5.3 Swap in 71 Blazer starts and dies
02-22-2013, 05:14 PM
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5.3 Swap in 71 Blazer starts and dies I am installing my first LS conversion- its a 2003 5.3 and auto into a 71 2wd Blazer. I bought the eng/tranny combo with conversion harness (modified stock) and the computer programed.
When I turn the key, it starts right up and immediately dies. I bought a fuel pressure gauge, reads 55 psi with key on- could it be the vats still enabled? Thanks for any help.
The pic had a bag over the air filter during bodywork-I removed it before trying to start the engine!
When I turn the key, it starts right up and immediately dies. I bought a fuel pressure gauge, reads 55 psi with key on- could it be the vats still enabled? Thanks for any help.
The pic had a bag over the air filter during bodywork-I removed it before trying to start the engine!
Last edited by chuckmc8; 02-22-2013 at 05:21 PM.
02-22-2013, 05:31 PM
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02-22-2013, 05:34 PM
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VATS will cut injector pulse after about 2 seconds. See if you lose injector pulse when it stalls.
Even with VATS kicking in, it should still run if you feed it some brake cleaner or something.
Even with VATS kicking in, it should still run if you feed it some brake cleaner or something.
02-22-2013, 05:43 PM
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it has an odd wire that I didnt quite understand- it is a small purple labeled "12V in start only" on the tag. I just put it with the starter wire. Anyone know if this is correct?
02-22-2013, 05:45 PM
#6
ao check the hot wires.
seen a guy waist 6-7 hr's 1 day tracing down a crank / fire but soon as key back to run from crank die problem.
found it out to be he had 1 hot wire in wrong place and it was on crank hot when it needed key hot & crank hot .
soon as he swaped it over it fired and run great.
seen a guy waist 6-7 hr's 1 day tracing down a crank / fire but soon as key back to run from crank die problem.
found it out to be he had 1 hot wire in wrong place and it was on crank hot when it needed key hot & crank hot .
soon as he swaped it over it fired and run great.
02-22-2013, 05:50 PM
#7
Yea thats what I am getting at.
I can't tell you the details or where to look, but I'm guessing you have 12v in "start" key position, but something doesn't have it in the "run" position.
I'm sure someone can chime in and tell you exactly where/what to look for.
I can't tell you the details or where to look, but I'm guessing you have 12v in "start" key position, but something doesn't have it in the "run" position.
I'm sure someone can chime in and tell you exactly where/what to look for.
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02-23-2013, 08:50 AM
#10
The small purple wire sounds like it might be for a starter relay. Do you have a starter relay wired into the neutral safety switch on the trans, or are you just using the original purple wire from the ignition switch? Also, what wire are you using to power up the harness? Should be the wire that originally went to the distributor. I have seen way too many people who like to get power by plugging it into the fuse box since these trucks have places to plug things in... but it doesn't work with them.
02-23-2013, 05:52 PM
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The small purple wire sounds like it might be for a starter relay. Do you have a starter relay wired into the neutral safety switch on the trans, or are you just using the original purple wire from the ignition switch? Also, what wire are you using to power up the harness? Should be the wire that originally went to the distributor.
For ignition, I am doing as you suggested-the ignition circuit of the 5.3 is powered by the wire that formerly powered the coil on the 350.
I double checked everything and couldn't find a problem, so I called the person that programed the computer an explained the situation. I am loading the Blazer on the trailer next week and trucking it over to his shop. He said that it sounds like the VATS is the problem. Hopefully, he will know how to get it going. I appreciate the advice you guys offered. I'll post the results next week after the computer check.
