LS Swap Volvo No Start
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Teching In
Joined: Apr 2014
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LS Swap Volvo No Start I have a 91 Volvo with a 2001 LM7 5.3 swap. It has a 4L60e and silverado harness, fuse box and pcm. It ran and started a couple weeks ago. I built an exhaust and installed new O2 sensors and now it will crank but no start.
I cannot hear the relays clicking in the fuse box when I let on. I pulled the fuel line and no fuel flows during crank. I jumped the fuel pump and it still works, but still no start even with fuel pump direct wired to battery.
I tried the old screw driver in the spark plug boot and didn't see a spark. At this point I assumed no spark and no fuel = dead PCM (maybe from welding exhaust) so I swapped out the PCM. That didn't fix it. I also previously checked all fuses and relays in the fuse box and found no issues.
Any thoughts? What would shut down both fuel and spark? The VATS is eliminated on both PCMs so it is not preventing start.
I cannot hear the relays clicking in the fuse box when I let on. I pulled the fuel line and no fuel flows during crank. I jumped the fuel pump and it still works, but still no start even with fuel pump direct wired to battery.
I tried the old screw driver in the spark plug boot and didn't see a spark. At this point I assumed no spark and no fuel = dead PCM (maybe from welding exhaust) so I swapped out the PCM. That didn't fix it. I also previously checked all fuses and relays in the fuse box and found no issues.
Any thoughts? What would shut down both fuel and spark? The VATS is eliminated on both PCMs so it is not preventing start.
Here's a bump to others that might know more about the stock PCM/harness arrangement. If you had a good ground when welding, I wouldn't think that would cause a problem -- exhaust shops weld with 'em on the lift by the thousands every day. Are you sure there wasn't something else that might have been disconnected when you were doing the work? One thought - there were a number of warnings in my PSI guide (PCM and harness from them on mine) about not disconnecting the battery with the ignition on - while the PCM was powered up. The warning mentioned possible damage to the computer in that scenario. Could anything like that have happened?
Thread Starter
Teching In
Joined: Apr 2014
Posts: 27
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I replaced the pc and it did not solve the issue. I think I forgot to mention that I also had put in a brand new battery. I tried tightening the primary grounds and the terminals but it made no difference.
Crank position sensor seems to be a relatively common cause of crank but no start. I'll look into that next.
Crank position sensor seems to be a relatively common cause of crank but no start. I'll look into that next.
