Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
When was the last time you had the cap and rotor button replaced on the distributor? I also need to know if you have a cpi fuel injection engine or a throttle body fuel injected engine please?
Do you have a fuel pressure gauge so you can see how much fuel pressure you have?
You really need to know what the fuel pressure is first. All the other things we can check would be for nothing if the fuel pressure is to low. Can you borrow one in the am?
It should have 9 - 13 psi.
Do you have a scan tool that will read live data from the ecm?
Live data would tell me what the sensors are doing, not just tell me the codes.
With no codes being set I do not think the map sensor will be a problem. It will most likely be low fuel pressure, or a vacuum leak, or the base of the throttle body is gummed up and not letting vacuum get to where it needs to be.
The throttle body would not have been taken off to do a timing chain. If tit where a bad sensor the computer would have set a code.
We really need to know what the fuel pressure is. The pressure regulator could be the problem, but it is best to test then replace parts as needed.
Thank you. That will help me help you much faster.
Do you have a helper that can try to start the engine for you?
I need you to pull the air cleaner and spacer off so you can see the injectors. Whit some one turning the engine over watch the injectors and see if they both are spraying fuel out in a nice cone shape.
It can be the coil, ignition module, or the timing can be off. The vacuum ports on the bottom of the tbi unit can be gummed up as well. Can you unbolt the tbi and look on the bottom and see if the passages in the base plate are stopped up with carbon?