hello guys long time since my last z but this time i came back with something special, i have now acquired a 1979 280z Fairlday, yes it is a true fairlady its rhd and when i got her she had issues( and still does)

when i got the car it wouldnt get spark or fuel, i swapped in a spare dizzy lying around and got spark but still no fuel, checked for power back to the pump no power, tried hot wiring pump got nothing, pulled sending unit and about threw up from the old gas and knarly gunk build up. dropped the gas tank and did the vinegar trick, re installed and put in new fuel pump, hot wired pump with a switch, turned the key and she started! but she was running really poorly, so i started some trouble shooting, i already replaced all the plugs, wires, cap rotor, oil, filters, and air filter, but she just wasnt running right so i played with the timing a little, nothing changed just ran and idled low and crappy, so i swapped afm, still crappy, swapped in another afm still crappy, so being the curious guy i am i unplugged the afm and started it and it ran and idled perfectly??? it idled at about 750, so i slapped a filter on the tb and drove it, it drove extremely well its just a little jerky with the throttle, it either wants throttle or it doesnt i cany just barely throttle it for some reason. i got back home plugged in an afm and it ran like crap again and died, so i am leaving it without an afm, i did adjust the pedal and throttle linkage a bit to make it barely open to keep the idle steady because it does fluctuate a bit but now its at 900 which is fine with me.

my question is is it ok to run it without the afm? the only drawback is i can tell its running rich, and is there a way to pull power for the fuel pump with a relay that i can wire to the ignition so it shuts off and on with the key? switches are annoying lol

here are some pics

 

How about you put a new AFM in it?

 

i tried 3 afms total all had the same affect, 2 of them came of perfect running cars

 

Cool car.....but that would be so awkward trying to shift with my left hand! Guess you would get used to it after awhile....

 

i have the same car 79 and everything

 

Each afm has to be tuned to the car that it is installed in. Adjust the timing to 15 instead of 8 initial. That will help te rich part and give the car nice power. I thinking the harness to the afm is the problem. Normally it's grounded with a little wire from its base to the car. It may be missing that ground. If you download a manual or have one do the wire harness check in the manual. Maybe a wire has a break in it.

 

i advanced the timing all the way to get it to run with each afm, i let it sit there an idle with each afm, then tried giving it throttle, as soon as that flapper moves it dies and i have to restart it...

ran a new ground wire to the afm bodies...

started it with the afm not connected to the tb, just plugged in, idles like crap, touch the throttle it dies.

it literally doesnt like any afm lol i am at a loss on what to do besides drive it with just a filter on the tb, you can tell its running retarded rich you can see black puffs coming out the exhaust, gas mileage is **** but it pulls to 6000rpms super strong....

any advice is appreciated

and gixxert, good for you rhd is f****** amazing lol

 

The issue is that it's not seeing the AFM, so it has no "in between" The TPS controls idle and full-throttle mixtures, the AFM everything in between.

You've got a broken wire somewhere, I think

 

ill try hunting for a broken wire, it definitely knows when there is one plugged in though, when i have it idling without it plugged in, then plug it in it bogs down, then i tap the throttle barely and it dies.

does the afm harness run directly to the ecu?

how hard is it to wire in a megasquirt and run map sensor instead, thats what i really want to do then swap on my turbo head and run some boost lol, my old turbo car ran way hard in comparison, i havent ried the search yet sorry in advance lol

 

i bet the afm spring is too loose. pop the cover off one and try adjusting it. hold the big gear shaped thing, loosen the screw the tighten the mechanism, dont let go until that screw is tightened. you can do this while the car is running even and keep trying the throttle until it free revs easily. if you let go of the gear then you gotta figure out how tight to go and it takes some practice but why not you have a few spares.

 

did the adjustment on one of the afms, didnt really work, plugged the original back in and turns out it revs fine but now the idle is super high, like 2000 to 3000 rpms, and after hours of searching i have narrowed it down to be a vac leak or the bcdd, i amgoing to try to remove the bcdd tomorrow and replace all the vac lines, but from all i have read its more than likely the bcdd is screwed up but apparently one can run without it. also the po removed the cold start injector and that crazy looking cylinder vac line mess that sits on the middle/ top of the intake manifold, is that the idla air control?

 

Get the FSM and meter out the AFM. Check the CHTS as well if you haven't done that already. If it's running without the AFM you're running in limp mode and it's gonna suck. Check for vacuum leaks as well.

 

Wow, you're on just about every forum I surf...lmao.

 

79 did not have the CHTS. Once you adjust the original AFM then get everything back to stock (timing, fuel pressure, no vac leaks ect...) Go over all of the electrical connections with emery cloth and di-electric grease. Also make sure the battery cables are good as well.

My guess is that the issue is not the AFM but something else. Also unplug the ecu a few times to clean those connections.

Where are you located? Perhaps some one close to you can help you out. I would love to get a hold of a rhd...

 

Don't use dielectric grease. Dielectric grease doesn't conduct electricity and reduces the amount of surface contact on your connectors. Reducing the surface contact area reduces the current carrying capability of the connector. I know the grease will keep water out and help with corrosion but it's not suppose to touch any metal contacts which is why it's really only used on the boots of your spark plug wires. The best thing to do is to replace the 30 year old connectors with new ones. I sell a complete kit to replace all the connectors and I hate to flog my wares but it's just a really good idea to replace them and that's as cheap as you'll find the connectors.

 

great suggestions guys, its snowing here in casper,wyo so i didnt get to work too much on it after work, i know it might be frowned upon but i am a just wing it diy guy, i replaced all the vac lines, by passed the bcdd, and then sprayed the whole intake and under side with starting fluid, hosed it down, my idle didnt budge at all, so i sprayed every rubber line i could think of everywhere in the engine bay where vacuum could be present, still no idle change so i thinks its safe to say vacuum leaks arent an issue anymore.

i did also dremel out the plate so i could adjust the timing more, forgive me for not knowing much about the timing atm as i dont have a timing light but in the factory plate position i had to have the distributor turned all the way clockwise, is that retard or advance? if i turned it counter clockwise it would want to die all this was done without the afm btw, so when i fixed all my vacuum leaks and bypassed the bcdd i plugged in the afm and it actually idles great and revs great in neutral, but try to drive and it has a serious serious lack of power, so i got out turned it counter clockwise and it pops back through the intake so that means my timing is off, turned it all the way back counter clockwise and limped her home.

so now after work today i dremeled the distributor and it snowed so i didnt get to go test drive the new postion but its far more counterclockwise, my question is why would it run super hard without the afm then with the afm my timing sucks ***? when you unplug the afm does the ecu retard/advance the timing a certain way as to kill the engine? i am kinda at a loss and dont want to have to drop the oil pump to rotate it to get timing back, thats why i dremeled a little farther on the plate... i just need some pointers and tips as to what to try next, my car is still idling high at about 2000 when its cold, didnt want to wait out in the snow for operating temp to see if the idles drops, checked play in the throttle linkage, messed with idle screw, it just likes 2000 rpm idle, btw way the car is a 79 if that helps

 

Set it to stock and run a can of seafoam through it. It will clean out the carbon from the system and it should help greatly

 

I had the same exact issue on my 78'. My problem was a combination between an afm, injectors,spark plug wires and the bcdd. But to me your problem sounds like it is the bcdd. How did you bypass the bcdd? Cover the hole inside the tb??

 

You can't set the timing at a 200rpm idle, and your timing is off. You should reset the oil pump. Just do it properly, instead of half-assing it, or your car will never run correctly. You've probably spent more time and money trying to ghetto rig your **** than you would have if you just bought or downloaded a Factory Service Manual and fixed it properly.

 

Did you ever check the ECU itself?