just like the title says: i cranked my car for the first time on friday after the buildup. i had replaced my pistons and head gasket to lower the compression. the first crank up was perfect. the car came to life and sounded GREAT! but then it kept stalling out. at first i could crank it up and it would come back to life again. the engine turns over no problem.... but then it stopped cranking. so i checked and my fuel pump stopped coming on...
the fuse was fine. so i listened for the pump.... and i heard a different pump... my air pump was cutting on under the hood (which i wouldnt have noticed, except i put the blockoff plate on it and had removed the upper pipe to the air pump... but hadnt removed the entire pump yet.) the wierd thing is that before the fuel pump kicked, the air pump NEVER came on before. im running the AEM 1052U EMS. which to my knowledge does NOT run the air pump.

my only guess is that the 1052u somehow magically kicked the signal from the fuel pump to the air pump.... idk how. but the aem was originally tuned for the engine when it was 11:1 compression so i know it should still run the car to crank at minimum. sorry for taking so much to explain but if anyone has an idea of what went on, please let me know what you think it could be if anything else. or how to check on my aem to see if it did this.

 

Cranking refers to the motor turning with the starter motor. Early cars had a handle you affixed to the front to crank by hand. Also the origins of the word 'cranky' apparently. But I digress.

Is the car no longer cranking (turning over with the starter motor) or is it cranking but not firing? I suspect the latter.

I doubt the wires are crossed and running your air pump rather than your fuel pump. The fuel pump comes on when you turn on the ignition (key all the way around in this car) before you press the starter button. Do you hear this? If not, your AEM may be stuffed. Mine failed to engage the fuel pump at one time and it had to be sent back to AEM for repairs.

 

Oh, and the fuel pump comes on when required. If the fuel rail is up to pressure the fuel pump does not run. So when you first turn the ignition on you hear the fuel pump bring the line up to pressure then stop.

 

well my fuel pressure gauge says zero. and yes the car is cranking (on the starter) but not firing. and the air pump NEVER turned on with the aem before. but exactly the same time as when the fuel pump stopped turning on, the air pump started running. and i know the fuel pump normally kicks on when the key is turned bc i have the walbro 255 and it normally makes alotta noise when you first turn the key. so it might be that my aem finally kicked the big one... i hope not

 

check all grounds, get your service manual and verify power to the pump, verify all relays are good.

otherwise, aem ems may have really kicked the bucket.

 

Put the stock ECU back in and just put the key in the on position. See if the fuel pump primes then.

Did you make sure to put the grounds on the back of the head back on?

 

o damn..... i might not have put those grounds on.... i think i completely forgot.

 

Where are these grounds?????

 

I think they are talking about the G101 ground, which is the main ground wire for the ECU.

Billman posted a a pic of it here, it's on the back of the cylinder head: https://www.s2ki.com/forums/index.php?showtopic=843125

 

I hate that ground wire. So awkward to get to! You have to bend your arm like a pretzel to get to it.