another "wont start" thread
07-29-2013, 02:18 PM
#1
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another "wont start" thread Guys
Im sure that there are a million of these threads on here, but when i search for wont/dont start, the search wipes out wont and just searches start. kinda hard to find results...
Anyway... please help me figure this out
5.3/4l60 going into 71 C10. HPTuners
Cranks strong, but wont fire...
i have set VATS to none.
I get
Blue and green pins 1 and 40 are grounded.
Blue pins 20 and 57 have 12v constant
Blue pin 19 has 12v ignition
I get 12V at injectors
I get 12Volts at coil harness to engine harness and to individual coil connectors
I get 12V to blue 33 TCC when brakes are not applied
My fuel pump is working, as i fixed a couple leaks in the line last night
I pulled the injector rails and disconnected all but 1 injector connector, put a paper towel under the injector, cranked the engine and the towel is bone dry. No fuel coming out.
This motor is from a junkyard. it was fired in the donor Tahoe in December right before i bought the motor, but has been sitting ever since while i work on the swap.
So, im going to go rent a noid light and a fuel pressure tester and see what i get
Im leaning toward dirty injectors. But im amazed that no fuel comes out. i would have expected a crappy spray pattern or at least a drip...
So, is there anything else that im missing that would just totally disable all injectors? Or is all this because of old injectors?
any helpful hints would be great!
Im sure that there are a million of these threads on here, but when i search for wont/dont start, the search wipes out wont and just searches start. kinda hard to find results...
Anyway... please help me figure this out
5.3/4l60 going into 71 C10. HPTuners
Cranks strong, but wont fire...
i have set VATS to none.
I get
Blue and green pins 1 and 40 are grounded.
Blue pins 20 and 57 have 12v constant
Blue pin 19 has 12v ignition
I get 12V at injectors
I get 12Volts at coil harness to engine harness and to individual coil connectors
I get 12V to blue 33 TCC when brakes are not applied
My fuel pump is working, as i fixed a couple leaks in the line last night
I pulled the injector rails and disconnected all but 1 injector connector, put a paper towel under the injector, cranked the engine and the towel is bone dry. No fuel coming out.
This motor is from a junkyard. it was fired in the donor Tahoe in December right before i bought the motor, but has been sitting ever since while i work on the swap.
So, im going to go rent a noid light and a fuel pressure tester and see what i get
Im leaning toward dirty injectors. But im amazed that no fuel comes out. i would have expected a crappy spray pattern or at least a drip...
So, is there anything else that im missing that would just totally disable all injectors? Or is all this because of old injectors?
any helpful hints would be great!
07-29-2013, 02:49 PM
#2
Spray some starting fluid in the throttle body, just to see if it starts for a second, that will point to dirty/stuck injectors.
Last edited by lizeec; 07-29-2013 at 10:27 PM.
07-29-2013, 03:22 PM
#4
You need to check if 1) the injectors are getting a pulse, use what they call a NOID light to check if you are getting a electrical pulse at the injector connector while it is cranking.
2) check to see if your getting a spark at the plug.. put a plug in the plug wire, lay it on the block/manifold so that the body of the plug will ground. Then crank it over and have someone watch to see if any spark.
Again, you most likely have read. .but the VAT is still enabled, even though your Tuner states it if off.. could be some other related settings.
Good Luck
BC
2) check to see if your getting a spark at the plug.. put a plug in the plug wire, lay it on the block/manifold so that the body of the plug will ground. Then crank it over and have someone watch to see if any spark.
Again, you most likely have read. .but the VAT is still enabled, even though your Tuner states it if off.. could be some other related settings.
Good Luck
BC
07-29-2013, 03:38 PM
#6
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I rented a noid light set but none fit into the truck injector connector, so i rigged it up with some aligator clips. crank on it, saw no lights.
Im using Drive By Wire (same pedal, TAC etc as the motor.. got it all, so i know it matches).
One thing i dont have hooked up is the cruise control and chmsl lines. those lines are floating/not connected.
Im wondering if i need to ground these lines or something to fire up.
I was reading elsewhere about the tps working backwards and the engine being commanded to give no fuel, like a flooded condition. The guy fixed it by reversing the tps lines. But of course, im drive by wire and dont have the traditional tps. But, im just wondering if i have the same sort of thing going on... something telling the engine not to fire the injectors.
Also, I did set VATS to none in HPTuners. Readback and made sure it stuck. Is there something else that i have to do to disable VATS???
Also, i keep getting dtc p0452, something about fuel pressure sensor low voltage. But i dont have a fps. I did disable the trouble code, but i still get the same message. Wondering if that has anything to do with it?
keep the ideas coming!!!
Im using Drive By Wire (same pedal, TAC etc as the motor.. got it all, so i know it matches).
One thing i dont have hooked up is the cruise control and chmsl lines. those lines are floating/not connected.
Im wondering if i need to ground these lines or something to fire up.
I was reading elsewhere about the tps working backwards and the engine being commanded to give no fuel, like a flooded condition. The guy fixed it by reversing the tps lines. But of course, im drive by wire and dont have the traditional tps. But, im just wondering if i have the same sort of thing going on... something telling the engine not to fire the injectors.
Also, I did set VATS to none in HPTuners. Readback and made sure it stuck. Is there something else that i have to do to disable VATS???
Also, i keep getting dtc p0452, something about fuel pressure sensor low voltage. But i dont have a fps. I did disable the trouble code, but i still get the same message. Wondering if that has anything to do with it?
keep the ideas coming!!!
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07-29-2013, 08:06 PM
#8
If your VATS is set to 'none' you should be good to go. The cruise wires have nothing to do with it running. My money is on stuck injectors. Did you spray some starting fluid in it to see if it will start? Ive personally had a whole rail of injectors that were stuck and put out absoulutley no fuel. Soaking them in Seafoam or the like fixed them.
07-29-2013, 09:05 PM
#9
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figured it out. started right up
injectors were fine
what it turned out to be is a break in on of the wires of the crank position sensor. fished that damn connector out and then ohmed it out and one of the lines was broken.
tore the harness up and found the break. soldered that and had my wife with her skinny little hands reconnect it...
fired right up
thanks for all your help guys!!
injectors were fine
what it turned out to be is a break in on of the wires of the crank position sensor. fished that damn connector out and then ohmed it out and one of the lines was broken.
tore the harness up and found the break. soldered that and had my wife with her skinny little hands reconnect it...
fired right up
thanks for all your help guys!!
