Help! No spark after clutch pedal install
07-14-2009, 09:49 PM
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Help! No spark after clutch pedal install Guys, I'm stumped and I could use some help...
I've started the LS1 in the Chevelle quite a few times, and it's always fired up fairly quickly with the exception of having to crank a few times due to a cam position sensor issue. The cam issue is that I mistakenly put an LS2/3 cam in an LS1 engine. I later learned that since the LS2/3 cam doesn't have the reluctor located at the rear of the cam, the LS1 cam position sensor doesn't pick up a signal from the cam. Typically it will just have to crank a few more times than normal for the PCM to correctly guess which stroke the engine is on before it properly fires up. Sometimes you'll get a backfire while cranking before the PCM figures out where the engine is at. I've got a proper LS1 cam to fix this problem, but that won't go in until later this week or next.
So, this week I installed the 4th-gen F-body clutch/brake/throttle pedal assembly. When I've started the engine previously, these components were connected electronically, but the pedal assembly was just laying in the floorboard, not physically installed.
When I tried to start it tonight, it cranks and cranks, but never gives any indication of firing. I don't even get the occasional backfire from the incorrect engine stroke guessing by the PCM. I've got fuel as evidenced by the fact that I can hear the fuel pump running, and I also have fuel in the rail when I bleed from the schrader valve. I bled the fuel from the rail and cycled the ingition a few times, and I verified that the fuel pump is refilling the rail properly. I don't have a fuel pressure gauge to measure pressure at the rail.
I pulled a plug to see if it was wet, but it doesn't appear to be. It looks dry and clean. I grounded the plug and cranked the engine, but I'm not getting any spark, and I don't have any idea why not. I verified that the fuses which supply power to the coils are good, and I verified that I have 13V at each of these fuses, and in the 4 hot-with-ignition power wires feeding into the engine harness.
Help!!! Thanks in advance.
I've started the LS1 in the Chevelle quite a few times, and it's always fired up fairly quickly with the exception of having to crank a few times due to a cam position sensor issue. The cam issue is that I mistakenly put an LS2/3 cam in an LS1 engine. I later learned that since the LS2/3 cam doesn't have the reluctor located at the rear of the cam, the LS1 cam position sensor doesn't pick up a signal from the cam. Typically it will just have to crank a few more times than normal for the PCM to correctly guess which stroke the engine is on before it properly fires up. Sometimes you'll get a backfire while cranking before the PCM figures out where the engine is at. I've got a proper LS1 cam to fix this problem, but that won't go in until later this week or next.
So, this week I installed the 4th-gen F-body clutch/brake/throttle pedal assembly. When I've started the engine previously, these components were connected electronically, but the pedal assembly was just laying in the floorboard, not physically installed.
When I tried to start it tonight, it cranks and cranks, but never gives any indication of firing. I don't even get the occasional backfire from the incorrect engine stroke guessing by the PCM. I've got fuel as evidenced by the fact that I can hear the fuel pump running, and I also have fuel in the rail when I bleed from the schrader valve. I bled the fuel from the rail and cycled the ingition a few times, and I verified that the fuel pump is refilling the rail properly. I don't have a fuel pressure gauge to measure pressure at the rail.
I pulled a plug to see if it was wet, but it doesn't appear to be. It looks dry and clean. I grounded the plug and cranked the engine, but I'm not getting any spark, and I don't have any idea why not. I verified that the fuses which supply power to the coils are good, and I verified that I have 13V at each of these fuses, and in the 4 hot-with-ignition power wires feeding into the engine harness.
Help!!! Thanks in advance.
07-15-2009, 07:47 AM
#3
Sounds like a ground... did you have to remove any to install the pedals?
The plug not being wet + no spark would seem that either the CAS is off... maybe a loose plug/pin... or that the ground for those is off/dirty.
Go back in your head as to what exactly you did while installing the pedals and likely may have missed something simple.
The plug not being wet + no spark would seem that either the CAS is off... maybe a loose plug/pin... or that the ground for those is off/dirty.
Go back in your head as to what exactly you did while installing the pedals and likely may have missed something simple.
07-15-2009, 11:52 AM
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Hoping this might be helpful. Instead of changing out the cam, you could swap the timing cover, cam position sensor, and the camshaft sprocket to LS2 stuff and lengthen the cam position wires to the now up front cam position sensor. This might be easier to you than having to pull the entire cam, but would require a little cash for the parts. I just wanted you to know all your options...
Sorry I can't add anything to help with the no spark problem. Although, I have to agree something must have changed during the pedal install. If you can find that you will likely have it! Good Luck!
Sorry I can't add anything to help with the no spark problem. Although, I have to agree something must have changed during the pedal install. If you can find that you will likely have it! Good Luck!
07-15-2009, 12:41 PM
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Sounds like a ground... did you have to remove any to install the pedals?
The plug not being wet + no spark would seem that either the CAS is off... maybe a loose plug/pin... or that the ground for those is off/dirty.
Go back in your head as to what exactly you did while installing the pedals and likely may have missed something simple.
The plug not being wet + no spark would seem that either the CAS is off... maybe a loose plug/pin... or that the ground for those is off/dirty.
Go back in your head as to what exactly you did while installing the pedals and likely may have missed something simple.
Thanks
07-15-2009, 03:22 PM
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Man this one has me stumped as well. Is it possible something got unplugged or a wire got cut while you were doing the pedal install. Do you have any way to read/clear codes?
07-15-2009, 03:49 PM
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Anything is possible, but I haven't found a damaged wire yet. I've got an AutoTAP, and it's not showing any codes at all.
As I think about it more, one other thing I did since last time I fired it up was to weld a patch into the driver's side floorboard. I wonder if in the process of welding, somehow the PCM could have gotten messed up? How would I know? I know it powers on, and the AutoTAP seems to be able to communicate just fine with it.
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07-15-2009, 05:35 PM
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I called Jes (Wait4Me) that originally did the harness and PCM for me, and he suggested checking to be sure that I have a good 12+V in the harness while cranking. I checked it at the main coil connector on the passenger side, and my 13V drops off to about 0.2V while cranking. Hmmm...
Jes was suggesting that this would be a bad ignition switch, but I'm not sure about that. The pink power wires that feed the engine harness aren't actually fed by the ignition switch. I'm using a hot-with-ignition spade connector on the original Chevelle fusebox to energize a 60A relay which receives power straight from the positive battery terminal. That relay provides power to 4 fuses which, in turn, provide power to the 4 pink wires in the engine harness. So, if the output of that relay is dropping to 0.2V while cranking, I'm not sure what's going on. I know the battery is decent, because it's cranking the engine over fairly quickly. I'll check the hot-with-ignition circuit on the fusebox to see if it's dropping off as well.
Jes was suggesting that this would be a bad ignition switch, but I'm not sure about that. The pink power wires that feed the engine harness aren't actually fed by the ignition switch. I'm using a hot-with-ignition spade connector on the original Chevelle fusebox to energize a 60A relay which receives power straight from the positive battery terminal. That relay provides power to 4 fuses which, in turn, provide power to the 4 pink wires in the engine harness. So, if the output of that relay is dropping to 0.2V while cranking, I'm not sure what's going on. I know the battery is decent, because it's cranking the engine over fairly quickly. I'll check the hot-with-ignition circuit on the fusebox to see if it's dropping off as well.
07-15-2009, 10:56 PM
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Turns out it was what I'd classify as a stupid mistake. When I was installing the pedals, I had apparently knocked the hot-with-ign spade connector loose from the Chevelle fusebox. I noticed that, and had already plugged it back in. The stupid part is that I had accidentally plugged it into the "ACC" terminal rather than "IGN". Props to Wait4Me for pointing me in the right direction, and thanks to all of you for your help!
