84 auto L-jet brain...anyone have one? norcal lemons UPDATE..FIXED
11-15-2009, 11:08 PM
#1
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84 auto L-jet brain...anyone have one? norcal lemons UPDATE..FIXED
The norcal lemons project has hit an intermittent problem....it has fuel flow and pressure....it fires off the cold start injector...then quickly dies....
We've tried jumpering the relay to the L jet brain and that doesn't help..fuel pump runs and delivers pressure....
does anyone in norcal have a known good L jet brain to "lend" to the nobel cause of lemons racing?
We've tried jumpering the relay to the L jet brain and that doesn't help..fuel pump runs and delivers pressure....
does anyone in norcal have a known good L jet brain to "lend" to the nobel cause of lemons racing?
Last edited by IcemanG17; 11-16-2009 at 06:44 PM.
11-15-2009, 11:35 PM
#4
Also check the grounds for the injector loom VERY well.
11-15-2009, 11:50 PM
#5
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11-15-2009, 11:51 PM
#6
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just to be clear here is the symptoms
it will fire, run briefly (maybe one second) then die......I checked the grounds for the injector on the passenger cam tower & we checked the "crunchy" wiring to all injectors..but no shorts....
the green wire "looks" okay but who knows...I do have a spare handy though.... the plug wires are good as is the coil wire...but the coil looks old, we'll test it.....
it will fire, run briefly (maybe one second) then die......I checked the grounds for the injector on the passenger cam tower & we checked the "crunchy" wiring to all injectors..but no shorts....
the green wire "looks" okay but who knows...I do have a spare handy though.... the plug wires are good as is the coil wire...but the coil looks old, we'll test it.....
11-15-2009, 11:52 PM
#7
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Temp/time switch is working or it wouldn't start.
Check the Temp II sensor. (L-Jet Temp II is measured pin to pin, vs. LH each pin to ground.)
Check the Temp II sensor. (L-Jet Temp II is measured pin to pin, vs. LH each pin to ground.)
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11-15-2009, 11:54 PM
#8
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did this happen with you frantic rebuild of the intake and timing belt? Where did all that come from? that intake could have been avoided, as you just need to use some sealant on the old gaskets, expecially on a race car. I dont think its the green wire as it wont start without it , and you are saying it runs for a few secs and then dies? cold start? if you confused Temp2 with the temp output, you could have a fried temp 2. It might start, but run REAL rich and die.
I forgot the ohms, but temp 2 is basically a variable resistor. I was able to put a ball park resistor between the two wires to get scots started to prove that was the issue. retracing the steps, it was misconnected up front and a trial start happened. this then fried temp 2. (temp 2 is not expecting voltage like which flows through the water temp plugs which look the same and can be confused.)
I forgot the ohms, but temp 2 is basically a variable resistor. I was able to put a ball park resistor between the two wires to get scots started to prove that was the issue. retracing the steps, it was misconnected up front and a trial start happened. this then fried temp 2. (temp 2 is not expecting voltage like which flows through the water temp plugs which look the same and can be confused.)
11-15-2009, 11:56 PM
#9
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11-15-2009, 11:57 PM
#10
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did this happen with you frantic rebuild of the intake and timing belt? Where did all that come from? that intake could have been avoided, as you just need to use some sealant on the old gaskets, expecially on a race car. I dont think its the green wire as it wont start without it , and you are saying it runs for a few secs and then dies? cold start? if you confused Temp2 with the temp output, you could have a fried temp 2. It might start, but run REAL rich and die.
never disconnected temp II.......just the injectors
11-16-2009, 01:00 AM
#12
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11-16-2009, 01:53 AM
#13
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ok so green wire: if this is the culprit can it still fire the ignition? because if the engine is fed fuel like dumping a teaspoon down the intake or spraying brake clean it will run for about 5 seconds then the fuel is gone.
The cold start injector is completly uncontrolled by the ecu, with the ecu unplugged the car will still start for about 1-2 seconds then stop.
the fuel pump cycles when the key is turned on after it has sat for a little while, fuel pressure hold at a steady 34-36 psi and the fuel pump runs continuosly when cranking and for about 1 second after the engine stops rotating
The cold start injector is completly uncontrolled by the ecu, with the ecu unplugged the car will still start for about 1-2 seconds then stop.
the fuel pump cycles when the key is turned on after it has sat for a little while, fuel pressure hold at a steady 34-36 psi and the fuel pump runs continuosly when cranking and for about 1 second after the engine stops rotating
11-16-2009, 03:06 AM
#14
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dont get it to run with starter fluid, eventually, you will seize the engine!
you have an ECU or connection issue. If it doesnt start right up, something is wrong.
you have an ECU or connection issue. If it doesnt start right up, something is wrong.