funbunion Posted August 20, 2009 Report Share Posted August 20, 2009 I have a Dec. of 86 ESI. I rebuilt the engine in my garage last summer and it ran perfect, and I mean perfect. I've done every "free" mod I can, ported and polished intake and exhaust, new injectors+clips (3 years ago), rebuilt throttle body, new air cleaner(K+N), new intake boot from maf to turbo, new vacuum advance, new plugs, wires, rotor button and cap, new bonding wires, new vacuum lines throughout engine compartment. All that said, here's the story... I bought a 16g from ebay a couple years ago before I rebuilt my engine. Due to many series of events, I only put a thousand miles or so on this "new" turbo before I disintegrated my #3 piston during an accidental over boost. I put another thousand miles on the 16g on the engine break in before it burned up(the turbo, not the engine). Long story short, I changed back over to my stock turbo, and now the engine bucks and surges over 4500rpm, but I have plenty of power between bucks. The old turbo always worked perfectly, and was only a few years old when I replaced it. Could it have something to do with the port and polish? Could it be vacuum? Am I a moron? Blind? Link to comment Share on other sites More sharing options...
Shelby Posted August 20, 2009 Report Share Posted August 20, 2009 sounds like the 86 fuel cut,,or air mass over run due to boost and air volume being more then the system was design'd for or a pressure relate'd air leak in the ic or hoses to or from it Link to comment Share on other sites More sharing options...
funbunion Posted August 20, 2009 Author Report Share Posted August 20, 2009 I wish. I took my boost controller out and I'm running stock 8lbs of boost. I pressurized my entire intake system with pump the other day and found no leaks. Any other ideas? Link to comment Share on other sites More sharing options...
Hoosierquest Posted August 20, 2009 Report Share Posted August 20, 2009 (edited) sounds like the 86 fuel cut,,or air mass over run due to boost and air volume being more then the system was design'd for or a pressure relate'd air leak in the ic or hoses to or from it Would a Dec. of 86 not make it an 87? What gap you running on your plugs? Try going smaller on your gap. You shouldent need to with only 8psi but it wont hurt to try. Edited August 20, 2009 by Hoosierquest Link to comment Share on other sites More sharing options...
pitboss Posted August 20, 2009 Report Share Posted August 20, 2009 when I was having the same neck jerking fuel cut at 4500 rpm in my 88 it was the return line that was partially clogged. The va causes the same issue but at a lower rpm, like around 3500. I blew out the return line with 120 psi from the compressor and it clogged up at first, then shot a bunch of crud out. Link to comment Share on other sites More sharing options...
FRO Posted August 21, 2009 Report Share Posted August 21, 2009 check the gas tank/pickup tube. also there is a small cone filter inline before the fuel pump. if its full of crud, you got problems Link to comment Share on other sites More sharing options...
Shelby Posted August 21, 2009 Report Share Posted August 21, 2009 air volume with a 12a @ 8 lbs is diff from that of a 16g @8 lbs air mass reads air volume Link to comment Share on other sites More sharing options...
funbunion Posted August 24, 2009 Author Report Share Posted August 24, 2009 air volume with a 12a @ 8 lbs is diff from that of a 16g @8 lbs air mass reads air volume I see. Sorry, I'm kind of a moron Do you think if I replace the 12a with a 16g it would solve this? Think the turbo is too tired and old? Link to comment Share on other sites More sharing options...
funbunion Posted August 24, 2009 Author Report Share Posted August 24, 2009 Would a Dec. of 86 not make it an 87? What gap you running on your plugs? Try going smaller on your gap. You shouldent need to with only 8psi but it wont hurt to try. Thanks, I'll give it a shot. Yeah, it's an 87, and I'm a nerd :rolleye0018: Link to comment Share on other sites More sharing options...
ragdoll_unlimited Posted September 8, 2009 Report Share Posted September 8, 2009 you might be spiking and getting fuel cut.....i dont have that problem anymore...$o.45 flip switch keeps that pump going no matter what! Link to comment Share on other sites More sharing options...
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