Xenn

So i have been meaning to update this for a few weeks now, work and winter storms do not help with that agenda. So since i swapped fuel pumps I have had no issues whatsoever (fingers crossed). When I swapped out the fuel pump i also swapped out the prefilter, the old one was clean, but within a week the new one got to this point and has stayed there since. Remains of a blockage or crud in the tank I donno, either way I thank ZedHead for his help in figuring out a possible solution to my problem. Sorry for the poor pic, my phone is a pos.

I finally gathered the parts i needed and did my swap today, drove it once hard and it seemed fine, idles smoother, less occasional popping. New pump is louder with the car off than the old pump, quiter with the car running, go figure. Ill update you if the problem comes back. Pic of shiny new pump below, and yes i did bypass the fuel damper.

True, mine is a ~5 year old aftermarket, but based on that and other liquid pumps ive had to take apart I assumed they all had an o-ring in the same area (just outside the impeller), i may be wrong though.

It happens most at exactly half a tank, less when full or empty, which makes no sense to me, but is basically the only reason I think its not the pickup tube. As for an o-ring issue, check the bottom of this page. http://atlanticz.ca/zclub/techtips/fuelpump/index.html This is quite the wack-a-mole problem, eventually im going to replace the car one bolt at a time.

I think Zed Head was mostly right, it happened again today but i was close enough to work to make it into a spot where I could look at my car, i was trying to find anything that seemed wrong or out of place, and i realized my fuel rail was making a "tist tist tist" sound like it was trying to pump air mixed in the gas, the lines were cold so its not vapor lock. After sitting for a few minutes this went away. Im thinking the o-ring on my pump may be shot, and as it heats up it starts to suck in more air. Ill find out when my new pump arrives, sadly this is just an educated guess, my free money this paycheck went to a new pump rather than a new FP gauge, if the problem persists that will be my next buy.

Yeah i know its overkill, basically i want it to either 1 not have to work hard to get the job done and thus be more likely continue working in less than ideal conditions (as well as hopefully be quieter), or 2 excaserbate whatever problem there actually is (rubber flap in the lines, clogged inlet) to make it eaiser to diagnose. ive blown out the lines both ways with air, but you never know if there is a problem still hiding. Its also too cold to drop the tank or rip out the lines, so if it is something like that im going to need to wait a month or two to fix it.

So since my fuel pump was new probably 5 years ago and has been through some tough times i ordered a gsl392 fuel pump to replace my current one (which was annoyingly loud as well), it should be here this weekend.

I had one but it died, i guess its time to buy an expensive nicer one.

Thanks for your replies. I dont think it is my dashpot or BCCD, my dashpot is disconnected, and ive driven with a bad BCCD, i can cover and test the BCCD though. As per ZedHead, i upped the idle speed, i only use good gas, premium from a busy gas station. I have a prefilter coming out of my gastank before the pump that is clean. Ive replaced the TPS and adjusted it. The fuel pump is wired directly into my fuse box, it bypasses the relay. I kinda think ZedHead was right from awhile ago, I think something is heating up and cutting out signal from my tach to my ECU or vice versa. I only have issues when the car is up to temperature. Never when cold.

Well for instance this morning, I was driving to work, coming up on a stop sign, put the car in neutral started to slow down, realized my brake light was on, looked at my tach and it read 0, sat at the light with my car off until it turned green, at which point i was able to start the car no problem, drove down the block and right as i was pulling into a spot to park my car, it died again, testing it i can hear the fuel pump going, but it wont fire when it turns over, waiting 1 minute it will start but while running it sounds like the engine wants to die, such as it runs fine, then it sounds like someone kills the power for a split second, rpms drop a few hundred from idle and car nearly dies then catches itself, it does this once or twice before finally turning off. Waiting 5 minutes the car will start fine and be driveable for long periods. Sometimes there is variation on this, but as i keep working on my car the symptoms become less when it acts up. It will seem to run fine for weeks, act up for a few days then be fine again. I have replaced the: distributor (and ignition relay) , ignition coil, ECU, temp switches in thermostat, fuseable links, alternator (and voltage reg), fixed and cleaned all grounds, removed the aftermarket alarm, repaired a bunch of wiring to the fusebox, replaced fuelpump, injectors, pressure regulator, and filter, AFM, and probably a few other things i cant think of.

It came back after like 2 weeks of running great, im running out of ideas, the fact that it will suddenly run fine for weeks or months then just crap again out i cant explain.

Do all lights blink if you hit the hazards? If so its not likely a wiring issue and it probably connected to the switch, I usually need to hold mine down to keep them going. If hazards are intermittent on one side its probably wiring, if hazards are intermittent on one light its likely the bulb about to die.

Basically everything everyone else said here, a hot switch is because of too much resistance in the system, if you get a relay harness it bypasses the switch for a power supply to the headlights and it basically becomes an on/off switch, making it so you dont really need to clean it. If you clean every connection from the battery to the switch to the headlights and back to the battery you wont need the relay, though it helps if you want to upgrade your lights to something with a higher draw. In addition to cleaning the switch and harness connecters if you go that way, I recommend you wire brush the metal tabs the fuses contact in the fusebox, I was melting fuses because mine was so corroded. Also the harnesses are super easy to set up, you basically run it from the battery to the headlights then plug one of the headlight plugs into it so it knows when to turn on/off.

Positive update, i went digging through the electrical rats nest that the previous owner turned the wiring by the fuse box into, when I found out that when I moved the harness, i could hear the fuel pump waivering, i chased the connection back to where the FP ties in, and they had used a funky connecter where you strip the end of one wire, the middle of a live line, set them next to eachother, then fold a strip of metal across them both, and its all encased in a little box which I had previously thought was a fuse or resister. So i tore that out and properly sodered it, as well as all the other wires that had been connected like that, and one with a small twist connection that was coming apart, suddenly the fuel pump does not waver when moving the harness, and my turn signals work again. I have no idea which systems I effected while under there, however my car has had no running issues since then (though it has only been a short time so far), I hope it serves as a warning to those to always properly wire electrical systems, with solder, because it can cause nightmare to diagnose intermittent failures for you later on, or the next poor person who has the car.

Good idea, ill try that.

So, a new piece of information. This morning on my way to work a semi pulled out in front of me on the sheet of ice we call a highway, i slammed on the brakes and horn and pulled off the road to not hit him (canadian driver) while i was doing this I noticed the horn was going in and out and i could hear clicking by the fusebox, once stopped i realized my car was doing its unwilling to run thing again, making me think I have a loose wire or dieing relay by the fusebox that is causing my problems, any suggestions as to where/what to look for when i go digging later? I know the wiring under there is a little shot, the previous owner did a headlight relay harness upgrade and bypassed the fuel pump relay, as well as installed a car alarm (which i have now removed BTW).

A quick question, i hear tell of grounds by the ECU and fusebox, does anyone have a pic of these, i have never found them.

Actually my car idles below the alternator charge point (600 for idle, 800 when the alt kicks in) I can tell because of the volt meter and the sound of the fuel pump, brake light comes on below about 3-400RPM. But you are right, its a non issue. I had the same thought about the tank, awhile ago when i was sorting out this problem. I replaced the fuel pump, bypassed the fuel damper, and blew the lines out with compressed air both ways and back into the tank, then installed an inline filter before the pump, there might still be some flake of something in the tank that likes to cover the hole though. I installed an inline fuel pressure gauge between the cold start injecter and rail just to check that, but it was cheap and broke already, I need to get a new one before i can check it, however the fuel pump does not sound different when dead. Problems usually happen at about a half tank or less though so maybe still. I recleaned all my engine bay grounds, and went a step further and did things like cleaned the metal contact where the bracket the ECU grounds to, connects to the intake manifold, the car sounds great again, a slow decay is hard to notice, mostly i notice in how eaisly it starts up now again but who knows how long i need to wait to see if it dies again. Its kinda sad the best running Z ive had likes to die randomly haha. Thanks for all your help Zed Head, im starting to feel like i have picked you guys clean for ideas now though.

Swapped ignition relay, happened again. Also the brake light comes on when i let up on the clutch, dropping the engine rpm to 0, not while still in gear, if that helps. I dont get a lot of time to experiment while im pulling off the road.

I actually have a spare ignition module, its a new distributor that I used on my last car, i got another ignition module for it hunting down a different problem in my last z, so i in actuality have 2 potentially good ones I can use. I could see it overheating due to some lost/missed ground connection, i was melting my running light fuse (yes melting) due to resistance in the system, i wire brushed all the connections and where the bulbs themselves touch and the fusebox connections (which was the big one) and that problem went away, but i could eaisly see the same problem killing my module. Can anyone think of any non-obvious grounding points for the ignition system? Ill probably go over all of them again just to try and make sure. Also it happen again tonight, this time i could see it happen, and it came in 3 stages: First there was a slight drop in power and a slight popping/misfire in the exhaust, then when on maybe 4 sec as i tried to figure out if it was an actual problem/should i try and pull off the road. Second it went to the could barely run, giving gas tries to kill it mode, since im moving i can keep it from turning off completely since it wants to run, but it has the effect when driving of feeling like going between engine breaking and gasing it back and fourth quickly, this goes on for maybe 2 seconds. Last it dies, hitting the starter turns it over but does not start it, occasionally you can get it to start and it will run fine for maybe a second or two then die again, waiting some longer amount of time that is always different it will start and run fine. Ive never really noticed the first part before, it has done it before though and not died, ive also had it die for just a spit second while driving then come back.

Blower motor I solved, alternator has not been an issue. I get the feeing that the turn signals and my car dieing could be related via the wiring in the steering column, it had no ignition switch when i bought it, and as of this last time at least, it acted like i simply turned the key offwhile driving, brake light came on and everything. Previously the tach moving was when i had the car running on some level when it happened (barly chugging at about 400 rpm, tach following engine, died when i gave it gas) this time it just died flat, but the same turn it off and wait a minute and it will fire up and run fine. Ive cleaned all thr electrical connections under the hood, did a dist swap with one i know works, have a new ignition coil, and replaced the fusable links with breakers, pics below.

Well it happened again, about 4 times on the way to work today, I finally noticed something new though, when it dies, the tach drops to 0 like i turned the car off even while im moving an in gear, any new ideas before i start ripping my ignition apart looking for loose or corroded wires?

Figured out the blower, the 6 pin power connection under the dash going to the switch is mostly shot, my blower originally didnt work because the previous owner plugged this connection in backwards, i destroyed it a little unplugging it since its only designed to go together one way, so one of the connections inside of it is loose, ill probably make or redo a connection to replace it soon. Car still running strong after the ECU swap.

I use my voltmeter as much as i can, and probably more than oil pressure (which is good to watch since my car slowly burns oil) , i know its position when charging so well i can tell if eqipment is on and how strong the draw is at a glance, one thing i have noticed is a slight draw when the engine wont run, which also points me to electrical, but I have also basically ruled out fuel and air as culprits. However it has ran "fingers crossed" flawless since the new ECU, but the weather has also been nice, so i get to wait till the next storm before i can tell if my car wants to die again.

Also looking into it, the 78z had an internally regulated alt the same as the zx, ill have to check if mine does or not before i bother swapping it as its an early 78.