No start issues again

[rockola1971]

According to my friend who's a mechanic that put his diagnostic reader on there the BCM needs to be replaced

If you believe him then grab a BCM that matches yours as close as possible. They arent expensive at all at salvage yard and ebay and are stupid easy to replace.

 

[Doubeleive]

Earlier on he had said plugs were pulled and were wet.

He pm'd after this and had failed to mention in that post that the fuel pump relay has to be jumpered in order to get fuel, so my guess is by doing that it's flooding the engine and is probably not getting any spark (ecm/pcm) injector pulse cut-off.

 

[rockola1971]

There's absolutely no blown fuses I've pulled every one of them and the only one that was blown was the stereo which I replaced I'm not going to invest any more money into this it's going to the junkyard. 2 months ago we hooked it up to the tech two tool so that they could reprogram the passlock BS and put a new ignition in and obviously that didn't work because here we are again and I'm not going to pay to have it done for a third time it can go to the junkyard like I said that's where it belongs you know not to harp on the same subject but I'm a single dad of four who just lost his wife work on my own I can't afford this I will rather bike than put any more money into this *************

That fuse likely blew for a reason. Fuses blow when excess current travels through them thats higher than their rating. Excess current is caused by a partial short to ground, dead short to ground or excessive load for the circuit. I would disconnect whatever is blowing the fuse since the aim here is to troubleshoot the no start issue and there is no sense in throwing another monkey wrench into the main problem.
It sounds like you have no spark or jumped time. Pull spark plug out and verify a nice bright blue spark. It should not be lazy orange/yellow. Battery has to be charged up to get a proper reading on the spark situation.

 

[Phisher]

That fuse likely blew for a reason. Fuses blow when excess current travels through them thats higher than their rating. Excess current is caused by a partial short to ground, dead short to ground or excessive load for the circuit. I would disconnect whatever is blowing the fuse since the aim here is to troubleshoot the no start issue and there is no sense in throwing another monkey wrench into the main problem.
It sounds like you have no spark or jumped time. Pull spark plug out and verify a nice bright blue spark. It should not be lazy orange/yellow. Battery has to be charged up to get a proper reading on the spark situation.

Yes the fuse blew because I touched ground and constant accidently when I was taping off all the wires that were cut from the stereo so here will start fresh again.. so new fuel pump new fuel filter engine turns and turns and turns but does not start if I spray it with starting fluid still does not start the only time I have power going to the fuel pump is when I stick a wire and pin 30 and in pin 87 to jump them together otherwise if the relay is in I still have nothing so what I'm gathering from you guys is I should start taking plugs out one at a time to see how they fire I also went and purchased a test light I'm going to start checking negative connections and positive connections and seeing if maybe there's a crown so you guys win you convince me to keep the beast for another day LOL thanks again guys

 

[rockola1971]

He pm'd after this and had failed to mention in that post that the fuel pump relay has to be jumpered in order to get fuel, so my guess is by doing that it's flooding the engine and is probably not getting any spark (ecm/pcm) injector pulse cut-off.

Yup. My guess too. No spark or jumped time. I would verify spark then if no spark I would look for 12 volt reference voltage and passlock signal going back to BCM in the below schematic. But it sounds like Pass Lock has been programmed correctly.
The having to jump the fuel pump relay should be easy enough to trouble shoot and could be related to the rest of the mess or is a totally unrelated problem.

 

[rockola1971]

Yes the fuse blew because I touched ground and constant accidently when I was taping off all the wires that were cut from the stereo so here will start fresh again.. so new fuel pump new fuel filter engine turns and turns and turns but does not start if I spray it with starting fluid still does not start the only time I have power going to the fuel pump is when I stick a wire and pin 30 and in pin 87 to jump them together otherwise if the relay is in I still have nothing so what I'm gathering from you guys is I should start taking plugs out one at a time to see how they fire I also went and purchased a test light I'm going to start checking negative connections and positive connections and seeing if maybe there's a crown so you guys win you convince me to keep the beast for another day LOL thanks again guys

We will get this thing running correctly. You just have to be patient with the Yukon and us.
Fuel pump is useless if no spark so we will worry about that later. It could be related to the cause of no spark if thats whats going on. Ignition coils are all independtly controlled by different connections to the PCM. For right now pull one spark plug and check it for spark on all cylinders driver or passenger side (dont matter which).
Check your INJA and INJB fuses(Both 15a fuses). One feeds your even cylinder injectors AND IGNITION COILS and the other feeds the opposite side. If one or both of those fuses is blown it will cause your mess.

 

[rockola1971]

ECMB Fuse (20a) is the feed to your fuel pump and since jumping the contacts makes your fuel pump come on that tells me that part of the circuit is fine and your problem lies in the control part for that circuit which is the fuel pump relay coil and its feed. Coil is fed by pin 9 Connector 2(Red) of PCM. Check for 12v while cranking at relay socket and also check to make sure there is continuity from the ground terminal in the relay socket to chassis ground. Measure resistance across relay coil on relay itself also. Could just be a bad relay. It is also possible that the relay contacts are burnt and will no longer pass current but are closing. (Thats a whole different check).

 

[Phisher]

We will get this thing running correctly. You just have to be patient with the Yukon and us.
Fuel pump is useless if no spark so we will worry about that later. It could be related to the cause of no spark if thats whats going on. Ignition coils are all independtly controlled by different connections to the PCM. For right now pull one spark plug and check it for spark on all cylinders driver or passenger side (dont matter which).
Check your INJA and INJB fuses(Both 15a fuses). One feeds your even cylinder injectors AND IGNITION COILS and the other feeds the opposite side. If one or both of those fuses is blown it will cause your mess.

I will do that I'm also going to just take a short video of what is going on before I start doing anything and I'll post it here so people can listen and see but right now I'm at a parts store I'm going to pick up a spark plug tester and a compression tester and then I'm going to grab a new multimeter that way I can test my positive and negatives throughout

 

[MassHoe04]

Compression test might be good information to know at some point, but I would think that you would hear it trying to fire-off. Even if several cylinders had poor compression it would get somethin poppin off. Would not be pretty, but you would still have something happening.

If compression were a factor, it would kind of start. You might notice blow-by. Or... in an extreme case of blown rings, maybe even raw fuel in your oil pan.

Not sure I would fixate on compression testing in trying to diagnose your particular issue. But I could be wrong. That is just my thinking.

 

[RET423]

VATS(which came out on the 86 vette) is an entirely different anti theft system than Passlock 1 & 2. He doesnt have a resistor on his key so he has Passlock which is a magnet and hall effect switches. A resistor will not trick Passlock.

His vehicle most certainly can be bypassed by using an appropriate resistor between the tumbler and the signal wire to the BCM, given the disconnected yellow wire he found inside the clamshell that is very likely what his "repairman" tried to do.

The resistor in the key system was replaced by a permanent resistor in the tumbler that made the connection as the tumbler rotated; even the resistor range stayed the same until at least 2007.

In 2002 the factory ECM even refers to the security system as VATS in the section where you can disable that garbage system.

 

[RET423]

According to my friend who's a mechanic that put his diagnostic reader on there the BCM needs to be replaced

That makes sense, if your ignition has "learned" your security resistor the BCM is the component that verifies that and allows the ECM to start and run the engine; if the BCM is not passing on the all clear the ECM will not let the engine start.

 

[rockola1971]

That makes sense, if your ignition has "learned" your security resistor the BCM is the component that verifies that and allows the ECM to start and run the engine; if the BCM is not passing on the all clear the ECM will not let the engine start.

If that were the case then the the security light would be flashing and the engine would start up and almost immediately die. Its been decades since GM vehicles had a ECM. They have a PCM, not ECM.

 

[RET423]

The security light doesn't always flash when VATS locks out the engine, the PCM is an ECM and to reiterate; the 2004 does use a resistance range to allow the BCM to satisfy the VATS.

 

[rockola1971]

The security light doesn't always flash when VATS locks out the engine, the PCM is an ECM and to reiterate; the 2004 does use a resistance range to allow the BCM to satisfy the VATS.

That resistance range is in the lock cylinder module, not the key like old school GM from the 80's.(My 85 vette has it) By your logic anything that has to do with the engine that is electronic is an "ECM". An ECM is an Engine Control Module. Again GM hasnt called any module an ECM for decades.

 

[RET423]

That resistance range is in the lock cylinder module, not the key like old school GM from the 80's.(My 85 vette has it) By your logic anything that has to do with the engine that is electronic is an "ECM". An ECM is an Engine Control Module. Again GM hasnt called any module an ECM for decades.

I never said the resistor was in the key, from my first post I said it was in the tumbler housing.

No, not everything that has to do with the engine is an ECM, but every Module that Controls the Engine is an ECM. If it also controls the Transmission it is also a TCM; if it controls both it functions as a PCM.

There is nothing incorrect about referring to the unit as an ECM when the engine control functions are being diagnosed because it IS the "Engine Control Module".

Your attempt to make an issue about that is like someone derailing a thread because the term "motor mount" was used and "motors are electric" ; it doesn't make you sound smart especially after you claimed in error that a 2004 Tahoe doesn't have a VATS system or a resistor that controls it.

The OP needs help and you don't know enough to help him but you are choosing to pollute the thread with error and meaningless distinctions; some of us are trying to help him get his car running.

 

[rockola1971]

I never said the resistor was in the key, from my first post I said it was in the tumbler housing.

No, not everything that has to do with the engine is an ECM, but every Module that Controls the Engine is an ECM. If it also controls the Transmission it is also a TCM; if it controls both it functions as a PCM.

There is nothing incorrect about referring to the unit as an ECM when the engine control functions are being diagnosed because it IS the "Engine Control Module".

Your attempt to make an issue about that is like someone derailing a thread because the term "motor mount" was used and "motors are electric" ; it doesn't make you sound smart especially after you claimed in error that a 2004 Tahoe doesn't have a VATS system or a resistor that controls it.

The OP needs help and you don't know enough to help him but you are choosing to pollute the thread with error and meaningless distinctions; some of us are trying to help him get his car running.

You just got done saying "If it controls both it functions as a PCM". The PCM in our year range is neither a ECM nor a TCM. GM didnt start splitting up the PCM into 2 separate modules (ECM and TCM) until 2007 model year. And GM never put the VATS system in our generation of C and K chassis. The VATS system was used in the mid 80's to mid/late 90's depending on model vehicle and production year and then ENDED and REPLACED with the PASSLOCK I, II and III system. They are NOT the same and do NOT work the same either. You using the term VATS is nothing but incorrect. Are you trying to get the OP to look up and troubleshoot an ECM and VATS system that isnt even in his 2002 vehicle? You using VATS as a generic term for ALL GM security systems is also incorrect if that is what you are doing. He has a PASSLOCK II system in his 2002 vehicle.

 

[MassHoe04]

I'll just throw one of my recent experiences out there, just in case it helps anyone at all... Maybe it won't help, but here is what happened.

Late last year, I hop in, turn the key to start and nothing. No click. No crank. No start.
Try again and it starts.

Happens intermittently, but always started. I was thinking Passlock II was beginning to fail.

Sometimes a second turn of the key would not work. I thought maybe a bad contact in the door latch was somehow interfering with the security system, telling it was locked or unlocked when it should be. So, I would open and slam the door closed, then cycle the lock/unlock on the power door locks. Sometimes it would start first try after that weird Rainman procedure.

Then, the door/lock/unlock process did not work a few times. Just the ignition switch after waiting a few minutes. It would always start at some point.

Still thinking I should go out and buy a Passlock II ignition sensor module.
Then, nothing I tried would work. I was dead in the water.

Yeah... It was my starter the whole time.
Replaced with new. Never had the no-crank/no-start come back.

I am glad I didn't drop money on a new Passlock II module. Had nothing to do with my problem.

Like I said... It may be a long shot, but I just wanted people to know that what I thought was a more complex problem intertwined with my Passlock II and security system was really just a simple problem of starter failure.

 

[rockola1971]

I'll just throw one of my recent experiences out there, just in case it helps anyone at all... Maybe it won't help, but here is what happened.

Late last year, I hop in, turn the key to start and nothing. No click. No crank. No start.
Try again and it starts.

Happens intermittently, but always started. I was thinking Passlock II was beginning to fail.

Sometimes a second turn of the key would not work. I thought maybe a bad contact in the door latch was somehow interfering with the security system, telling it was locked or unlocked when it should be. So, I would open and slam the door closed, then cycle the lock/unlock on the power door locks. Sometimes it would start first try after that weird Rainman procedure.

Then, the door/lock/unlock process did not work a few times. Just the ignition switch after waiting a few minutes. It would always start at some point.

Still thinking I should go out and buy a Passlock II ignition sensor module.
Then, nothing I tried would work. I was dead in the water.

Yeah... It was my starter the whole time.
Replaced with new. Never had the no-crank/no-start come back.

I am glad I didn't drop money on a new Passlock II module. Had nothing to do with my problem.

Like I said... It may be a long shot, but I just wanted people to know that what I thought was a more complex problem intertwined with my Passlock II and security system was really just a simple problem of starter failure.

The Passlock 1,2,3 do NOT prevent an engine from being cranked over and started. The security system allows the vehicle to be started and then shuts it down within seconds if the Passlock security checks are not met. The very old system (VATS) used an actual resistor on the key (incorrectly called a chip) and was designed to prevent the vehicle from being srated at all and stolen if the wrong key was used or the ignition was popped with a screwdriver. The Passlock system is triggered by ANY key that unlocks the ignition lock which allows vehicle to be started. So If I had a copy of your key, I could steal your vehicle. But if a screwdriver or similar tool was used to break the ignition lock which allows it to be turned forward then the vehicle would start and run for a few seconds and shutdown because the key is not inserted activating the magnet system in the passlock device integrated into the ignition lock. The magnets have to be moved by the metal key and that triggers an electornic switch which sends a resistive signal (most likely derived to a current type signal or possibly voltage drop precise voltage range) which is being looked for by the BCM. The BCM then has to send over a permissive signal to the PCM to allow engine to continue running after a set amount of seconds.
Fun system to have fail while you are driving down the highway at night at 70mph and a semi to the right of you and one behind you! Fun times!

 

[MassHoe04]

The Passlock 1,2,3 do NOT prevent an engine from being cranked over and started. The security system allows the vehicle to be started and then shuts it down within seconds if the Passlock security checks are not met. The very old system (VATS) used an actual resistor on the key (incorrectly called a chip) and was designed to prevent the vehicle from being srated at all and stolen if the wrong key was used or the ignition was popped with a screwdriver. The Passlock system is triggered by ANY key that unlocks the ignition lock which allows vehicle to be started. So If I had a copy of your key, I could steal your vehicle. But if a screwdriver or similar tool was used to break the ignition lock which allows it to be turned forward then the vehicle would start and run for a few seconds and shutdown because the key is not inserted activating the magnet system in the passlock device integrated into the ignition lock. The magnets have to be moved by the metal key and that triggers an electornic switch which sends a resistive signal (most likely derived to a current type signal or possibly voltage drop precise voltage range) which is being looked for by the BCM. The BCM then has to send over a permissive signal to the PCM to allow engine to continue running after a set amount of seconds.
Fun system to have fail while you are driving down the highway at night at 70mph and a semi to the right of you and one behind you! Fun times!

Thanks for that overview!