91_4x4runner Posted June 24, 2008 Share Posted June 24, 2008 Howdy guys. My '78 280Z is stuttering on acceleration (under no load... just revving). It seems to idle fine. I've replaced the ignition coil and pulled/soaked the injectors. When I give it gas, the rpm's drop. Within a second, I hear a loud pop coming from the AFM area. I hope it isn't the AFM, but it wouldn't surprise me. Any other ideas? Thanks, Eric. P.S. I need to take apart the entire intake manifold and replace the hoses/fix the vacuum leaks. Quote Link to comment Share on other sites More sharing options...
HoustonZ Posted June 24, 2008 Share Posted June 24, 2008 I have the exact same problem right now. I checked the normal stuff. New plugs, thermotime sensor, tested injectors, coil, vac leaks. Quote Link to comment Share on other sites More sharing options...
91_4x4runner Posted June 24, 2008 Author Share Posted June 24, 2008 Likewise.. I've got new plugs in and checked the injectors. I haven't yet replaced the thermo sensor or fixed my vac leaks, but it idles fine... where I'd expect the vac leaks to really hurt it. Quote Link to comment Share on other sites More sharing options...
S130Z Posted June 24, 2008 Share Posted June 24, 2008 i had a similar problem when i changed my intake on my zx, i was getting to much fuel, bog down and it would backfire through the intake. check your fuel pressure regulator. if you have a bad vac leak it will also bog, check your grounds too. Quote Link to comment Share on other sites More sharing options...
Buma Posted June 24, 2008 Share Posted June 24, 2008 Check the timing and see if it is advancing properly. Quote Link to comment Share on other sites More sharing options...
RayG1988 Posted June 24, 2008 Share Posted June 24, 2008 I have the same exact problem with my Z. In fact sometimes it doesn't even rev above 4k rpm, when I moved the AFM around a bit it makes a difference. I actually had to tie it up so it stays in position. Quote Link to comment Share on other sites More sharing options...
HoustonZ Posted June 25, 2008 Share Posted June 25, 2008 Timing is good. I loosed up my valves to .012/.010 and that helped alot. Quote Link to comment Share on other sites More sharing options...
91_4x4runner Posted June 26, 2008 Author Share Posted June 26, 2008 After a while, it got to the point where it wouldn't idle at all. I pulled the fuel rail and the wire harness. I then started disassembling everything (found at least 2 vac leaks). I have two problems now though. I've got the entire intake disassembled and unbolted (4 bolts), but I still can't pull the damn thing off the block. Is there some special trick? The only thing that is still bolted on (as far as I know) is the EGR pipe, but its cracked and I should at least be able to pry the manifold away at the front.... God I feel like an idiot. So far my problems amount to: Vacuum leaks Bad injectors (seem to be sticking open) Clogged fuel rail (if i turn the pump on with the return line unplugged, still no fuel shoots out) Stuck intake manifold Idiocy Quote Link to comment Share on other sites More sharing options...
HoustonZ Posted June 26, 2008 Share Posted June 26, 2008 Did you unbolt the shared bolts between the intake and exhaust manifold? Quote Link to comment Share on other sites More sharing options...
91_4x4runner Posted June 26, 2008 Author Share Posted June 26, 2008 That would be a negative..... *red face* When I looked at my other intake manifold, I only saw 4 bolts. Which bolts are shared by both? Quote Link to comment Share on other sites More sharing options...
HoustonZ Posted June 26, 2008 Share Posted June 26, 2008 Here ya go. I believe this is right, going off the top of my head. I had the same problem the first time I took my manifolds off Quote Link to comment Share on other sites More sharing options...
91_4x4runner Posted June 27, 2008 Author Share Posted June 27, 2008 I'm going to test my injectors tomorrow evening, but on the off-chance that they're bad, what are my alternatives? I checked out a few websites and stock replacements range from 60 to 100 dollars PER injector. This is friggin' crazy. 360 to 600 dollars plus tax for a new set of injectors that flow what... 150cc? [/rant] It doesn't look like the needles are coming all the way down to close the flow of fuel... what are my alternatives? New rail/ different type of injectors? Someone have spares? Thanks, Eric. Quote Link to comment Share on other sites More sharing options...
HoustonZ Posted June 27, 2008 Share Posted June 27, 2008 I'm pulling my N/A '77 injectors off next weekend. Want to buy mine for cheap? Quote Link to comment Share on other sites More sharing options...
m4xwellmurd3r Posted June 27, 2008 Share Posted June 27, 2008 there's a guy on ebay that sells reconditioned injectors that are flow matched within 2% a full set of injectors, harness clips and the test sheet are like 140, but the only one's I see him selling right now are probably too big Quote Link to comment Share on other sites More sharing options...
91_4x4runner Posted June 27, 2008 Author Share Posted June 27, 2008 Absolutely. All of 'em work, right ? Quote Link to comment Share on other sites More sharing options...
HoustonZ Posted June 27, 2008 Share Posted June 27, 2008 Yeah, they're all working. PM me for more info. Need any other EFI parts? Quote Link to comment Share on other sites More sharing options...
91_4x4runner Posted June 27, 2008 Author Share Posted June 27, 2008 PM sent. I'm sort of jacking my own thread on this one, but I wanted folks to see this. I just got the "stage 4 rear brake kit" from bajaracer. These rotors are huge! They're the same size (or bigger even) as the front rotors on my 4Runner. For reference... my entire hand stretches just barely past the hub portion. Quote Link to comment Share on other sites More sharing options...
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