81280zx

i just rebuilt mine also and it wouldnt start then when it did the car idled hard and miss fired found out that the timming was way off and the tps was gone on it. I would double check your timming on it just to be safe and u not looking at a fadded line like i was.

right now im trying to adapt the old tps to the new t/b so i havent ran it hard yet untill i get that all fixed and adjusted. I have noticed that with it disconected that it has a slight tremble at 4200 at wot but it clears up and then pulls hard. But i have adjusted the timming again so that may have made it better all around. But when im just getting up to speed it does fine except at wot so for now im just taking it easy till i fix the problem and it can break in better.

ok so far i unpluged the tps and now it runs ok but still does its thing at 4k but not as hard. could having the egr not hooked up cause it to do this? im also trying to still figure out the vacume lines but i have the canister and the disty hooked up and the fpr and there are no vacume leaks so far that i have found.

When i had oil leaks i would pressure wash the motor really good to get it clean and then run it for a bit and see where the oil is coming from just make sure u blow out the tps and other electrics afterwards.

Thanks braap for explaining that about the tps i didnt know u had to use the stock one cause i have seen people using the tps that came with the 60mm tb. I will put my stocker back on and adjust the timming to what u said 12-15. And do i keep the advance unpluged or just leave it hooked up? I also found that the vacume line from the canister came undone from the t/b to. Thanks again for taking time to explain that to me.

ok today i took it out for a drive and under normal throttle it runs good but once u go and do a wot pull on it the motor cuts out at 4k or a little bit before. I already checked the timming on it and its set at 9btdc without vacume advance on. I tried richening it up thinking it was running lean and then it just stubles sooner. The car is acting like it has a rev limiter under wot. So now i was woundering how some of u are running the 60mm with the afm still on if u had to richen it or lean it out alot. I was thinking it wasnt getting enough fuel but under no load it will rev past 4k. So right now im stumped on this one. If any of u could help me with this problem i would apreciate it. And sorry for asking if this has already been disscused before. Thanks

thanks braap so far its running good so now i have to button things up and then i will take pics and post up to show u guys how it went

ok here's the update i rechecked the timing and of course i was looking at the wrong mark it was way off so i took out the screw that only ltes u go so far and played around and i saw a thick line come around and bam! the car idled smooth then i also replaced the tps and the smoking went away but there is just a wierd smell coming from the muffler but im thinking that it's cause its a fresh rebuild on it. I wanted to thank everyone that has helped me on this to get it right and that got me thinking more and foucousing more on this car. I will keep u guys updated on how it goes as i put everything back together and i will try to post up some pics of the motor,

the smoke seems to be whitish but really cant tell

right now its set at 8 btdc like the book says but it still runs like crap at that timing. was also considering it could be that i went to the 60 mm tb. Im getting really confused on this rebuild

i think it might be detonation caused buy a vacume leak cause i messed with the timing and it really didnt do much with the knocking but did calm it down then it was stumbling if u hit the gas hard. Im woundering if it could my my 60mm t/b

all of the rings had markings on them to indicate which side was upwards. i know the pcv valve is in good conditon but i can change it to make sure and i will also check the valve steam seals to see if the poped off or not. Would anyone know what the knocking sound would be when u hit the gas real quick?

i honed the cylinders on it and they came out very nice. also i swaped the cam from my stock head to the n42 head could that cause a problem?

hey all i have a 81 zx and i just rebuilt it and she is now running but she is also smoking at the same time. It is idleing rough with a slight miss to it. The stuff i did was put new rings on it and position them the way the chiltons book says. Put a n42 or 47 head on it that has all new seals new bearings and cleaned the pistons off. It also have a n47 intake mani with a 60mm t/b and im trying to adjust the afm to the new t/b cause when u hit the gas real quick it has a knock sound so i think it may be running rich or to lean. before i put the new t/b on and the head and mani it ran good but the rings were gone and smoked under power. Any suggestions would help alot or if anyone has had this problem before. Also when u slowly accelarate it it doesnt knok at all it goes throuhgt the power band nicely. Thanks all for the help!

oh ok thanks dc thought i was loosing my mind lol