ER34 barely starts and then stalls RB25DET Neo Apexi Power FC

[Triallity]

I have just replaced my leaking head gasket and now it can only start and stall like this. I can't figure out whats causing this. The start up in the video is the longest it ran. I have an apexi power fc installed as well. I have also upgraded the injectors and the mass air flow at the same time which doesn't help me.

https://youtu.be/E5nXTLYB_DA

I'll try to go down all the stuff I've done/checked;

Fuel wise I've verified its getting fuel to the rail. I have upgraded the stock injectors to Deatschwerks (600cc) injectors 21s-05-0600-6. I have scaled the values in the ecu to 67%. I can't find any specs on the latency but doesn't help when i try different values.

I have also installed a Z32 maf which also I have double checked to make sure its wired in correctly. I should of just left the factory maf in for the initial start. I have selected the vg30 maf in the apexi but I know it still needs a proper retune.

The headgasket I intalled is a Tomei 1.5mm and I also installed Tomei 260 poncams with the Tomei timing belt. I made sure I installed the belt with all the timing marks lining up on the engine and on the belt. The tension was set properly too. The valve clearance was also checked and is good too.

Now as for the Apexi I noticed the air flow signal voltage goes up exactly the same as the throttle position signal voltage. I am confused by this, is this normal on an Apexi unit?

As for spark I removed the Cam angle sensor and spun it by hand I can hear the injectors firing. But I hear a louder click from the rear/middle of the engine when doing this. I don't know if this normal from another part or a (bad?) injector.

I've been checking grounds and cleaning them and looking for any possible broken/damaged wires.

My cas appears to be original and I'm kinda thinking its faulty but it seems to work.

As for when its running or ilding it seems it just has the key turned off when it stalls. Also when running it just wants to drop revs and dip then barely catch itself.

[Skym]

Something is not set correctly. Sounds like it is running too rich in the video clip.

Also could be a combination of things and each area needs to be checked:

Make sure cam timing is set correctly, as with skimming the head, fitting a thicker headgasket the cam timing will most likely be out (I think retarded). Stock cam timing might not work anymore.

Here's more info -

http://www.kelford.co.nz/sole-purpose-of-degreeing-your-cam

Make sure CAS timing is set correctly to match and there's no play between CAS shaft to front of exhaust cam which the NEO RB25DET's are known for when have loose cam belts. Failing CAS can make engine harder to start when cold and hot.

Make sure ECU has the ignition timing set to match CAS adjustment.

Make sure idle rpm is set higher, as with cams the engine runs slightly richer at idle (see Tomei cam specs vs recommended settings on ECU for rpm and A/F ratio, which is on their website / online catalogue). You'll need a wideband for the A/F ratio part.

Make sure TPS is on the correct voltage value / on the idle contact as the ECU won't kick the rpm up to prevent the engine stalling if not on idle contact (voltage value on NEO's). With 260 duration cams the idle can lump, so this would make the problem worse.

[Triallity]

I did get it running. I put some mass air flow voltage range correlation to 160% in all of the values. The car can be driven but it runs like ****. Hopefully all it needs is a retune. I'll keep in mind of the cas timing changing from the mechanical modifications. I don't know what that percent value means, my afr gauge is inop because I can't get the exhaust back on. The garage I was renting flooded from melting snow, at least its now out somewhere drier to try and fix this properly.

[NoLimit0596]

Try injector 62% and lag time 0.22 and reset your maf correction to 100%

[Triallity]

I got my afr working it goes extremely lean at idle past 18 and on throttle tip in it would sometimes go 10 afr. I did try your injector settings but they didn't help the maf correction still needed to be around 160%. I could get it at 13.5 on cruise which got me to a more suitable place to work on it. I'm going to do an intake leak check in the next few days. The airflow readings from FC commander look normal no goofy spikes. The engine revs look uniform as well no spikes or dead zones on the graph view. If the intake is sealed I'm just going to tow it to Calgary and have Autodream or Vex retune/diagnose it.

[Skym]

Up to 17 A/F ratio can be intake or exhaust leak. Look for hoses over the top of the engine that are missing or not connected.

[Triallity]

All the hoses are accounted for I'm worried about the upper manifold gasket leaking and fuel injectors orings onto the manifold. When I took the upper part off I forgot the center bolt of the three that's from underneath. I tried pulling it off and I hope I didn't warp the sealing surface.

[Skym]

If the engine runs lean enough at idle it can stall (similar to pulling the fuel pump fuse or turning the fuel pump off with Consult and letting the engine run lean, stall before working on the fuel system), so that intake manifold leak could be a possibility.

If tightened the top part of intake manifold down in sequence as shown in the manual and to correct torque, it should be ok. But it's recommended to have the intake and exhaust flanges skimmed to make sure they are straight, flat. You can do that so amount of times before you have to replace the manifolds.

Spraying around the seal / flange should make the engine stumble, so will know if there is a intake leak. The vacuum is not a good way to tell, as the cams might have affected the readings (different to factory readings).

Resizing injectors, MAF correctly should make the engine idle fairly normally. But there are settings / tables that are only accessable by Apexi tuning software on a laptop or I think dataloggit.

Also did you disable the feature they say to in the Apexi manual (I think onboard boost control feature???)??? It's known to cause problems with starting engine.

[Triallity]

I finished the intake leak check and it holds at 20psi shop air with no bubbles from soapy water on all the seams/hoses. It even takes a bit for the air to bleed off.

The afr's just jump completely to each extreme is what worries me. Hopefully its just some setting I did or from before that just doesn't cooperate with what it has now. I have a tune from the stockish setup from before

It does have a integrated Apexi boost control solenoid on my car. I don't know if that boost setting is on/off I'll check tomorrow. It seems to just splice into the stock solenoid wiring. There is an Apexi boost sensor too that reads off the manifold. Maybe that's suppose to read before the throttle body? I have the L-jetro version so it shouldn't get confused from a pressure/boost sensor.

[Skym]

If adjusted tune for intake, exhaust mods then it most likely will be the fuel map is too lean for the aftermarket cams. When apply throttle the ECU looks at the TPS tables / settings which add fuel to prevent engine going suddenly lean when press throttle which explains why the engine goes rich.

Most likely you just need to adjust the fuel, ignition, startup, etc.

[Triallity]

I got it retuned, it did just need a complete adjustments and a new maf the one I bought is faulty/wrong. The idle stays around 14.7 and holds 900 rpm but is a bit rough my guess is from the lower compression and cams. The iacv black plastic set screw had to be turned quite a few turns back to achieve idle. The car made 330 whp but I have problem with massive boost spike (20psi+) and then drop to wastegate pressure, I'll make a separate thread about that.

[Skym]

There are clone / fake MAF's that give incorrect measurements.