changed some stuff, still NO fire.
10-18-2008, 06:49 PM
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changed some stuff, still NO fire. deleted vats, changed crank position sensor, put the right MAF on there, still no fire.
it will backfire and whatnot, we sprayed ether in the intake, and had a small popback from intake but still no fire.
I am stumped.
a friend of mine says it just sounds like timing is off, causing this, I had everything put together by a sponsor on the board.
what about ignition coils? could I have messed up somehow putting these on? I wouldnt think so, its coil per plug, etc.
also occasionally a loud psshhh will come from the intake area.
it will backfire and whatnot, we sprayed ether in the intake, and had a small popback from intake but still no fire.
I am stumped.
a friend of mine says it just sounds like timing is off, causing this, I had everything put together by a sponsor on the board.
what about ignition coils? could I have messed up somehow putting these on? I wouldnt think so, its coil per plug, etc.
also occasionally a loud psshhh will come from the intake area.
10-19-2008, 12:09 AM
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Most likely your actual cam timing. If the cam sensor were inop it will still fire up on every other ignition key cycle. The ncomputer simply will try to fire at what it thinks is 0 degrees on one cycle and then 180 degrees on the next key turn.
10-19-2008, 06:52 PM
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Who put on / adjusted the rockers? If they are too tight they may hold the valves open. Usually if this is the case you can tell by the sound it makes while cranking. Kinda sounds like the starter is almost freewheeling/ no compression. I'm assming you already verified there is spark, you have fuel pressure, and the injectors are firing.
10-19-2008, 07:19 PM
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well i cant positively say the inj are fire. On hptuners, i am getting inj readings on both bannks. Also i put on the rockers, but I had a full spec sheet of every part on the ls1 motor, and I torqued them down with a tq wrench to proper spec.
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10-20-2008, 05:08 PM
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If you don't have a "noid" light just rig up a small test light with two pins to connect to the Injector clips. Plug the test light into both pins on the connector and crank the engine. The light should flash each time the injector is triggered. This will verify the computer is firing the injectors.
HTH
HTH
10-20-2008, 05:58 PM
#9
If you don't have a "noid" light just rig up a small test light with two pins to connect to the Injector clips. Plug the test light into both pins on the connector and crank the engine. The light should flash each time the injector is triggered. This will verify the computer is firing the injectors.
HTH
HTH
go to Radio Shack and get a 5 volt LED, then follow insructions above...
10-20-2008, 08:53 PM
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stock rockers, what yall were telling me on the injectors, can i do this with a DMM, i HATE using test light on anything newer vehicle related.
p.s. had a conversation with a few ppl, we think it could possibly be i bought another bad crankshaft pos. sensor (gm shop had a case of 3 bad ones from oreillys) we are gonna try a GM one. or the cam might be 180* out. If the cam is 180* out i have F'ed stuff up already im sure. A sponsor here put together the motor, but hey still more testing before we determine that.
p.s. had a conversation with a few ppl, we think it could possibly be i bought another bad crankshaft pos. sensor (gm shop had a case of 3 bad ones from oreillys) we are gonna try a GM one. or the cam might be 180* out. If the cam is 180* out i have F'ed stuff up already im sure. A sponsor here put together the motor, but hey still more testing before we determine that.
10-20-2008, 09:17 PM
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If the cam is exactly 180 out and not off one or more teeth either way, it will still run fine. This is assuming that the crank gear is installed properly. If the crank gear is adjustable (advance or retard cam timing) and it is installed straight up (no advance or retard for the cam) when the dot on the crank gear is straight up, the woodruff key on the crank will be at about the 2 o'clock position.
Last edited by Navy Blue 01 B4C; 10-20-2008 at 09:42 PM. Reason: more info
10-20-2008, 10:06 PM
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well im calling the shop tomm. im at COMPLETE loss right now.
btw if i recall correctly the key IS at the 2 oclock pos. so would that be good or bad?
btw if i recall correctly the key IS at the 2 oclock pos. so would that be good or bad?
Last edited by chetmo; 10-20-2008 at 10:21 PM.
10-20-2008, 10:55 PM
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The injectors are pulsed in milliseconds so it would be very had to tell with a DVM.
Do a compression test, that will eliminate the rocker questions,
IF you have some compression-------
Use your multimeter to check for voltage at the injector plug. One of the two pins will have battery voltage with the key on. The ECM pulses the ground (other pin) to fire the injector. If you have 12V then use the test light.
If the crank sensor is bad you won't have spark at the plugs or injector pulses.
Don't get frustrated, just systematically run tests and you should be going soon.
10-20-2008, 11:03 PM
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so the cam isnt "out of timing" and i have the issue somewhere else, Car is 10.4-1 compression setup, running stock rockers, I used different rocker bolts from a sponsor on here(forget which one) and torqued them to spec.
like stated earlier its like the valve is opening on startup, I could check this by pulling a plug and shooting a few lbs of air through it. So i can see if im getting voltage from inj via DMM and ground it to the car, instaed of the pulsing ground? if CKP sensor was out, would it cause the valves to be open?
like stated earlier its like the valve is opening on startup, I could check this by pulling a plug and shooting a few lbs of air through it. So i can see if im getting voltage from inj via DMM and ground it to the car, instaed of the pulsing ground? if CKP sensor was out, would it cause the valves to be open?
10-20-2008, 11:19 PM
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You CKP has no affect on how or when the valves operate. It just tells the computer where to crankshaft position is to fire the sparkplugs and injectors.
Your "compression ratio" is 10.4-1, you need to see if you have any compression with a compression tester. This will show whether your valves are hanging open. Where are you located? This might be easier if I walk you through some of it over the phone.
Your "compression ratio" is 10.4-1, you need to see if you have any compression with a compression tester. This will show whether your valves are hanging open. Where are you located? This might be easier if I walk you through some of it over the phone.
10-21-2008, 12:19 PM
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heads are stock CC. so they shouldnt be the issue, i was told by the builder i can do a compression test and i will either get 0 or 140+ on all cylinders and that would eliminate internal issues if i had compression