RunNE1 Posted April 30, 2004 Share Posted April 30, 2004 I have tried most of the things I found in the archive post. I checked for vacuum line leaks, tears in the intake hoses, made sure all the clamps were tight, inspected the rotor. I still have a problem though. When I first start driving the car it runs fine for a few minutes. It will rev high and accelerate smoothly. After a few minutes though, if I give it too much throttle, it starts to hesitate like I hit a fuel cutoff point and them the rpms drop. I can still hear the fuel pump whirring away(stripped interior). When the rpms drop down to around 1500, it tries to accelerate again but only manages to sputter and pop. If I rev it in neutral, it does not have this problem. I did find that the hose clamps on the fuel filter I replaced a month ago were very loose. I even swapped out the air meter and it had no effect. One thing I noticed was that the output line of the fuel filter felt like it had alot more pressure than the line going into the filter. Is this normal? Any suggestions?? Thanks Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted April 30, 2004 Share Posted April 30, 2004 We need to know more about your setup. What motor are you running, and/or what type of fuel/air induction? Possible solutions for a chevy LS1 might not be the same things you would look for on a SU carbed 2.4L L6. Quote Link to comment Share on other sites More sharing options...
datsunlover Posted April 30, 2004 Share Posted April 30, 2004 Id start by looking at the Throttle Valve Switch and checking your injectors. Quote Link to comment Share on other sites More sharing options...
RunNE1 Posted April 30, 2004 Author Share Posted April 30, 2004 It is a 1980 280ZX w/ a stock engine. The only mod is a cone filter replacing the complete stock intake assembly. One other thing, I just had the exhaust redone, from the ex. manifold back. Could there be a problem there? What exactly am I looking for w/ the throttle switch? Thanks Quote Link to comment Share on other sites More sharing options...
TomoHawk Posted May 1, 2004 Share Posted May 1, 2004 The TPS (throttle Position Sensor) tells computer you are at idle or WOT, and the computer richens the mix slilghtly. Check out the Net for a procedure to check & adjust properly. Quote Link to comment Share on other sites More sharing options...
datsunlover Posted May 1, 2004 Share Posted May 1, 2004 Hmm.. Im not positive, but I thought it was basicaly the same FI as the 75 and on cars, but the 280zx added an O2 sensor.. if that is the case, technicaly, its NOT a tps, because its not a sensor. It's just two switches. Anyway, My FSM (for a 75 280z) gives a vauge blurb on checking it with a continuity tester (Multimeter set to beep when you touch the to leeds) The FSM said to pull conector off (car not running for this test) and check for continuity between terminals TWO and THREE (middle one, and the one to the right of it when your standing on the drivers side of the engine bay) at zero throttle. After a certain amout of throttle ( the fsm says something like 28 degrees.. yah.. I gave it about 1/4 throttle) it will switch, and terminals two and ONE should have continuity. If your looking down at the terminal, its like this (I think) 1 2 3 | | | Or you could just try replacing it and seeing if that fixes the prob.. They are only like $40 I think! Hope this helps. Quote Link to comment Share on other sites More sharing options...
RunNE1 Posted May 1, 2004 Author Share Posted May 1, 2004 Thanks for the help guys. I will check the TPS today and few other things. Thanks Quote Link to comment Share on other sites More sharing options...
TomoHawk Posted May 1, 2004 Share Posted May 1, 2004 You won't need to replace the TPS unless it broken or really rusted. All there is are 3 contact tabs, and a plactic fork-thingy to bend the center tab to make contact with the two side tabs. i.e., just a really simple SPDT monentary switch. It's even conceivable that you could move it to the dash and use a SPDT togle switch! Quote Link to comment Share on other sites More sharing options...
COZY Z COLE Posted May 1, 2004 Share Posted May 1, 2004 I also have a 80 280ZX and a FSM for it. It says, for both hesitation-stumble on acceleration and for backfiring , check for intake air leakage at the P.C.V. valve, dipstick and oil filter cap seals, manifold gaskets, and the air flow meter hoses. It also says to check your fuel pressure. Good Luck on this. LARRY Quote Link to comment Share on other sites More sharing options...
RunNE1 Posted May 9, 2004 Author Share Posted May 9, 2004 Well, after rechecking the filter, I think I have found the culprit. Brown gasoline . It looks like my tank is screwed up. It seems that both the filter and fuel pickup were clogging up. Hopefully, the tank is salvageable. Thanks for all the help guys. Quote Link to comment Share on other sites More sharing options...
Guest crunchy Posted May 9, 2004 Share Posted May 9, 2004 i have a simaliar problem with a difference, i have replaced afm, pump, ecu,dissy, tps and coil, the problem is around 3-4000 it does a big hesitation and blows out heaps of black smoke from over rich but the rest of the time it cruz fine. done the filter and plugs and leads but no go, i thinking maybe an injector isnt very happy, any ideas before is finds a new home over a cliff Quote Link to comment Share on other sites More sharing options...
datsunlover Posted May 10, 2004 Share Posted May 10, 2004 Sounds like the same prob I had in my 81 280zx. Turned out to be an injector on that one... Id look into getting them cleaned/replaced.. Or maybe for starters, check the little electrical conectors on the injectors. sometimes they start cracking from age or get coroded over time and dont make a good conection, which would cause the injector not to fire sometimes... Quote Link to comment Share on other sites More sharing options...
RunNE1 Posted June 18, 2004 Author Share Posted June 18, 2004 Well finally got the car running. The gas tank was the problem. When I removed it, I could see rust everywhere. There was a even some glue-like liquid at the bottom of the tank. I almost went the fuel cell route, but did not want to have to open the hatchback to fill the tank. So, I had the tank dipped and coated. It did not get rid of all the rust, but at least it is all coated over. Thanks for all the help guys. Quote Link to comment Share on other sites More sharing options...
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