I am hoping to pick someones brain for some troubleshooting help. I have a 2009 H/C/I Z06 with a Racetronix fuel pump. It developed a crank no start condition that started randomly, then eventually wouldn't start.
I checked all fuses.
I can jumper the fuel pump where the relay is and hear it run.
After reading multiple threads I concluded it was probably the crank position sensor.
I replaced it but still will crank but not fire.
So i bought a tech2 clone.
I can see the crank position sensor voltage and also see that it read counts when cranking it.
However when trying to read the fuel pump control module data, I get no communication. Also get the same communication error when trying to command the fuel pump.
I did a continuity test on pins 6 and 14 on the OBD2 connector and got 65 OHMS, which I believe is good.
There are no codes.

Is the fuel pump control module bad? That is that part of the fuel pump assembly, correct?
Is there anything else I should be looking at?

Thanks for any help.

 

When the fuel pump is running, have you attached a fuel pressure gauge to the fuel rail to confirm that you have fuel pressure? You should read about 58 psi.

You are aware that if you install a new crankshaft position sensor, you must perform a crankshaft position sensor relearn procedure, right?

 

For any single module “no comm” the first thing to check is it’s power and grounds before condemning it….sorry but I don’t have a wiring diagram for an ‘09…60 ohms is what you’d want to see (two 120 ohms terminating resistors in parallel) but that only needs to be checked if you can’t communicate with ANY module on the high speed bus.

 

The stock C6 Z06 does not have a fuel pump control module. Does your aftermarket fuel pump have one? If so, a Tech2 will not read it, or command it to turn the fuel pump on/off.

 

Attaching a fuel pressure gauge is the next thing i was going to try.
One of the reasons I bought the Tech2 was to do a crank position relearn, but I cant do that until its running.

 

A very basic fuel pressure test that might help is to remove the cap on the end of the fuel rail and very quickly touch the end of the schrader valve (similar to what you see when removing the cap on a tire pressure valve). Might want to be sure there is no ignition source that could light the fuel as it escapes. Sensing pressure by trying this test after a period of time since the last crank will tell you two things; the pump is pumping and there is residual pressure. If no pressure is sensed, crank the engine once and try the test again.

IIRC, the engine will not crank if there is no pressure and it will try to run the pump for 10 seconds before giving up... I think that's the way it works. Someone will correct me I'm sure...

So if there is pressure, you can probably assume that it's the correct amount of pressure.

Nick

 

There is pressure there, I just am going to make sure its correct.

 

That was one thing I was unsure about. I read in another thread that the Z06 doesn't have a FPCM like the ZR1, but has one in the fuel pump assembly.
"The CAN Bus circuit starts with the ECM, the circuit passes thru the EBCM (ABS controller), then to the fuel pump control module, then to the BCM." Is what i read.

 

As you can see here in the communication bus diagram from Alldata for your 09Z only the ZR1 engine is equipped with the FPCM…in the schematic LS3/LS7 is bypassed around the module denoting it’s not equipped !!…as far as your Crank Position Sensor a quick way to tell its faulty is look at your Tach during cranking…if the Tach doesn’t move good chance the CKP is faulty…if you installed an aftermarket sensor and not OE that can be a problem too…do you know how to check the fuel pump relay circuit ??…if you need some help it’s not difficult..you really only need a 12 volt test light…you said you jumpered the load side of the relay and the pump operates so you need to concentrate on the coil side of the relay !!…I see you’re in Ocala but I can come up your way after Thanksgiving with my diagnostic equipment and help you out if you want it.

 

Thank you for the clarification.
Fuel pressure is good at the fuel rail. So I don't think its a fuel issue at this point.
How do I check the coil side of the relay? I don't have a test light but do have a multimeter.
On to the CKP. The tach does not move when cranking.
The Tech2 shows under ignition data:
5 volt reference 1: 5.0 Volts
5 volt reference 2: 5.0 Volts
5 volt reference 1 Circ OK
5 volt reference 2 Circ OK
CKP sensor 252 RPM when cranking
What are my next steps?
Thanks for all of your help!!

 

I was going to explain the test in writing but a video would be easier to understand...a test light is better than a multimeter for this test because you will see a bias voltage on the control side feed that is talked about in the video and that will screw you up...we know load side is good because you were able to run the pump...how did you get the pump to run ??...Tech 2 using output controls or jumper pins 87 and 30 directly ??...you can use the Tech 2 to turn the pump under "output controls" but you should do it at the relay

Now to check CKP...you saw RPM at 252 which leads me in the direction that the CKP is good but let's check injector pulse and spark to make certain it's good or not. Remove a plug wire off the coil pack and keep it about 1/4 inch away...now crank the car and see if you have spark...if NO spark we will now check for injector pulse...remove the connector off an easy injector to access and now connect test light to B+...now touch test light to ground and make sure it lights...the injectors have 2 wires...a power wire (12 volts) and control...the ECM will ground that control wire so that is why we hook test light to B+...the control wire is a striped wire so as you crank the engine over the test light will blink when you touch the tip of the test light to that striped wire...if no spark or injector pulse the CKP is likely bad...I don't know how that Racetronix is wired but that may be suspect if that's when all your troubles started...what brand sensor did you use...I hope not Dorman if it was aftermarket !!...also if you have a fuel pressure gauge if CKP is bad the pump will show pressure for 2 seconds but as the engine continues to crank the fuel pressure will decrease...the ECM uses ignition reference signals from the ECM to keep that control side feed E7 energized...there is a "bypass test" at the CKP sensor or at the ECM that can be used to fire the plugs, energize the injector control and run the fuel pump....so no trouble codes for fuel pump circuit or CKP ???

 

I got the fuel pump to run simply by turning the ignition on, goes straight to around 56 psi and stays at that level the entire time im trying to crank it.
The CKP is a Carquest brand. No one had an AC Delco in stock. I had to order the AC Delco CKP and now have it just in case.
The fuel pump is https://www.racetronix.biz/k/fuel-pu...-e85/tu475-450 with the upgraded FPWH-008 and IPH-008 wiring harness installed 2 years ago.
I will need to get a test light and run the the other tests.

 

If the pump runs for 2 seconds after turning the ignition is on the FP circuit looks OK…you’ll need to see if you actually have spark and injector pulse to verify it’s the crank sensor…I’ll use a scope to verify it’s good 100% or not…I don’t like to guess even looking at the Tach.

 

Ok, This gives me a good direction to go. I will test and report back
Thanks again for all of your help.

 

No problem !!…cranking no starts are fairly easy to diagnose…just have to see if it’s fuel or spark…also compression and if it’s occurring at the right time is the other “variable” !!

 

**Update**
This morning was the first chance I had to do some testing. I decided to test the injector voltage and pulse first, so i disconnect the injector plug from from #2 cylinder. I have voltage to the injector with the ignition on. I then have my wife get in and crank it while i check injector pulse. It starts right up!! I had her shut it off, reconnected the injector plug and it started right up again.
I think it likes her butt in the seat better than mine, lol.
I made no changes, so I would assume that I need to check all of the grounds on the harness and also check for opens and shorts.

 

So when it doesn’t start is it still a “crank no start” or “no crank no start” ??…you need not check ALL the grounds but only the ones associated with that circuit…maybe when it doesn’t start again you can recheck for injector pulse and spark.

 

So far it has always been a crank no start.
I am going to check injector circuit, coil circuit and CKP circuit.

 

If you’re seeing an RPM signal and have injector pulse and a spark the car “should” start…I like hooking up my scope to the crank sensor and check 100% if it’s working right or not.

 

Agree with all previous posts concerning checking the fuel pressure---and checking to see if you have SPARK by removing a wire a spark plug then grounding the plug --crank and see if you are getting spark

ALSO remember your car is 13 YO I have seen this many times on older cars that the Anti Theft system will create a No Start---
If you have access to a tuner try to turn the THEFT system OFF--
Another issue is that the KEY gets worn out from years of use--The key has an OHM pill hidden in the BASE and gets worn and sends the wrong OHM reading TRY to use your spare key to see if it works