Guest bastaad525 Posted October 21, 2003 Share Posted October 21, 2003 And here I thought I was out of the woods. Why wont it just be okay for a while??? The motor still seems fine... so... I'm happy about that at least... but now yet another new problem rises to greet me. I'm driving home on the freeway, and suddenly the tach just drops to zero, and the engine is dead. I've still got power (electrical I mean), everything else seems to be working (lights, gauges, etc.). It rolls like this for about 5-10 seconds, then starts itself back up... it was still in gear and the key in the on position, so it just picked back up like nothing happened. Happened a couple more times, very briefly, until I got off the freeway. Then it just cut out completely on the street. Wouldn't start itself back up, and when I pulled over, wouldn't start when I cranked it. I still have power, lights are still on, and I can hear the fuel pump going. So I get ready to call AAA, give it one more crank and it fires right back up. Then dies... fires back up again... it does this a couple times. And when it died it was like just very sudden... not like sputtering out. Anyways... finally it stays running. Took it REAL easy all the way home and it didn't do it again. It HAS done this before... started doing it right after I replaced the water pump a couple weeks ago... but never so bad that it just cut completely and forced me to pull over. It also did it on the way to work on sunday, after the low compression cylinder mysteriously fixed itself. About 50% of the time that it does this the car will also backfire, if that means anything. Since this started, I've checked and double checked, and cleaned, and even completely redid a lot of connections, mostly the stuff that has to do with ignition... the couple times I did this, the problem would cease ... for a day probably not because of anything I did. I also double checked all my grounds again, and checked and cleaned all the connections at the ECU. I figure it's gotta be ignition right? If it was the fuel injectors cutting out I dont see how it would cause the tach to die also... I run my tach signal off the wire that, when stock (I'm running an MSD 6A), would go to the negative coil terminal (it now runs to the MSD white/signal wire, after where the tach splices in). I think/hope this also eliminates the MSD unit as a possible cause, as the tach gets the straight from the ECU, before that signal goes to the MSD. So if the MSD was cutting out, but signal was still coming from the ECU or module or wherever the MSD and tach both get their signal from, I would think the tach would still keep working. I think that also eliminates the coil, cap, rotor, plug wires... any of that stuff, not to mention I've replaced all of that stuff recently. So I'm not left with much... I'm figuring... maybe it's the CAS? I know a lot of people say the '81 CAS's are problematic... could it cause this? What are typical symptoms of a CAS going bad? Or... could it be that little black module on the side of the round clamp that you mount the coil in? I was going to test this theory by seeing if I could bypass this module the way I did in my N/A motor... surprisingly it started when I did this, HOWEVER, it also ran REALLY badly, especially if I tried to rev it at all. I've had one of the modules on an N/A dizzy fail before and got pretty much the exact same symptoms, except I didn't notice if the tach died or not. Only other things I can think of are just some bad wiring problems, or the ECU fuffing up. Tips please Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted October 21, 2003 Share Posted October 21, 2003 Another reason I think it may be that module on the side of the coil... I remember, in my N/A, that when the module went bad, the car would still start and run fine, but when it got warm enough, it would just shut off. Let it sit for a few, and it would start right back up... only to shut off again after another few minutes. The similiarity here is that... the car runs fine when I first start it... the first time it did it was when I was halfway to work, and now today when I'm halfway home. But never when I first start or for the first however many minutes of me driving the car. And it seems to be more of a freeway thing... doesn't happen really on the street. Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted October 21, 2003 Share Posted October 21, 2003 Mine did that when the CAS was bad, of course mine was an 83, and in the dizz, and I replaced it with a 300ZX one. Does it turn over and sound like the timing is off? Thats what mine did, and I would have power everywhere I was supposed to, with no spark. Quote Link to comment Share on other sites More sharing options...
Guest szlash280z Posted October 21, 2003 Share Posted October 21, 2003 mine did that same thing when my fusible link was bad. I replaced it and haven't had that problem since. once all my gauges died but the speedo and boost, but the engine was still running. I tried to nurse it home, but it was a thunderstorm and standstill traffic. I didn't know it was running with no fan and started to overheat until my valves started ticking. so I parked and waited, wiggled the fusible links and everything was fine again. I don't know if your car has links, cuz I don't know what year it is. Quote Link to comment Share on other sites More sharing options...
David K Posted October 21, 2003 Share Posted October 21, 2003 My zx started dying on the freeway and rolling for 5-10 seconds also. I would step on the gas and you could hear nothing but the pistons sucking air through the intake. I havent fixed the problem yet. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted October 22, 2003 Share Posted October 22, 2003 As far as I know my setup only has one fusible link... I didn't do the wiring so I dont know what it's for, but I asked the guy who did it if it had any and he pointed out one to me. I checked it and it looked fine. Lockjaw - what do you mean it would sound like the timing is off when you're cranking it over? When your CAS went bad, did it start out erratically and then just finally quit? Did the tach drop to zero when it would happen? I'm planning on putting a newly rebuilt '83 dizzy in my car soon anyways, friend of mine has one for $150, but that probably wont be for about two weeks. The one reason I DONT suspect the CAS is because if that was bad I would think it would stop supplying fuel too... the ECU relies on the CAS for all of that right? But I'm pretty sure it's pumping fuel into the cylinders when it dies and I try to start it... every time I finally got it to start back up it blew a puff of smoke, like you see from too much fuel being put into the cylinders with no spark and suddenly it starts up and burns off all that fuel at once, and I could smell it too. My friend is going to give me another one of the coil brackets with a module on the side. I'll swap that out and see if it solves the problem. If not then I guess the car will sit until I swap in the '83 dizzy. I dont want to take a chance it's going to strand me. Quote Link to comment Share on other sites More sharing options...
Guest scottjuly79 Posted October 22, 2003 Share Posted October 22, 2003 My car periodically does the exact same thing as yours. I first replaced the power transistor (black module mounted on the coil bracket) and it stilll did it, then I replaced the coil and it was fine for about 6 months, now it is doing the same thing again. I am going to try a new distibutor (thinking it's the CAS) if that doesn't fix it then I am completelystumped!!! Quote Link to comment Share on other sites More sharing options...
lifegrddude Posted October 22, 2003 Share Posted October 22, 2003 As weird as this seems, check the harness that attaches to the key hole. Mine had worked a bit loose and would do that periodic run/cut deal. I just pushed it back on tight and it hasn't done it since. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted October 22, 2003 Share Posted October 22, 2003 I MAY have found the problem... pretty much everyone here having the same problem, caused by something coming loose. At first I WAS just going to try replacing that module on the side of the coil but the two that my friend had didn't work at all.... no spark whatsoever. So... taking a tip from you guys' cases, I went on a wiggle spree just wiggling every wire I could think of to see if anything was loose (I had done this before but only with the wires connected to the ignition components). Sure enough... there is a green relay box with four wires coming out of it, which is mounted just in front of my battery. It's not the fuel pump relay, as I can disconnect it completely and the fuel pump will still operate (but the car will not start)... so I'm not sure exactly what the relay is for, but it is the only one there is that I can see. Gave the wires going into it a few shakes and sure enough the car dies. Unwrapped all the electrical tape wrapped around them (and I mean there was a LOT) and went at it one by one until I found the glitchy one. Redid the connection there and wrapped tape around the whole damn thing this time, relay and all, really really tight, to try to keep it from seperating at all any more in the future. Drove the car home, 30 mins on the freeway in 90 degree heat (which is when it always seems to do it, on the freeway, in traffic, on a hot day) and it didn't cut out once . So I'm happy with that. Still, I'm still not 100% convinced... if only because a) I really had to shake the hell out of the wires to get it to cut out... I dont see them getting jounced like then when riding on the freeway, they were pretty well strapped down as it was before I went to check them, and last time I thought I had figured it out when I found some iffy ignition connections... redid them and cleaned everything up and checked everything and the car seemed fine for two days no problem... and then wham it's doing it again. So... we'll see. It definately seems to be the most likely. In the meantime, more problems... minor ones. For one, thru trial and error, I have found that the car runs MUCH better with the O2 sensor disconnected. Does this mean it's 100% for sure that the sensor is bad? I've been meaning to get another one but $$$$$... keeps going faster than I can count it Secondly... and I'm not sure what to make of this, but I pulled the plugs yesterday and saw something really odd. They had a mustardy yellow kinda crust on them. I've never seen plugs that color. And I've seen the buildup on there like that before, but it's usually black, not yellow. Third... looking at the plugs I also see that the #1 isnt running like the others. #'s 2-5 match the description above, #1 just looks like it's running too rich. So... another faulty injector? and lastly... my starter... which I'm not even 100% sure it IS the starter... my friend says it may just be that the ignition is too far advanced. I dunno... it's set to 20*BTDC at idle just like it's supposed to be. Either way, it usually cranks like the battery is dying. Also, the car has just been much harder to start in general lately. Until yesterday it would usually start right up, or turn over for two seconds at the most before firing. Now even with the MSD sometimes I really gotta crank it, five seconds sometimes, and then, if I dont have my foot on the throttle, blipping it, it will immediately stall. FRUSTRATING!!!! Not sure what to make of this one either.... Quote Link to comment Share on other sites More sharing options...
Guest szlash280z Posted October 22, 2003 Share Posted October 22, 2003 that green relay is the Fuel Injection relay. The car won't run without it. My link problem took forever to fix, I even drove the car around doing donuts and hard stops and it never cut out once, but every once in a while it would when driving straight slowly, or up a hill, etc. completely random. the only reason I found it was when I tried to wiggle stuff on the starter and my arm kept hitting the bracket. I had the ignition in the RUN position, so when I bumped the bracket I could hear the clicking of relays etc. then I wiggled them and saw once arcing and sparking! so it doesn't take much to have a relay or link phuck with you like that. My car runs better with the o2 disconnected also. My sensor is bad becase I broke it trying to take it off. I took my wifes plugs out of her car, they had a mustard looking substance on them too. The fuel looked pretty bad when I changed the fuel filter 5 mins prior, so I think the mustard is a fuel related thing. if your battery has a good charge, but the starter cranks like crap, then something is likely dying in the starter. Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted October 22, 2003 Share Posted October 22, 2003 Mine turned over like the timing was way advanced, or like it jumped time, I mean it sounded awful. Also I ran into the problem of it cutting off only when at idle for extended periods, it would run fine and drive fine, no matter what the temp, but idle it with the hood closed, and it did not take long. And it would stumble, and when you gave it gas it would spit back out the intake. NASTY. I am running without the O2 sensor, which usually affects your mileage more then anything else. I got 20 mpg last time the ZX was out for an extended period of time, in mixed driving, with a turbo trans and 3.90 gears. And while I don't spend a lot of time at full throttle, I still get into boost easily, and even did the ricer flyby on a honda driver who did it to me and thought it was funny. Little did he know, I did not even need full throttle. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted October 23, 2003 Share Posted October 23, 2003 Okay, so, answer me this, if the relay was shorting like that, would that also cause the tach to drop to zero, even if the motor is still turning? Remember that all my other gauges were still working fine, and that my tach is getting it's signal from the coil - signal. I really want to let myself hope that this was the problem and that it is now fixed. I've just recently replaced the fuel filter... maybe it's just one batch of bad gas causing the mustard look? About the O2, the car seems to run much richer with it plugged in, so if it's affecting gas mileage it must not be in a good way The exhaust smell is almost non existant with it disconnected, and the car runs much better, more evenly, less misfiring and spitting and jerking and surging, and a smoother idle. This is much more noticeable effect when the car is hot. So if the timing is too advanced it can cause the motor to crank over oddly? I've heard some funny sounds come from the motor when it was cranking a few times... again, my timing is set to 20* BTDC exactly as the factory recommends... should I retard it a couple degrees? Heheh so many honduh stories from us Z guys... I just handed some S2000 driver his ass yesterday... thinking he was fast Quote Link to comment Share on other sites More sharing options...
Guest szlash280z Posted October 23, 2003 Share Posted October 23, 2003 your coil will not spark unless the ECU is working. the ECU will not work if the EFI relay gets shorted out. when the coil can't fire, the tach won't work. so yes, your tach will drop to zero if that relay isn't working properly. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted October 23, 2003 Share Posted October 23, 2003 cool than that was most likely the problem after all... I wasn't sure just what that relay does, I thought it was only a relay for the injectors or something like that, actually at first I thought it was the fuel pump relay (I have since found out that the guy who did the swap did not use a relay for the fuel pump at all), didn't know it was so important to the whole thing. *sigh* of COURSE... now that that problem is solved yet another one comes up... another alternator fried last night, and I have to wonder, did I just get unlucky? Or is something frying them. When will it ever stop.... Quote Link to comment Share on other sites More sharing options...
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