New motor starts then dies.
 

hi,

So i try to do my first startup of my built engine. it starts!...for 1 second then dies immediately. Start it in NA setup with a stock tune.

I called a more mechanical sound friend over the phone, he said. He hears a vacuum leak somewhere. I check all the vacuum hose/lines, and they're fine.

What I've cleaned/checked so far:
- MAF sensor
- MAP sensor
- Any vacuum lines that connect to the intake manifold
- check the torque of intake manifold bolts.
- stock intake system

I wanted to check the fueling, but I'll do that on my next day off. I also forgot to check if it posted any CEL codes, I'll do that as well.

Any advice or ideas what is the issue would greatly be appreciated.



https://www.youtube.com/watch?v=NMP8QyfgjpQ

update: car starts and runs while the MAF is disconnected. @FrickingReallySlow spotted that my fuel during the startups differ from MAF vs No MAF startups. Something is up with the fuel. Spraying starter fluid had the car running longer with the MAF connected. I did do a quick visual and connection check on the fuel pump assembly, but haven't pulled it out yet. I do hear the fuel pump prime when i put the Car's ignition to the ON position.
Will most likely change the fuel filter if i do pull the fuel pump.

https://www.youtube.com/watch?v=otuGnzoRlxk

Damn you got a lot of problems lol. You sure you didn’t switch another connector ;) couple things to try

1. Start up with MAF disconnected.
2. Spray some starter fluid into the intake (after air filter) while cranking and if it starts longer and dies when you don’t spray then it’s a fueling issue

Man you don't know the half of it. I had problems at almost every stage of this build. But I've figured out the common denominator is me, lol. If only it were just some simple connectors, this time. also I don't even hesitate to ask on these forums or at least give a good search. I'm sure someone has either had these issues or someone with the knowledge could point me in the right direction. all this if also for anyone that would have any dumb issues i have.


1. Yea i have just seen a video of someone suggesting doing that.
2. i thought of this but no starter/lighter fluid lying around.

Check the third bottom bolt on the injector ECU

I'm aware of bolt being the ground for the DI ecu. I will check it, but I'm sure it is tight and fine. thanks!

So that fuel pump fuse that you pulled out on the last thread about the swapped sensors. You put it back yeah?

Yes it's back in and i am getting fuel.
There's just some visible evidence on those intake runners.:lol:
In the short video, if you look closely at the intake runners you can see dried up fuel where there's it sprayed from a fuel line i removed to check my fueling. There is a ton of octane 100 top of my new engine. :bonk::bonk:

Oh where do you get 100 octane in California? Can’t tell from your video if you capped off your sound tube delete but that seems too obvious

https://www.sunocoracefuels.com/fuel-finder

I used this website to find any shops/stations that offer it. Yup, it was capped off.

There are a lot of options for race fuel. Somewhat confusing.

I feel your pain, it can be very frustrating battling these kinds of issues, but on the plus side your nearly there at this point

These are complicated little engines so it’s probably best to pull codes from the ECU to truly figure out what is wrong, I know that cam phasing and crank position play a big part in the initial start up sequence (as they do in all cars I guess) and that you may get an initial crank but once the ECU doesn’t see the expected signal or position from either or both it shuts down. I’m sure you’ve double checked both sensors but I know the cam position sensors are very easily damaged lifting the engine in and out and they are become brittle from the engine bay heat too.

Outside of the usual fault finding which you appear to have done (air, fuel,spark) I think codes may be your best option.

Did you also check that all the plugs are in place? I once tried to start it up and forgot to plug them in.

I unplugged the MAF and fired up the car. It didnt stop running until i stopped it! Went to a local auto parts start for a MAF replacement. Got that one in there and same thing as the Old MAF. starts and shuts off.
There isn’t any codes posted. There are 2 codes but i know what they caused by:
P0102 - Mass or Volume Flow “A” Circuit Low
P0113 - Intake Air Temperature Sensor 1 Circuit High Bank 1
These are from when i start the car without the MAF plugged in.

I think theres a vacuum leak but Ive checked everywhere on intake manifold. Evap solenoid, evap hoses under intake, pcv hose, brake booster hose and intake system. Is there any location i havent thought of for vacuum leaks?


I have also pulled out the multimeter and check continuity on the engine harness, all good there. So im stumped again.

How would i know if the cam sensors arent working? A code or visual inspection? I have looked at them prior to getting the motor into the car but i know for sure there wasn’t any damage to them. I will check all 4 for visible damage. I just dont want to purchase something that wouldnt fix the issue.

SHouldn't have anything to do with cams. VVT is disabled on startup until at least a couple minutes worth of idle. Also the fact that disconnect MAF resulting in being run on default maps says a lot. Are you sure you bought the EXACT OEM part not a "compatible" one. Don't cheap out on this. Also are you sure you flashed your ECU back to the original factory CalID

I bought a cheapo one at autozone and have returned it. It was a bandaid solution until i get an OEM one. When i called the local dealerships and they didnt have any in stock. I ordered an OEM from them, should be here friday or saturday.

Yes, i have flashed it to the correct CAlID. I flashed it a few times with the stock tune just to be sure.

I asked my tuner about this and he said that i might have my timing incorrect but i know i timed it properly. I took a photo of my timing marks right before i put the timing cover on.
Just hoping it’s the MAF sensor.

Oh i also have tried to start the car with the MAF unplugged then had someone plug in the MAF. It eventually dies 2-4 seconds later after MAF is connected. Reason being is, i wanted to see if the MAF is connected if it would post a CEL, it did not. Purchased some MAF cleaner and cleaned the MAF, didnt work.

I will also post a video of the car running with the MAF unplugged later tonight.