geordieggg

Seems like this was my last post as well, but I got the last problem sorted eventually.........:stupid: Here's the story so far: Car is a GS31 that's had the original L20A removed and replaced with an L28 by PO, whoever did the swap left all the L20 EFI gear (manifolds, ECU, AFM etc) there and hooked it up to the L28. Car ran fine when I first got it, started first go. Since putting the motor back together and doing a few laps at Teretonga (a local race track), I've had the car out a couple of times, without any major problems. She seemed to run a little rich on cold starts (a bit smokey when revved but it cleared as it warmed up) and drove fine. On Saturday, drove it around town a little bit, bought it out home and parked it in the hay shed. Saturday night, had to move it out, started fine. Did what we had to do in the shed, so I started it back up, moved it inside and parked it in the middle of the shed. Sunday, had to move it from where it was, wouldn't start. Cranked a coupe of times and coughed. Did this three times, then just plain wouldn't start and hasn't since. I've checked, it's got spark, air and fuel. Nothing has changed on the car since parking it Saturday night and trying to start it Sunday morning, so it's got me stumped! Now when I try to start it, it smells like it's flooding, so I checked the coolant temp sender and the thermotime switch, both check out ok (checked the coolant one through the harness at the ECU, and was still fine). What else could it possibly be? Is it possible for the cold start valves to stick open? I know the thermotime switch should only allow the cold start valve to open for a set amount of time, should I just remove the cold start valve and see what happens when cranking?

Have you changed the ECU as well? If not, check all sensors, I know this sounds stupid but I had endless probs withmy car because the connections to the thermotime switch and temp sender were bad. Cleaned them up (both the terminals and the plugs) and it was all good. Only other things I can think of are the throttle position switch and maybe the air flow meter (if you're still using it)??

Thanks for the reply.......... Timing hasn't been changed since I got the car, and neither has any of the FI stuff. Drove the car about 1000k's to get it home with no problems, so the ECU was running fine. Car ran slightly rich the whole way, but considering the way I drive, it's safer being slightly rich at low revs than too lean at high revs........ Compression is good, min 178psi up to about 188psi, that's in all cylinders with a stone cold motor. I've had the damn thing running, and between the last time it was running and when it stopped, the only things I have done were charge the battery, and bolt the fuel pump and ECU back into their spots. Since I did those three things, it has been having the problems described previously, so I suspect it's an electrical problem..........

After getting advice from you guys (and girls) last time, I got my Zed running again. It's a 260Z 2+2, with an L28 that has L20 EFI. Since then, I had to replace the thermostat, which shouldn't have been an issue. Car didn't want to start, so pulled all the temp sensors out and cleaned all the contacts (even pulled all the bolts out of the housing and cleaned them, to make sure of a good contact on the block). After cleaning everything, the car started up straight away, so I letit run for 5 minutes or so and turned it off. That was 3 weeks ago, and the damn thing hasn't started since. It cranks over fine, it's got heaps of spark. Initially it'll crank for as long as normal with a cold start and give one quick cough and splutter, like it wants to start. This might happen two or three times, then after that it won't start. Remove the plugs and they are dripping with fuel. I'm positive the fuel pressure's ok (haven't had a gauge on it to double check), I've cleaned the lines from the tank to the fuel rail, drained the tank. Tank itself is very clean (no sediment). I've been through the EFI book from this site, checked everything through the harness, and everything checks out fine. Anyone got any suggestions??

I'm not 100% sure, I've gto the same on my car and it's not hooked up either. I'm guessing it's vacuum controlled (obviously) and it adjusts the throttle slightly, probably only to help with cold starts (to let more air past the butterfly). My best guess............

My old 280zx with a disc brake rear end had a similar problem, it turned out the caliper was seizing. Used to just catch a high spot on the disc when driving and thump a bit, occasionally seizing on and slowing the car right down. Check it's not actually a brake problem while you're at it. Lift the rear end and chock the front wheels, start the car and put it in gear, see that helps you pinpoint where the noise is coming from, then go from there.

Like beandip says, if you ever want to install a vacuum gauge for anything more that tuning while the car's stationary, put it before the brake booster. The biggest problem with doing it with triples is the fact that installing it on one manifold may be ok, but can you guarantee that all three carbs are perfectly in sync? If not, then I wouldn't bother installing one full stop. Why do you want to install one?

Cool, thanks for that, never knew that it was such a common fault.

After sorting out the EFI problems I had previously, got the car back together and all was well. Latest problem that's just developed is the fuse for tail/dash lights keeps blowing. Anyone have any pointers on where to start looking? Everything seemed fine Thursday night, cars been out once and came back with the negative terminal of the battery sitting on the manifold, but this shouldn't cause any issues, should it? Theoretically, it should only be acting as another earth, correct? When I first turn the lights on, you can see the volt gauge drop right down until the fuse blows. Had a check the other night, using a multi meter. It's earthing out at the tail and park lights, and also at the switch, with the battery disconnected. Looking at the wiring diagram I have, the only way this can happen is if the fuse box itself is earthing out, which is a possibility, as everything was working fine until I put the whole car back together (centre console, all interior trim etc). Here's what I've done so far: Removed all tail & park lights - were working fine prior to car being put back together Removed stereo - wired in by a previous owner Removed alarm - wired in by myself Removed fuse box - no change, everything still earthing Removed any other wire I've touched - no change unplugged the alternator & starter - no change It's earthing through the tial & park light sockets, the combination switch (one of the two green wires and the thick white/red trace wire), the fusible link in the engine bay, as well as various places inside the car. Before I have to do something as bad as removing the dash, anyone got any ideas on where to look? To clear a couple of things up, everything was fine when everything was hooked back up, just not in place. Checked all the lights and indicators etc before putting all the interior trim & centre console etc back in (that's with the alarm and stereo etc all in and working properly). After putting all that back in, it was all working ok, until one night I went to move the car back into the garage and the fuse went. With the battery disconnected, I'm getting a closed circuit through some of the main wires to the switch and the fuse box when I check resistance with a multi meter, which is where I assume the problem is. This is checking with everything removed (alarm, stereo etc), so I don't think it is the alarm or the stereo or anything I've hooked up causing the problem. Looking at the wiring diagram I have, the only thing I can think of is either the wiper motor is shorting out or it's something called an "Amp assembly" - what this does I have no idea.............

yeah, it was a lucky find - someone had previously cut and resoldered the wires and I happened to be probing around and for some strange reason checked the voltage both sides of the solder and found the difference. For the record it was either the black/white or black/yellow, there's a white/red one there that had 12v the whole time. From memory it was the black/yellow causing the problems (whichever one runs to the starter solenoid). Thanks again guys for your help.......

Hey, thanks for the reply, but too late I'm sorry - turns out one of the ignition wires was broken about 2 inches from the switch, fixed that and she's been running ever since.

Just get your old sender unit and gauge out and send them to someone who repairs gauges. I worked for a company in Melbourne that could repair sender units and we always got the gauges at the same time, to calibrate the two. Anyone who can repair gauges should be able to do it. From memory it was usually around the $50-$60 mark fro the repair, takes a couple of days.

Yeah, have checked all sensors and connections, but I'm positive it's not any of that. I'm thinking it's the 3v at the key that's causing the problems, as the sensors aren't getting the right voltage, so they can't supply the ECU with the correct signal. For what it's worth, the ECU wiring on this car (from factory) is the same as the 280z you got over there, so I assume the rest of the wiring would be pretty close to the same.

Hey all, newbie here - been a member for a while but haven't had anything of interest to say, however I do have a big problem with my S31 Fairlady which I can't sort out, hoping someone here can help me........ To save me typing it all out again, here's links to what's been tried so far (courtesy of www.datsun.co.nz): http://datsun.co.nz/phpBB/viewtopic.php?t=1853 http://datsun.co.nz/phpBB/viewtopic.php?t=1907&start=0 And the latest: http://datsun.co.nz/phpBB/viewtopic.php?t=2430 I wasn't sure which category to put this in, so hopefully this will find the right person.....

Hey all, newbie here - been a member for a while but haven't had anything of interest to say, however I do have a big problem with my S31 Fairlady which I can't sort out, hoping someone here can help me........ To save me typing it all out again, here's links to what's been tried so far (courtesy of www.datsun.co.nz): http://datsun.co.nz/phpBB/viewtopic.php?t=1853 http://datsun.co.nz/phpBB/viewtopic.php?t=1907&start=0 And the latest: http://datsun.co.nz/phpBB/viewtopic.php?t=2430 I wasn't sure which category to put this in, so hopefully this will find the right person.....