CamH Posted April 19, 2009 Share Posted April 19, 2009 Here's what I've got: 1983 rebuilt L28ET with forged bottom end with compression bumped to 8:1 Factory distributor Good condition factory turbo injectors No intercooler Factory turbo in good condition MegaSquirt II v3.57PCB LC-1 wideband O2 sensor MSA downpipe 240Z coil NGK BPR6ES plugs gapped to .020 Here's what it's doing: When I start the engine, it starts up almost immediately, and runs very well. It revs easily and is very smooth, and idles nicely. After short time, it will begin running very poorly - extremely rich according to my wideband. After that, I can rev it up and once I let off the gas the engine will immediately die, and I cannot restart the engine until I turn the MS off and then back on. I really need to get this sorted out because I am about ready to give up on this engine and put in a different one with carburetors soon because I really need to be able to drive this car. Thanks in advance for any help. Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted April 20, 2009 Share Posted April 20, 2009 Could you post a data log of this happening, with your MSQ file? Quote Link to comment Share on other sites More sharing options...
CamH Posted April 20, 2009 Author Share Posted April 20, 2009 Unfortunately, I do not have a data log for the particular way it is running at this time. I left the power cable for my laptop at home the last time I went to work on the car. I do, however, have a copy of the MSQ file I am currently running. Could I please get someone to look it over before I rip out my nonexistant hair? I can get a datalog to accompany it probably tomorrow evening. megasquirt200904201520.msq.zip Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted April 21, 2009 Share Posted April 21, 2009 I'll need to wait for the data log, but will take a look at the two files once the log is up. Quote Link to comment Share on other sites More sharing options...
CamH Posted April 22, 2009 Author Share Posted April 22, 2009 Here is a datalog of exactly what the car is doing. This is with the MSQ file posted above. camhdatalog.zip Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted April 22, 2009 Share Posted April 22, 2009 Does this one have a MapDaddy or other real time barometric pressure sensor installed? If not, turn the barometric correction off. The barometric readings in the log look rather weird. Quote Link to comment Share on other sites More sharing options...
Guest Rolling Parts Posted April 22, 2009 Share Posted April 22, 2009 Could be the coil gets hot and needs to cool off. That would also show up as a "super rich" condition as some of the plugs stop firing just before the coil quits altogether... Quote Link to comment Share on other sites More sharing options...
CamH Posted April 23, 2009 Author Share Posted April 23, 2009 Does this one have a MapDaddy or other real time barometric pressure sensor installed? If not, turn the barometric correction off. The barometric readings in the log look rather weird. Are you referring to the MAP sensor? If so, I am running the standard ones that comes with the V3.57 PCB. So, it may help to turn off the barometric correction off, right? Quote Link to comment Share on other sites More sharing options...
CamH Posted April 23, 2009 Author Share Posted April 23, 2009 Could be the coil gets hot and needs to cool off.That would also show up as a "super rich" condition as some of the plugs stop firing just before the coil quits altogether... Well, the coil is still cool to the touch after running the engine. How likely is it that only the internals of the coil are overheating? Quote Link to comment Share on other sites More sharing options...
Guest Rolling Parts Posted April 23, 2009 Share Posted April 23, 2009 When you said you had a "factory distributor", is that from an 82-83 ZXT? How are you driving the coil (from the MSII, a ZXT ignitor, or a ZX transistor)? How old is the 240Z coil? A lot of ignition stuff gets old and flakey. The 30 year old ZX and ZXT ignition stuff can fail in just the way you're describing. Quote Link to comment Share on other sites More sharing options...
CamH Posted April 23, 2009 Author Share Posted April 23, 2009 When you said you had a "factory distributor", is that from an 82-83 ZXT?How are you driving the coil (from the MSII, a ZXT ignitor, or a ZX transistor)? How old is the 240Z coil? A lot of ignition stuff gets old and flakey. The 30 year old ZX and ZXT ignition stuff can fail in just the way you're describing. Yes, I mean the factory 82-83 ZX distributor. I am driving the coil with the BiP373 coil in the MegaSquirt. I have switched between two known good coils and neither one has offered improvement. I am not sure of either ones age. Quote Link to comment Share on other sites More sharing options...
Guest Rolling Parts Posted April 23, 2009 Share Posted April 23, 2009 Great job, it's not the coil then. I had the exact same setup last year and had the same problem. Any chance that the "dwell" setting on the MS side that drive the coil? I forgot to set the dwell and it ran fine for 10 minutes and then quit. I just re-looked up the manual and they recommend something like 3ms as a staring point. Gee, I hope it's that simple! http://www.megamanual.com/ms2/vb921.htm Quote Link to comment Share on other sites More sharing options...
CamH Posted April 23, 2009 Author Share Posted April 23, 2009 I believe my dwell is set at 2.9 which ought to be about right. I will double check my MSQ and report back. Quote Link to comment Share on other sites More sharing options...
CamH Posted April 23, 2009 Author Share Posted April 23, 2009 Hey, here is a copy of my dwell settings if anyone wants to take a look at them. Quote Link to comment Share on other sites More sharing options...
dexter72 Posted April 23, 2009 Share Posted April 23, 2009 So will this happen when just idling?. If you drive it what happens?. Quote Link to comment Share on other sites More sharing options...
CamH Posted April 23, 2009 Author Share Posted April 23, 2009 I've only driven it once since the install. It had the same problem, and I would have to shut off everything, turn everything back on, and it would drive fine for a few hundred feet. Quote Link to comment Share on other sites More sharing options...
dexter72 Posted April 23, 2009 Share Posted April 23, 2009 Since it shows you are in oregon i will guess it's still cold out. What are your warm up enrichment settings?. Bigphil has a video on youtube, showing how to set the settings up. Quote Link to comment Share on other sites More sharing options...
Guest Rolling Parts Posted April 23, 2009 Share Posted April 23, 2009 It would not be something as simple as a partially blocked fuel return from the EFI swap? It slowly builds too much pressure and then kills the engine with over-rich? Might be nice to make sure all else on the engine/fuel system is right with a fuel pressure gauge on the rail and/or a volt meter to make sure about the grounds are good in that 240Z. Hard to say what's the gremlin w/o being able to watch what's going on and catching it "in the act". Quote Link to comment Share on other sites More sharing options...
CamH Posted April 23, 2009 Author Share Posted April 23, 2009 Sorry about that, I am actually in the military and stationed in Southern California. So it has been pretty warm lately. Here is what my warmup wizard looks like currently. Quote Link to comment Share on other sites More sharing options...
dexter72 Posted April 23, 2009 Share Posted April 23, 2009 I am going to go with Rolling parts on this one, what is the fuel pressure?. I can't open up zipped files at work so I can't see your MSQ. Does the timing change in Megatune when this happens?. Does dwell change?. Is your wideband still good?. While the engine is running wiggle check all your connections to make sure you have good solid connections. Do this inside the car to at all the connections you made for megasquirt. Quote Link to comment Share on other sites More sharing options...
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