bryand2 Posted January 13, 2015 Share Posted January 13, 2015 Hey guys, I have an 82 l28et that was swapped into my 77 280z. Also swapped in the z31 turbo ecu, maf, cas and distributor guts. The problem I am having is the injectors are firing on deceleration and flushing down the cylinder walls. I was hoping someone could help identify if this ecu is supposed to be doing that or something got wired wrong possibly? Quote Link to comment Share on other sites More sharing options...
NewZed Posted January 13, 2015 Share Posted January 13, 2015 How do you know the walls are getting "flushed"? That would be a lot of fuel. Z31 goes up to 1989 from 1984. The ECCS systems seem to be change over the years. Fuel cut is described in some of the FSM's but overall, the 80's FSM's are poorly written. Describe your Z31 system and what you're using for inputs and someone might have some suggestions. Quote Link to comment Share on other sites More sharing options...
z-ya Posted January 13, 2015 Share Posted January 13, 2015 Try calibrating the TPS? Quote Link to comment Share on other sites More sharing options...
FricFrac Posted January 13, 2015 Share Posted January 13, 2015 Mega Squirt time Quote Link to comment Share on other sites More sharing options...
Kash Posted January 15, 2015 Share Posted January 15, 2015 I assume you are getting heavy backfires? Check your TPS. Quote Link to comment Share on other sites More sharing options...
bryand2 Posted January 17, 2015 Author Share Posted January 17, 2015 Hey guys, yes I am getting very heavy backfires. The tps is getting checked today. As far as the walls getting flushed down I thought it was because of the oil smell out the exhaust but just discovered I sometime in the past week dropped a ringland or piston ring. There is scoring on cylinder wall of #1, which leads me to believe that the cylinder wall flush down may have contributed to the scoring. Compression test results showed 110 psi on cylinder #1 with the engine cold and 90 psi with the engine warm. All other cylinders check out at 150 psi. Newzed, my z31 system consists of 86 z31 turbo ecu, maf, cas, and optical wheel. tO4e turbo, front mount intercooler, stock injectors, rail, fpr and tps. My main concern is that if I am going to replace all the pistons and have the block honed, if the injectors are still firing on decel and causing washdown it will lead to bottom end problems again so I am trying to get this figured out before the rebuild. Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 18, 2015 Share Posted January 18, 2015 More likely you detonated and broke the ring and lands. I would take your injectors out and send them for cleaning and balancing. To break a ring land in #1...my bet is the inlet screen or something is compromising flow and you lean-detonated it as opposed to 5/6 which is where it usually manifests. Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted January 21, 2015 Share Posted January 21, 2015 I also broke a ring land on #1 several years ago. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted January 22, 2015 Share Posted January 22, 2015 (edited) I had that issue of backfiring on deceleration. I never diagnosed the issue, but when I swapped my ECU with another ECU of the same year the backfiring went away. My thinking at the time was the injector driver had a fault so it was not able to control the injector on-time properly. Edited January 22, 2015 by SleeperZ Quote Link to comment Share on other sites More sharing options...
Kash Posted January 23, 2015 Share Posted January 23, 2015 (edited) Yep, broken ring land on #1...numbers look very similar to mine several years ago when I cranked my boost up beyond 17psi on a .080 shaved p90a head. Edited January 23, 2015 by Kash Quote Link to comment Share on other sites More sharing options...
G-E Posted January 25, 2015 Share Posted January 25, 2015 The 87 ecu is the one you want btw... much more modern electronics, better transitions, and still low-impedence. Quote Link to comment Share on other sites More sharing options...
malibud Posted January 25, 2015 Share Posted January 25, 2015 Does it matter auto or manual when it comes to the ecu from a 87 z31 ? I have access to a auto Thanks Quote Link to comment Share on other sites More sharing options...
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