NiiChan GT-R

...Bit of follow-up, running the pump for ~thirty seconds prior to warm start totally works. So I'm guessing its the check valve, otherwise a leaking injector would still prevent the car from running smoothly, and I don't seem to be losing pressure from the fpr/return line. Check valve ordered Hopefully that'll put this at bay for a while...

I've had my car since 2009, and I drive it daily to work, so I'm pretty familiar with it. I first noticed the problem creeping ip a few days ago, but didn't have any further issues until yesterday. I've tested it repeatedly a few times, and still seem to have it

Thanks for the suggestions... So doing a search, it sounds like check valves/leaking injectors are a culprit typically... I tried starting the car this morning first thing, with the pump lead unplugged, and it wouldn't start up, so I guess I'm losing pressure overnight. Though I do need a guage to confirm with certainty, the car should run for a few seconds if I had pressure, right? I'll try running the pump before startup in about another ten to fifteen... Is there any particular indicator I should look for, to tell whether its a pump check valve, or an injector leaking? Thanks.

Hi, maybe I can get a bit of additional insight into my issue 75 280z, stock EFI. Starts up wonderfully from cold. I can turn the car off, and start up again within about five minutes, and it's fine If I leave the car to sit for about 10 - 15 minutes, then it will start up, and run extremely roughly for a couple minutes, occasionally dying, before evening out eventually. It seems like if I move the AFM wiper slightly counter-clockwise, the situation alleviates somewhat, which indicates that adding fuel is helping. I would think that that would point away from any issues like a weeping injector, bad thermocline valve keeping my csi open too long, etc.... I'm sort of leaning toward it being the auxiliary air valve closing too late? I cleaned the connectors, and that didn't seem to make much difference, so maybe I should try plugging up the hose at both ends, and seeing how it runs? If anyone has any additional input into what could be causing this problem, any help would be appreciated

I adjusted the dashpot a few months ago, where previously it had no effect on throttle travel, I screwed it in to provide for some damping... I could feel the difference when shifting, but the cold bogging remained, so I shrugged it off for the time being. The BCCD I haven't paid any attention to... I remember that it (I assume) made revs hang at about 1500 after releasing throttle at one point a long time ago, but I haven't noticed any effect from it in a while, so I'll take a look at it...

So if anyone remembers me, I had a car that was jerking and running a bit unsteadily (75 280z), and was able to rectify this by cleaning a bunch of the electrical contacts. I've since done some more homework and determined that the primary culprit was the TPS; my TPS seems to get dirty very easily (and usually fouls a day or do after a rainstorm if I don't clean it immediately after). This will either cause an unsteady idle, or uneven performance at more than 3/4 throttle, so it's easy to diagnose. I have the cover securely on the TPS, so I don't know how it gets fouled, but as long as I spray it with contact cleaner every couple months, the car runs fine as my daily driver. Also, if the idle contact isn't just BARELY touching at idle, then the jerking behavior returns. If the idle contact on the TPS isn't set to where it disengages if you crack the throttle even just a bit, the car runs awfully. ...Is this normal? I don't care too much, seeing as I can keep it clean and adjusted and have no problems. It's sort of odd that my Z31 with L-jet doesn't need that sort of attention to the TPS, but whatever. The one thing that does sort of have me wondering, is the last bit of bizarre behavior the car exhibits. Until it's 100% warmed up, after the iac has closed but before it's all the way to operating temp., idle will dip down to 500 momentarily on releasing throttle, then climb back up to 900 where it's set, after about a second. I wonder if the car is looking for the leaner TPS setting to kick in a bit sooner on release of throttle, but again, if I don't have it just barely engaged at idle the car bucks. Once the car is totally warmed up though, after 15-20 mins, everything works normally. These are my observations: feel free to comment upon them as you like

Thanks... From glancing offhand behind my desk at work, thumbing through the PDF on my phone, it looks like it ought to be either connector C5 or C6 per the manual that I'll be dealing with, I should be able to confirm that once I check the car again. From there, I suppose I'll be trying to find a way to replace or route around the plug. ...Everything else on the car that's electrical still does work, all interior lights, rear defroster, audio etc.... Everything but for those two gauges, and an intermittent seatbelt buzzer. So hopefully I will find correlation among the pins and those

...Does anyone have a diagram of these mapped out, as to which terminal does what? I'm talking about the two big plastic plugs by the transmission tunnel/firewall in the passenger's footwell. I don't even know how to begin searching for them or what they're really called... Each has two rows of about five pins each, I can provide a pic if needed. My temp. and oil pressure gauges quit working, someone told me to check these connectors and clean them out with contact cleaner and a brush... Well, one of the connectors was pristine, the other more or less is disintegrated. So I'm wondering if anyone can direct me to what the function of each of the plugs is, so I can figure out what's affected by the broken/corroded pins. Does anyone sell a sufficient replacement connector? Thanks, oh yeah, car is 75 280z.

...Well, that sure worked I've leaked a terrific amount of gas, which I mostly expected, though I didn't quite expect for the amount of crisp bacon-like breakage that immediately occurred... Hooray for well ventilated spaces. Time to replace everything with FI rated clamps and lines, which the car probably doesn't have (definitely has the slotted band-type clamps, which I've been told not to use), and I was bound to do anyway

This pump has both wide and thick terminals, but there are also connectors present here that can be interchanged between them after the flat terminals. So I'm thinking, disconnect the pump to check for fuel tank blockage, and while I'm at it stick a line from the pump to a jug of fuel to see if it won't get sucked up. If not, cross fingers, reverse polarity. Unless someone warns of impending doom

So first off, the 280z from my other post is just fine, I've been driving it daily for however long it's been with no issue ...That's when I get cocky and get another car! So, the fuel pump was suspect; I wound up getting twelve volts at the terminals when the AFM flap was open, but the fuel pump wouldn't run; new pump, problem solved. However, rather than pumping any fuel, it seems only to make noise; i have the fuel line from the pump inserted into a jar for the time being, no dice on getting any fuel. I drained the gas tank, the gas inside was liquid rather than solid syrup/rust/bits of fuel tank, just smelled a bit odd (ten years old presumably) so I was fine with re-filling the tank without fear of issue... But I'm going to again check for blockage now. So of immediate concern is a notice on the installation guide, something to this effect: "if fuel pump is wired with reversed polarity, pump will run but not pump fuel"... Now I checked the terminals with a multimeter to ensure that + met + and - met -... Is it possible though that this new pump is wired reverse of the original? I'm extremely leary of reversing the terminals as I was previously under the impression that this would do nothing but kill the pump. So is it possible that the +/- terminals on my new pump run reverse, and if so is it safe to switch them in order to check? Thanks, -Dan

Alright, time for a bit of an update... Regarding the above, the tach has never jumped, dropped, or reflected anything other than what the engine was doing. When the car would cut out, revs would remain steady until I put the Clutch in, at which point I'd either die or have a lumpy, poor idle slightly before dying. I'll follow-up with part two in a moment. Here's the latest... Timing appears correct, and I measured the vacuum, which is a steady 19 at idle, no jumping or wavering at all. Does the right things with vacuum as you rev the car, or stab the throttle. I was sort of amazed that all the little solenoids for the AC and etc. don't seem to be my problem. I've been looking for a way to test the stock ignition module, and I'll probably still make a post about figuring out how to do so in the appropriate section. But that's the next system I set out and tackled, as follows: Checked the air gap between the magnetic pickup in the distributor. That was fine. I proceeded to pull the ignition module from the kick panel, it seems to not be the original one to the car but is the stock style. The box looked newish, including the connectors, but I hit them with contact cleaner and screwed them back in anyway. I just sort of stared at it other than that, not really knowing how to test it with multimeter. The plastic "jug" junction box with the distributor wires on the passenger's side engine compartment contained wires that looked a bit worse off, so I removed and replaced, cleaning the connectors. Before my next venture of checking fuel pressure I decided to take the car for a spin... The cutting out issue (which had returned above 3k rpm typically) then seemed to disappear, the car still ran a bit roughly, and would die (as if I took the key out) at stop lights sometimes. I readjusted the afm by about a tooth or three that it seemed to need, and bent the idle contact a bit on the tps to ensure that contact was firm at zero throttle. Also hit the connector with my trademark cleaner. Well... If the problem didn't seem licked, and if I hadn't had nothing but positive exeriences for the last week or so, driving a few times the 50 mile round trip to work and being fairly rough with it... Then I'd be too embarrassed to declare victory. And even so, I'd still say I'm nervous, considering my past experience with these issues. I don't feel like I did anything, so hopefully it was one of those dumb little connectors, but I don't feel like I can be sure even after a few long trips, through heat, rain, traffic and open road. Still a voice in my head tells me I'm kidding myself if I think I licked it with just that. I still wish I knew anything conclusive about the ignition module and I almost want to just ditch it all for a crane xr700, but I'll let this unsettling development continue for a while... Never did check fuel pressure.

The above mirrors my situation; I do seem to be able to turtle around under 3k without difficulty mostly... And the car never has difficulty starting, or issues immediately at startup. Seems to "reset" the car. When you say "ignition module" you mean the thing next to the fusebox in the passenger's side kick panel that costs about $300, right? Or the assembly in the distributor? I should also add that the tach never jumps around and is always accurate. When the car cuts out the gas pedal has no effect; foot on the clutch and it idles, badly. Does that discount anything? So I've had little time to work on the car, but lots to read and map; here's my plan for Sunday: 1- leaky injector test. Check to see that fuel pressure at the rail holds once the car is turned off 2- ensure fuel pressure before and after regulator are correct 3- wiggle/clean ecu connector, see if manipulation does not improve running 4- ensure that the engine has spark by testing with timing light to see if ignition module failure shows itself. 5- measure resistance of afm pot to ensure smooth progression 6- fuel pump check valve (That's a sentence fragment, because I haven't figured out yet how I will test it) ...Please feel free to add to, or provide any feedback. I'm intimidated, but really thank you guys for the help. I almost just wanted to stop by motorsport auto and buy a new ecu, icm, fpr and pump just on principle, as I was looking forward to taking my car to jccs, but it's too late for that now, so I have time to relax and apply thought.

I checked that the ECU is bolted very firmly in, but chickened out when it came to removing the connector. There are two wires dangling next to the ECU, disconnected from anything, each with a round female terminal connector. I can't seem to figure out from the service or Hanes manual what those must be, or if they're necessary. Another ignorant question, where are the grounds that I should be checking? Maybe a strange thing, the car only has these issues under load; I can rev the car freely, it runs smoothly in neutral. The problem has become more intermittent, sometimes if I let the car idle the idle will dip to about 300 and the car will die. Sometimes it idles steady, and sometimes if I rev the engine the revs will dip 200rpm below idle on the way down, then return to normal. The AFM again wants something different every time I touch the car. I'd say I'm back to square one I'm fairly certain that this is some sort of electrical issue, when the car "resolves" (which doesn't depend on anything I do), it sounds like I hear a bit of an electrical "click" from behind the dash, or firewall. Any idea what that could be? I did use contact cleaner on the temp. sensor connectors, no dice. It does appear to be a used sensor. Since it's only $30 for a new sensor, I'm thinking this may be my next course of action, I guess I should take some resistance readings first... I'm ready to give up and take the thing to a mechanic again, as I think I've reached the limits of my skill. I did try Mike's Z shop in Whittier, but to put it lightly, I got ripped off and they couldn't fix the issue. I gave them another chance to fix it, and all they did was accidentally (I think) disconnect a bunch of vacuum hoses, and give me a car that worked worse than it did before. Does anyone in SoCal actually know how to work on these things? I'm stuck here. Anyone want to buy it?

Ok... Sorry for the lack of response from me lately, I've unfortunately had little time to either work on the car, or post on the Internet, but here's status: -Reconnected evap. system. Also, plugs looked good still, have proper gap. -Replaced all six injector connectors and hit the injectors themselves with contact cleaner. This was clearly an issue. Car runs fine after that, previous issues seem gone with a BIG if; if I drive sedately, the car is fine. If I accelerate vigorously through the gears, it scoots along... No roughness or jerking on the way up. ... But for a minute or so after that acceleration, the car runs roughly for a few moments, sometimes the gas pedal has no effect, and if I come to a stop it will often die, or at least idle not so smoothly; running seems overly rich from the smell, but i cant be certain yet, and fingering the afm wiper during these periods of rough running seems to have no positive effect in either direction. The condition is similar to running the car with the fi temp sensor disconnected. So when I get home today I'm going to replace the connector and hit it with some contact cleaner. In the meantime, what else could generally cause that condition? I'd need a fuel pressure gauge to check for sure, but could it be the fuel pressure regulator? Vac line seems ok. Thanks for dealing with my headaches