rossiz

ok gang... i spent yesterday afternoon fiddling and i believe i have the problem identified. i just read through all your posts and can't tell you all how grateful i am for your time and attention to my little z and it's quirky issues, as well as impressed by the knowledge base on this forum. kinda cracks me up when you start talking amongst yourselves and the conversation slowly drifts from "the car won't start" to quantum physics (or at least that's how it sounds to an electrical simpleton) at any rate, with the help of some basic deductive basic logic and a good deal of luck, the issue revealed itself. and the winner is.... (wait for it)..... FW AND THE RELAY PLUG!!! i just used the engine itself as a tester and while it was running i started as far back on the harness as i could get to and started carefully wiggling wires until i got to the plug itself. i couldn't effect any change wiggling individual wires, even at the plug, but when i push on the plug itself, normal to the spades in the relay, the motor would die. the connections were all clean and greased, all fit tightly, but because it's a 6-spade plug, i figured they weren't being held in contact properly or one was not correctly seated in the plastic housing. so i took the entire plug apart, examined each crimped connector and plugged each lead directly to it's respective spade on the relay. here's the odd thing: i get exactly the same result - if i push sideways on the connector/spade (again, at 90 degrees to the spade) even very gently, the thing cuts out, and as soon as i let go, the connection is back. i did this on both the new relay and the old one, and both act exactly the same. i haven't taken one of the relays apart yet (will tonight) but it seems odd that they would be so very sensitive to any movement like that. usually relays are pretty simple beasts. does this sound familiar/right with how the relay spade connections should act, or do i somehow have 2 equally bad relays - made 35 years apart and by different manufacturers?? anyway, i have all the plugs on the relay and need to order a new 6-plug connector along with new crimp-on connectors and a good crimping tool (sources, anyone?) so i can re-build the plug and keep all the wires in the right places. btw - all the wires are blue except one, which is green. if i'm not mistaken, at least 2 (maybe 3?) of the blue wires get 12V+ which seems funny... oh, and thanks for the info on the injector testing - i cut up a string of xmas lights and just started testing every possible combination and came up with the following: light will light (and burn out!) testing either pin in the plug to one lead and the other to the engine block (ground), both leads to the pins and i get flashes when the engine is running. i now have a few bulbs in my emergency kit, along with a multimeter (which at some point i will have to figure out how to actually use).

ZH - good strong, blue spark, all plugs, visible in direct sunlight - and all plugs are dry, so i'm pretty sure i'm good there. so... do i put the two leads of the bulb to the two pins on the injector plug, or one to a pin and one to a ground?

ok, so i'm confused now re: testing the injectors for signal... if there's power between either of the pins and ground, but both pins are +, then how does the ECU "pulse" the injector? and why are there two pins if they're both +?? and if the power is at both pins with the key on but the car not cranking, why aren't the injectors constantly fired??? sorry if i'm hopelessly stupid on this - i have no electrical training, just basic "batteries & bulbs" sort of stuff. please explain exactly how i test the injector pulses with a christmas bulb so i can confirm their status next time the car won't start.

FW - thanks for the encouragement, i could use it. the idea of the EFI system being reliable (as in ALWAYS starting) is as appealing as it is elusive to me. i tested the injectors with an electronic multimeter set to "volts" and touched the two probes to the two pins in the injector plug while a friend cranked the engine. no reading whatsoever. i then put two LED's back to back in the plug (couldn't tell which pin was + or - so i had one in each orientation) and neither blinked. i didn't have a christmas bulb on hand (will put some in my tool kit). it was lucky i was at the office of my engineering consultants - they had the multimeter and LED's. just spent the last 3 hrs online looking up SU conversions while fuming over missing dinner w/the family to go meet the tow truck and get the z home. i wanted to hate it for it's intransigence, but when i got there it just looked so damn cool i couldn't stay mad at it. when i first got the car, i replaced the fusible links with maxifuse blocks, re-wired the primary system with 8 GA marine wire and relocated the fuses and all the relays to the cabin on the passenger side to get them out of the weather. just checked the fuses and they're all fine. i had a new relay on hand that was the same configuration as the EFI relay (6 spades) so while i was on my hands and knees under the dash (getting used to "assuming the position" for this vehicle) i decided to test it. i first tried starting w/the old one (no love) then yanked the plug out of the old relay and plugged in the new one. the car started right up. BUT... then i plugged the old one back in to confirm it was bad and it ALSO started right up. so this is completely inconclusive to me - not sure if a relay could be intermittent, and what would cause it to be. FYI - i had cleaned all the spades on all the relays and slathered them w/dielectric grease when i did the re-wire a couple of months ago, and all looked clean and tidy when i did the swap tonight, so i don't think it was a case of the plug/un-plug scraping off corrosion on the old relay. i think i've checked all the connections in the EFI loom - i even unplugged the the big multi-pin ECU connector hoping to find crustiness, but it looked clean and fresh (and frightening - so many teeth!!) so i just quietly put it back together and backed away. the one set of connectors i haven't been able to fiddle with are the two plugs at the dropping resistors - i'll rip them apart tomorrow and see how they look. for now i'll leave the new relay plugged in and just keep doing test drives in circles around the block until it decides not to start again, then i'll do some more testing.

i've been having intermittent hard-starting, which has culminated in total non-starting. the car has been my DD for a few months and i've replaced all the sensors, injector connectors, fuel lines and vacuum hoses. it either starts perfectly or starts after much cranking, then runs really well with no hint of fueling problems. at first i thought it was a hot-start issue, but now it will not start cold. the plugs are dry, decent color and all are providing spark - i rested them on the valve cover and cranked the motor and saw them all fire in order. fuel pressure at the rail is 35-40 psi and fuel pump is running fine. for some reason the injectors don't seem to be getting a signal. i put a voltmeter and then some LED's across the two terminals on the injector plugs and cranked the motor - no lights. is this the correct way to test them? i'm pretty sure there is some kind of bad connection somewhere that is stopping the injectors from getting their signal/power/whatever and i haven't the foggiest how to even start diagnosis. i have the FSM and it is horribly confusing to an old carb guy... pin 37? continuity? wtf??? had the car towed home - for the second time, and can no longer rely on it as a useful source of transportation. the toughest part is that i absolutely love the stupid car. any help would be greatly appreciated.

i believe my problem is an EFI electrical issue which has somehow been exacerbated by or is simply coincidental to hot-start conditions, so i'm going to start a new thread to try and keep this thread on-topic. let's just say today wasn't a banner day for the z...

at this point the z is officially downgraded from DD to "toy" status, as i can't count on it to actually fire up when i need it. currently sittling in a coffee shop killing however much time it will take for the thing to decide it's cool enough to start again. the thing that has me perplexed is that while i'm having no-start issues for sure every time it's hot, it's also been hard to start a few other times when it WASN'T hot, so i'm not convinced that heat soak is my only problem. i'll try to lay out the symptoms and maybe some sage advice can come my way. it has three distinct starting modes: mode #1 - starts right up, immediately and runs great. mode #1.5 - gives a quick fire at first crank, then dies immediately and needs a great deal of continued cranking until it starts, then it runs just fine. mode #2 - gives a quick fire at first crank, then dies immediately and WILL NOT START no matter what, for 1/2 hr. or so - not even a pop, nothing. #1 is the norm first thing in the morning, but i've recently had #1.5 happen a couple of times first thing on a cold motor, and last night on a fairly cold motor. it started fine, i then drove a mile up the road to pick up my daughter and came back out and it was a #1.5 while humiliated teen sighed and rolled her eyes with embarrassment. just now, the engine was hot, it's a sunny, mid-60's afternoon, i stopped at the hardware store for 10 min. and then the z gave a big fat #2 with NO start whatsoever. yes, the #2 moniker is a concious refernce to what it feels like to sit there wondering if i'm going to get home/to work/that meeting/etc. or not. i took out the plugs and they are all bone dry, which tells me i'm not getting any fuel. my pressure guage is between the filter and the rail and measures almost 40psi when i'm cranking or when i pull the solenoid wire off the starter and run the fuel pump w/the key to try and prime in more cool fuel. it seems like the injectors just refuse to open at all. could this be an electrical issue?? the odd thing is how it runs perfectly whenever it runs - just has this starting issue. is there a different control for firing the injectors during cranking vs. when it's running (like the fuel pump relay logic)?? i am completely flummoxed... help.

ok, been away for the weekend so couldn't post about the "friday fiasco" until now... family trip involving a ferry (read as: can't be late) and i run a few errands for work, the day is sunny and 60's, last stop at an office for 20 min. while the z sits out in the sun. i come out and it does the typical dance: tiny "almost start" and immediate die, then NOTHING - no amount of cranking even gets a pop. i pop the hood and let it sit for a full 20 min. and still nothing. the manifold is still hot, but not excessively so - i can put my hand on it by the injectors. i'm about to make my family late, so i call my son to come rescue me in the truck. he arrives with my tools, i pull all the plugs - they are bone dry, not a hint of fuel - deposits are all a nice mocha. i crank the engine w/the plugs out to blow out some air, then put in the plugs and it fires right up. unfortunately this nonsense makes us miss our ferry and the vacation is delayed - anniversary, i'm in the doghouse. mighty pissed off. while this doesn't seem to be the "classic hot-start" issue, i'm not sure WHAT my z's problem is, but it DOES seem to be directly related to heat soak - seems to be happening every time i have the typical situation: hot car, 10-20 min. sit, then problem starting, then starts when it cools down. i've got to get this figured out, as the car is next to useless if i can't depend on it to start without a half hour of nonsense every time it's hot. do i really have to spend $1,000 on headers, fuel rail, injectors and revised exhaust just to have a car that will start regularly?!? ugh. if it weren't such a cool car, i'd have kicked it to the curb already.

wow, very cool - and you definitely get a pass on the lack of updates ;}

my point exactly: get some fuel in to start the engine and draw the vapor from behind the injectors. yes - it would be fiddly, but maybe it could be controlled more effectively by the HellFire? just a thought from a non EFI guy... 1978 280z - stock i/e manifolds, exhaust, fuel rail, heat shields, original injectors (i think) recent new parts (in last 6 months): - entire cold start system (thermotime sensor + connector, injector, AAR + hoses, connector) - PCV valve + hoses - FPR + hoses - AFM boot/hoses/connectors - all injector connectors (including cold start) - fuel pump check valve (rebuilt) - plugs, distributor cap, wires - water temp sensor + connector - thermostat - all fuel lines in the engine bay - most vacuum lines in the engine bay (vacuum currently measures 19 at idle) PO replaced parts/service (have receipts): - AFM (sept 2013) - ECU (1995) - injectors cleaned (2006) - fuel filter (2006) modifications: - K&N filter + cold air intake - EGR system removed and both manifold connections blanked-off - fuel pressure gauge installed between fuel filter and rail (reads constant 35psi) - fuel filter between tank & pump i've included some pics of the engine bay and one of the injectors - maybe you all can tell if they are original and if they are the "plastic insulator" kind (looks plastic to me)

today i had what i think was a hot-start episode: warm, sunny afternoon, car up to full operating temp, went into the grocery store for about 20 minutes, came out and the car would not start at all - nothing, not even a pop after much cranking. i pulled the solenoid wire off the starter and turned the key to start to run the fuel pump, trying to circulate some fresh fuel around the rail - could hear it going and saw my pressure gauge blip up a little while the pump ran, but still no starting even after a few tries at this. maybe priming doesn't work because the fuel just runs around the rail and recirculates, without actually going down the short 90 degree hose runs to the injectors. took out a couple plugs and they were bone dry. let it sit for 5-10 min with the hood up, and then it started - ran rough for a moment until i reved it up above 2k and then it was as if nothing had ever happened. so i'm thinking - what if i set up a momentary push button switch to fire the cold start valve, even though the engine is hot? it's pretty far away from the block, so maybe it would be cool enough to provide enough fuel to get things started? i don't know how injectors work, but i thought they opened up when they received a pulse of power - if this is the case, wouldn't it just take a few cranks to pull some air/fuel in? i'm really not digging the feeling that it's just pot-luck whether my car will start when i come out of the store. especially since i had just gotten the car washed and it was looking SOOO nice, attracting admiring glances, then (sigh) hood up, fettling in the parking lot, hoping i could get home before the ice cream melted...

wow... no takers on this one. guess i'm off to search for more info...

Is this service still available? If so, what would be the cost for a pair of 280 hood vents?

got it - thanks for the replies. funny thing is the first thing that happens when i hit 5K is a horrible vibration/rattle at the shift lever bushing (ordered the bronze bushing upgrade) which is so disconcerting i immediately back off. i had noticed that the ponies taper off pretty rapidly after that, so no real desire to dip the needle into the red, but just wanted to know in case i got a little pedal-happy...

it sure looks like the PO ripped out the retainer - i can see the two bits at 180 degrees from each other. the retainer is a round disc with two areas stamped out, leaving a band across the center - it's pretty delicate. looks like someone grabbed it w/a pair of needle nose pliers and ripped it out. if you file off the crimped lip the remains of the retainer will come out. i can't imagine why they would do that, maybe there was some crap lodged in there and they were trying to remove a "restrictive component" of the fuel system? or maybe aliens...

i've done a bit of searching, but can't find anything definitive about safe revs for my '78 280. to be clear - this is a DD and i'm not drag racing or autoxing, so i'm not looking for the very last pony out of the engine, but i'm really not used to this motor at all (more familiar with old american iron) and i've been afraid to rev past 5500 because i have visions of something coming through my hood... after sorting through various fueling and electrical demons, the car is running fantastic (finally) it's really addictive to wind it up and send the rear end sideways (on a closed course, being driven by trained professionals only ) but i don't want to break it. i know there are "theoretical limits" to the design - that's not what i'm looking for either, as it's a 35 yr old motor and i need to keep it reliable. so how far can i push it on a regular basis without shortening it's life prematurely?

no worries - the job got done so the day was not wasted :classic: i'm wondering about how your check valve was empty - does it look like it was tampered with? i don't know how the parts could have blown out, and if so i would think that the retainer ring would be stuck in your fuel lines somewhere...

no worries cap'n - i'm actually really excited that i was able to fix the original part, and i wouldn't have been motivated to do so if i had the replacement part :} one thing i have to mention: i just got back from taking the car out for a test drive and WOW!! it's running so incredibly well now! it seems odd that having low pressure would have such a dramatic effect, but it idles smooth as silk now (was always rough before, no matter what i twiddled with) and i swear it's picked up a load of power. i was having so much fun lighting up the tires that i was literally drifting around corners with excitement! it's like a new car - really! this is my first z car, so i had no idea what to expect, how it should actually run. it's been a fun adventure because i've been fixing problem after problem and every time i pick up performance that i never knew was even there :} gonna go back out to play in the car (why sure, honey - i'd be HAPPY to pick up some vegetables for dinner!!)

well i was completely SOL with the volvo check valve, and the worst part was i had a day blocked out to get the job done (a free day can be harder to come by than an NLA part for me). so i figured i'd take a look at exactly just what was "toast" about my OEM check valve. it's such a simple part - just a spring, a retainer and a stopper - that maybe it could be re-built? the answer is yes - and it's not a hard job at all. the biggest challenge is getting the thing apart, as it's all held together by the crimped lip at the output end of the valve (the barb that the hose goes on). i used a file to carefully remove the crimped material until i could see the perimeter of the retainer. then i gently pried it out with a small screwdriver and removed the spring and rubber stopper. i expected the retainer to fly out as soon as i got it loose, but it didn't because the spring wasn't applying enough pressure on it. turns out this is why the valve wasn't working. i inspected the stopper - it was fine. still soft/supple and no tears or wear. the inside of the casing was dirty and looked a little corroded, so i used fine steel wool to clean out the seat. to do this, i put the threaded end of the check valve into a drill and twisted the steel wool into a long thin finger to get it into the valve seat, then spun the valve and the steel wool polished out the inside of the valve nicely. the spring is tapered - the small end grabs/holds the back of the rubber stopper and the wide end sits against the retainer. the spring is very light, so it doesn't take much to stretch it out so it will apply sealing pressure. you have to be careful to stretch it evenly, not just one coil. i stretched it till it was about 1/8" longer than the valve housing (at the start it was just resting against the back of the retainer). i snapped the retainer back in and here's where i got really lucky - a 10mm craftsman socket has a beveled interior that's just the right size to peen over the tip of the valve body and hold in the retainer. i set the valve, threaded side down on the vice anvil and put the socket over it, then gave it a few taps with a hammer and the metal peened nicely around the retainer. i then put the valve back into my drill and spun it against some 320 grit paper to de-burr the tip. i tested the valve with compressed air and it now functions perfectly in both directions. just for kicks i checked the little filter screen at the pump inlet (the long, narrow cone) and it tore apart as i was removing it. no worries, because i have an inline filter now between the tank and the pump. the bottom of the cone was packed full with crud, so i'm guessing that probably wasn't helping things either. put everything back together, primed the fuel pump (need to fill the tank all the way up for that) and she fired right up. my fuel pressure is now up to a solid 36psi - before it was at 30 or 32 at best. i'm guessing that the combination of the bad valve and restricted filter screen were the issues. best part is, the system is holding pressure perfectly. we'll see if this helps the hot start issue...

the threads are not a match to the pump housing - too big. car in the air, fuel pump out, scrambling for the right part... :disappoin

well now cap'n... i guess now your screen name makes sense :laugh: actually, i tend to avoid dealers in general as my experience has usually been that they: 1) are annoyed/bothered by me being there to waste their time with a goose hunt for a wacky old part (vs. buying a new car) 2) charge 2x the cost of getting it anywhere else (because they'd rather be selling me a new car) 3) smirk/chuckle at my "project" (and recommend that i buy a new car) yes, my own baggage, i know. i'm gonna try going town to nebar (industrial hose guys) and see if they'll whip me up a length of hose with the right fitting. rather give my $$ to those guys.

so i'm going crazy trying to locate one of these audi hoses... i'm not interested in getting a used part - if i'm going to pull my fuel pump apart and replace the check valve, i'm going to use new hose. i've searched and found the part as a fuel rail feeder hose to a 2001 audi s4 (used part seen here: 01 2001 AUDI S4 A4 B5 2.7 - GAS FUEL LINE / HOSE / PIPE 8D0201541AA - WolfAutoParts.Com) but i can't seem to find it new anywhere??? anyone know where i can buy this? if not, i will go to a local shop and have them install the proper fitting on a piece of fuel injection hose (516" right?) or is there a screw-together fitting, like the an6 fittings that i see on sst braided hoses, that will fit and work for this application?

wow, you guys rock! to FW: i greatly appreciate the commiseration re: the teenager. my sons (there are 4 of them) all think the z is cool, but mostly they're interest lies in trying to get me to lend it to them for the prom - not happening. i will block out some time this weekend to tear into the electrical connections - i've already replaced all of the FI plugs and half the others during sensor replacement, but i haven't done a thorough walk through the entire system. sage advice, no doubt i will find more dodgey bits that need a bit of love & dielectric grease... to St S: thank you SO MUCH for the link - the FI book is downloaded and i'll be poring over it for the next few nights. i had looked into the FI Bible, but i think it was just too much too quickly for me and i found myself glazing over and falling behind - like sitting in a math class that's a level too advanced. maybe after your book i'll be ready for it. better yet, maybe after cleaning up connections and replacing the check valve and main injectors, i won't NEED to deal with it! to Unusual: agreed, i'll stay the course and see it through. my dad used to say "with an old car, it's always somethin' - until you replace everything, then you have a new car!" i'm pretty close to there on the FI system at this point...

i'm looking to do the same w/my 78 280 - lower about an inch. car is DD but it's a sports car and i drive it as such, so i'd like to reduce some of the body roll from the tall-ish current (i believe stock) spring height. i pulled off the big bumpers, which lifted it up even more. i plan to get some bigger/wider wheels (currently 14" rims) to reduce some of the sidewall flex but i don't want to have to roll fender lips or endure an overly harsh ride. i've read that progressive springs can provide the comfort along with better control (i use these on my sports bikes with great results) but don't really know where to start on spring rates, etc. before the flames start re: progressives - i will never track or autox the car

well, apologies to all for opening up this wound... i had NO IDEA how much this topic had been discussed and how many tender nerves there were regarding this piece of equipment. i suppose i should have done more searching before stuffing my newbie foot down my gullet. lots of good info though, and i've learned quite a bit in the last few hours reading through a few carb threads. in the end, it seems there are enough completely contradicting opinions, stories, examples, etc. that unless i actually get to see and drive in a 280 w/this setup it's still up for grabs whether i'll actually gain or lose. as far as giving the FI half a chance, i guess i'm still shaken from the ride home in a tow truck a week or two after i had the car up and running due to (i think) the sensors in the thermostat housing and a cold start valve that flooded my engine to the point of ruining a brand new set of plugs - and i was completely helpless, couldn't do a thing other than call AAA and wait 2 hrs for the ride of shame. the other night i was going to take my teenage daughter to another appointment and she winced, saying "pleeeease can we NOT take the z? i just can't handle stalling again!". talk about a knife to the heart for this old guy... i spent my youth hooning around in old heaps and never thought twice about it, knowing that with a screwdriver, pliers, some tape, wire and a broken piece of hacksaw blade (to gap points, of course) i could always get it started/keep it running. the FI system just seems so friggin binary - it either works, or i'm SOL on the side of the road, head in the footwell, arse in the air fiddling with multi-pin connectors and uttering curses in vain attempts to trace a mysterious problem that i can neither see nor hear. truth be told, the car is running really well right now, and i've ordered a new bosch fuel pump check valve (thanks cap'n O) which i'm hoping will keep my system pressurized and help w/the intermittent starting issues, which is really the last big issue that i see. but then, that's what i was thinking before the big ride w/AAA... i just saw the big carb option and thought dreamily how this could simplify sooo much under the bonnet and maybe magically solve all the problems in one shot. i'd really like to not be worried about being "that guy" you hear about on the traffic report that's causing the rush-hour jam by being stalled dead at the freeway on-ramp so i could focus on other mods, and driving it (exhaust, suspension, wheels/tires are on the short list). seemed like a carb could be a back-up plan in case the FI thing just didn't work out.