B body lt1 confusing issues
10-21-2016, 11:17 AM
#16
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Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,648
Re: B body lt1 confusing issues
Sounds good injun. Yes that dowl pin spot is where we aligned it, nice pic by the way. Also the lt1 and pcm are out of another 94 caprice. I will check everything i have left, leaving valve check and timing check at the end. I understand about helping everyone, if you get a chance to check the log or need more just let me know. Thanks for helping.
Courtesy of Shoebox
You can find the pictures I've posted on this site - best source of LT1 info on the internet:
4th Gen LT1 F-Body Tech Aids
10-22-2016, 01:50 PM
#17
Registered User
Thread Starter
Join Date: Oct 2016
Posts: 10
Re: B body lt1 confusing issues
Hey guys not sure if i asked this or not. So i got noid light set, i know that would probley show if the injectors were working or not but how can i check if there clogged or leaking?
10-22-2016, 03:28 PM
#18
Administrator
Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,648
Re: B body lt1 confusing issues
If you had a faulty injector, not getting a pulse, or not responding electrically to the pulse, you would have a trouble code for injector circuits. If you have the DTC, key on, check for 12V on the pink injector wire at each injector connector. Then with the connector off the injector, check resistance across the two pins of the injector, looking for 11-16 ohms. If volts and ohms are OK, the problem would be lack of the ground pulse from the PCM that fires the injector. That's where the 'noid light comes in.
Check the fuel pressure. Key to run, allowing 2 seconds for the pump to prime and shut down. Observe pressure as shutoff - should be at least 40 PSI. Watch how fast the pressure drops. If the injectors are leaking, the pressure will drop rapidly. There are several problems that can cause the pressure to drop rapidly, so this would only prove they are not leaking if the pressure did not drop.
If the pressure drops, first check the vacuum compensation line for the fuel pressure regulator. Check for wet fuel. If no wet fuel or strong fuel smell, the FPR is not leaking. Still don't know if it's the injectors because it could also be the check valve in the fuel pump. The check valve is difficult to check.
Pull the fuel rails up, keeping the injectors intact. With a cold engine, outdoors, fire extinguisher at hand, clear container under each injector, turn the key to "run" (NOT "START") and let the fuel pump prime for the 2 seconds it takes to pressure the system. When the pump shuts down, check the injectors for drips. If no drips, not likely they are leaking.
Now check the spray pattern. Pull the coil wire off the Opti so the engine will not have spark. Keep the end of the coil wire away from any ground, so you will not have a spark that ignites raw fuel. With a clear jar under each injector, have someone turn the key to start and hold it for a few seconds. Observe the uniformity of the injector spray pattern. Repeat as necessary to observe all 8 injectors. See if the quantity of fuel in each jar is roughly the same. That is about as close as you can get D-I-Y to checking for leaks and plugging.
You assume all risks inherent to spraying fuel in the engine compartment.
Check the fuel pressure. Key to run, allowing 2 seconds for the pump to prime and shut down. Observe pressure as shutoff - should be at least 40 PSI. Watch how fast the pressure drops. If the injectors are leaking, the pressure will drop rapidly. There are several problems that can cause the pressure to drop rapidly, so this would only prove they are not leaking if the pressure did not drop.
If the pressure drops, first check the vacuum compensation line for the fuel pressure regulator. Check for wet fuel. If no wet fuel or strong fuel smell, the FPR is not leaking. Still don't know if it's the injectors because it could also be the check valve in the fuel pump. The check valve is difficult to check.
Pull the fuel rails up, keeping the injectors intact. With a cold engine, outdoors, fire extinguisher at hand, clear container under each injector, turn the key to "run" (NOT "START") and let the fuel pump prime for the 2 seconds it takes to pressure the system. When the pump shuts down, check the injectors for drips. If no drips, not likely they are leaking.
Now check the spray pattern. Pull the coil wire off the Opti so the engine will not have spark. Keep the end of the coil wire away from any ground, so you will not have a spark that ignites raw fuel. With a clear jar under each injector, have someone turn the key to start and hold it for a few seconds. Observe the uniformity of the injector spray pattern. Repeat as necessary to observe all 8 injectors. See if the quantity of fuel in each jar is roughly the same. That is about as close as you can get D-I-Y to checking for leaks and plugging.
You assume all risks inherent to spraying fuel in the engine compartment.
10-22-2016, 03:36 PM
#19
Registered User
Thread Starter
Join Date: Oct 2016
Posts: 10
Re: B body lt1 confusing issues
If you had a faulty injector, not getting a pulse, or not responding electrically to the pulse, you would have a trouble code for injector circuits. If you have the DTC, key on, check for 12V on the pink injector wire at each injector connector. Then with the connector off the injector, check resistance across the two pins of the injector, looking for 11-16 ohms. If volts and ohms are OK, the problem would be lack of the ground pulse from the PCM that fires the injector. That's where the 'noid light comes in.
Check the fuel pressure. Key to run, allowing 2 seconds for the pump to prime and shut down. Observe pressure as shutoff - should be at least 40 PSI. Watch how fast the pressure drops. If the injectors are leaking, the pressure will drop rapidly. There are several problems that can cause the pressure to drop rapidly, so this would only prove they are not leaking if the pressure did not drop.
If the pressure drops, first check the vacuum compensation line for the fuel pressure regulator. Check for wet fuel. If no wet fuel or strong fuel smell, the FPR is not leaking. Still don't know if it's the injectors because it could also be the check valve in the fuel pump. The check valve is difficult to check.
Pull the fuel rails up, keeping the injectors intact. With a cold engine, outdoors, fire extinguisher at hand, clear container under each injector, turn the key to "run" (NOT "START") and let the fuel pump prime for the 2 seconds it takes to pressure the system. When the pump shuts down, check the injectors for drips. If no drips, not likely they are leaking.
Now check the spray pattern. Pull the coil wire off the Opti so the engine will not have spark. Keep the end of the coil wire away from any ground, so you will not have a spark that ignites raw fuel. With a clear jar under each injector, have someone turn the key to start and hold it for a few seconds. Observe the uniformity of the injector spray pattern. Repeat as necessary to observe all 8 injectors. See if the quantity of fuel in each jar is roughly the same. That is about as close as you can get D-I-Y to checking for leaks and plugging.
You assume all risks inherent to spraying fuel in the engine compartment.
Check the fuel pressure. Key to run, allowing 2 seconds for the pump to prime and shut down. Observe pressure as shutoff - should be at least 40 PSI. Watch how fast the pressure drops. If the injectors are leaking, the pressure will drop rapidly. There are several problems that can cause the pressure to drop rapidly, so this would only prove they are not leaking if the pressure did not drop.
If the pressure drops, first check the vacuum compensation line for the fuel pressure regulator. Check for wet fuel. If no wet fuel or strong fuel smell, the FPR is not leaking. Still don't know if it's the injectors because it could also be the check valve in the fuel pump. The check valve is difficult to check.
Pull the fuel rails up, keeping the injectors intact. With a cold engine, outdoors, fire extinguisher at hand, clear container under each injector, turn the key to "run" (NOT "START") and let the fuel pump prime for the 2 seconds it takes to pressure the system. When the pump shuts down, check the injectors for drips. If no drips, not likely they are leaking.
Now check the spray pattern. Pull the coil wire off the Opti so the engine will not have spark. Keep the end of the coil wire away from any ground, so you will not have a spark that ignites raw fuel. With a clear jar under each injector, have someone turn the key to start and hold it for a few seconds. Observe the uniformity of the injector spray pattern. Repeat as necessary to observe all 8 injectors. See if the quantity of fuel in each jar is roughly the same. That is about as close as you can get D-I-Y to checking for leaks and plugging.
You assume all risks inherent to spraying fuel in the engine compartment.