fuel pressure but no fuel in injectors

[fred.tucker]

We blew the engine because of tbelt neglect. Replaced engine with one that wouldn't get good compression. Replace it with another engine, we have great compression....runs strong. But it starts randomly. Did ECU reset. Has fuel pressure. Will fire with ether to carb. Imagine injectors not firing or randomly. Need suggestions on what to chase down

[2010AveoLT]

first things first, what is the Year, Make, Model, and Mileage of the car? this will help us narrow down the amount of research we need to do, as there were two different engines across the Aveo's and all of its platform mates Lifespan of 7 years in the North American Market.

[fred.tucker]

Sorry for lack of info. The car is an 05 Aveo with 110k miles, the new engine is also an 05 with 84k miles. The car has a manual trans.

[avguy]

So when it doesn't start, it cranks fine but no cylinders fire at all? And then you remove the hose from the throttle body, spray carb cleaner, and it fires right up and runs fine with no miss? Did you try noid lights on the injectors to see what's going on with them on the no-start? I imagine this could be caused by a few things, but I would recheck all the wires, including the grounds, to make sure they're solidly connected.

[petrified.rabbit]

this sounds like the oil pressure switch on the back passenger side of engine. especially if if sat a little while being worked on.

[2010AveoLT]

So when it doesn't start, it cranks fine but no cylinders fire at all? And then you remove the hose from the throttle body, spray carb cleaner, and it fires right up and runs fine with no miss? Did you try noid lights on the injectors to see what's going on with them on the no-start? I imagine this could be caused by a few things, but I would recheck all the wires, including the grounds, to make sure they're solidly connected.

actually Avguy, Noid Lights are to check the Injector Driver Circuits coming from the PCM, to see if the Injectors are getting a clean PWM Signal. I would go ahead and check resistance on the Injectors themselves just to be safe: the Specification for the Injector Resistance is 11-14 ohms. and the OP already mentioned that it fires on Carb Cleaner/Starting Fluid/Ether.

[avguy]

actually Avguy, Noid Lights are to check the Injector Driver Circuits coming from the PCM, to see if the Injectors are getting a clean PWM Signal. I would go ahead and check resistance on the Injectors themselves just to be safe: the Specification for the Injector Resistance is 11-14 ohms. and the OP already mentioned that it fires on Carb Cleaner/Starting Fluid/Ether.

Acually 2010AveoLT, I'm not understanding your logic there. The OP said it runs well once started, which tends to indicated that the injectors/wires are sound. So that's the reason I suggested the noid lights to determine if there is a signal issue during those times of no-start. And yes, I did see that the op started on fluid, but I asked specificallly how it was done. Wires and sensors could be moved around differently if he just lifted the filter box connector and sent it through the hose, versus disconnecting the hose and spraying it into the TB.

[fred.tucker]

Could this be an issue with the security system