Random high idling

1980-1986 Datsun 720 forums. All 720-specific topics and discussion can be found here.
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justinae
Posts: 62
Joined: Sat Oct 17, 2009 5:57 am
Car: 1980 Datsun 720 King Cab
Location: Portland, OR

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Hi all. I'm pretty new to the forum and don't have a ton of mechanical skill, but probably enough to create more problems for myself.

Anyway, I've owned my 720 for a couple of months now and it's been great. But just as the weather started getting cold (Portland, OR) I noticed that the idling was staying really high and I was getting about 50 miles less per tank. Hovering in the mid 2000 rpm. Normally it's just sub 1000. But it only does it intermittently. I try to tap the gas and sometimes that works to bring it back down, but usually it doesn't.

About 3 years ago the guy I bought it from had the hoses replaced. I've read on this forum about vacuum hoses, but not sure if those were the ones he replaced or not. The cars rebuilt about 2 years ago.

Any recommendations. I'd like to get my hands greasy if it's not a major job. I've adjusted the idle on another vehicle before but not sure if that's just putting a band aid on a deeper problem.

Thanks for any advice,Justin


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PEZi
Posts: 21113
Joined: Thu Dec 11, 2008 8:21 am
Car: Mitsubishi Lancer Evolution IX Mitsubishi Racing Edition
Location: Pikes Peak, CO
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well... just to be safe check the vac lines... make sure none have come loose or are brittle etc

if the problem doesn't lie there... well how is your temp? these trucks tend to run a little on the cold side... especially so when its cold outside... so if the truck thinks its still cold it may be trying to warm up still (choke staying closed)

which leads me to another point... the choke may be stuck closed as well... fuel likes to get gunky in there when its cold out


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

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[Q. But it only does it intermittently. I try to tap the gas and sometimes that works to bring it back down, but usually it doesn't.

Some times the linkages dry out. Chance the return spring and use some WD40, you'll be good to go.


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