DatsunBoy77 Posted February 1, 2003 Share Posted February 1, 2003 This is about a 83 turbo motor swapped into a 280Z. Firts off the thing is fouling out plugs. It seems to be running rich but once you floor it at high RPM's it wants to stall. I was going to check the TPS and i noticed the connecter that plugs into the TPS only plugs in to the middle and top one. The top one is for idleing and the bottom one is for WOT, right? Is this why it stumbles and almost stalls at WOT? Was there ever a connecter that connected to the bottom one in that plug? If i am confusing anyonelet me know. Thanks in advanced. Ryan Quote Link to comment Share on other sites More sharing options...
fl327 Posted February 2, 2003 Share Posted February 2, 2003 This is about a 83 turbo motor swapped into a 280Z. Firts off the thing is fouling out plugs. (that could a million things) It seems to be running rich but once you floor it at high RPM's it wants to stall. ( set timing to 20 BTDC, if timing is set a ways off, it throws off the whole range, timing is controlled by ecu and likes to start around 20 BTDC, i tried to advance mine a little once and right when it was boost time it would want to stall)(also check efi grounds, should be three off the main harness, they are factory grounded to the manifold. I was going to check the TPS and i noticed the connecter that plugs into the TPS only plugs in to the middle and top one. The top one is for idleing and the bottom one is for WOT, right? ( tps on L28et only has two wires off it and only plugs in one way, i think you are ok there, you may need to adjust it so that the it has contact at idle and disengages once pedal is depressed, and engages second contact at about 1/3 of its travel) Is this why it stumbles and almost stalls at WOT? ( no, a bad tps or misadjusted one will run rich at cruising speeds Was there ever a connecter that connected to the bottom one in that plug? If i am confusing anyonelet me know. Thanks in advanced. (pretty confusing, but thats ok) Quote Link to comment Share on other sites More sharing options...
DatsunBoy77 Posted February 2, 2003 Author Share Posted February 2, 2003 The car has many open vacumm lines that i can see, mostly things like the egr are blocked off. This isn't my car but i am helping them. It idles at like 1100 or just a little below. I think the timing may be off because of this. We tryed to advance the timing, but when we would turn the distributor the car would start to to die. Turning the distributor towards the clockwise is advanced, correct? Thanks for the help. Ryan Quote Link to comment Share on other sites More sharing options...
VinhZXT Posted February 11, 2003 Share Posted February 11, 2003 Is he using the turbo intake manifold? If not that could be the problem. There is a vacuum control valve on the turbo intake manifold you need in order for the car to run right. This is a little valve that screwed into the 4 runner of the intake. I learned it the hard way. In the process of cleaning up the mess on my turbo intake I removed this valve and the car runs so rich. I had to put this valve back into for the car to run properly.. Hope this helps you out Vinh Quote Link to comment Share on other sites More sharing options...
Guest livewire23 Posted February 11, 2003 Share Posted February 11, 2003 I have this same problem, and have spent the last 2 weeks trying to diagnose it. I'm about to go finish up the reassembly of my engine and fire it up. I got pissed and took everything off it and reattached it. In the process I found that the fuel pressure regulator was bleeding off pressure too early. You might want to check your FPR, because it can cause the engine to run lean under a load, when it needs fuel the most. I'll tell you when I have any progress. Im running a 77 280Z with a stock L28, so this could have nothing to do with the turbo. Quote Link to comment Share on other sites More sharing options...
bumble zee Posted February 11, 2003 Share Posted February 11, 2003 did you play with the afm yet?? tighten that spring, that will help it out Quote Link to comment Share on other sites More sharing options...
Guest livewire23 Posted February 11, 2003 Share Posted February 11, 2003 I was thinking about doing that, but I figured thats kind of a cheating fix... You're just covering up the problem by... err, let's see, tightening the spring reduces the air flow and increases the A:F ratio, or is it the other way around? Anyway, Im lazy so I'll try that. Quote Link to comment Share on other sites More sharing options...
fl327 Posted February 11, 2003 Share Posted February 11, 2003 afm is idle circuit when you play with the screw shouldnt do anything after that. Quote Link to comment Share on other sites More sharing options...
bumble zee Posted February 11, 2003 Share Posted February 11, 2003 tightening the spring will make it run leaner, and loosening the spring will make it run richer. Quote Link to comment Share on other sites More sharing options...
DatsunBoy77 Posted February 16, 2003 Author Share Posted February 16, 2003 OK, check it out, since then he switched back to a 77 distributer, 77 wiring harness, and 77 ecu. Now the car runs up to redline. Problem is now no cold start valve because there is was no provsions on the 77 wiring harness. This thing isnt relly being driven though and mostly just being started. Hates being started now in the cold. It really is rich at idle but leaner up top. He gave the car to me so now i am gonna try and get an uncut harness and wire it up correctly. Now as far as vacum lines I will go out when it gets warmer (-10 now). I will have to make a custom intake piping for the vacum lines to plug into. Quote Link to comment Share on other sites More sharing options...
TimZ Posted February 16, 2003 Share Posted February 16, 2003 It really is rich at idle but leaner up top. You mentioned before that there were several unused vacuum ports. Do you have a vacuum line running to the FPR? Are all of the unused ports plugged? Quote Link to comment Share on other sites More sharing options...
DatsunBoy77 Posted February 17, 2003 Author Share Posted February 17, 2003 Odd you should mention that because i haven't started it yet since i have plugged them up cbut it has been too cold to start it right now (below 0) withought a cold start valve hooked up. tHIS IS A SUMMER car so it isnt driven now anyways. Quote Link to comment Share on other sites More sharing options...
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