Vandergriff84 Posted April 11, 2013 Share Posted April 11, 2013 (edited) So I have an RB25det and it was running all this past week. I was having some trouble getting the Idle down to stock setting and so I went through the usual task to try to set it at 650. I can tell it is running rich just by the smell of the exhaust. The only thing that I had found wrong was tps closed plate voltage so I reset it the .47V and then went through the idle adjustments again and it still would not go lower than 900. So the next day I go out to start it up and it fires for a second and then dies and never really gets going. I cranked it again and get no firing at all. So I checked and it is getting spark but I do not hear the injectors clicking like they normally do. The fuel pump is working fine and comes on as soon as the CAS is rotated. I put a multi meter on the injector harness and all I get on any of the signal wires is 0.3V. I am kinda at a loss for ideas unless its in limp mode but even if that were the case it should run for a few secconds. I would greatly appreciate some input from you guys who have had more expirience with these motors. Edited April 11, 2013 by Vandergriff84 Quote Link to comment Share on other sites More sharing options...
Domzs Posted April 11, 2013 Share Posted April 11, 2013 So you have spark and fuel pump operation . Need to make sure you have fuel press. . To check for injector pulse you'll need a noid light or a homemade test light ( low amp. bulb ) . Plug into the injector connector to see if you get any pulse . But first , i would spray some carb spray or starter fluid to see if it runs ( this will eliminate the ignition system ) . Quote Link to comment Share on other sites More sharing options...
djz Posted April 11, 2013 Share Posted April 11, 2013 You should have 12v on one of each of the injector wires, the other wire is pulsed to ground by the computer, if you don't have 12v start with the relay for the injector power supply and the wiring for that. Quote Link to comment Share on other sites More sharing options...
Vandergriff84 Posted April 11, 2013 Author Share Posted April 11, 2013 Thanks, that is pointing me in a good direction. I will check into the relay tomorrow and see if I can't get 12v back at the signal wires. I have pulled a spark plug and it sparks as I turn the CAS so I am farly sure that the Ignition system is working properly. Quote Link to comment Share on other sites More sharing options...
Vandergriff84 Posted April 12, 2013 Author Share Posted April 12, 2013 So I checked the 12v constant to the injector harness and it is fine. when I check to see if I have 12v on each injector wire though I get nothing. However when I hook up a noid light to each wire and the 12v constant each injector lights up as I turn the CAS. I read some where about the injectors seizing up so I took a small hammer and tapped on each injector. At first it seemed like this did nothing but when I put cyl 1 spark plug back in so that I could listen more directly to the injectors I started to hear them click as I turn the CAS. It is not very loud which makes me think there is still something wrong with the signal to the injectors. So I put the CAS back in and went to crank it and it fired for a seccond like it had done before and stopped but now it fires for a seccond every time I crank it where as before it had only fired the first time I cranked it. I find it hard to believe that all six injectors would seize up after sitting a day or two and or go bad all at the same time. When my spark plugs went bad last summer I remember turning the CAS and hearing each injector loud and clear so this is really driving me nuts. One thing that had change last night when I started to hear the injectors click is the pullup resistor that I had connected to my tack signal and pin 49 had broken while moving things around. So that rases question as to whether this is really a good place to connect that since it powers the ECU and Fueling system. I have not tried changing out the ECCS Relay but I might do that today. Does anybody know what kind to buy? My harness was done by Wiring specialties or Mckinney I'm not sure and they had put some generic realys in. Quote Link to comment Share on other sites More sharing options...
Domzs Posted April 12, 2013 Share Posted April 12, 2013 So the noid light flashes as you turning the CAS ? Have you tried to run it with carb spray ? You have spark but is it strong enough , i'd try carb spray first . Quote Link to comment Share on other sites More sharing options...
Vandergriff84 Posted April 13, 2013 Author Share Posted April 13, 2013 Ok, So I tried the carb spray this morning and It fired up. The only strange thing is that it back fired through the intake shooting flames out the throttle body. My right hand is hairless now. I checked the voltages on lthe ignition relay and the ECCS relay and both are good. So the question now is why would it not be sending signal for fuel but not enough and why did it shoot flames out the intake? Is there a valve stuck open? I guess it's posible that I had the CAS on slightly off when I sprayed starting fluid but that doesn't explain the rest of it. I checked each of the injectors with jumper wires and each one of them click loud and clear when ground is aplied. So at the moment each injector is clicking when the CAS turns but it is so soft you can hardly hear it. Another thing that I don't understand is that all 6 injectors click at the same time when the CAS first turns. At this point I'm thinking its a bad ECU but why it would have gone bad I do not understand. Quote Link to comment Share on other sites More sharing options...
Domzs Posted April 13, 2013 Share Posted April 13, 2013 (edited) Backfired will happen when you have the throttle open too wide while spraying . Have someone spray while you crank ( with slightly open throttle or none at all ) . What year is your motor ? Should be able to get some sort of DTC from the ECM . Edited April 13, 2013 by Domzs Quote Link to comment Share on other sites More sharing options...
Vandergriff84 Posted April 13, 2013 Author Share Posted April 13, 2013 It is an R33 S2 RB25det other than that I don't know the year. Quote Link to comment Share on other sites More sharing options...
Domzs Posted April 13, 2013 Share Posted April 13, 2013 (edited) It should have some kind of diag. port ( if you wired it ) . OBD 2 port if it's a 96 and newer . R33 will have a OBD 2 and/or Nissan Consult connector Edited April 13, 2013 by Domzs Quote Link to comment Share on other sites More sharing options...
Vandergriff84 Posted April 13, 2013 Author Share Posted April 13, 2013 I assume I can just go buy a consult from the auto store to check it. I hate to spend a bunch of money on it. Quote Link to comment Share on other sites More sharing options...
Vandergriff84 Posted April 13, 2013 Author Share Posted April 13, 2013 I forgot to mention I do have the port but the wiring harness was originally made for S1 motor. The guy who sold it to me said it was S2 so I bought a S2 motor only to find a few things didn't connect up. I changed the connections that needed to be changed but that port is still the way it came. I don't think there is a difference though. Quote Link to comment Share on other sites More sharing options...
Domzs Posted April 13, 2013 Share Posted April 13, 2013 Nissan Consult scanner is very expensive ( 5k plus ) . If you have an OBD 2 port , you can use a generic scanner . You need to see if the ECM has any trouble code(s) . Quote Link to comment Share on other sites More sharing options...
Vandergriff84 Posted April 16, 2013 Author Share Posted April 16, 2013 So I have gone through everything again. I have spark. I have 12v constant to injectors I have 12v from all relays. The car fires when you first crank it then dies right away. I checked the signal wires again today on all six injectors and when I first turned the ingition on I had 12v to each injector. After cranking it I tested it again and when I first put the multimeter on the sigal wire I says 10-11v then drop instantly to 1v or less. I pulled the CAS off again and spun it manually and as usual all six injectors click at once and then cycle but only for a split seccond then nothing. So every time I let it sit for a while I have 12v to the injector signal wires but as soon as I crank it the 12v I guess gets to week creating a week signal to the injectors. I don't have a light hooked up for my check engine but when I check the voltage on that wire I get like 0.6V I am not sure if it sends a groun signal or a 12v to iluminate. I am hating myself for selling the other ECU I had. They seem to be really expensive right now on ebay. Does this sound like a bad ECU to anyone else? Quote Link to comment Share on other sites More sharing options...
Domzs Posted April 16, 2013 Share Posted April 16, 2013 The wire for CEL from ECM should be ground when key on . Without the ability to scan the ECM for trouble code(s) makes diag. more difficult . Quote Link to comment Share on other sites More sharing options...
Vandergriff84 Posted April 17, 2013 Author Share Posted April 17, 2013 Yeah I am kinda at a stand still here. I have been reverse engineering the ECU today and for the life of me I can't seem to find where the 12v comes into the signal lines. Each injector is hooked up to an N channel switch which only supplies a ground source. I did find that one wire pin had come half way out of the ecu connector which I think goes to the AAC so that might explain why it was idling high. Does anyone know if you can check for codes without a consult? I don't want to go spend a bunch of money on one just to find its a bad ECU or vice versa. Quote Link to comment Share on other sites More sharing options...
Vandergriff84 Posted April 17, 2013 Author Share Posted April 17, 2013 Ok so I checked the diagnostics and I got code 12 which according to some other writeups is for Air Flow Meter. I then checked the voltage at the afm and got nothing. Continuity test shows two of the wires conected to ground. So at this point I am going to try to find out why I don't have any power going to the afm and possibley power it strait to see if that fixes the problem. Quote Link to comment Share on other sites More sharing options...
Vandergriff84 Posted April 17, 2013 Author Share Posted April 17, 2013 Ok so I checked the diagnostics and I got code 12 which according to some other writeups is for Air Flow Meter. I then checked the voltage at the afm and got nothing. Continuity test shows two of the wires conected to ground. So at this point I am going to try to find out why I don't have any power going to the afm and possibley power it strait to see if that fixes the problem. I turned my multimeter off and then on again and it read 12v going to the afm. Not sure what was wrong with that maybe it has a low battery. I disconnected the afm wiring cleared the codes and now it starts up just fine. So now I am going to hook the wiring back up and see if it works. Quote Link to comment Share on other sites More sharing options...
Vandergriff84 Posted April 17, 2013 Author Share Posted April 17, 2013 Ok so the wire I was using for ground on my afm some how no longer has a ground connection so I picked up ground from another wire in the afm loom that did have ground and now it starts and runs just fine. There is something strange about that being that I had checked all of those wires before and each one measured continuity back to the ECU. So now I just need to wire up my tach again and see if I can get the idle right and timing adjusted. I will update the progress later today. Thanks for the help guys. Quote Link to comment Share on other sites More sharing options...
Vandergriff84 Posted April 18, 2013 Author Share Posted April 18, 2013 Well the motor lives again. I feel stupid that it took me that long to figure it out but I am glad that it is fixed. I do have a question for the rest of you out there though. I can't get the motor to idle lower than 800 and the fsm says to set timing when it is idling at 650. I don't have the adjustment screw on the ecu because it is S2 and I have gone through the usual procedures with the tps,cas and IAC. I have my CAS all the way one direction just to get it to advance to 5 degrees or seccond mark and that makes it idle higher than not advancing it. So my question is what else is there to do to get it to idle lower? I don't have any vacuum leaks, at least I can't find any. The key on my cam gear is broken so I have to eyeball the CAS into the right place and I can tell when it is on right because it wont run if it is off. Is it possible that it is getting a verying signal from the CAS since the key is broken? Can the fuel injectors be leaking or putting more feul in than supposed to? Quote Link to comment Share on other sites More sharing options...
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