So it had been a long time since I did a tune up on the truck and it seemed to be losing a little power. So I grabbed a can of Seafoam and threw it in the tank. All of a sudden when I push the peddle down past a certain point it's like a switch gets thrown and I'm running on 3 cylinders. Back it off a hair and runs fine again. So I figured it's time for a tune up. Did the air and fuel filters, plugs, cap, and rotor. Old plugs looked really good. Almost like they had been recently installed. Still had the right gap and no erosion or deposits. I changed them out anyway.
No help.
I don't know if the Seafoam caused it or it was just a fluke that it started doing it shortly after adding it to the tank or if something else is going on.
It runs just fine as long as I don't put too much of a load on it.
Any ideas
Thanks
Engine runs rough under load
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LowFlying720
- Posts: 34
- Joined: Fri Aug 15, 2014 10:24 pm
- Car: 85/86 Nissan 720
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LowFlying720
- Posts: 34
- Joined: Fri Aug 15, 2014 10:24 pm
- Car: 85/86 Nissan 720
Re: Engine runs rough under load
I'm Thinking about putting a new carb on it as I'm guessing the Seafoam may have dissolved some of the internals of the carb.
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LowFlying720
- Posts: 34
- Joined: Fri Aug 15, 2014 10:24 pm
- Car: 85/86 Nissan 720
Re: Engine runs rough under load
forgot to mention that it won't idle (just dies) when it's cold and doesn't idle well even when it's warm (dies sometimes).
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petercscherer
- Posts: 54
- Joined: Tue Sep 09, 2014 3:23 pm
- Car: 1972 Datsun 240Z
1982 Datsun 720 2WD
Re: Engine runs rough under load
Check out the thread "Warm Death". It should solve your problem or at least get you looking in the right direction.
warm-death-t593811.html
warm-death-t593811.html
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LowFlying720
- Posts: 34
- Joined: Fri Aug 15, 2014 10:24 pm
- Car: 85/86 Nissan 720
Re: Engine runs rough under load
I replaced the relay this summer to solve the dying while driving issue.
My current issue with idling is when it's cold and the automatic choke has turned of. Once it's warm it stays running for the most part. I need to get a tach on it because I think it's idling a little slow.
Because of the way that when it's sputtering (feels like running on 3 cyl) is like a switch is turned as your pusing down on the peddle, I"m wandering if the problem is something to do with the secondary. As in when it starts to open and there's no or inadequate fuel in the secondary bowl or a plugged jet and it's leaning it out.
Troubleshooting: I'm thinking of wiring the secondary shut and seeing if the makes a diff.
Question: Is the vacuum pot hooked to the secondary the actuator or is it mechanically actuated off of the throttle linkage? If it is vacuum actuated then do I need to disconnect the vacuum to keep from damaging it with it wire shut?
Also I've been looking at the post about removing and capping all of the vacuum lines and I really like the how clean that looks and I may be going that direction once I get this issue sorted out.
My current issue with idling is when it's cold and the automatic choke has turned of. Once it's warm it stays running for the most part. I need to get a tach on it because I think it's idling a little slow.
Because of the way that when it's sputtering (feels like running on 3 cyl) is like a switch is turned as your pusing down on the peddle, I"m wandering if the problem is something to do with the secondary. As in when it starts to open and there's no or inadequate fuel in the secondary bowl or a plugged jet and it's leaning it out.
Troubleshooting: I'm thinking of wiring the secondary shut and seeing if the makes a diff.
Question: Is the vacuum pot hooked to the secondary the actuator or is it mechanically actuated off of the throttle linkage? If it is vacuum actuated then do I need to disconnect the vacuum to keep from damaging it with it wire shut?
Also I've been looking at the post about removing and capping all of the vacuum lines and I really like the how clean that looks and I may be going that direction once I get this issue sorted out.