Anime_fun Posted July 31, 2011 Share Posted July 31, 2011 Hi everybody Should start with saying that i did a search and didn't come up with something similar I bought a new afm recently beacause mine was a wreck, the number was A31-625-000 and my ECU has the number A31-601-000 The car started fine and ran good on idle and revving the engine, backfired a little, but not much. Then all off a sudden the revs just went down and the car died, now it won't start at all! I checked all plugs and they got a spark, the fuel pump works and sends plenty of fuel, and i have changed almost every sensor/wires on the engine.. Any wild guesses or ideas? Quote Link to comment Share on other sites More sharing options...
dexter72 Posted July 31, 2011 Share Posted July 31, 2011 Remove a couple of spark plugs and see if there wet. Maybe fuel fouled. Are the injectors working?. They should click during cranking. Have some crank it over and listen for them. Place a screw driver on the injectors and place your ear against the Handle end of the screw driver, listen for the injetors clicking. If no clicking they are not working. Try to spray starting fluid or carb cleaner into the throttle body and see if it runs. Yes the engine will run on both. Quote Link to comment Share on other sites More sharing options...
240zBoy Posted July 31, 2011 Share Posted July 31, 2011 I had a similiar problem couple weeks ago. Actually pretty stupid lol, I ended up regrounding my battery to the block and tightening up the cables real solid after cleaning the terminals and it was all good. Then I ended up spinning a bearing which was prob cause of the overheat problems I was having...dope Quote Link to comment Share on other sites More sharing options...
Anime_fun Posted July 31, 2011 Author Share Posted July 31, 2011 I have brand new injectors, 200cc, with new wires Now the car will start, but backfires like crazy and sounds a little down on power Quote Link to comment Share on other sites More sharing options...
NewZed Posted July 31, 2011 Share Posted July 31, 2011 (edited) What year car? Why did you buy A31-625-000 if yours was A31-601-000 (or vice-versa, can't tell which is old and which is new from your description)? The backfiring sounds like what mine was doing when I had a bad AFM. Edited July 31, 2011 by NewZed Quote Link to comment Share on other sites More sharing options...
Anime_fun Posted July 31, 2011 Author Share Posted July 31, 2011 It's a '77 280z The reason i was buying the afm was that i didn't find any 601.. but it openes and works fine so it shouldn't be a problem then? Quote Link to comment Share on other sites More sharing options...
NewZed Posted July 31, 2011 Share Posted July 31, 2011 The AFM, in general,is supposed to match the ECU. The ECU takes the voltage returned from the AFM to determine injector open time. I don't know if the Nissan engineers actually changed the potentiometer circuit or the spring tension or the shape of the air flow channel between the various AFM numbers, so couldn't say what the difference is between those two AFMs. Some AFM numbers appear to be the same AFM in function, except for small differences like the fuel pump contact switch. But there might be bigger changes that cause problems like you're having. The ECU and AFM inputs and outputs are kind of mysterious. You might get more ideas if you gave some history on the car. Did it run with the "wrecked" AFM? Has it ever run? Can you put the old one back on and get it to run? Things like that. Quote Link to comment Share on other sites More sharing options...
Anime_fun Posted July 31, 2011 Author Share Posted July 31, 2011 The car has never run on full power, my old afm has never worked and i have never gotten the car past 3500 revs Have runned it with the old afm and it don't backfire, but it won't let the engine rev or let it get full power, kinda like a preset from Nissan that if the afm breakes it can drive home, but not on full power Quote Link to comment Share on other sites More sharing options...
NewZed Posted July 31, 2011 Share Posted July 31, 2011 These old ECUs don't have the "limp home" mode that the newer computers do. They're primitive. Have you measured fuel pressure with the engine running? Fuel flow doesn't tell you much. Your problem sounds more like it's fuel related, with the lack of high RPM power, the dying and the backfiring. By the way, I think that your 1977 280Z is supposed to have 188 cc injectors. Are you running non-stock injectors or is that a typo? Quote Link to comment Share on other sites More sharing options...
Anime_fun Posted July 31, 2011 Author Share Posted July 31, 2011 (edited) I have aftermarket injectors yes, bought them from OsideTiger Have not ran a full test on pressure, but im going to now! Recently bought a pressure regulator from Black Dragon, but haven't received it and they have not contacted me in any way, so im not sure what they are doing.. Edited July 31, 2011 by Anime_fun Quote Link to comment Share on other sites More sharing options...
Anime_fun Posted August 30, 2011 Author Share Posted August 30, 2011 (edited) Finally got it running and it was a combo of a broken fuel pump and a broken/corroded TPS, so i bought a Walbro GSL 932 fuel pump and disconnected the TPS and it ran like a whole new car! Not on 100% yet, but close to 80-85% power. Edited August 30, 2011 by Anime_fun Quote Link to comment Share on other sites More sharing options...
rossman Posted August 30, 2011 Share Posted August 30, 2011 Glad to hear you got it running. Are you still using the large injectors? It's never going to run properly with those injectors connected to stock FI. Quote Link to comment Share on other sites More sharing options...
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