I just got done dropping in my second rebuild in my TA. It wont fire up. I checked the grounds and they are ok, good battery and all wiring is ok just like i did the first time. only this time my injectors are not spraying so it wont fire up. i have gas up to the fuel rails and pump is priming good. But when i unscrewed the fuel rails to check the injectors, they are not spraying. Why could this be happening? is it my pcm or optical sensor?

 

Always hard to answer the questions when no info is provided regarding the vehicle. Basic info - what year is it? You need to add a "signature".

Have you scanned it for codes? If the PCM was not getting the low res pulse pattern from the optical cam position sensor, it would set a code, but would not turn on the SES light. When the code sets, the PCM shuts down the fuel system.

Just one possibility.

 

sorry, i was in a hurry. Its a 96' Trans am, stock shortblock, port n polished stock heads. CC503 cam, 1.6 RR, Jet Hot Longtubes & Y Pipe, Hooker Catback.

I dont have a scanner so i dont know the codes. Is there any way to check to see if it is indeed the pcm or optical sensor? and if the pcm shuts down the fuel system that mean my pump would not be priming when i turn the key right?

 

 

Check your fuses. A blown fuse can cause a no power condition to the injectors. Just a possibility.

 

Just remember that when you are in a hurry and don't provide car info, people won't be in a hurry to help you.

Pump priming won't be affected unless the PCM is just dead (not likely). Do you have spark? If no spark or fuel injector activity, it's probably opti related. The necessity of a scanner can't be over emphasized.

There is a test you can do at the ICM connector to see if there are opti pulses relayed by the PCM.

http://shbox.com/1/4th_gen_tech2.html#opti_test

 

For me the 2 easiest things to overlook are opti harness and the ground on the driver side frame rail. Is your belt off by any chance? mine wouldn't start with my belt off one time. These are 3 things that have stumped me before hope it helps

 

An OBD-II code scanner costs as little as $40. As I already indicated, if there is a problem with the optical sensor in the Opti, it sets codes. That's how you check the "optical sensor".

The fuel pump will still prime when you turn the key to on. When you try and start the engine, and the PCM can not find the low res pulse for 2 camshaft revolutions, the PCM will shut down the pump and the injectors.

That is just one possibility. Look at the huge list in the shop manual.

 

Well i still have not fired up the car, i put in a new accel opti and new GM opti harness, i no longer have any codes and injectors are spraying, i also know i have spark because i checked and shocked myself and all fuses are ok. I really dont kow where to turn from here. Im thinking i overdid the valves. can i just loosen them up a bit and try to fire it up and see what happens?

 

Have you ever bothered to check for codes?

 

mom always said a hard heads makes for a soft a$$

 

man... check the codes and fuel level, n pressure. did you shock yourself on purpose, I used to know a old drunk n that's how he'd check for fire

 

I had issues trying to start mine for the first time... valves were too tight.This helped me.
http://shbox.com/1/4th_gen_tech2.html#adjust_valves

 

When we put mine back together we had the timing 180* out at first

What a PITA