I will keep this as short as possible. And I have I read literally every thread in regards to this issue on here for the past week. Any help is greatly appreciated.

Specs:

• UPP Twin Turbo
• 6.7 Lq9 Stroker
• Boost-a-pump

Replaced:

• Walbro 255 LPE Pump

Ok so the car has sat for 3 years. Used to be a STS Twin turbo kit with the same engine above. I bought a UPP twin turbo kit and installed it. Replaced the fuel pump since it was not building pressure. I am now getting constant 58 psi while the pump is priming but drops down to 52 psi when it is done priming, with new 93 octane in the tank.
Car does crank but will not start. I have checked all grounds and I am finding nothing wrong with them. I have read many posts as well in regards to this topic and I have hooked up my battery charger to the battery and it does read over 13 volts.

Few things I have not done are check if the fuel injectors (Siemens 60 lbs on 93 octane) are working which they did 3 years ago before it went under the knife and check for spark (new NGK TR6).

DTC codes I am getting are as follows:

PCM P1626 h - VATS, I fixed this with the 30 minute relearn procedure. Ecu was relocated to inside of the car to foot well, no wiring was cut or spliced simply reached with the amount of loom GM provided on the harness.

TCS - Codes below I am assuming is because the car has not moved and had no power for 3 years.

• C1232 hc
• C1233 hc
• C1234 hc
• C1235 hc
• C1248 hc

· SDM - I doubt these will cause the car not to start.

• B0026 hc - Clock Spring is broken
• B0090 hc - Misplaced the Airbag on and off module in glove box for passenger side. Ordered another used one

· LDCM

• U1064 h

RDCM

• B2283 h
• B2285 h

SCM

• No Comm.

RFA

• U1064 h

 

First thing I’d do is see if you’re getting spark and injector pulse...just pull off the plug wire from the coil pack and hold it close while someone cranks it over... if you don’t know how to check for injector pulse I can run you through that..you only need an incandescent 12 volt test light..,you can see if you are getting one or the other or neither...that will give you some direction !!...also PCM fuse 16 and the INJR 1 and 2 fuses can be checked...ignition relay 42 is pretty important too !!

 

C5 Diag, Thanks for your response. I forgot to add that i did check PCM Fuse 16, INJR 1 and 2 fuses and ignition relay 42. All tested fine. I will try the Spark and Injector Pulse. If you can add the info for the injector pulse it will be a great help.

I also would like to add I do have HP tuners however I am not a tuner. I bought the software and about to load it up to see if it reads anything else.

Best Regards,
Bobby

 

Check for current or history DTC’s !!...To test for injector pulse disconnect an easy injector...I’d check for system voltage at the PINK wire KEY ON first..if you are getting 12 volts on the feed wire now we concentrate on the other wire...take a 12 volt test light and connect it to battery POSITIVE...while cranking the engine touch the tip of the test light to that wire...the test light will flicker “dimly” if the PCM is grounding that wire...might be a little hard to see in bright daylight. The thing is if you don’t have spark AND injector pulse you may have a bad crank sensor...a quick way to tell is during cranking the Tach doesn’t move...also if you have a fuel pressure gauge hooked up the pressure will drop like a rock from 58 PSI !!

 

I guess I must have missed the sentence when you said it drops from 58 to 52 after the pump primes this may be another issue !!...also after sitting for 3 years sometimes these injectors get “stuck”...even if you have power and the PCM is grounding the circuit they may be mechanically not opening (pintle valve)...sometimes a few light taps may get them to open or if no gas stabilizer was used the gas when evaporated produces a varnish that requires an injector cleaning !!...sorry I missed that !!

 

C5 Diag, You didn't miss that. I actually added that, but I think you were already replying when I was correcting my post. Going forward any changes will be a new reply.

I do agree with the injectors portion with what you said above. I have not had time to do any further testing as I will need to gather some tools from my work to test.

For now: I also hooked my HP tuners and attached a snapshot of it while I tried to crank the motor.

 

Scan data during cranking doesn't provide really any useful info...for now I'd see if you are getting spark...see if the injectors are getting power and then check for injector pulse...like I said you can lightly tap on all the injectors and take a long screwdriver and listen if you can hear them click during cranking. ..also getting back to the fuel pressure turn the key on and check the priming pressure...turn the key off and the pressure shouldn't drop more than 5 psi in 1 minute...if it's more you may have a leaky injector or some other fuel component issues....try disconnecting the MAF sensor and see if it starts....but first check the YELLOW wire on the MAF sensor and see if you are getting 5 volts there...the "5 volt ref." is the most important voltage on the car.....NO 5 volt ref. equals a NO START !!!...don't know if the car is speed density tuned or not.

 

C5 Diag, Apologies for the delayed response. I had a co worker help me out at lunch today with couple of the things you asked.

To answer your questions.

• I'd see if you are getting spark. - Yes, tested two plugs and I am getting spark. Orange / Yellow Spark.
• See if the injectors are getting power - Each injector clip is showing 14.43 volts, Each injector had 12.6 ohms (Siemens Ev6 60lb should be 12.5 ohm by manufactures specs)
• and then check for injector pulse...like I said you can lightly tap on all the injectors and take a long screwdriver and listen if you can hear them click during cranking. - Still need to test
• also getting back to the fuel pressure turn the key on and check the priming pressure...turn the key off and the pressure shouldn't drop more than 5 psi in 1 minute...if it's more you may have a leaky injector or some other fuel component issues.... - Fuel pressure is 58 and immediately drops to 52 psi and does not go any lower in the first initial minute. Tested with an Actron Gauge.
• Try disconnecting the MAF sensor and see if it starts....but first check the YELLOW wire on the MAF sensor and see if you are getting 5 volts there...the "5 volt ref." is the most important voltage on the car..... NO 5 volt ref. equals a NO START !!!...don't know if the car is speed density tuned or not. - The MAF Yellow Wire is giving 5.03 volts, the car will not start without MAF either and the car does not have a speed density tune.

 

I guess we can rule out a bad MAF. Let's see if you're getting injector pulse first and also listen if you can hear the injectors "clicking"...not the best test but without a DSO it will have to do !!

 

Hello C5 Diag,

So last week I ended up buying an injector tester. This tool had some awesome reviews: AllSun EM276


Anyhow, I took two injectors out and one I cannot hear any pulsing. And the other I can but literally have to hold my ear close to it (not ideal). I am assuming it may be the injectors since it sounds no where nearly to the sound of the injectors being tested in the video. Although I have not tested all 8 yet, I tested it exactly like the video indicated outside of the car.
I also noticed the fuel rail was sorta dirty in few injector areas I am assuming this may be due to the fact the car sat for 3 years. Need to clean that up or possibly just get new rails.


I think next I will test the injectors back in the car with fuel rail on and the fuel pressure gauge connected to see if pressure drops once I pulse the injector.

Let me know your thoughts.

 

Not familiar with that tool. Did you have a fuel pressure gauge to check fuel pressure drop while “pulsing” each injector??...don’t know what you mean by injectors were dirty in a few injector areas??

 

I tested two injectors outside of the car to check if they pulse. It was hard for me to test for pulse while doing it alone so I bought the tool above.

As for your question ...don’t know what you mean by injectors were dirty in a few injector areas??

• On the underside of the fuel rail where the injector sits in the fuel rail that area was a bit dirty. Almost as if it was rusty fuel dried out.

I am thinking of cleaning the fuel rail out now and then putting it back on the injectors and testing it for pulse and fuel pressure drop one injector a time with this tool. Similar to this video below (start at 16:00 minutes) but the gentleman is using an OTC tool not the cheaper version that I bought.

 

Injectors are bad. All stuck. Weird

 

Did you actually do a "fuel injector balance" test ??...did you OHM out the injectors ??...they should be between 11-14 ohms...how did you make that determination ??...Happy 4th !!

 

I say fuel but to have 8 bad injectors makes no sense. Your issue is elsewhere and no a dirty rail isn’t the cause either.

Are you getting your fuel pressure reading using a manual gauge at the rail? If the rail itself has pressure and the plugs are sparking the engine should fire.

 

To further that, if you have rail pressure and spark but no fire then no the injectors aren’t pulsing properly but to have 8 bad seems more a computer issue.

 

Josh, You could be right I am boggled too why 8 would go bad but they are not pulsing on the bench test either and have sat 3 years (Siemens 60lb Deka). I will look into it further with a different set and see what results I get. Really appreciate your input stand by for results.

 

Now I'm not saying that you don't have 8 bad injectors but did you ever check that you do have 12 volts on the pink wire at the injectors and that the injector driver was indeed grounding the circuit (the striped wires) ??...I explained how to check that in post #4...you have to make sure that the electrical side is working properly....now if you don't have injector pulse at all injectors most would say that yeah, the PCM is bad....but hold on now...a bad TPS and or wiring will keep the PCM from grounding the circuit...anything over 80% throttle position (clear flood mode...keeping the gas pedal to the floor)... NO INJECTOR PULSE so no fuel so no start !!...just something to keep in the back of your mind !!

 

Okay guys, Coming back after a month to post back. Been travelling for work. So I figured out all 8 injectors were stuck. I got 7 out of 8 to work with my Injector tester and a light tap to the injector itself with a screw driver tip. I bought another set installed them today. The car turned on and died within 2 seconds exhausted now will check later.

 

Hook up your fuel pressure gauge and see what the fuel pressure is static with key on..,now start the car and see what the fuel pressure does...have you checked for injector pulse at the injector connector ??...I have no idea about this injector pulser you are using !!...disconnect an injector and with your 12 volt test light connected to battery positive see if that test light blinks when probing the striped wire on the injector while cranking the engine over !!....you can spray a healthy toot of Brake Kleen into any vacuum line and see if the car attempts to start or starts...if it does you have a fueling issue !!