280zgod

heres the schematic to help out. thanks again. ~Jerrod 75diagram.pdf

hey everyone its been awhile. alright some time ago i mentioned that my dash lights hadnt worked since i took out the stereo in my 75. well i think i finally figured it out, i hope. your opinions would be much appreciated before i proceed. alright in the schematic it shows a green wire with a white tracer connecting the ignition to the light switch in the combo and then also to all of the dashlights and headlights and such. the headlights have their own ground up front and are on a diferent ground from that of the dashlights. they have always worked. but the dashlights i believe have their ground through a red wire with a blue tracer as shown in the schematic. this went to the stock radio where the radio acts as its ground, if im reading the schematic correctly. if anyone knows the answer to this it would be nice cuz once its light im going to try this grounding theory of mine out. so i have no radio and if i ground this red wire with blue tracer im assuming my dashlights will once again work. if anyone could take a look at the schematic and give me their opinion it would be much appreciated or if anyone knows the danger of grounding that wire please let me know. once again its the red wire with a blue tracer that goes to every dashlight and then to the radio which ijm assuming grounded the circuit. thanks for your time and i hope that wasnt too confusing. ~Jerrod

you think OBDII has lots of gizmos well then watch out for OBDIII cuz from what i hear that is definitely going to have the gps and possibly a feature that allows the smog people to shut your car off and regualte driving speeds. we in california need to act fast and hard.

to my recollection there was a thread like 6 months ago on this site about 6 carbs on the z and someone who had done it and there were pictures of it on this site anyone else remember that?

when i redid the head i got a new radiator one of those bigger ones from msa since my old one had a hole its only been in for about a month month and a half.

but the problem was occuring before i changed it out and then again i guess it couldve been the old type where if the car overheated the thermostat would lockdown and force an overheat hmmm. is there any problem with just removing the thermostat all together?

i havent checked the timing yet since id been checking it every week to make sure it wasnt off cuz the car does this weird thing but anyway. the water in the top of the radiator is ice cold and the water at the bottom hose is boiling hot. no water ever makes it to the top hose as far as i can tell but since i did get a new thermostat maybe thats the problem. my car normally runs so dead cold that maybe with the new thermostat its heating up to be able to open the thermostat to let water out i dunno im rambling. anyway yeah im totally lost but ill retorque the head down cuz i havent since the head was torqued down when i redid it. see if that helps.

well i tried messing with the AFM and it didnt help car still overheating and now a new mystery warm water makes into the heater hoses but not into the lower radiator hose so im thinking maybe a clogged passage from the water pump somewhere??? i dunno has anyone ever had clogged coolant passages on their z?

removing the bumper shocks on our crash bumper models was a pain. i had to drop the gas tank out and then they bolt through the bottom of the car into the inside under the carpet in tight lil spots but the good news is the front ones are easy to remove and when your done you will be happy trust me it was worth the effort.

out here in califorrnia i removed my crash bumpers and drove around for about three months. got pulled over for the exhaust but cops never noticed the missing front plate and crash bumpers. i currently have the fiberglass msa bumpers on my 75 280z and no cop has cared.

yeah i was thinking that the lean issue might be the problem i just dont know why its running lean. i dont think there are anymor leaks into the manifold since the idle is stable at 700rpm and normally when there is any leak at all from the manifold the idle jumps to 2k or more. as for the head gasket i replaced that about 2k miles ago when i had the head rebuilt adn all the timing parts and gaskets replaced and its worked fine up until two days ago. i drove it fine all morning then later that night i start it up and it overheats im thinking its something wrong with the efi system since it always is a problem with that thing. but ill see what i can do ill play with my unadultered AFM and see if that can correct the leanness and if that doesnt help i dunno what to do. thanks for the input guys.

ok the other day my 75 280z with efi started overheating. it has a bigger radiator, oil cooler, and electric fans and normally runs well below or at the bottom of the4 temp guage even at full throttle. I have replaced the radiator cap, water pump, thermometer, and flushed and refilled the cooling system. there are no leaks from the coolant system that i can see. also my car normally runs extremely rich (dunno why) but anyway i checked the spark plugs today and they were blistered white. Anyone have a guess as to the problems? any suggestions would be nice.

well found out the problem. my friends car was out of gas it was running on fumes we gave it a gallon and vrooom but an injector blew a leak so back to work but at least its in time and running great. thanks for the input everyone. ~Jerrod

ok hey everyone. my friend and i have been changing out the head gasket on his 1975 datsun 280z and we came to a problem yesterday. after it was all back together we started it up and it revved fine ran ok but the timing was off. so we pulled the oil pump and moved the gear to get correct timing and achieved that. then we set the valve lash to cold since he had the head redone and it needed to be reset. after that we attempted to start it again and it starts but cant rev past idle. any call for fuel at all kills the motor. could we have possibly messed up a few cylinders setting the valve lash and if thats the case would it cause that kind of problem or is something else the source? thanks for your time and help. ~Jerrod

yeah i gave up the egr battle a long time ago i just plugged the end of it where the pipe used to go down into the exhaust manifold. so try as it might that egr aint sucking nothing but plug. and my z runs fine btw except now the FI has failed again and it cant start but when it did runh it ran well. ~Jerrod

cool thanks there is an ace two blocks from me ill have to check it out

yeah z fuel pressure is 36psi and i myself use 180psi line but where is this mystical 250psi line you speak of blake i would really like some. i went to a bunch of custom rubber line stores and the highest they carry is 180 whered you get 250?

oh its the first fuel injector then yes you can loosen the rail enough to get that one injector off without completely removing the fuel rail. Actually i got all mine off without removing the rail but anyway. yeah so 5/16" fuel hose and it should be relatively easy to do good luck.

i just did this last week to my 75 z. my mechanic recommends new fuel injectors but if you want to just replace the hose... first off which injector is it? cuz that will make a difference to how easy it is to pull off or whether or not you need to remove the fuel rail. Secondly is it an injector with the stock like brass fitting connecting the fuel hose to the injector or does it have one of those stainless adjustable brackets? if its got the stock fitting then you either have to take a grinder and grind through that without damaging the injector or buy a new one. if its just a piece of hose with a hose clamp holding it to the injector then you just remove it like any other hose and replace or buy a new injector for fun. normal 5/16" fuel line should work fine for all the lines unless youve increased the fuel pressure then you would need to buy fuel injection hose still 5/16". hope that helps a lil bit.~ Jerrod

hey, ive got an n42 block, head with a schneider .460, 270; .460, 280 cam in mine with fuel injection, headers, 2 1/2" pipes to the back exhaust, msd, and well i get about 12 miles to the gallon but i also have a fuel leak from the tank now and if remeber correctly before the leak i got between 15- 17 depending on my driving so most of the time 15 heh. anyway hope that helps~ Jerrod

since we have borg warner T5 tranny's for the Z can the T56 be used or am i just hoping for too much?

well looks like i found out the truth about my car... apparently its not a zx 5 speed. it would seem to be a stock 75 5 spd because the gearing isnt matching up with the numbers for a zx tranny. and the nice lil datsun speed calculator where it has the gearing for all those and you enter the tranny you have and the diff and tire size is perfectly matching up for me that i have the stock 5spd and the stock 3.54 dif. so never mind i seem to have found my answer. ~Jerrod

ok ive been running random math through my head trying to figure what ratio dif i need to top out at about 120-125 and ive come up with 4.4 or so would do that for me. i have a 3.54 in it right now and so i did the math by taking my current top speed presumably 160 and then multiplying it by 3.54 and then dividing by 4.4 and i got a number in the 120's. just wondering if that is an accurate way to calculate the top speed change or not. im thinking it is since there is only one variable being changed and since the wheels, and tranny gears are remaining the same i can consider them a constant or 1 so 1(3.54)(160)/4.4= 120ish works in my world... any thoughts? i have a 280zx tranny the one with the wide gap between 2nd and 3rd if that helps anyone in the know. thanks for your time.~ Jerrod

i have a 280z with an n42 block and head and i used the felpro one they suggest for it and it works great with my stage 3 msa cam as for the oiler i dont know but the fel pro should work fine.

man you are awesome i have that problem i keep wondering where the fumes are coming from. i bought a new shifter gromet and had my exhaust completed welded together and checked the firewall. it must be one of those others. thanks for the advice on this subject im definitely going to find the culprit now that i have some idea on this thank you thank you. ~Jerrod