Dan B Posted August 31, 2010 Share Posted August 31, 2010 So I just go my LT1 engine fully wired and plumbed into my 280z, and its having some strange problems. With the MAF sensor connected the engine will rev way up (and it seems smooth as though it is not misfiring) and then start backfiring and cut out as though it is starved for fuel. with the MAF disconnected and the ECM put into speed density mode it will run a little better, and will go for maybe 30 seconds and rev fairly nicely until it suddenly just shuts off as though the fuel and or spark has been turned off. It will throw a MAP voltage high code. To my knowledge all the other engine sensors are connected except the oil pressure sensor (has been replaced with the Datsun one). could that cause the ECM to shut it down? Any other ideas? Quote Link to comment Share on other sites More sharing options...
Dan B Posted August 31, 2010 Author Share Posted August 31, 2010 Also with the MAP disconnected it seems to run best of all, however it still cuts out after a short while as though it has been turned off by the ECM Quote Link to comment Share on other sites More sharing options...
deja Posted September 1, 2010 Share Posted September 1, 2010 I don't think the oil pressure sensor will cause that because when I first installed my engine I had a bad sensor and the engine ran fine. What fuel pressure are you getting at the fuel rail? Did you disable the VATS in your ECM? For that MAP high code Check wiring to MAP sensor for shorts. Of course it could be the MAP itself. Quote Link to comment Share on other sites More sharing options...
Dan B Posted September 1, 2010 Author Share Posted September 1, 2010 I got it figured out. Turns out when disabling VATS I had accidently turned on Data Fuel Enable, which cuts the injectors after a short time. Now i just need to figure out why its not running on all cylinders... Quote Link to comment Share on other sites More sharing options...
deja Posted September 1, 2010 Share Posted September 1, 2010 Congrats. If your engine has been sitting for a while you might check the injectors. I had several totally plugged. I got it figured out. Turns out when disabling VATS I had accidently turned on Data Fuel Enable, which cuts the injectors after a short time. Now i just need to figure out why its not running on all cylinders... Quote Link to comment Share on other sites More sharing options...
gvincent Posted September 9, 2010 Share Posted September 9, 2010 Yes Deja is right about the injectors, I was getting spark to all cylinders and used a NOID light to make sure all the injectors were getting the pulse voltage but was still running rough. I put 12 volts to the injectors and could hear them click one at a time but some would not click while repeating the voltage fast indicating they were sticking. I ended up taking the fuel rail off with the injectors and cleaning a lot of real fine rusty crud off of them using Q tips. I then set up a test rig with carb cleaner in a solid plastic bottle and used some tubing hose and a small hand pump to get a few pounds of pressure behind the carb cleaner and cleaned them one at a time. Use a hose on the injector tip to another bottle to collect the spray so it doesn't go all over the place.. Don't do this with GASOLINE as you are already using carb cleaner which is flamable but not as explosive as gas. I used an old pigtail connector for the injector with a push button switch and a small lawn mower battery to rapidly open/close the injector while forcing cleaner through it. Re-installed the injectors with new top and bottom rubber O rings and she has been running fine all year. Quote Link to comment Share on other sites More sharing options...
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