll be tough for you to recreate this though, as your area likely doesn't get this cold. I'm curious if you'll see any change in cold starts though.

[Me78569]

I should be able to tell if if the 350 bar start harder than the 330 though at 0* ish.  

[Me78569]

Have you run another tank through it yet?   rule out a bad batch of fuel?

[kzimmer]

I filled up yesterday with a fresh tank. Was at 1/8th. This morning I started it after it had sat for almost 4 hours and it took quite a bit of cranking. Also was plugged in. But again, once it was running, it was great. Drove around running errands today and it ran fine as always. Running the same fuel in my VW without issues.

 

I wanted to do some data logging today but I can't hook up anywhere, the pavement is too damn cold lol.

Edited December 29, 2017 by kzimmer

[AH64ID]

Was it making white smoke while you were cranking?

[kzimmer]

Wasn't watching, just listened from in the house, hit the remote start. But all of the other times I never noticed any smoke.

[AH64ID]

What’s the chance the remote start isn’t waiting long enough for the grids?

[kzimmer]

10 minutes ago, AH64ID said:

What’s the chance the remote start isn’t waiting long enough for the grids?

 

Extremely good chance. It only waits for 10 seconds. Not adjustable. But the truck was plugged in and usually only cycles for 10 seconds anyway. However all of the other times it was key crank and normal grid times, no remote start.

[AH64ID]

2 hours ago, kzimmer said:

 

Extremely good chance. It only waits for 10 seconds. Not adjustable. But the truck was plugged in and usually only cycles for 10 seconds anyway. However all of the other times it was key crank and normal grid times, no remote start.

 

Hmmm.... 

 

At those temps the fuel under hood should be warm, meaning the VP should have no issues compressing it but no white smoke means no fuel. 

 

Did you verify the pop on the injectors or just assemble them?

[kzimmer]

21 hours ago, AH64ID said:

 

Hmmm.... 

 

At those temps the fuel under hood should be warm, meaning the VP should have no issues compressing it but no white smoke means no fuel. 

 

Did you verify the pop on the injectors or just assemble them?

 

I set the pop pressure to 365 (ish) bar myself.

[dogsled]

Could be a crank angle , cam position sensor going. My beast did this to me last winter in deep river. Minus 40 and my truck was plugged in for 6 hrs.