280zx 2by2 Posted March 24, 2008 Share Posted March 24, 2008 the car is stock I have been puting in new GP sorenson injectors in my 1981 zx non-turbo EFI(of corse) got finished today and it will not start, didnt change any thing with the timing, didnt really change any thing but the injectors, i reconected all the electrical lines, vacuum hoses, and fuel lines was i spose to fill the regulator or something of that nature with gas? all of the electrical should be good but i havent checked for spark air should be good is there something about the GP sorenson injectors, i have already looked at the forums for the reputation of the injectors but didnt research that much on the install (i have the Chilton repair manual for the car) but every thing went smooth untill the final step also i have no leaks and i have fuel pressure although my (new)fuel pump sounds weak but i have never had a problem with pressure Quote Link to comment Share on other sites More sharing options...
nando280zxt Posted March 24, 2008 Share Posted March 24, 2008 Check for spark, make sure your plug wires are in the correct order, i know you just bought them, but make sure your injectors are flowing the right amount. All you really need is fuel, compression, and spark! Start with that first. Quote Link to comment Share on other sites More sharing options...
280zx 2by2 Posted March 24, 2008 Author Share Posted March 24, 2008 thanks, think i may have found the problem, its in the injector harness/conector, i bought new ones to replace the old one but decided to keep the old ones because they were in better shape than i thought, problem is that i dont think the old clips are working with the new injectors... thanks though-that might not be the problem and ill be right back here tomarrow afternoon Quote Link to comment Share on other sites More sharing options...
280zx 2by2 Posted March 24, 2008 Author Share Posted March 24, 2008 ok i put on the new harnesses today and it still wont start, i have spark i have fuel pressure i have air im sure i have compression i read last night where the temp sensor or some sensor(may have been the 02 sensor) would keep the car from cranking any input or questions would be great Quote Link to comment Share on other sites More sharing options...
nando280zxt Posted March 25, 2008 Share Posted March 25, 2008 Yeah, if the head temp sensor isn't connected the car won't start. Its on the right side of the engine it almost looks like a water temp sensor. It should be screwed into the head. Quote Link to comment Share on other sites More sharing options...
280zx 2by2 Posted March 25, 2008 Author Share Posted March 25, 2008 are ther any more of those kind of nessisary sensors or switches? i have every thing needed for combustion i just dont have combustion, its something to do with the computer and or sensors Quote Link to comment Share on other sites More sharing options...
woldson Posted March 25, 2008 Share Posted March 25, 2008 Yep oil pressure sensor, pass side kinda near the fire wall on engine block. also fuel cut in afm. Quote Link to comment Share on other sites More sharing options...
280zx 2by2 Posted March 25, 2008 Author Share Posted March 25, 2008 fuel cut in afm. sorry for my ignorance but what is this? Quote Link to comment Share on other sites More sharing options...
Gollum Posted March 25, 2008 Share Posted March 25, 2008 Ok, what size are the injectors? When I switched out my NA injectors to turbo injectors (180cc to 260cc i think) and my car didn't run until I adjusted the AFM to put in the correct amount of fuel. If you have air fuel and spark in every cylinder then it's either the air/fuel ratio that's bad, or spark timing. Could theoretically be compression too, but the motor ran before so it should be fine. Quote Link to comment Share on other sites More sharing options...
nando280zxt Posted March 25, 2008 Share Posted March 25, 2008 In a rough answer, it means that sometimes the afm reads to much air/to little (i believe,woldson correct me if im wrong) and your ECU cuts fuel. Fuel Cut Off is what i believe its called. I've usually heard of that happening to people who intercool and jack up boost to about 13-15 psi. Then the afm needs to be adjusted. But you have a NA so that doesn't matter. Quote Link to comment Share on other sites More sharing options...
nando280zxt Posted March 25, 2008 Share Posted March 25, 2008 There ya go gollum gives a perfect example! You may need to adjust your afm. Quote Link to comment Share on other sites More sharing options...
280zx 2by2 Posted March 25, 2008 Author Share Posted March 25, 2008 stock replacements, dont get me wrong, this car worked fine before except for injector leaks Gollum, your swap was a much larger increase in size (stock to turbo injectors)mine was really sorry stock to correctly working stock, could this need for a tune aply to me? also, how do i do the tune? Quote Link to comment Share on other sites More sharing options...
nando280zxt Posted March 26, 2008 Share Posted March 26, 2008 there should be a screw under the afm that will allow you to adjust. Here's a good link to show you how. http://www.geocities.com/jfairladyz/AFMrebuild.html?1144191577198 Quote Link to comment Share on other sites More sharing options...
280zx 2by2 Posted March 26, 2008 Author Share Posted March 26, 2008 thanks even if thats not the problem that could really help me if i get the car running agian!!! Quote Link to comment Share on other sites More sharing options...
sweetleaf Posted March 26, 2008 Share Posted March 26, 2008 What did you remove to R&R the injectors? Quote Link to comment Share on other sites More sharing options...
woldson Posted March 26, 2008 Share Posted March 26, 2008 http://www.atlanticz.ca/zclub/techtips/efisystem/280zfuelinjectionbook.pdf Before anything read this! It is the finest read that a member posted a long time ago. Wish I could remember his name. Quote Link to comment Share on other sites More sharing options...
Gollum Posted March 26, 2008 Share Posted March 26, 2008 Dang it, I'd writted up a nice little page on how to adjust the AFM. It must have gotten lost somewhere in the midst of the chaos of work yesterday. Reading through that link woldson posted would be a good idea, but don't take everything as biblical. One thing in particular he says truly concerns me. "While the engine is warming up, oil is thicker; there is more resistance, so more fuel is needed" Either he's trying too hard to simplify his wording, or his idea of how fuel works in an engine is completely wrong. Fuel Vapors are what burn, not the liquid itself. When an engine is cold there's less fuel vapors becuase more of the fuel is staying liquid. So until the engine starts getting warm you need a TON of fuel in order to create enough vapors to get the engine running smooth. THAT is why you MUST run rich when cold, and it's also the source of the majority of the smog cars produce. Even on a road trip you'll produce more smog in that one start up in the morning than your car will all day long. It's one of the main focuses of smog reduction engineers are still chasing after. Back to the AFM The IDLE MIXTURE was mentioned, but that honestly has very little effect on overal mixture. If you open it up (usually siliconed on, just cut into the seam with a knife and then pry off) you'll see the gear attatched to the spring in behind everything else, and you should see a bolt holding it in place. First, before anything, mark the gear with a sharpie. Now you'll know where to put it back to if you screw something up. Loosen the bolt that holds it and then adjust. I'd start off by loosening it about 3 teeth (counter clockwise, or letting it unravel on it's own power) then tighten the bolt back up. See if that does it. If not, go 3 teeth the other direction. If none of that makes any noticable difference to your situation put it back where it was, your problem is elsewhere. Quote Link to comment Share on other sites More sharing options...
nando280zxt Posted March 26, 2008 Share Posted March 26, 2008 That way you can see if its too lean/rich.....good idea. Im not too sure if the problem is the afm.....im thinking an electrical problem somewhere? And you've made sure you don't have any vacuum leaks right? Quote Link to comment Share on other sites More sharing options...
280zx 2by2 Posted March 26, 2008 Author Share Posted March 26, 2008 im pretty sure bout no vacuum leaks but not electrical, whats making me angry is that it could be any one of the sensors or a combination and i cant wiggle all of them at a time i just need a list of all nessisary sensors or any electrical wires or vacums that are needed for the car to start Quote Link to comment Share on other sites More sharing options...
280zx 2by2 Posted March 26, 2008 Author Share Posted March 26, 2008 thanks woldson, ill read over this and see if any infocan transfer to my 81, some should... Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.