The problem has returned.

1980-1986 Datsun 720 forums. All 720-specific topics and discussion can be found here.
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NST_311
Posts: 26
Joined: Fri Mar 19, 2010 2:25 pm
Car: 1986 Nissan 720 Pickup

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Hey guys, I haven't been on in a VERY long time. It seems I only get on when something breaks down :facepalm: The cold start up problem has reared its ugly head again. I changed the vac lines, changed the cat and muffler, switched to Pennzoil Ultra, and I just recently put a K&N filter on. I'm stumped because now when I get it to finally start, it shoots white smoke but yet it still smells like gas. I'm just really frustrated now. I had it working fine for about 7 months until Monday. It started after I changed air filters actually, though this shouldn't effect it. Right as I started to begin to fix the electrical problems, this happened :tisk: It seems as though the truck can not be running well without something going haywire. Any advice?


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fastboatman29212
Posts: 493
Joined: Sun Jul 25, 2010 6:45 pm
Car: left this forum. Sold my truck.
Location: South Carolina

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How does it run once you finally DO get it started? Put a timing light on it, check the plug color (both intake and exhaust side), check the distributor and rotor, look at all vac lines, especially the one to the distributor.

flinterman2000
Posts: 1011
Joined: Mon May 04, 2009 5:32 pm
Car: 2000 Nissan Wingroad, 85 Datsun 720 Pick Up.

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These trucks like to keep us thinking. It could be sticking rings causing low compression when cold. When you changed the type of oil the problem stopped. Is that correct? If so something helped the engine either free up or increase compression. The condition of the plugs will tell you if your compression is low or just have it checked, but it needs to be checked cold.

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NST_311
Posts: 26
Joined: Fri Mar 19, 2010 2:25 pm
Car: 1986 Nissan 720 Pickup

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It runs fine once its started. I changed the plugs roughly a year ago and the old once seemed OK. The engine in it is actually ten years younger than it should be, my grandfather swapped it out when he bought it in 95. Maybe compression, but I really don't want it to be that. Bad choke maybe? Fuel delivery problems? The carb itself? I tinkered around with it and kind of fixed the problem, though today it did the same thing minus the smoke. I guess I'll keep messing around with it until I figure something out :tisk:


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