5.3 swap backfires thru exhaust when trying to start
#1
5.3 swap backfires thru exhaust when trying to start
I've got a junk yard 5.3 from a wrecked 2002 Suburban that is backfiring thru the exhaust when I try to start it. It will turn over and run for a second but then dies. I used HP tuners to turn off the VATS and have a stand alone program running it. Does anyone know what could be causing the backfire? The engine is on a homemade run stand with the O2 sensors connected with open pipes and the MAF sensor was plugged in but laying on the ground.
#4
94LTZ - yes I'm using the harness/ECU that came with the engine. The crank position sensor was what I originally suspected when it had a no start condition. Found less than 1 volt there but no obvious issue. Then I noticed that the CAM position sensor wires were bare going into the sensor. Fixed that and the voltage at the crank position sensor went up to 12.
wayfast - I think you are correct. I had poured some gas into the intake to see if it would fire off because many have reported stuck injectors on these junkyard engines. I got it started and let it run for a min. to get the extra gas burned off. Hopefully that was all that it was.
Thanks for the help.
wayfast - I think you are correct. I had poured some gas into the intake to see if it would fire off because many have reported stuck injectors on these junkyard engines. I got it started and let it run for a min. to get the extra gas burned off. Hopefully that was all that it was.
Thanks for the help.