Cranks sputters but no start
03-29-2009, 07:01 PM
#1
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Cranks sputters but no start Tried to start my ls1 and it just sputters.
All injectors have 12v, coils have spark and Fuel spits out of the schrader valve.
New o2 and crank sensers.
What did I miss?
All injectors have 12v, coils have spark and Fuel spits out of the schrader valve.
New o2 and crank sensers.
What did I miss?
03-30-2009, 09:38 AM
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That's the way mine acted when the fuel pump went out. Even though fuel comes out the schrader valve it may not have the pressure it should have. Check the fuel pressure to be sure.
03-30-2009, 08:56 PM
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03-30-2009, 09:36 PM
#10
With electronic ignition, you'll need a real-time scanner to see the timing advance/retard.
As far as I know (not too much about distributor-less ignitions), as long as you line up the crank & cam at TDC, the computer should take over with the spark advance. If you're mechanically out of time, the ECM will be all kinds of stupid.
I would put a compression gauge in cylinder 1, and make sure the crank lines up at TDC on the compression stroke.
As far as I know (not too much about distributor-less ignitions), as long as you line up the crank & cam at TDC, the computer should take over with the spark advance. If you're mechanically out of time, the ECM will be all kinds of stupid.
I would put a compression gauge in cylinder 1, and make sure the crank lines up at TDC on the compression stroke.
03-31-2009, 03:52 PM
#12
Spark is uncontrollable without a scanner. It is completely controlled by the PCM.
What I can tell you is that if TDC of cylinder 1 lines up with the TDC balancer mark, there should be no more than about 10 degrees of play in the balancer either way - this checks the tightness of the cam chain.
If TDC of cylinder 1 & the balancer don't line up, your engine needs to be taken apart and re-timed.
What I can tell you is that if TDC of cylinder 1 lines up with the TDC balancer mark, there should be no more than about 10 degrees of play in the balancer either way - this checks the tightness of the cam chain.
If TDC of cylinder 1 & the balancer don't line up, your engine needs to be taken apart and re-timed.
04-01-2009, 06:17 AM
#13
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That brings up another question.
"TDC to cam alignment"
Wait! (thinking)
Lets see, with a scanner and timing light it should be aligned within 10 deg.
I think thats what your saying.
The alignment was supposed to have been done by the engine shop. Looks like I will have to do this myself to get it done right!
What kind of scanner? Whats the price on them?
"TDC to cam alignment"
Wait! (thinking)
Lets see, with a scanner and timing light it should be aligned within 10 deg.
I think thats what your saying.
The alignment was supposed to have been done by the engine shop. Looks like I will have to do this myself to get it done right!
What kind of scanner? Whats the price on them?
04-01-2009, 06:23 AM
#14
You don't need the scanner to mechanically time it.
In all honesty, if your crank & cam are aligned, & your cam & crank sensors are working properly, your ECM shuold take over & do the rest.
Those scanners are big bucks, too. You'd be better off borrowing one if you can. I'm not good with tuning, but I can tell you this: when I recently scanned my 2000 T/A, I came up with a spark advance of about 25* at idle at 178*F.
Hope that helps.
In all honesty, if your crank & cam are aligned, & your cam & crank sensors are working properly, your ECM shuold take over & do the rest.
Those scanners are big bucks, too. You'd be better off borrowing one if you can. I'm not good with tuning, but I can tell you this: when I recently scanned my 2000 T/A, I came up with a spark advance of about 25* at idle at 178*F.
Hope that helps.
04-01-2009, 04:11 PM
#16
It may. Here's me just thinking:
I don't know the actual numbers, but let's say your cam gear has 20 teeth. There's 360* in a revolution, so if you're one tooth off, you're 18* out-of-timing. (360/20=18) So even one tooth can cause HUGE problems with your timing.
I don't know the actual numbers, but let's say your cam gear has 20 teeth. There's 360* in a revolution, so if you're one tooth off, you're 18* out-of-timing. (360/20=18) So even one tooth can cause HUGE problems with your timing.
04-01-2009, 08:43 PM
#18
im going with mechanical timing it may look on when timing it by putting the chain on but turn it over by hand twice it will be whackkkkkk re check the mechanical cam to crank timiing i bet that it what it is
04-02-2009, 09:53 AM
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I just talked to Lunati and they recommended a computer scan and upgrade to match the new cam.
I know for sure that I set the timing between the cam n crank to OEM marks.
We will see!
I know for sure that I set the timing between the cam n crank to OEM marks.
We will see!
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