RB25 Series 2 Rich with stock ecu lean with standalone

[95_240]

Details first. Compression test was fine, boost leak tested and fixed leaks, maf was changed out with a working one, tps is new, new coilpacks and plugs, freddy intake manifold, q45 throttle body, and everything else is pretty much stock. I have also replaced the injector seals and tested the rail for any leaks.

Now with the stock ecu my vacuum is at 20, idle is around 900, and the afrs are about 14-15 before I do anything. It actually idles smooth on startup but as soon as I rev it up a little it stumbles then smooths out some but the afrs stay around 12-13 after I let off the gas. Every once in a while it will stall after doing this. I haven't been able to take it out for a drive since I fixed the boost leaks but I have a feeling it will drive like it did before. Then it would surge and buck really bad throughout the rpms regardless of boost.

The standalone I'm using is Adaptronics e420d. It has a map sensor that I'm using. When it is at idle the vacuum is at 14 and it idles like crap. The afrs are about 16-18 and most of the time when I rev it the engine stalls. Even though it has lean readings it smells very rich. I don't know if this is normal with the batch firing and wasted spark. Maybe it is misfiring causing the low vacuum? I still believe the problem exists somewhere else as I am having problems with the stock ecu.

I have talked to a couple of shops near me that are supposed to be experts with rb25's but their solutions are to use the standalone to tune out any problems. I believe that I should get it running correctly before using the standalone to tune it. I'm looking for any help you can provide.

Thanks

[Carl H]

you need a tune period...
cant expect a car to run correctly on a fresh standalone on a base map, you're lucky the car even runs on the base map.
driving around on an untuned ecu is dangerous as you can cause massive engine damage because of the lack of a tune.

as far as the stock ecu having an unstable idle, you need to calibrate the tps and make sure the speed signal from the speedo head is getting to the ecu.

[95_240]

The tps is set to .45 volts closed and the ecu is getting a speed signal.

I just did a boost leak test again and noticed air escaping from the valve cover breathers and the dipstick. I deleted the pcv and have the valve covers running to a catch can. So the only way I guess I can get positive crankcase pressure is blowby past the rings. I just used the leak down tester I have and it was showing about 50% leakage across all cylinders. I didn't warm up the engine which could lower the leakage and I was using a harbor freight tool so it may not be accurate. But when I was testing there was plenty of air coming out the dipstick. So I guess every cylinder may have bad rings unless they are supposed to leak that bad when the motor is cold.

[95_240]

Well.... I warmed the car up and got the same result on cylinder 1. 50-60% leakage and air blowing out the dipstick. Put a little oil in cylinder 1 and it dropped to about 20%. Looks like it's time to get a new longblock and set this one to the side to slowly rebuild.

[95_240]

Odd but I just compression tested the engine cold and these are my results.

1 - High number because oil was still in the cylinder from the leak down test.
2 - 160 psi
3 - 180 psi
4 - 180 psi
5 - 160 psi
6 - 180 psi

This leads me to believe that it is not the piston rings. Maybe the harbor freight leak down tester that only operates at 15 psi doesn't generate enough pressure for the rings to seal? I think this is the result I got last time I compression tested it and when I warmed the car the numbers were a lot closer together. I'll be testing it again with the car warmed up once I go to get more gas to put in it and will post those numbers.

On a plus side, my plugs were black before from running too rich and this last time I warmed up the car it burned off some of the black and they started to turn a brownish color. It was consistent with all the plugs. Yay!!!!

[Carl H]

yeah 15psi harbor freight tester doesnt work...if you replace the regulator with one that is capable of 100psi then you'll be good to test.

[Darius]

If it is already blowing air out the dipstick on 15 psi, imagine how much it will blow with 100 psi. Yikes!

[95_240]

The harbor freight actuator actually goes up to 100 psi it's the gauge for the leakdown percentage that only goes up to 15 psi. I switched that out with a 100 psi gauge and tested a couple of cylinders. This time I started at 95 psi and it only leaked down to 85 psi. So about 11% leakage. I also had to put a different o-ring on the plug adapter because the other was leaking. The same amount of air came out of the dipstick but I read that it is normal for some are to pass the rings.

[95_240]

Not sure what I did but I think I fixed my car finally!!!! Took it for a quick test drive and it ran pretty good. So time to get the adaptronic put on and tuned.

[95_240]

So on my way to alignment it started acting up a little. Car drove fine when it was cold and then after about 10 minutes running warm I started to have problems. It would hesitate every once in a while at full throttle and would stall in neutral. The rpms were at 1200 cold and warm at first. Then they struggled to stay at 200 and it would stall. I have a coolant temp sensor that I'm going to swap out. I'm also thinking the O2 sensor could be the problem as well. My car should cool down enough on the rack and hopefully it drives normal after it is cool. I'm curious if my ideas are plausible or if anyone else has any suggestions.

Thanks


P.S. The first ten minutes it was warm it was running good and this is on the stock ecu. Could it also be the iacv?

[95_240]

Just did a boost leak test and it is leaking from the injectors. Since I have a crappy freddy the injectors never quite lined up and every time I installed the fuel rail I had to use the bolts to pull the rail into place. I guess after enough uninstalling and installing the threads were weakened. When I hit boost one of the bolts was ripped from the manifold unseating the first few injectors. So I'm going to helicoil temporarily but then it will be probably be a custom made intake manifold. Has anyone had any experience with building their own manifold and if so do you have any tips?

Thanks

[Boostin6rb]

Don't mean to bump a super old thread, but did you get this sorted out? Was the vacuum leak on the injectors the problem? Main reason I'm asking is I wonder how well the Adaptronic worked out for you? I know they make a lot of plug and play units for other Nissan and just scoping out first hand experience. Here is where I saw them; turbosource.com

[95_240]

Fixing the injector leak did help some but the main problem was my intercooler piping. Testing at 15 psi showed no leaks and then I cranked it up to 30 and it was leaking everywhere. Had new pipe made and it solved the problem.

I kept the stock ecu on the car because it was running fine. I have however upgraded turbo etc. and will be putting the adaptronic on and getting it tuned in January hopefully. I'm running the e420d universal ecu not the plug and play. I have a friend that has been running the same ecu for a year or two on a Toyota Beams motor. I think my main issue is finding a tuner. To me it seems simple enough to tune and it is straightforward just the tuners I have talked to are lazy or trying to sell me a new standalone. There are a couple of threads on Skylines Australia discussing adaptronic and it is pretty popular there.