New build won't start, backfiring through throttle body
07-31-2017, 10:46 AM
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New build won't start, backfiring through throttle body The short story is I bought a running and tuned car and changed a BUNCH of stuff. But the issue I'm sure is with the huge mistake I made by trying to cut out some "unneeded" wiring. The wires I cut were coming from the BCM and that's it, they seemed to go nowhere. Well I was wrong. After cutting the wires the car wouldn't do anything. It was completely dead. No dome light no door ding nothing.
While this issue was there I took the engine out and had it rebuilt. I used the same cam for the rebuild, only added new bearings and pistons raising the compression ratio from 11.5 to 13.1.
I have the car back together now and reconnected most of the wires that I cut before. I have fuel, spark and compression so it should start right? Well It doesn't. In fact it's backfiring through the throttle body. I want to say it's a timing issue. I know I'll need it retuned but I figured it would at least start and run.
Is there a wire or wires I could have crossed up? Something I didn't reconnect at all? I mean I have all of the elements for it to run so I thought I had reconnected everything. Any thoughts? Please help!
While this issue was there I took the engine out and had it rebuilt. I used the same cam for the rebuild, only added new bearings and pistons raising the compression ratio from 11.5 to 13.1.
I have the car back together now and reconnected most of the wires that I cut before. I have fuel, spark and compression so it should start right? Well It doesn't. In fact it's backfiring through the throttle body. I want to say it's a timing issue. I know I'll need it retuned but I figured it would at least start and run.
Is there a wire or wires I could have crossed up? Something I didn't reconnect at all? I mean I have all of the elements for it to run so I thought I had reconnected everything. Any thoughts? Please help!
07-31-2017, 04:23 PM
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I can only hope/guess the cam is properly installed. As far as codes the scanner isn't able to communicate with the car. Also no engine light shows up in the dash at any point.
07-31-2017, 09:21 PM
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Did you remote mount your coil packs. More than one time I've seen that mod with this exact problem. If you're not careful, the wrong coil is firing with the wrong cylinder.
07-31-2017, 09:32 PM
#5
Did you check the coil wires to make sure they were put back on the engine so that the left and right sides are in the right places? I recall that each head has different color wires triggering the coils on each side so people don't make this mistake, but...
08-01-2017, 06:39 AM
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I'm pretty sure they are correct but as I troubleshoot this I'll need to check again.