[Corytodd]

Man I pulled the intake replaced the OPSU and intake gaskets and pumped some carb cleaner through the injectors..I put it all back nice an easy. Crank no start Go to checkin. No fuel being pumped. Pump no working so I ran a 12 from the box pump works still no start. Check fire Got fire. So now I don't know. The fuses are all good and I've moved the relays around to know that's not it. I did put a cheap pump in there and have only ran a few miles around town. Any help appreciated. New on these cars

 

[cocobolo95]

You have fire, your fuel pump is running. Have you put a fuel pressure tester on the fuel rail & checked fuel pressure? I believe key on prime pressure on a ls1 engine should be around 56 psi.

Also you need to pull the fuel rail up & check to see if fuel injectors are opening. Have assistant crank engine while you check for spray from injectors. Have a fire extinguisher at hand & catch cans under the injectors.

Have you checked for codes with an obd 2 scanner? I ask because there are codes that don't light the ses, but can keep your engine from running.

How about your security light. When you turn key to on, the security light should come on. Then go out after several seconds. If security light comes on & stays on, fuel injectors are disabled. If security light doesn't come on at all, you need to fix that.

To help you troubleshoot, here's a link to the 99 service manual. Be advised that GM changed the format of 96 & newer service manuals. It's harder to find what your looking for, but not impossible. www.mediafire.com/?40mfgeoe4ctti

 

[Corytodd]

Man I pulled the intake replaced the OPSU and intake gaskets and pumped some carb cleaner through the injectors..I put it all back nice an easy. Crank no start Go to checkin. No fuel being pumped. Pump no working so I ran a 12 from the box pump works still no start. Check fire Got fire. So now I don't know. The fuses are all good and I've moved the relays around to know that's not it. I did put a cheap pump in there and have only ran a few miles around town. Any help appreciated. New on these cars

You have fire, your fuel pump is running. Have you put a fuel pressure tester on the fuel rail & checked fuel pressure? I believe key on prime pressure on a ls1 engine should be around 56 psi.

Also you need to pull the fuel rail up & check to see if fuel injectors are opening. Have assistant crank engine while you check for spray from injectors. Have a fire extinguisher at hand & catch cans under the injectors.

Have you checked for codes with an obd 2 scanner? I ask because there are codes that don't light the ses, but can keep your engine from running.

How about your security light. When you turn key to on, the security light should come on. Then go out after several seconds. If security light comes on & stays on, fuel injectors are disabled. If security light doesn't come on at all, you need to fix that.

To help you troubleshoot, here's a link to the 99 service manual. Be advised that GM changed the format of 96 & newer service manuals. It's harder to find what your looking for, but not impossible. www.mediafire.com/?40mfgeoe4ctti

thanks for your time an info. I can't find an auto parts store with a fuel press tester. I was trying to plumb one in on the left rail. But haven't got there. I do have fire. Thst I know. Yes sir. I dont have power to my gray wire at the fuel pump. When I inspected the pump a couple of the wires had some bare spots where i was wiring a new plug on or some shit. One was the purple one. Which I was wondering why my fuel guage stoped working. Whst I'm asking is if my gray wire was grounding out on the top of the pump on the hatch I created where would I find the problem.ive moved the relays around and fuses are good. When I stop cranking on it sonetines it back fires real loud. And sometimes quiet. But the gray wire is dead w key on. But pump works with direct 12v I was also messsin around the pcm on right firewall I cant find my water temp plug or even the wire so I was moving the wires around while I had the intake off but still didn't find it. I just recently rebuild the motor and the harness isn't routed the exact way. Or I pulled the water temp plug off the harness. I'll be home in a min. I'm going to try a few more things is the ground on pcm down by the starter and I can't tell where the coils are ground. Like I said I'm having the no start problem after putting the intake back on. Thanks again for your time an efforts I hope you can make since out of my reply. Let me know where I should start to get it fired back up. Thx

 

[cocobolo95]

First of all, when you turn key on, fuel pump only primes for about 3 seconds. If you don't test the voltage on gray wire when key first turns on, there will be no voltage to fuel pump.

Harbor freight or ebay will have fuel pressure testing equipment. There should be a shrader valve on fuel rail to hook pressure tester up to.

Try testing gray wire for voltage whie an assistant cranks engine. Should be voltage then unless problem with ignition.

Check out your relay for fuel pump. With key on there should be 12 volts at terminal C1. It has orange wire. There should also be a good ground at terminal A1 it has black/white wire. Terminal C2 comes from PCM it will also have 12 volts on it when key turns on for about 3 seconds. Or when cranking engine. It has a dark green white wire. And at terminal A2 will be the gray wire that gets power when PCM gives 12 volts to terminal C2.

 

[Corytodd]

						First of all, when you turn key on, fuel pump only primes for about 3 seconds. If you don't test the voltage on gray wire when key first turns on, there will be no voltage to fuel pump. Harbor freight or ebay will have fuel pressure testing equipment. There should be a shrader valve on fuel rail to hook pressure tester up to. Try testing gray wire for voltage whie an assistant cranks engine. Should be voltage then unless problem with ignition. Check out your relay for fuel pump. With key on there should be 12 volts at terminal C1. It has orange wire. There should also be a good ground at terminal A1 it has black/white wire. Terminal C2 comes from PCM it will also have 12 volts on it when key turns on for about 3 seconds. Or when cranking engine. It has a dark green white wire. And at terminal A2 will be the gray wire that gets power when PCM gives 12 volts to terminal C2. [/QUO

 

[Corytodd]

Well. I checked what you said. The security light stays on. The orange wire has no power on the relay. One thing I forgot I did drop the starter looking for the water temp plug I wonder if I pulled a wire loose down there. What causes the security light to stay on? I know it's something pretty simple but I damn sure can't figure it out. More help please.

 

[cocobolo95]

For the orange wire going to fuel pump relay, check it's fuse. And not just a visual check. Use your multimeter set to ohms and test. I've seen many fuses that looked good but tested bad.

Security system has 2 components, the ignition lock assembly, which reads the key resistance. And the body control module ( BCM ) that has antitheft system as part of it.

When key resistance reads the correct resistance BCM sends a 50 hertz fuel enable signal to PCM. When security light stays on, this means either key resistance is wrong or wasn't read correctly. In turn, BCM withholds fuel enable signal & fuel injectors don't open. Engine doesn't run.

Shoebox site has good write up on security system. Even though it was written for earlier 4th gen cars, it works for later 4th gen cars also. www.shbox.com
25-27 in how to section.