Injectors problem or PCM?
Thread Starter
Teching In
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From: San Diego, CA
Injectors problem or PCM? I've got a swap that I'm trying to finish up. I crank the engine, but it doesn't start. It will pop every now and then. If I spray starter fluid in the intake, it will pop and fire until it runs out of starter fluid. This leads me to think that I'm not getting the injectors to fire properly. Also, I am getting 53psi to the fuel rail measured consistently during cranking.
Here's a picture of the VCM scanner during cranking. Note that my injector duty cycle is 2%. What could be the problem? Has anyone seen this before?
I have VATS turned off and the engine is pulled from a 2007 5.3L Silverado (L59 model)
Thanks!
Here's a picture of the VCM scanner during cranking. Note that my injector duty cycle is 2%. What could be the problem? Has anyone seen this before?
I have VATS turned off and the engine is pulled from a 2007 5.3L Silverado (L59 model)
Thanks!
Teching In
Joined: Mar 2008
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From: La Canada, California
Have you seen this?
http://www.blackfbody.com/media/LS1_Engine_Kit.pdf
I am just preparing to start my LS1 and found several helpful hints inside, checkout the info on injectors.
http://www.blackfbody.com/media/LS1_Engine_Kit.pdf
I am just preparing to start my LS1 and found several helpful hints inside, checkout the info on injectors.
If the engine has been sitting for an extended period, and/or the injs have been out of the rails...Could be they are stuck shut, and just leaking some fuel, causing the "pop"...
I see this frequently on j/y engine supplier I do injs for.
I see this frequently on j/y engine supplier I do injs for.
Thread Starter
Teching In
Joined: Aug 2007
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From: San Diego, CA
I have brand new injectors installed. I've tapped the injectors with a soft hammer as well. I've also individually tested the injectors with a 12V supply. Each one of them clicks open when 12V is applied!
I think I've checked everything, but I know that I'm not THAT clever...
I think I've checked everything, but I know that I'm not THAT clever...
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Thread Starter
Teching In
Joined: Aug 2007
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From: San Diego, CA
Guys, sorry to bring this back up. My engine still won't start. Is there anyone that has successfully swapped a 2007 L59 5.3L Gen III engine?
I'm not getting any codes and I'm getting pretty frustrated with this.
YES VATS is off.
I'm not getting any codes and I'm getting pretty frustrated with this.
YES VATS is off.
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Are you properly powering up your PCM? Do all the appropriate PCM leads have power and ground?
Did you convert your harness to a stand-alone setup using an aftermarket or homemade fuse/relay block?
Also, more experienced wiring guys would be able to answer this.... does the PCM need power to the "crank volt" wire in order to start, or is that exclusively for the starter relay?
Did you convert your harness to a stand-alone setup using an aftermarket or homemade fuse/relay block?
Also, more experienced wiring guys would be able to answer this.... does the PCM need power to the "crank volt" wire in order to start, or is that exclusively for the starter relay?
Thread Starter
Teching In
Joined: Aug 2007
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From: San Diego, CA
Hey FastKat,
I think I'm properly powering up the PCM. It's a 2007 L59 engine with the PCM having blue and green connectors:
Blue CONN: Pin1, 24, 27, 40, 64, 67 are all grounded
Green CONN: Pin1, 40 are all grounded
I still have the option of hooking up the crank volt wire and I've tried with the crank volt wired up and also without it wired up. Neither makes a difference.
Thanks! Any more suggestions?
I get 52-54psi at the fuel rail during cranking. It seems like I get an initial fuel injector spray and then they just immediately turn off for some reason.
PCM power --------
Blue CONN: Pin 19 to IGN; Pin 20, 57 to BATTERY+
Green CONN: None.
I wired up my own fuse/relay panels. I have effectively 2 relays: IGN, CRANK. There is 12V on the IGN wire while the engine is cranking.
I think I'm properly powering up the PCM. It's a 2007 L59 engine with the PCM having blue and green connectors:
Blue CONN: Pin1, 24, 27, 40, 64, 67 are all grounded
Green CONN: Pin1, 40 are all grounded
I still have the option of hooking up the crank volt wire and I've tried with the crank volt wired up and also without it wired up. Neither makes a difference.
Thanks! Any more suggestions?
I get 52-54psi at the fuel rail during cranking. It seems like I get an initial fuel injector spray and then they just immediately turn off for some reason.
PCM power --------
Blue CONN: Pin 19 to IGN; Pin 20, 57 to BATTERY+
Green CONN: None.
I wired up my own fuse/relay panels. I have effectively 2 relays: IGN, CRANK. There is 12V on the IGN wire while the engine is cranking.
The L59 is a flex fuel engine. Could the problem have anything to do with the pcm not knowing what type of fuel it is trying to send to the engine? Tonight when I get home from work, I'll look at my AllData schematics and make sure you have power and ground connected everywhere it needs to be.
I couldn't find a flex fuel schematic for an 07, but on an 06, C1 pin 75 also has to have ignition voltage to it. What do you have on that pin?
Last edited by LS1MCSS; Jul 15, 2010 at 06:48 PM.
Thread Starter
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From: San Diego, CA
I've tried to run this engine with and without C1.75. It looks like the IGN0 wire and is used with the Auto transmission. I took out all of the automatic transmission wiring because I'm running a toyota 5-speed.
Sorry, I wish that was the issue.
I have HPTuners and when I use the VCM scanner, this is what I see:
~150rpm during cranking
12 degrees of advance
27% TPS
1% injector duty cycle
Now the 1% duty cycle seems to be a problem, unless the engine can start with that. I just know that when I get the engine to fire a little bit, the duty cycle has always been higher.
Yes, I've bought all new injectors. Yes, I've "cleaned" them by applying 12V to each one. Yes, the injectors have 12V going to them during cranking.
And I don't get any errors on my PCM. Strange, huh?
Sorry, I wish that was the issue.
I have HPTuners and when I use the VCM scanner, this is what I see:
~150rpm during cranking
12 degrees of advance
27% TPS
1% injector duty cycle
Now the 1% duty cycle seems to be a problem, unless the engine can start with that. I just know that when I get the engine to fire a little bit, the duty cycle has always been higher.
Yes, I've bought all new injectors. Yes, I've "cleaned" them by applying 12V to each one. Yes, the injectors have 12V going to them during cranking.
And I don't get any errors on my PCM. Strange, huh?
Are all the hot wires to the PCM staying hot while the engine is cranking? I don't know what you're swapping this into, but I know some older vehicles, I think ones with points, have a provision to bypass some sort of ballast resistor... in other words, the wire is hot in run, but not in start.
Can the oil level switch keep you from starting the engine? (not the pressure gauge, but the oil level switch)
If this is an automatic, is the transmission in the park position? I know the PNP switch tells the PCM what gear the trans is in, but I don't know if that will shut the injectors down if trying to start it in gear.
Can you read any codes with a scanner?
I am trying to think of things that will cause the PCM to shut the injectors down without turning off the coil packs. The only thing that comes to mind is the vehicle top speed governor, and maybe the engine governor? I think the VATS system will keep the engine from turning over completely.
Can the oil level switch keep you from starting the engine? (not the pressure gauge, but the oil level switch)
If this is an automatic, is the transmission in the park position? I know the PNP switch tells the PCM what gear the trans is in, but I don't know if that will shut the injectors down if trying to start it in gear.
Can you read any codes with a scanner?
I am trying to think of things that will cause the PCM to shut the injectors down without turning off the coil packs. The only thing that comes to mind is the vehicle top speed governor, and maybe the engine governor? I think the VATS system will keep the engine from turning over completely.
Looking at that schematic and my engine schematic, I would still run power to the Blue 75 (Ign), which I think you are referring to as C1.75. Nothing in my schematic explicitly suggests it's for automatic transmissions only... and even if it is, unless your PCM has been reprogrammed to work as a manual, you might still need it. Maybe a long shot, but I would keep it hot in run and start anyway.
Last edited by FastKat; Jul 15, 2010 at 08:02 PM.
The wiring on an 07 must be different from the 06 schematic I posted. On the 06, C1, 57 has nothing to do with the tranny. It goes through a 10 amp fuse to the ignition. You obviously have a volt meter because you know where and when your getting voltage. Set it for ohm readings. The injectors will all have a pink wire going to them. Probe the other wire going to any injector, ground the other wire on the meter, have someone crank the car and see if you get any reading on the meter. If the pcm is sending a ground signal to the injector, for them to work, you should get some type of movement on the meter. Also, 27% TPS seems like a lot for just cranking without touching the gas pedal.
I don't have my lt, so I can't open EFI. But, 150 crank speed seems low?? Is there a threshold rpm that will have to be met in order for the injs to fire??
What does the MAP read, key on/engine off?
I also see 10.8ms on both banks of injs?? This can't be right if the on time is 2%.
Spend the $20 and get a set of noid lites and find out what the injs are doing.
Are all the components from the same vehicle?
What does the MAP read, key on/engine off?
I also see 10.8ms on both banks of injs?? This can't be right if the on time is 2%.
Spend the $20 and get a set of noid lites and find out what the injs are doing.
Are all the components from the same vehicle?
Thread Starter
Teching In
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From: San Diego, CA
Are all the hot wires to the PCM staying hot while the engine is cranking? Yes. I get 12V at IGN and CRANK when the engine is cranking. I've tested this out to the injectors as well.
Can the oil level switch keep you from starting the engine? (not the pressure gauge, but the oil level switch) This, I am not sure of. I did change the original truck style oil pan to the f-body oil pan. I think the oil level switch is the same for both, but maybe someone can confirm?
If this is an automatic, is the transmission in the park position? I have pulled out the 4 wires that control p,n,drive and have tied them to high, low, etc. to simulate Park or Neutral transmission.
Can you read any codes with a scanner? There are no codes with the scanner. This is very odd, because I have a lot of the stuff in the DTC's (with HPTuners) still on. (Meaning, I haven't unchecked the SES enable box and set the Error Mode to 3-No error reported.)
LS1MCSS, I don't know if you made a typo or not, but to clarify, C1.57 is orange colored power wire. It is connected directly to battery. C1.75 is IGN0, This signal should be hot during accy, ign, crank. From my schematics, C1.75 goes to the 4L60E where it generates signals like TCCPWM and 1-2 shift for my PCM (if I had an auto transmission attached.)
Old Geezer, I'm not sure what the crank speed should be on a stock 5.3L engine. I have a 24x crank speed sensor, which I think is the right one for this engine (2007 L59). I think I've got a 164tooth flywheel instead of the 158tooth. I don't know about a threshold rpm, but it's an interesting thought.
The MAP is reading 20 at both key on, and also at cranking. It doesn't change.
The TPS is 18% with key on, no cranking. It jumps to 27% during cranking.
The INJ Banks are saying 10.8ms during cranking.
I have noticed that there is a correlation between injector duty cycle % and engine rpm on the chart.
The TAC module and pedal are from another vehicle of the same model and year. I have assumed the PCM and engine are from the same exact vehicle since the engine came with the PCM and other wiring harnesses still intact from it being pulled out of the car.
About the noid light, I will look into one today.
Thanks guys for the ideas! It's getting my brain turning again!
Can the oil level switch keep you from starting the engine? (not the pressure gauge, but the oil level switch) This, I am not sure of. I did change the original truck style oil pan to the f-body oil pan. I think the oil level switch is the same for both, but maybe someone can confirm?
If this is an automatic, is the transmission in the park position? I have pulled out the 4 wires that control p,n,drive and have tied them to high, low, etc. to simulate Park or Neutral transmission.
Can you read any codes with a scanner? There are no codes with the scanner. This is very odd, because I have a lot of the stuff in the DTC's (with HPTuners) still on. (Meaning, I haven't unchecked the SES enable box and set the Error Mode to 3-No error reported.)
LS1MCSS, I don't know if you made a typo or not, but to clarify, C1.57 is orange colored power wire. It is connected directly to battery. C1.75 is IGN0, This signal should be hot during accy, ign, crank. From my schematics, C1.75 goes to the 4L60E where it generates signals like TCCPWM and 1-2 shift for my PCM (if I had an auto transmission attached.)
Old Geezer, I'm not sure what the crank speed should be on a stock 5.3L engine. I have a 24x crank speed sensor, which I think is the right one for this engine (2007 L59). I think I've got a 164tooth flywheel instead of the 158tooth. I don't know about a threshold rpm, but it's an interesting thought.
The MAP is reading 20 at both key on, and also at cranking. It doesn't change.
The TPS is 18% with key on, no cranking. It jumps to 27% during cranking.
The INJ Banks are saying 10.8ms during cranking.
I have noticed that there is a correlation between injector duty cycle % and engine rpm on the chart.
The TAC module and pedal are from another vehicle of the same model and year. I have assumed the PCM and engine are from the same exact vehicle since the engine came with the PCM and other wiring harnesses still intact from it being pulled out of the car.
About the noid light, I will look into one today.
Thanks guys for the ideas! It's getting my brain turning again!
Going by Alldata, and i could be wrong BUT the part number i show for that vehicle for the crank sensor is 12585546 which is a 58X sensor, it defintaly could be your problem.
Mark