Help! RB25 wont start

[Vandergriff84]

Hey guys, I am in Raleigh, NC and I have been working on a 260z RB25det swap for a while now and I am having troubles keeping it running. I did the swap last winter and I had it running this spring and summer. I took it to get it painted and then I left it sit for about 4 months. I finally got the time to install my autometer gauges the other week and I cranked it up to make sure everything was working. It struggled a bit to start and to keep running at first and I had assumed it was from sitting for 4 months. Now a week later I have tried to start it to take it out and set the speedo and it wont start. Nothing has been changed on the motor or electrical to the motor and it appears to not be getting spark. I hooked to tach up using the pull up Resister on pin 49 as I had seen many post as a working method to get the tach signal without blowing the ecu. I have checked that the cas is working by rotoating it and the injectors click. I have changed the old gas out for new and bleed the lines. The coil packs have power to them but I do not know how to check and see if it is getting spark signal. If any one has any advice I would greatly appreciate it. Also I have not had a chance to get in with any of the Z clubs around here but I would love to talk to some one who lives in this area with an RB Z.

[pat1]

You covered your bases but you need to find out of you have spark. Pull one of your coil packs and either turn the motor over with the starter or pull the cas and twist it. Put a spark plug into the coil and ground it out and then watch for the spark, The ecu send a ground signal to the igniter (depending if you have a s1 or s2 rb25)> Do you have a s1 or s2? does it have a igniter? If not you have a s2. The igniter is in each of the coil packs.

 

 

you need the following to get a engine to run

 

fuel are you getting fuel? what's your fuel pressure? Are the plugs wet?

spark ???

compression I can't see the motor going bad sitting

[Vandergriff84]

I haven't tried putting a spark plug into the coilpack yet, I will try that tomorrow. I have tried turning the cas with the ignition on and the injectors click so I assume it is getting fuel. I even tried another cas today and that didn't do any thing. I may have flooded it before trying to get it to start and it just hasn't dried out yet. Its really wiered how it would go from running to not running just like that. The only thing that I did in between running and not was I added a gasket between my TB spacer and the intake.

[stony]

I had the same problem back in the day. Turns out the gas that sat in my injectors over the winter evaporated leaving a film over the screen in the injectors. once i removed and cleaned it started right up. The way i found this out was i sent the injectors off to be checked and they flowed very poorly some didn't flow at all. all the injectors shop did was replace the screen and they all flowed great.

[Vandergriff84]

Well It lives again. Come to find out the spark plugs that I had put in it this spring stopped working which might explain why it ran rough the last time i started it. I pulled the coil pack off and hooked it up to one of the old spark plugs that came in the motor origionaly and it sparked just fine. So then I pulled out the plug in the motor and tried that one and got nothing. The origional plugs were Denso so I went and got a new set from the store and now it runs fine. I had put ACdelco plugs in it in the spring which the guy at Autozone said were the same and would work but I guess he was wrong in some regard.