VinhZXT Posted November 9, 2009 Share Posted November 9, 2009 Hi Guys, I never thought I would be in this position but I need help. I am helping a friend of mine getting his LS1 engine running. The engine doesn't have MAF sensor, radiator and O2 sensors and it won't start. It has sparks and fuel pressure but the PCM not sending pulses to the injectors. I disabled the VATs system from the PCM. I took the PCM and hooked it to another LS1 swap car and it ran so it's not the PCM. It's something missing from the engine and prevent the PCM from sending signal to the injectors. If anyone of you have started your LS1 engine up in similar condition please let me know. Thanks Vinh Quote Link to comment Share on other sites More sharing options...
dan5138 Posted November 9, 2009 Share Posted November 9, 2009 Most FI systems won't run without a MAP or MAF sensor. Some older systems will start and idle, but that is about it. The 02 sensor shouldn't stop it, it will just run rich without it. Quote Link to comment Share on other sites More sharing options...
VinhZXT Posted November 9, 2009 Author Share Posted November 9, 2009 Man I am really stump on this one. I took my friend's LS1 Z over to the shop and disconnected all the above sensors (MAF, O2 and air temp) and his car started up just fine. I put the new PCM into my friend's Z and my friend's LS1 Z started up and runs fine. So the PCM is OK. Something else I am missing on the engine that prevents the PCM from sending pulses to the injectors. I also compare the tune file from this PCM to Clive's tune file and there is no noticable differences. One thing I noticed is on my friend's LS1 Z, when I disconnect the water temp sensor it won't start. Originally the water temp sensor was busted on this motor so we replaced it and it still won't start. We also don't have the belt hook up also. This means the alternator is not hook up also. Quote Link to comment Share on other sites More sharing options...
EvilC Posted November 9, 2009 Share Posted November 9, 2009 Vinh, I was getting nothing at the injectors when I had my issue. The PCM was not staying on during the crank cycle so nothing was sent to the injectors to fire. I am not sure if it is the same issue. Are you getting the motor to turn over and just not fire up?Last time I forgot to hook up the crank angle sensor and the motor would not fire up. I am pretty sure you checked all your connections to the motor. I am not going to be much help....I am the newbie! Quote Link to comment Share on other sites More sharing options...
VinhZXT Posted November 9, 2009 Author Share Posted November 9, 2009 Clive, Yes I remember I've made a mistake hooking up your ignition wire. So I definitely won't make that mistake again. Right now I hot wire all the pink and orange wires to the EFI harness to the battery. Then I just used the starter wire and touch the 12V battery to start the car. I disconnect the PCM connectors and measured all ignition sources and battery sources and ground at that point and they all checked out good. I am seriously running out of idea on this one. Quote Link to comment Share on other sites More sharing options...
jasper Posted November 9, 2009 Share Posted November 9, 2009 Do you have a scanner??? Codes??? Does it have a resistor(s) for the injectors?? Are you missing the ground or the positive for the injector. Quote Link to comment Share on other sites More sharing options...
Cable Posted November 10, 2009 Share Posted November 10, 2009 I am thinking its a ground issue with the LS1 harness. Quote Link to comment Share on other sites More sharing options...
rags Posted November 10, 2009 Share Posted November 10, 2009 Either a bad ground or faulty CAS would be my guess. I'd swap the CAS with the car that runs to rule that out then start checking grounds. Joe Quote Link to comment Share on other sites More sharing options...
VinhZXT Posted November 10, 2009 Author Share Posted November 10, 2009 Well guess what... you are all failed the test. No one would have guess this one right. All 8 injectors were all dead. It was pretty simple after I thought about it. We hook up the noid light to the injector and see no pulse. We then unplug the connectors to the injectors and try the same test and the noid lights are flashing. We lift up the fuel injectors and connect 12V to them and none of them click. We remove the fuel injectors and beat the crap out of them and slowly 7 of them start working. So we replace the dead injector and put everything back and it started up. Don't over look the simple stuff guys. Quote Link to comment Share on other sites More sharing options...
dan5138 Posted November 10, 2009 Share Posted November 10, 2009 8 stuck injectors on that new of an engine? Wierd, injectors would have been the last thing I would have checked on a newer engine : /. Quote Link to comment Share on other sites More sharing options...
VinhZXT Posted November 10, 2009 Author Share Posted November 10, 2009 The motor has been sitting for a long time. I will make sure I keep this in mind when fire up my engine in a few years. My engine has been sitting for 3 years now. Wow time flies. Quote Link to comment Share on other sites More sharing options...
deja Posted November 10, 2009 Share Posted November 10, 2009 I had the same issue getting my new LT1 started, bad injectors. Give away for me was totally dry plugs after attempting to start it mamy times. The injectors were used and had been sitting for a couple years. Same as yours they wouldn't even click when +12v was applied. Quote Link to comment Share on other sites More sharing options...
zed240au Posted November 10, 2009 Share Posted November 10, 2009 had similar issue with my car on start up had spark had pulse at injectors ended up pulling injectors from engine left them connected and turned them upside down on engine turned out only 4 injectors where firing fuel out plugged in another set of injectors and it fired up fine guess fuel rail was blocked or injectors where dead just my experience Mick Quote Link to comment Share on other sites More sharing options...
Kbhead Posted November 10, 2009 Share Posted November 10, 2009 When you say the injectors are dead, are the connections corroded or can the injectors be cleaned, then reused? My engine has been sitting for a few years as well. Quote Link to comment Share on other sites More sharing options...
EvilC Posted November 10, 2009 Share Posted November 10, 2009 Hmm, glad to hear you got it all worked out V. Is that another v8 Z in philly? Quote Link to comment Share on other sites More sharing options...
deja Posted November 10, 2009 Share Posted November 10, 2009 Mine had sat for a couple years. When I took the rail apart it was full of what looked like a fine balck powder. I assume that was what was left of the gas left in the rails. You can get injectors cleaned. There are several on-line places. One I have used is http://fuelinjectorconnection.com/shop/ When you say the injectors are dead, are the connections corroded or can the injectors be cleaned, then reused? My engine has been sitting for a few years as well. Quote Link to comment Share on other sites More sharing options...
VinhZXT Posted November 11, 2009 Author Share Posted November 11, 2009 KB, Not the connectors. We beat the crap out of the injectors and they start to work. I removed my fuel rail and empty all the gas last night. Clive, No, this is a kit car. Quote Link to comment Share on other sites More sharing options...
wajouba Posted November 20, 2009 Share Posted November 20, 2009 I took my injectors to bosch so they would clean them, and they were surprised my car even started! LS1 into 240sx, the LS1 was on the side for 3 years! Quote Link to comment Share on other sites More sharing options...
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