z or bust Posted July 31, 2007 Share Posted July 31, 2007 OK so I just got done building my 83 280ZX n/a. I pulled the engine out and rebuilt it and put a stock turbo on it, 650 front mount intercooler, still running n/a electronics, only at 6 psi boost, got an ebay knockoff bov. I don't know what else, but here's the deal. It ran awesome for about a week no problems whatsoever. but now when i'm getting up it sputters, surges, cuts out...whatever you want to call it. Also when its at idle it revs fine all day long. but the minute I take it for a drive it starts to sputter again. What could it be. I was thinking that it might be a fuel pump but I don't want to buy one and replace it and find thats not the problem at all. Has this happened to anyone?? Quote Link to comment Share on other sites More sharing options...
nismopu Posted July 31, 2007 Share Posted July 31, 2007 OK so I just got done building my 83 280ZX n/a. I pulled the engine out and rebuilt it and put a stock turbo on it, 650 front mount intercooler, still running n/a electronics, only at 6 psi boost, got an ebay knockoff bov. I don't know what else, but here's the deal. It ran awesome for about a week no problems whatsoever. but now when i'm getting up it sputters, surges, cuts out...whatever you want to call it. Also when its at idle it revs fine all day long. but the minute I take it for a drive it starts to sputter again. What could it be. I was thinking that it might be a fuel pump but I don't want to buy one and replace it and find thats not the problem at all. Has this happened to anyone?? I am by no means an expert on this but I believe they run a stiffer spring in the turbo AFM for the trap door. Its possible this broke on your N/A AFM and is causing the issue your describing above. I have heard it happening with other vehicles, more commonly toyotas. Anyway, something to check out and if its not the problem I hope someone here can help you. peace. Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 31, 2007 Share Posted July 31, 2007 but now when i'm getting up it sputters, surges, cuts out...whatever you want to call it. Not really, spend some effort and tell us exactly what it's doing specifically. Cutting out means something totally different to me than surging, and sputtering. Really, what do you call it? Is it like someone turns off the key, then turns it back on rapidly... Or is it like someone turns off the key and leaves it off, turning it back on after a brief pause? Or is it acting like someone is pushing on the gas pedal on and off rapidly(or conversely, like someone holding the throttle pedal steady and pumping the brake pedal on and off)? Or is it popping out the intake? What noises do you hear? Any smells? Vague descriptions lead to guesses that don't help you figure it out at all. Not trying to flame anybody, but it really is what you call it that will determine what the diagnosis or SWAG will be in reply. Quote Link to comment Share on other sites More sharing options...
z or bust Posted August 1, 2007 Author Share Posted August 1, 2007 Ok i was afraid my description was vague. Its like you said Tony on and off the gas pedal. Basically feels like the car cuts out. It sounds like also the intake might be backfiring because there is popping coming from up front. What gets me is that its fine at idle so, I'm no expect, but doesn't that pretty much exclude the AFM from the picture? Also it only really happens if and when its under boost. Hope this time I made it more clear. I'm just frustrated cause I just got the car on the road and now this. Quote Link to comment Share on other sites More sharing options...
Tony D Posted August 1, 2007 Share Posted August 1, 2007 Surging and backfiring is usualy the sign of a lean mixture. If your injector connectors are not clean at either end, they can build up enough resistance that the injector pulsewidth starts dropping out or not firing at all and you backfire/surge/buck, etc. Cleaning the electrical connections is beneficial in general, but make sure you use dielectric on the connectors when you reassemble them so Oxygen doesn't quickly recorrode them. Seems the Nissan Connectors were great for 20 years (er...) and then once cleaned, you have to go back repeatedly to keep them that way! The AFM may be in operation under boost, but only at lower rpms and lower flows. So that isn't out---or more aptly the connectors on it aren't out. YOu can run the tests in the FSM for all the sensors and circuits relating to the ECCS in about 45 minutes---it really narrows down where you may have a problem sensor/harness/component, and since you are pulling the plugs at the ECU anyway why not check? Quote Link to comment Share on other sites More sharing options...
z or bust Posted August 1, 2007 Author Share Posted August 1, 2007 Yeah I've thought about the connections at the AFM but I didn't think about the injectors. The weird thing is, is that it started to do that earlier the same day then stopped but now it won't go away. Could it also maybe be a bad fuel pump?? I wish I had an FSM but I don't. I'm still trying to get my hands on one. Quote Link to comment Share on other sites More sharing options...
Hyuri Posted August 1, 2007 Share Posted August 1, 2007 Go to http://carfiche.com and look for the 82 Datsun 280ZX manual. It's not exactly right for an 83, but between that and the Haynes I've been keeping up. You may have to wait a while to get it though; just check back every hour or so until it's available. Quote Link to comment Share on other sites More sharing options...
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