converted_to_datsun Posted March 30, 2012 Report Share Posted March 30, 2012 What kind of milage Can you get with smog stuff removed right on a 78 Or 79 620? I'm having trouble getting 15 with the hack job done on mine Quote Link to comment
metalmonkey47 Posted March 30, 2012 Report Share Posted March 30, 2012 I do about 25MPH on a bad day in my '76 with a Weber. Sounds like you're getting pretty shit gas mileage. Most of that garbage isn't working at this point anymore and can be removed. Hold onto PCV and ditch the rest. Quote Link to comment
converted_to_datsun Posted March 30, 2012 Author Report Share Posted March 30, 2012 Most of it was hacked off before I got it. I think there's leaks from the sloppy removal. Part of it is how my carb is tuned because i'm missing the idle adjustment and it needs timing done Quote Link to comment
SHAMUS'WAGON Posted March 30, 2012 Report Share Posted March 30, 2012 Thanks for starting this thread. I've been wondering the same thing with the '79 620 I recently bought. Haven't been calculating milage, but wondering if it will be better or worse without all the smog shit. It's like hell trying to see anything under the hood compare to my 71 goon with absolutely no smog at all. Quote Link to comment
datzenmike Posted March 30, 2012 Report Share Posted March 30, 2012 There'll be no change for the better as the 'smog' equipment really doesn't significantly affect the running. Removing it can introduce things like vacuum leaks. 15 MPG is seriously bad, you should be able to get close to 30 on the highway and over 20 in town. Do you have the stock carb on it? Sounds like the choke may be stuck on. Timing could be off Got any pictures of the smog removal changes? Quote Link to comment
converted_to_datsun Posted March 31, 2012 Author Report Share Posted March 31, 2012 Supost to be worse without smog stuff. Not sure how much tho. And the lines from the exhaust were crimped instead of being removed and plugged... vacume lines are plugged but dunno if there's leaks. Missing idle adjustment so carb is tuned to compensate... timing needs done bad but can't till I get the idle. And water pump went out today....probably part of the problem. Had to be towed 20 miles home. I'll post picks when I can. Going to try and fix most of it by Monday so i can go to work. My wife will probably make me get rid of it if I break down again so hopefully i can get it back on the road... Quote Link to comment
converted_to_datsun Posted March 31, 2012 Author Report Share Posted March 31, 2012 Oh and yes stock carb I just rebuilt. Electric choke isn't working so goin to make it a manual choke Quote Link to comment
datzenmike Posted March 31, 2012 Report Share Posted March 31, 2012 Electric choke isn't working so goin to make it a manual choke There'll be no change for the better as the 'smog' equipment really doesn't significantly affect the running. Removing it can introduce things like vacuum leaks. 15 MPG is seriously bad, you should be able to get close to 30 on the highway and over 20 in town. Do you have the stock carb on it? Sounds like the choke may be stuck on. Timing could be off Got any pictures of the smog removal changes? Well there's your problem. The choke won't shut off. Wire it (the blue wire) to the idle cut solenoid (the red wire) right beside it. That will get it working. Quote Link to comment
converted_to_datsun Posted March 31, 2012 Author Report Share Posted March 31, 2012 It's wired it the right way but it's not shutting off. I'm going to get a cable and make it a manual choke tomorrow probably. And I just put a nre water pump in today and the idle adjustment. So tomorrow my buddy is going to help me tune it and set my timing, then I'll be running great for the first time since I got it. and my last tank I got less than 15... maybe 12? haha and i drive 40 miles a day for work Quote Link to comment
converted_to_datsun Posted April 1, 2012 Author Report Share Posted April 1, 2012 I put these up in another post but here's What they did. Quote Link to comment
datzenmike Posted April 1, 2012 Report Share Posted April 1, 2012 It's wired it the right way but it's not shutting off. I'm going to get a cable and make it a manual choke tomorrow probably. And I just put a nre water pump in today and the idle adjustment. So tomorrow my buddy is going to help me tune it and set my timing, then I'll be running great for the first time since I got it. and my last tank I got less than 15... maybe 12? haha and i drive 40 miles a day for work The choke heater only has power to it when the motor is running (alternator charging) It's easier to connect the choke heater wire to the idle cut solenoid wire to make it work. Quote Link to comment
converted_to_datsun Posted April 1, 2012 Author Report Share Posted April 1, 2012 ok maybe I'll try that first. i just ordered a haynes manual so I'm gettin set up better now. I hope to be done with the mechanical work soon so i can stard on the body work. Quote Link to comment
sick620 Posted April 1, 2012 Report Share Posted April 1, 2012 I do about 25MPH on a bad day in my '76 with a Weber. Sounds like you're getting pretty shit gas mileage. Most of that garbage isn't working at this point anymore and can be removed. Hold onto PCV and ditch the rest. 25mph thats hella slow... im doing like freeway speeds barely in my 76 with weber but mines a short be... ahahaha Quote Link to comment
sick620 Posted April 1, 2012 Report Share Posted April 1, 2012 datsun mike what is the idle cut solenoid? and how should mine be wired? lol please say what you just said in newb terms... maybe with a picture? thankyou... Quote Link to comment
datzenmike Posted April 1, 2012 Report Share Posted April 1, 2012 Hot motors have a tendency to 'run on' or diesel, when the key is turned off. To stop this, an electric solenoid is placed into the fuel circuit to the idle mixture screw. When the key is ON fuel can get to the idle screw and the engine runs. When the ignition is turned off fuel is cut off and the motor can't 'run on' and stalls quickly. If the solenoid fails or does not have 12 volts to it there will be no gas to the idle circuit and it may start but will not idle. The idle cut solenoid on the Hitachi is usually a Red wire and goes directly to the ignition switch. It's the hex shaped thing with the red wire in the picture below. Quote Link to comment
Jayden71 Posted April 1, 2012 Report Share Posted April 1, 2012 Hot motors have a tendency to 'run on' or diesel, when the key is turned off. To stop this, an electric solenoid is placed into the fuel circuit to the idle mixture screw. When the key is ON fuel can get to the idle screw and the engine runs. When the ignition is turned off fuel is cut off and the motor can't 'run on' and stalls quickly. If the solenoid fails or does not have 12 volts to it there will be no gas to the idle circuit and it may start but will not idle. The idle cut solenoid on the Hitachi is usually a Red wire and goes directly to the ignition switch. It's the hex shaped thing with the red wire in the picture below. Good to know, thanks Mike (again). I need to do this in my goon Quote Link to comment
datzenmike Posted April 1, 2012 Report Share Posted April 1, 2012 Earlier L motors don't all have them but all L20B's do. Quote Link to comment
converted_to_datsun Posted April 1, 2012 Author Report Share Posted April 1, 2012 I'm not sure the idle cut is working right all the time either them... sometimes the motor fires a few times after shutoff. after the rebiuld and cleaning it does it only every once and awhile tho. the wireing in my truck is cut and spliced everywhere and removed in some cases.... lots of work for me i guess. On the pluss i did get the part for my idle adjustment and dial it all in. it runs 110% better and not as much fuel dumping out my tail pipe. tomorrow is timimg and plugg the smog stuff the right way. it's too far gone to put the smog back in not to mention the fact that i have no idea what's been removed Quote Link to comment
converted_to_datsun Posted April 22, 2012 Author Report Share Posted April 22, 2012 So update time. I replaced my coil plugs wires cap rotor radiator water pump and am getting 20 to 25. Next weekend a long time Datsun guy is comming to show me how to remove all in needed smog and vacuume lines. I'll update what I learn in the process Quote Link to comment
datzenmike Posted April 22, 2012 Report Share Posted April 22, 2012 Hang onto those parts. Just in case. Quote Link to comment
converted_to_datsun Posted April 22, 2012 Author Report Share Posted April 22, 2012 Well most of it was gone when I got the truck so there's mostly just loose ends to tie up. I'm going to try and figure out how to make it deq if I ever have to. Right now I live outside deq Quote Link to comment
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