Cold blooded idi loaping

Oledirtypearl86

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Hey I have a 86 F-350 with a 6.9 idi I went to start it tonight to move it and the temp out side was 12 f it started just fine but it started to like loap like some fruit cake put a loap tune on a duraturd but it cleared up after about a minute of idleing and idled just fine this is the first time I've had it do this anyone else ever come across this ?
 

chillman88

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Maybe had one cylinder that wasn't firing until it warmed up a hair?
 

Golden Helmet

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Was it behaving like this?

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That was a 26*F morning. I still don't know for sure what caused that, or the weirdness starting @ the 35 second mark in where it was smooth at ~600rpm but missing at ~750rpm. Like yours, it smoothed out after about a minute and a half. I started cycling the glow plugs twice on very cold mornings (35*F or below, yeah I'm Californian LOL ) and I unplugged the cold advance solenoid which causes me some problems, and I've been good since.
 

chillman88

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That video does sound like a cylinder not firing. I recognize it from getting the truck running after having no fuel in the injector lines. Scared the crap out of me the first time it happened!
 

Oledirtypearl86

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Yes kind of like that but more exaggerated it was a big bounce in rpm let me see if I can go get a video if it will do it againe also mine jumped rpm so hard rocked the whole truck
 

Oledirtypearl86

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So I just went out and started the truck it's been sitting a few hours not plugged in Its like 4f outside and it started like it's 4 outside 10 seconds of cranking then fired up and hi idled am I feel like I'm worrying about nothing but a start on a cold humid day
 

Macrobb

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If you've got an injector leaking down, that can cause a miss at first. If you see white smoke while it's missing, it's often a dead glow plug(shorter cycling will result also).
Both of these will usually clear up if you rev it up to like 1500 for <30s.
 

franklin2

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Mine sounded just like that when I had some bad glowplugs. But that can only happen if you have a manual button, the glowplug controller will short cycle and not glow the plugs long enough for it to even fire off if there is just one bad glowplug.

When it is missing and it's a bad glowplug, you will also see lots of white smoke out of the tailpipe(I should say more smoke that usual). That is unburnt raw fuel going out the tailpipe from the cylinder that is not firing.
 

Thewespaul

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You have a couple bad glow plugs, your injectors are fine. The lopeing is just the engine running on a few cylinders until there’s enough heat for the other to ignite. If this happens again, slowly bring rpms up to 2000 for a bit, then drop it down to idle.
 

Oledirtypearl86

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Thank you guys I didn't think glow plugs because I put a new set of motocrafts in this summer but I started it this morning and it was -1 and the wind was howling and it took 15 seconds of cranking but she fired up and ran just fine I just worry starting now compared to when it's -35 and I don't have a plug in to keep the old girl warm
 

snicklas

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If you’re not going the quick clicking of the relay and getting a proper length WTS light (last night we fixed the high current lead to the glow plug relay on my sons 89 and at about 35 degrees it stayed on for 8-10 seconds and fired on the 3rd of 4th revolution) then its not plugs. May be some air intrusion. The extended crank is the system getting re primed. Even the other night when the engine hadn’t run in close to 4 hours, on a brand new starter (the failed starter is why it hadn’t been run in a few hours, it was tow started to move it to the driveway) it started in less than 10 seconds with no plugs or ether.

Try a check valve like @Thewespaul has suggested in the past. Could be just the lift pump allowing some drain back.
 

Oledirtypearl86

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I will do what check valve do you all recommend I know there are a lot of choices out there and I still use a mechanical lift pump and have a spare on have but it did smoke something terrible when it was loaping all raw fuel
Also ivonly had to use ether a few times and it was like -45 with a wind chill of -55 to -65 out and when I got it started I left it running for the day
 
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