30 degree cold start (opinions wanted)

[BrianX128]

It's not much at all. 120-150 rpms I'd guess. You can make it as much as you want by extending the solenoid on the side of the pump. All it does is shoot out when the throttle isn't resting on it, it doesn't have the strength to push the throttle. When I still had my winter "beater" idi, I jb welded the end of it to make the high idle 1100. My quad cab idles at 600 and high idle is 725 ish.

 

[Cariboo4x4]

I been troubleshooting hard cold start on a 1989 F250 7.3 idi last 4 weeks. Batteries were the culprit. I had starter rebuilt and all battery cables clean and tight. I switch this truck over a couple years ago to manual glow plugs. It had new motorcraft glow plugs and motorcraft glow plug relay. Lift pump brand new and new rubber hose before lift pump. I bled out all air to injectors. Holding glow plugs on for 15 seconds and cranking engine first time my digital multimeter showed batterys went down to 8.5 volts. Also cranking slowed down. 2nd try batteries were shot. I checked for air intrusion and removed rubber return line to filter housing. Plug filter housing with brass plug and sealer. I put 4” length of clear tubing on air bleed valve on filter housing and poking valve with bent screwdriver fuel came out instantly. I learned if truck block heater plugged in for 3-4 hours truck would start instantly with glow plugs. No way it would sart not plugged in. Batteries failed at first glow plugs 15 seconds on and cold crank. I discovered a neat way to find out if air intrusion occuring: After bleeding air from air valve with clear 4” hose on it the hose stayed filled up with diesel about 2” up hose. I bent hose up so diesel wouldn’t trickle out. Then after 6 days I poked air valve wity my bent screwdriver so fuel wouldn’t trickle out and no air came out. I had it plugged in that 6th day and it started instantly with glow plugs on for 15 seconds. I also learned on this forum to pump fuel pedal once after turning key on. That pre sets the cold start solenoid. If you forget to hit fuel pedal once and it start up you can press fuel pedal once to activate cold start solenoid.

Where I am at now is truck runs nice and with minimal smoke with cold start solenoid activated and I believe a cold start advance solenoid also is engaged same time as cold start solenoid. Yet once engine gets hot enough to deactivate cold start solenoid engine idles a tiny bit rough and quite a bit more smoke which I believe is unburnt diesel. I think it may be worn injectors. 330,000 kms on entire engine. I am thinking if I change the timing on this old engine it may help yet not sure if I should do that and haven’t ever messed with 7.3 idi timing. For now just keeping truck plugged in till I can afford new batteries.

 

[Cariboo4x4]

Correction after I tried cold start in -14 F with an assistant pressing glow plugs for 15 seconds and then cranking engine it turned over fast initially yet batteries were quickly at 7.5 volts after 5-6 seconds of cranking.

 

[IDIBRONCO]

I think that the 15 seconds of glow plugs is a little bit long. I use mine for 8 seconds. Too long of a heat time will burn them out unless they're self limiting, which Motorcrafts aren't.

 

[Rdnck84_03]

I think that the 15 seconds of glow plugs is a little bit long. I use mine for 8 seconds. Too long of a heat time will burn them out unless they're self limiting, which Motorcrafts aren't.

I agree. I actually just pulled all of the glow plugs in my 83 this morning to test them while doing return o-rings. They are ZD9's that I installed when I got the truck in I think 16 or 17. All still glow good and hit full glow in about 5.5 seconds.

James

 

[IDIBOBS]

Hi All,

I'm very new to diesels, just wondering what y'all think of this 30deg F cold start. Any concerning noises or does it sound consistent with other idi's?

**two prior 15sec crank no-start cycles trimmed from video, couldn't upload to forum**

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Thanks, stay warm out there!

I’d say that’s not normal at all. It’s been in the mid teens here and mine starts the same at 15 deg f as it does at 100deg. It sounds like it’s running really slow during start like bad battery’s or starter. Also sounds like it has air in the system and the plugs need to stay on longer. Might be cold advance or high idle. Did you press the throttle all the way down to set the high idle before you turned to start?

 

[rreegg]

I think that the 15 seconds of glow plugs is a little bit long. I use mine for 8 seconds. Too long of a heat time will burn them out unless they're self limiting, which Motorcrafts aren't.

How many “cycles” of 8 seconds do you do? I’m always worried about burning them out and try to wait the same number of seconds OFF that I keep them ON for - then cycle more or less depending on how cold it is. Been high 20s here lately in the morning and maybe do 6 cycles of 5-8sec. In warmer weather I’ll do fewer cycles of less seconds

 

[IDIBRONCO]

I'll do 2 cycles when it's in the teens. My IP timing is slow and it starts easier that way. I'll wait 15-20 seconds between cycles. I'm having to learn this one as I go. I just put this IP on a few days before New Year's day. It still starts easier than my last one did. It had a seal that would leak when it was cold outside. Above 55* and it would start without any issues.
You shouldn't have to do 6 cycles. If everything is good, glow plugs and pump timing, 1 cycle of 8 seconds should be enough down to the teens at least. I guess there could be other factors though.

 

[TheBirdman]

If I recall, it was about 15F when I filmed this:

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I replaced the glow plugs about 8 years ago, return lines around 2 years ago, batteries are 2 years old costco interstates, and I put a gear reduction starter on it a few years back.

 

[Black dawg]

Something that I never see mentioned in cold start threads, especially where others jump in and say "my truck started just fine at minus whatever temp, yours should start better than that", is that the actual engine temp might not be the same as current air temp, depending on how long the air temp has been stabilized.

Big difference between parking my truck with air temp at 30 degrees and waking up to 0 degrees vs parking truck at 0 degrees and waking up to 0 degrees.

 

[TheBirdman]

I started mine up yesterday and its been -10 all week, it started even easier than in the vid, even after sitting 2 months. It didnt even smoke.
Surprised the **** out of me really, becasue I know for a fact its sucking enough air in the lines that it barely made it to menards and back last time.

and Im not trying to say all IDIs should start like mine, its clearly a freak of nature, and it used to start crappy for pretty much its whole life up till last year.

 

[Black dawg]

Some are exceptional starting for whatever reason, but in owning many of them and working on lots of them, more of them tend to be on the tougher starting side of things than the real easy starters

 

[Rdnck84_03]

@Black dawg I second that! It doesn't matter on either of mine if it is 110 or 20 degrees, it requires atleast a 7sec glow to hit. Even if it is at operating temp and I shut it off for more than 15 minutes, it will require a 5sec glow.

If it is below 20 I usually give it 8-9sec glow and hit the starter, if it doesn't hit in first 3 revolutions I will stop and immediately give it another 6sec glow. This almost always starts it within 4 revolutions.

I try not to stress the starter anymore than absolutely necessary, the glow plugs and solenoid I use to control them are much cheaper and easier to change than the starter.

James

 

[Old Goat]

Timing might have something to do with starting.
I installed the new IP, Injectors, Glow Plugs last July/Aug.
Old pump (UKN miles) the engine would start almost instantly, rev or 2. Could sit all day and never need to hit the Gp`s. (manual switch) summer time or something over 50 deg.

In the winter time hit the switch 12 sec or so it would start w/o too much trouble maybe hit the plugs again.
Say we went to Costco and in there couple hours in the winter, snow on the ground. She would usually start with in 2 or 3 rev`s.

Now with this new IP, if she sits for an hour, I need to hit the GP switch. never had to do that before. So Iam thinking only difference is I might be too advanced on my timing.


Goat

 

[The_Josh_Bear]

I agree the timing does make a huge difference in starting. The more retarded the timing, the easier the start in my experience. And of course then you have IP health, starter health, battery health, good grounds, etc.
Another factor is the compression ring condition and if rebuilt or stock gap. The stock gap is huge and allows a lot of blow-by, whereas Total Seal or a custom smaller ring gap makes them start awesome.