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Fresh Build, runs like poo. Hard starts. Datalog inside

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Kingarex

10+ Year Contributor
95
0
Jul 3, 2012
Cheney, Washington
So I stacked a bearing last year and tore down and decided to add some fun stuff to the car whilst it was down. I went to JE forged Pistons, Eagle Rods, All ARP bolts, New Clutch, Oil Cooler, 3G Lifters, and a few other things.

I'm running the same compression, Same 16g Turbo, Same 1050cc Injectors, Same HKS 272/258 cams. The only thing I really changed was the Rods and pistons, but again, I kept the compression ratio the same.

Upon first starting, We had to crank it for nearly an hour (off and on of course) as we checked connections and sensors. I replaced the CAS, CrankAS, The Coil Pack, The plugs, Wires, oil pump, water pump and igniter as well as the MPI/MFI Relay With all new parts before the build.

After an hour, after all new sensors and relays, and 5 gallons of new gas, (And 2 car batteries) it finally fired up. But only after we DISCONNECTED the Maf sensor.

It usually starts, runs on its own for 2 or 3 seconds then winds down and dies, The More I start it, and the longer I run it, the better it gets. To the point where I can start it first try, and it runs great on its own (Warm) Eventually it idled on it's own control for 20 minutes.

We eventually reran the Vacuum lines and plugged the MAF back into the intake tube (Which is the Injen setup), but it seems to run VERY rich. The only thing that is not hooked up is the emissions crap. I planned on keeping it, but the cylinder next to the charcoal canister got ruined during install somehow and now has open vacuum ports (Which are broken off). So I don't know if I should delete it, Fix it, or ideally if I can somehow bypass (tell the ECU to ignore it.)




Included is a datalog of;
me getting in, and holding the starter until it roughly started, then ran for a little bit and died on its own. AT NO TIME DID I TOUCH THE THROTTLE.
 

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Ya the temp registering at -74 would make for very hard cold starts as the engine is getting way more fuel then it actually needs which is causing a flooding condition. My supra suffered from the same thing until I changed out the cold start sensor.

the combo of vacuum leaks and the over fueling thats where I put my money. Start with fixing the vacuum system and then tackle that temp problem. Could be the coolant temp sensor on your t stat housing.

Wait I actually remember a similar thread guy had a similar problem and the car would only start when the maf was unplugged. I'll try and find it to link it for you.
 
oh my gosh I looked over that datalog probably 100 times. how did I miss that!!!

Well its 29 degrees here, but not -74 HA HA HA.

So the temperature wire got torn off by accident when we were pulling it, so I put a blade connector on it and plugged it back in. Does it go to another wire via a harness or does it clip onto the thermostat housing? I may have it completely wrong. It's been 2 years since I pulled the engine.
 
The sensor that is making it read -74 is the one towards the firewall more. A two wire plug like this http://www.dsmtuners.com/forums/151542278-post39.html like stated above your ecu sees the engine cold so it gives it more fuel. The vacuum leaks are adding to the problem as you are getting un metered air going into the engine. If you dont have to worry about emissions then you can delete all the emissions crap. Here's a link http://www.dsmtuners.com/forums/articles-miscellaneous/198327-taboo-speed-shop-vacuum-diagram-removal-1g-2g.html#post152901120
 
Dang... I could kiss you on the mouth (No ####) I'm so excited.

I looked at that wire that I messed with and that was the gauge wire, Then I looked below it and sure enough the two wire harness had a wire pulled out of it. I pulled the pin and soldered it together and it fired up first try and ran perfect. I let it run clear to open loop and it was wonderful. ZERO COMPLAINTS. I'm so excited. Thank you so much guys.
 
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