stevofoxono Posted May 10, 2011 Share Posted May 10, 2011 i swapped over my afm today and now my z's kind of buggered. Turn the key, lots of black smoke from the exhaust, sounds like intakes restricted and it can't hold idle. The stock afm is back in the car, I changed over the plugs cause they were black as.. At this moment everything is the same as yesterday (apart from the plugs) nothings been disconnected but my 280 is running rough as hell. Could the problem be ecu or something? I'm buying new ignition leads tomorrow just incase thats the problem but i'm kind of worried that i've dropped a piston or something... mechanic mates coming over tomorrow and checking compression Is there anything i should be looking for?.. Quote Link to comment Share on other sites More sharing options...
RB30X Posted May 10, 2011 Share Posted May 10, 2011 I would say it's got something to do with swapping the airflow meter. The harness on them can get brittle and you may have damaged it. Why did you swap it anyway Quote Link to comment Share on other sites More sharing options...
stevofoxono Posted May 10, 2011 Author Share Posted May 10, 2011 There's a topic about changing them over on this forum, Swap over the stock 280 afm for a camry 98-02 one. Its bigger and the plug lines up without a problem.. Cheap+potential for a bit of power, I like doing things within my small budget lol Quote Link to comment Share on other sites More sharing options...
MaygZ Posted May 11, 2011 Share Posted May 11, 2011 I would recommend that you swap the old AFM back in and see if the problem goes away. If it does, problem solved. If not then investigate with the OLD AFM on to ensure that when you swap it back over, the AFM is the only variable. Quote Link to comment Share on other sites More sharing options...
RB30X Posted May 11, 2011 Share Posted May 11, 2011 My first VL was a horrible thing. The air flow meter harness was dodgey and played up like you mentioned. The thing would stop and go as it pleased. If youve moved it around to replace the flow meter, that would have started the problems. Quote Link to comment Share on other sites More sharing options...
stevofoxono Posted May 11, 2011 Author Share Posted May 11, 2011 I'm thinking its something to do with the plug/wire, Did a compression test just incase, cyl 1-4 were between 140-145, cyl 5,6 were at about 130 but i'm assuming thats because my battery was just about dead. What should I be looking for with the afm harness? fray'd wire/coper exposed or is there something less obvious? The stock afm is back in the car at the moment btw. RB30X how did you fix the vl? Quote Link to comment Share on other sites More sharing options...
MaygZ Posted May 11, 2011 Share Posted May 11, 2011 The stock afm is back in the car at the moment btw. Is it running any better? I don't know much about AFM, but if it's from a smaller engine, won't it think - due to air flow - that it's revving a lot faster than it is and therefore supply it with more fuel?? Quote Link to comment Share on other sites More sharing options...
stevofoxono Posted May 11, 2011 Author Share Posted May 11, 2011 actually running worse with the stock afm weirdly enough. but with the camry bit its only marginally better.. might hold off till i get my megasquirt before doing any other upgrades.. lol Quote Link to comment Share on other sites More sharing options...
MaygZ Posted May 11, 2011 Share Posted May 11, 2011 I like doing things within my small budget lol ... might hold off till i get my megasquirt ..... Quote Link to comment Share on other sites More sharing options...
stevofoxono Posted May 12, 2011 Author Share Posted May 12, 2011 poor till i get my tax return should be getting about $3000 back, Megasquirt 2 built new for $400 (included postage) i've found on the ebays Quote Link to comment Share on other sites More sharing options...
maddos Posted May 12, 2011 Share Posted May 12, 2011 Could the AFM not have been directly compatible and cooked your ECU? Quote Link to comment Share on other sites More sharing options...
stevofoxono Posted May 12, 2011 Author Share Posted May 12, 2011 thats what i'm fearing, Got new leads today, theyre nice and red and got them for cost price so not to fussed they didn't fix my car. Autoelectrician mates coming over tomorrow. Gonna wire up a new plug and if that doesn't work gonna check the ecu. I've seen ecu's for $50 off ebay so it shouldn't hurt to much Quote Link to comment Share on other sites More sharing options...
stevofoxono Posted May 13, 2011 Author Share Posted May 13, 2011 A wee bit of progress, took apart the ecu- no problem. checked wiring from afm to ecu- no problem Opened up afm- where the third wire went into the plug on the inside it had broken away from another copper plate thing. Fixed that up. Started car, still won't hold idle without gas. It's coughing from the intake.. I'm guessing i have a leak somewhere between the afm-throttle body-intake manifold to block. Going to go through it all when the sun returns. Would there be anything else i should be looking for? Cheers for the help so far! Quote Link to comment Share on other sites More sharing options...
Daedalus-Z Posted May 17, 2011 Share Posted May 17, 2011 I'd still suspect the AFM, I had a Z31 300zx many years ago which had MAF problems and the symptoms were similar to what you are describing. Was just driving down the highway one day and BAM, it died. I'd assume the 280zx uses a similar MAF setup? I'm not sure how intelligent the ECU in the 280zx is, but it may be worth disconnecting the battery for a few hours and letting the ECU 'forget' whatever information it may have retained about the different AFMs that have been connected to it. If it's a hotwire type (the 300zx's were) it's also important to ensure that the wire doesn't have any oil or other contamination on it as it can affect the reading it's giving. Apparently even the oil from your fingers is a bad thing if you've been touching it. Probably stating the obvious, but if you can find another 280ZX AFM from somewhere to test it with, that would be the simplest way to determine if the AFM is at fault. Quote Link to comment Share on other sites More sharing options...
RB30X Posted May 17, 2011 Share Posted May 17, 2011 Check, clean and use electra clean on all of your terminals inside your harness plugs. Your looking for that green coppery residue sitting on the pins. Make sure the 'male' pins are clean and straight and the 'females' are tight enough to get good contact on the male pins (oh dear ) Coolant sensor, TPS, AFM, Coil, Crank angle sensor, the other one on the coil??, etc All these plugs have a say in how the engine runs and if they arent communicating properly, thats when you start pulling your hair out and pay mechanics to replace items of your efi one by one at the discust of your wallet. Quote Link to comment Share on other sites More sharing options...
Gordon Dobie Posted June 17, 2011 Share Posted June 17, 2011 A cause of fouled plugs can be fouled injectors. Over time a wax resdue can build up in the injectors causing a poor spray pattern. The injectors should emit a fine mist in an umbrella Patten which will vaporise almost instantly but when the injectors are clogged with wax they deliver a jet of wet fuel which does not vaporise properly. Wet fuel won't burn fully resulting in excess carbon deposits on the plugs and as carbon is an exceltent electrical conductor the electric current tracks through the carbon instead of jumping the plug gap. The unburnt fuel eventually vaporises and burns then exits the exhaust in a black cloud. The solution is have the injectors cleaned and use injector cleaner in your fuel tank every couple of months. Gordon Dobie Datsun Racing Team Chief Engineer (retired) Quote Link to comment Share on other sites More sharing options...
dazzed Posted June 20, 2011 Share Posted June 20, 2011 and lots of bad corroded electrical harness connectors Quote Link to comment Share on other sites More sharing options...
stevofoxono Posted June 20, 2011 Author Share Posted June 20, 2011 Thanks for the advice, z has been up and running again for the last month or so (probably should have posted something ) Replaced the intake/exhaust gasket and presto, good as new. Found out my extractors were genie aswell Taking it to mild to wild exhaust shop close to my fathers work to have them redo my gasket (slight exhaust leak, apparently i didn't use the right gasket glue) At the same time getting my new intake manifold+pallnet fuel rail+fuel pressure regulator put in. By the end of July i should have a megasquirt bought and hopefully installed. Getting a fair bit of work atm so lots of new shiney parts for the fairlady. Will post pics up most probably in a new thread when the engine bays all sexy and i've got the fender mirrors/watanabes/front air dam all finished. Should be awesome Quote Link to comment Share on other sites More sharing options...
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