My blazed wont start. I have no fuel at the gauge . I have tested from the relay to power at the pump connector. Ive bench tested the pump and its working. I do have power and a good ground at the pump. It just doesn't prime cycle with the key. What am I missing?

 

In the underhood fuse panel, there is a vacant
terminal next to the fuel pump relay.





With the ignition in the OFF position, apply
battery voltage to the terminal.
Does the fuel pump run?

 

Ill check that in the morning.

 

Well ive had my battery on charger for a couple of hours. Went out to unplug it but for kicks I turned the key. Not totally sure but you need a great battery for these things to work. It started. Ran for 20 or 30 seconds then died. My battery is over 3 years old so I'm going to replace it and see if that was all the problem was. Here's for hoping.

 

Might want to check voltage at the battery while the engine is running. It should be 14.2 volts. If available voltage at the pump motor is low, the fuel pressure will be low. If pressure drops below ~50psi, it might not start at all.

 

That is my precise thought. Well now it is.

 

Ok new battery bought. Old one had dead cell. We now have fuel pressure. Roughly 55-58 psi. Neighbor has scanner and said that there is no injector pulse. Not I'm skiddish of this because I'm an old school carb guy. What am I getting myself into? I'm not afraid of it but there are so many wires under that hood. I have a more than enough tools. Anything special ill need to get into the top of this thing?

 

Fuel pressure is low. At 70F, and a perfectly tuned engine, it may require a little longer crank time to get her running. A quick shot of carb cleaner in the throttle body would help.


The injectors are supplied battery voltage when the ignition is in the start and run positions. The PCM sends a ground pulse to each injector to open it. The pulse signal originates at the crankshaft position sensor, and it is also used for ignition spark. Sooo, if you have a good blue, not orange, spark at the ignition coil output, the crankshaft position sensor is doing its job. If you have ignition spark at the coil, but no injector pulse, I would suspect a problem with the Passlock security system.

 

Does a 99 trailblazer have a chip in the key? I bought this with only one key and no fobs.

 

Blazer and Trailblazer are two totally different vehicles. In 1999, "Trailblazer" was a trim package only. The vehicle is still commonly referred to as a "Blazer", NOT a "Trailblazer". VERY confusing for us to diagnose problems . In 2002, Trailblazer became a model. Your first post is titled "99 Blazer fuel woes". From that title, we assume that the "99" is correct, and that the 8th character in your VIN is "W". To answer your question, yes, the key is chipped. If "AU0" is on the RPO sticker in the glove box, originally the vehicle came with key FOB's. No AU0, no key FOB's.