TheProtoSmith Posted September 20, 2020 Author Report Share Posted September 20, 2020 (edited) I should have been more specific, it runs and sounds fine, but there is like very little power. Atleast at low rpm, high rpm feels comparable to both coils firing There is also the chance that I have the car too far leaned out and it is just low in power. Edited September 20, 2020 by TheProtoSmith Quote Link to comment
datzenmike Posted September 20, 2020 Report Share Posted September 20, 2020 Well try this as it eliminated the distributor as any cause. 1 Quote Link to comment
TheProtoSmith Posted September 20, 2020 Author Report Share Posted September 20, 2020 Same result.. a little less obvious though Quote Link to comment
datzenmike Posted September 20, 2020 Report Share Posted September 20, 2020 Runs rough accelerating ? Quote Link to comment
TheProtoSmith Posted September 20, 2020 Author Report Share Posted September 20, 2020 (edited) Smooth but non linear Torque curve. Rises steady, until 80% throttle after that throttle input does nothing. Sounds like too lean to me but I'm definitely learning a lot about these Nissan 4 bangers. Is jetting the only way to tune air mix for non idle conditions.... Seems a bit coarse to really dial in a machine Edited September 20, 2020 by TheProtoSmith Quote Link to comment
datzenmike Posted September 20, 2020 Report Share Posted September 20, 2020 Well there it may be the secondary not working or secondary jet partly blocked. 1 Quote Link to comment
TheProtoSmith Posted September 20, 2020 Author Report Share Posted September 20, 2020 So rebuild carb? Or is it there a way to just blow out the secondary. That jet was sheared when I replaced them Quote Link to comment
datzenmike Posted September 20, 2020 Report Share Posted September 20, 2020 24 minutes ago, TheProtoSmith said: Is jetting the only way to tune air mix for non idle conditions.... Seems a bit coarse to really dial in a machine Yes but remember the carburetor is a totally mechanical device that mixes gas with air using only the air being sucked into the running engine for power. It hasn't changed in over 120? years. EFI on the other hand uses sensors and a computer to precisely calibrate the perfect mixture and fuel under pressure is injected not using the engine at all. Only recently have wide band O2 sensors been cheap enough for anyone to have them. They will tell you at a glance what the air fuel ratio is. Before this there was the art of 'reading' the spark plugs to know what was going on. Quote Link to comment
datzenmike Posted September 20, 2020 Report Share Posted September 20, 2020 3 minutes ago, TheProtoSmith said: So rebuild carb? Or is it there a way to just blow out the secondary. That jet was sheared when I replaced them You changed out the secondary jet? What number was on it... what number did you replace it with? Quote Link to comment
TheProtoSmith Posted September 20, 2020 Author Report Share Posted September 20, 2020 17 hours ago, TheProtoSmith said: Alright old jets are out one was cracked, both were too big. Like #200 ish mix screw now makes a difference wooo. Did a 92 and 97 on the new jets. Now I gotta tune this carb in. Runs pretty well when both coils are on and like ass when you full throttle. Which should mean the system it too far retarded right? (Because of the full throttle second coil shut off circuit?( Maybe I installed backwards? Quote Link to comment
datzenmike Posted September 20, 2020 Report Share Posted September 20, 2020 I thought you meant that you tried 92 and 97 in the primary jets. Secondary jet should be in the 160 -170 range Quote Link to comment
TheProtoSmith Posted September 20, 2020 Author Report Share Posted September 20, 2020 O. Is my face red. I'll swap that out right away. Just to confirm secondary jet is on the left?. Quote Link to comment
datzenmike Posted September 20, 2020 Report Share Posted September 20, 2020 This is OK it's an easy fix. On the Z24 the secondary if closest the vale cover. All non California secondary jets are #170 Quote Link to comment
TheProtoSmith Posted September 20, 2020 Author Report Share Posted September 20, 2020 Welp lol that jet was sheared on mine and all I've got on hand today is a 150. So I'll use that to make a pass at emissions. 1 Quote Link to comment
TheProtoSmith Posted September 21, 2020 Author Report Share Posted September 21, 2020 alirght jet is replaced now running a 92 and a 150, So definitley a bit lean but i'm ok with it. Car is running great now. I gotta do valve lash next but I'm gonna make another run at emmissions after work today. wish me luck 1 Quote Link to comment
datzenmike Posted September 21, 2020 Report Share Posted September 21, 2020 I forget, What primary jet did you have originally??? When you take it apart again a 4x4 runs a #111 primary and the secondary is #170. A 2wd runs as low as a # 107 1 Quote Link to comment
TheProtoSmith Posted September 26, 2020 Author Report Share Posted September 26, 2020 We did it boys. Finally passed at round ten. 105 jet on the primary, 5dbtdc, and a whole bunch of fine tuning later, Cesar the 720 can finally be registered. 6 Quote Link to comment
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