First start / no start

[gallonoffuel]

Hi folks,

I've posted an extensive thread at S10Forum.com and LS1Tech.com about this ordeal and I recieved some great suggestions but none have turned out to solve this.

Some background.. I have a 2000 S-10 pickup that had a 4.3 and 4L60E. I replaced that with a 5.3 Vortec and 4L60E from a 2000 Sierra. The only internal mods are a 2002 LS6 cam and springs. The wiring harness is from Current Performance Wiring and plugs into the stock power distribution box in the truck.

What's happening is on first crank, I get a few revs of firing/ignition and then nothing. Continuous cranking yields nothing, it just cranks with no activity. Every time i let off the key and re-crank, it sputters again for a few revs. I have HP tuners and have logged some of the important bits. After a few revs, the injector duty cycle drops to 0% and continues there until i let off the key.

Here is a screenshot of 4 distinct crank attempts. http://i.imgur.com/ZSqIMeM.png


Here's is a video of what it sounds like.

http://www.youtube.com/watch?v=_CqqvpJfqHE


Sometimes it'll fire for a few more revs but never gets to 'running' status. It runs longer (2-3 seconds or so) on a squirt of starting fluid but I don't have arms long enough to spray and crank at the same time.

The fuel pump is stock, and I think the check valve is dying. Prime fuel pressure is 62, and bounces between 55 and 65 during crank. It drops off quickly after the pump shuts off. I have a new pump en route. A GM tech suggested I try pinching the return line a bit to maintain some pressure, and I did, and no difference.

I have checked the CKP and cam position wiring and sensors and they are good, and brand new. I have good data from the coolant temp sensor which is new, IAT, MAP, and MAF which are reused. I have disabled VATS through HP Tuners. The rest of the tune is stock 2000 Sierra. I really feel like VATS is not actually disabled.

I have written a VATS-disabled tune, and reread that tune back to verify it's listed as disabled, and it says it is. Column lock is also set to 'none'. The injectors fire 3 times or so for each crank attempt and then go dark.

I have a new PCM en route as well, thinking it might be something there. I have ground straps running everywhere to try to rule that out.

Any leads would be most helpful. I can't spend any more time on it this week but Friday I plan on installing the new fuel pump and trying the new ECM.

[mecanicman]

I suggested it on s10 forum but I think you missed it. You can ad a status bit to see the vats is working or not. I believe you can also add a status bit to see cranking/running status. It will allow you to rule out vats.

[gallonoffuel]

I suggested it on s10 forum but I think you missed it. You can ad a status bit to see the vats is working or not. I believe you can also add a status bit to see cranking/running status. It will allow you to rule out vats.

Ah, yes I think I did miss the point of that comment. I was looking for those PIDs for the charts, not the status bits. I'll try adding those if I can find them and see what happens during crank. It'll have to wait until tomorrow though.

[welorello]

Hi, What factory tune did you start with?
Also if you do spray intake with carb cleaner how much longer does it run?
Looking at fuel psi on video your fine unless you have a volume problem which can be tested by simply turning on the pump with the tuner you should fill a mason jar in about ten seconds?

[gallonoffuel]

Hi, What factory tune did you start with?
Also if you do spray intake with carb cleaner how much longer does it run?
Looking at fuel psi on video your fine unless you have a volume problem which can be tested by simply turning on the pump with the tuner you should fill a mason jar in about ten seconds?

The tune is the factory 5.3 tune from the sierra, i only read it from the stock PCM and disabled VATS and then wrote that right back to the PCM. If i spray starting fluid I can keep it running as long as I want, I think, but I only ran it for ~10 seconds because I've seen bad things happen with starting fluid. I have not done a fuel volume test.

[welorello]

Do you have any dtc? Also im wondering about the vats let me check to see how that version of passlock works ill get back to you

[gallonoffuel]

Do you have any dtc? Also im wondering about the vats let me check to see how that version of passlock works ill get back to you

The only DTC was EGR which is now deleted and plugged in the intake.

[welorello]

Look for Giggles try this reset the vats to on and just reset the keys so the pcm and bcm share security

30 Minute Re-Learn Procedure
•Turn ON the ignition, with the engine OFF.
•Attempt to start the engine, then release the key to ON (vehicle will not start).
•Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF.
•Turn OFF the ignition, and wait 5 seconds.
•Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes ( the vehicle is now ready to relearn the Passlock™ Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK).

Important: The vehicle learns the Passlock™ Sensor Data Code and/or password on the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle.
•Start the engine (the vehicle has now learned the Passlock™ Sensor Data Code and/or password).
•With a scan tool, clear any DTCs if needed (history DTCs will self clear after 100 ignition cycles).


Look GM security is not hard to keep working, people think you need a tech2 but I don't know how hptuner disables it I know it can jut not sure how it does it....yet

[welorello]

Also if it runs on carb cleaner which I hope is what your using it means two things
1. the problem is fuel
2. the engine can and does run

know you need to figure out
1. is the pump not pumping
2. are the injectors not spraying

[gallonoffuel]

Also if it runs on carb cleaner which I hope is what your using it means two things
1. the problem is fuel
2. the engine can and does run

know you need to figure out
1. is the pump not pumping
2. are the injectors not spraying

I've done the key relearn several times. The security light on the dash is off. The tune says VATS is disabled anyway, but the truck knows the key. Whether the passlock in the S-10 is compatible with the sierra pcm, I have no idea, but that's why I bought HP Tuners in the first place, to disable VATS. But I have also put th stock tune back on with VATS in all 3 states that HP Tuners supports (PWM, serial, and none) and none of them seem to make any difference.

The pump is pumping, the injectors stop spraying when the duty cycle drops to 0 and shown in the data graph in the original post. The injectors pulse about 3 times during crank and then never again, until I let off the key and crank again. They are not being commanded to pulse after those initial few. The question is why?

[welorello]

The coil signal and the injector pulse both take the input from the crank sensor so its not possible to have one and not the other and have a bad crank sensor injector.png

so the question is with two people and a test light you need to figure out if you lose the power to the injector or the ground

[welorello]

inject2.png

notice how the ign 1 relay supplys voltage to the injectors and the crank sensor this circuit will be ruled out if the truck continues to run on carb spray however if it dosent I would jump 87 and 30 on the relay to see if it runs \

[gallonoffuel]

The coil signal and the injector pulse both take the input from the crank sensor so its not possible to have one and not the other and have a bad crank sensor injector.png

so the question is with two people and a test light you need to figure out if you lose the power to the injector or the ground

So are you saying the PCM has feedback as to whether the injectors pulsed or not? In other words, if there's an injector fault, will the PCM stop commanding them to fire? The duty cycle drops to 0% after a few revolutions. I suppose I'm putting a lot of trust into the data collection from the PCM, and that my graph of the injector duty is accurate.

[welorello]

Its not that the duty cycle drops to zero it does because the engine stops rotating



No the computer can only say the injector didn't short to ground, you would have a p0200 injector mailfuction.. So the computer interpret's the injectors are firing two ways both of which are when the engine is running
1. the engine misfire you get a code
2. the fuel trims run lean or rich

Duty cycle is sent to the injector dosent mean it gets there

[welorello]

The Data collection on every scan tool on the planet has a problem with the first 5 seconds, SnapOn, Bosch, Launch, Cheap Chinese every thing other then the tech2 A scan tool will not diagnose this problem It will help but it boils down to TEST LIGHT and TWO PEOPLE

[gallonoffuel]

Its not that the duty cycle drops to zero it does because the engine stops rotating



No the computer can only say the injector didn't short to ground, you would have a p0200 injector mailfuction.. So the computer interpret's the injectors are firing two ways both of which are when the engine is running
1. the engine misfire you get a code
2. the fuel trims run lean or rich

Duty cycle is sent to the injector dosent mean it gets there

Right, that is what I expected. I'll do some more logs with the status bits and PIDs that are relevant when it gets above freezing outside, and see what else I can dig up. Appreciate the help.

[welorello]

If you need more think you saw my pm

[FastByFelix]

Just a thought..... Do the injectors have constant power after you return the key to run????

[gallonoffuel]

Just a thought..... Do the injectors have constant power after you return the key to run????

Yes, I checked that this week and it seems fine.

Here's some more updates:

Got a new PCM, tried a few different stock tunes from HPT repository as well as the stock tune from the last ECM (which is the ECM that came with the engine). No change. Rechecked all the grounds and vacuum sources and all appear ok. Pulled the injectors and fuel rails and flushed those out, they seem to be ok. I have strong spark on all cylinders. Added a VATS status bit to my HPT scan and it says 'PASS'. Replaced the cam position and map sensors. All of this and it still does the same thing. A few injector pulses and then nothing.

[5FDP]

Just for kicks, unplug the MAF and try to start it.