05 GT Won't Start

[lankers]

A little back story on the car. About a month ago, it dropped a valve so I took it to the shop and they replaced the valve that it dropped, had to machine the head, had Detroit Rocker cams from Brenspeed installed, and had delete plates installed.

Since I got it back, it would randomly rev up to ~2500-3000 rpms during a cold start. It would start normal and rev to 1700 and about a second later, would rev to the 2500-3000 rpms.

I started it today to let it warm up and it started and revved like it has done before, but about the time it got to about 2500 rpms the rpms started to come down and it just died.

Since then, all I can get it to do is turn over and occasionally it will hit a cylinder or two. I changed the fuel filter, but had the same problem. I also made I'm getting good pressure from the fuel pump. I checked all the fuses for the ignition/fuel pump and they're all good. I also probed the fuel injectors and coils and am getting 12v to them.

Anyone know what it might be?

 

[Alfiedagr8]

Any codes?
Is it tuned?
Does it start with the MAF disconnected?

Do u have an RPM signal? Easy way to know this is pull a coil see if u have spark while cranking. Or u can look at the tach while cranking see if it shows some rpm.

 

[lankers]

Any codes?
Is it tuned?
Does it start with the MAF disconnected?

Do u have an RPM signal? Easy way to know this is pull a coil see if u have spark while cranking. Or u can look at the tach while cranking see if it shows some rpm.

I have a tune from Bama for it. No it doesn't start with the MAF unplugged and I don't seem to be getting any rpms on the tach. I let it crank over for a few seconds and the needle never moved. Any idea what might be causing that?

and no codes being shown

 

[AbdullaGT500]

Sounds flooded, mine did it once with hot rod cams and a bama tune, and also many times with the whipple. Pull the fuel pump relay and crank it over for 10-15 seconds, then put the relay back in and try.

 

[Alfiedagr8]

If it is flooded u can simply hold the throttle to WOT and then begine cranking. Holding the throttle makes
The PCM go into flood mode.

Ok since your not having a tach signal verify that u do or don't have a ckp signal. U can either check for spark while cranking. If there is spark then u have a good rpm signal from the CKP. U can also check for injector PW. Also if there is a CKP signal u will also have the fuel pump
Turn on while cranking. What u can also do is turn the key to the on position with out cranking the engine. Drain the fuel rail pressure so the pid reads 0 psi. While the key is still on the on position. Then crank the motor. When the PCM receives a valid rpm signal from the PCM it will turn on the fuel
Pump again, fire injectors and spark. Of course the motor still has to
Sync with the CMP but the fuel pump will turn on with just a valid rpm signal. A good sync with CMP is not required for the fuel pump
To turn on. I know I talk slot but what we need to find is if your getting a good rpm signal from the ckp so by checking this other stuff then we must have. Let me know
If I confused u.

 

[JimsWhite05GT]

Check the reset button for the fuel pump?

 

[lankers]

well it started for me tonight. didn't change anything. guess I'll have to drive it until it messes up again to be able to trouble shoot it. thanks for the info guys