@2014ImpalaLTZ : We just went through this with @adm750. It ended up being his Ignition Control Module (ICM), but he had tried a replacement ECM, too. My experience says ECMs are incredibly reliable for many, many years. They should be the last thing you try replacing.

Read through this thread:

2004 Impala 3.8 cranks won't start

Hi all - I've found some valuable insight and tips searching this forum before joining today as I worked down a 'cranks - no start' issue in my son's 2004 Impala so THANK YOU to all the enthusiasts and posters who unknowingly helped me work this problem. I've have come to believe that the PCM...

www.impalaforums.com

UPDATE: You've got a 2014 ... 10 years newer than the Impala in the above thread. Not sure if you've even got an ICM on that engine ... but if you do ... that was something "common" stopping all of his Injectors from firing.

Another "common" thing would be Fuel, of course. Do you know if you're getting fuel to the Cylinders?

 

I can hear the fuel pump running prior to start and the fuel filter is recent.

 

Have you measured the Fuel Pressure at the Rail? Does this vehicle have the 2-pump system ... one in the Tank ... and one under the Hood (the High Pressure Fuel Pump)?

And do you know if your Crank and Cam Sensors are working properly? Did you use ACDelco Sensors? I've seen cases where using off-brand Sensors have been a problem.

 

60psi fuel pressure

 

I think that's good ...

Have you verified the Plugs are Firing?

Does this Vehicle have an ICM? On that 2004, the Coils (only 3 of them on a 6-cylinder Engine because it fired two cylinders at a time) sat on the ICM. Maybe your Engine just has a Coil on each Plug ... so 6 Coils ... and no ICM? On the 2004, the ICM was in control during initial Cranking, then turned control over to the PCM/ECM. Maybe, without an ICM, your PCM/ECM is in control right from the get-go?

 

Cam position sensors are new AC Delco. Never touched crank position sensor. All replacement parts are AC Delco.

 

2014 3.6L VVT is direct injected

 

Yeah ... it's like my 2011 Equnox ... except I have the precursor Engine ... the 3.0L ... before they switched to the 3.6L in 2012.

Well ... you have to verify you're getting Spark on each Cylinder. I'm not a mechanic ... but is that where the Noid Light comes in?

And how about Air? Is your MAF Sensor on the Snorkel giving the PCM a valid input ... because it might be possible that if the reading is ZERO, for example ... that no Fuel Injectors will fire. Not sure if you can back-probe that Sensor while Cranking to see what it's outputting?

With the 2004 Engine ... and this might be common processing with all of these Engines ... the PCM was also looking at the MAP and ECT Sensors at startup (along with the Crankshaft Position Sensor CKP).

====
Why did you do these "repairs" if the Engine was running well previously? Were you just trying to be proactive ... anticipating problems ... since you were at 159,000 miles? I'm at 186,000 with my Equinox and it's still all Factory-Original. Have only changed a Purge Valve, the Tires (on my 2nd set) and the Battery (1) ... 1 set of brake pads (close to a 2nd set) ... and almost 50 Oil Changes and 4-5 Tranny Fluid Changes. That's it!

 

Six coil-on-plug

 

How would I check MAF output?

 

Well ... my Harbor Fake OBD-2 handheld can read it ... and I've even gotten logged data from it when I was having issues with my 2002 Impala ... but that was with the Vehicle running! You're not running (yet) ... so I don't think the OBD-2 port will reveal anything for you.

You'd probably have to back-probe the Plug ... and then read the Voltage. Check YouTube videos. Seems to me, though ... now that I think of it ... I remember reading where people have disconnected it all together ... so maybe the PCM substitutes a ConstantVal number in place of the MAF if it sees a flat ZERO input ... just to get the Engine running? Not sure.

You know ... anytime something stops working, we always ask the question: "What Changed?". In this case ... we know what "changed": you changed the Timing Chain, the Cam Gear/Phasers, the Solenoids, and the Cam Position Sensors (all ADDelco parts) on an Engine that was running fine (not trying to blame you here ... just re-affirming that we know how we got here ... it's not like a Vehicle with an unknown history).

It appears you have Fuel.

You most likely have Air.

But are the Coils and Plugs being Fired? That was the problem with the 2004 ... and it was due to the Module that was supposed to be passing signals to the PCM/ECM, but wasn't. If you don't have an ICM (and I don't think you do) ... and the Crank Position and Cam Position Sensors inputs go directly to the PCM/ECM ... then it could be the PCM/ECM at fault ... but that's highly unlikely, I'd say ... especially on an only 9-year-old vehicle!

Let me ask a simple question: you've checked all Fuses and Relays, right?

This is where having the Wiring Diagrams comes in handy. AllData has inexpensive subscriptions (especially around the Holidays when they run special pricing. Forget Helm .. they jacked their pricing through the roof a few years ago when they went to the Memory Stick.

 

The chances of the ECM losing the basic flash are about zero. Unless the write enable pin goes high on the EPROM nothing can be written, they can retain data for decades.

My money is on a missing signal be it from a pinched/broken wire or connector issue with the engine being torn down. I'd follow the troubleshooting flowchart before jumping to any conclusions.

 

Check grounds and all battery cable connections

 

@2014ImpalaLTZ : I was reading through my 2011 Equinox Helm Shop Manual ... which covers my 3.0L V6 ... very similar to your 3.6L VVT ... also Direct Injection, VVT, and 6-Coils on 6-Plugs. The ECU/PCM gets the Crankshaft Position Sensor (CKP) and Camshaft Position Sensors (CMP) directly ... to in turn ... fire the Injectors. Have you been able to verify the Injectors are getting Power from the ECU (using a Noid Light)?

 

Since the battery sat for 8 months....did the fuel also sit for 8 months?

It ain't got no gas in it

 

It has 3/4 of a tank. I ordered all AC Delco replacement parts on this project through Amazon. The only parts I couldn’t confirm as AC Delco were two cam position sensors which did not come in an original box so I replaced all four again since I couldn’t tell them apart. This seemed to help by making the cranking sound more even but still no start.

 

Fuel timing spark

Make sure your timing is perfect and make sure the relays in the fuse box are good
Don't misuse dialectic grease
Check your engine compression

 

I followed ASE mechanic Miker Brewer on GoTech YouTube video step by step concerning the timing set replacement and then checked the cam positions for phases one and two with the special cam timing tools upon completion. I marked each chain link position on its corresponding sprocket tooth with a paint pen then triple checked each one. I manually spun the crankshaft 7 rotations to verify no piston-to-valve interference and there was none. I am reasonably certain the timing is correct. I’m replacing the crankshaft position sensor today. My research tells me that a failed crank sensor will result in a no start condition as well. It has 159K miles on it. It was working when I drove the car in the bay. Not sure why it would fail but I’m running out of ideas.

 

The purpose of this project was proactive. I read that after 100,000 miles, a 3.6L that hasn’t been maintained well with regular oil changes has the reputation of jumping time and grenading. My daughter bought the car used at 98K miles from a dealer so I had no way to confirm it’s past. It was starting to exhibit some new valve rattle so I started researching.

 

@2014ImpalaLTZ : Failed Crank Sensor (CKP) could certainly stop you dead in your tracks ... since that's the primary Signal the ECM/PCM is using to fire the Injectors. Really need to test for a signal coming out of that Sensor (to the ECM/PCM) ... but not sure if a simple Digital Volt Meter would be fast enough to do that? That's where (I believe) the Noid Light works.

Maybe the new CKP Sensor does it...

 

I installed the new Crankshaft Position Sensor today but still no start. I tested for spark today and I have a good spark at the spark plugs. Compression is 100psi +/- ~10%. Low pressure fuel pump is pushing 60psi. Tomorrow, I will check fuel pump volume. Does anyone know how much fuel should be delivered in what timeframe? Currently, I’m dismantling the fuse box to see if any pins were damaged but they all look good. Thanks to everyone for your help on this. This is the most stumped I’ve ever been with an engine repair.

 

@2014ImpalaLTZ : I’m no mechanic, so I’ll ask the question … is it possible to have Spark and still not be firing the Injectors? Or, is it possible to fire the Injectors and Coils/Plugs out of sync?

One way would definitely be Fuses … whether on the Fuse Box … or “in-line”. IIRC, the wiring to the Injectors on my 2002 is “Spliced” … and it has an in-line Fuse. Maybe your Injectors still are not firing?

Another way might be via cross-wiring?

 

@Colt Hero - that's where I was heading....

@2014ImpalaLTZ - did I miss where you tested the injector harness with the noid lights...? if so, I apologize but I did not see where you'd confirmed signal at the injectors when cranking. Autozone rents the test set for $25. go get in the 'Zone and let us know the results. You can't really check 'fuel volume' unless the injectors are being run. If you have 60psi and it's not running, I suspect the injectors are not being told to turn on. which, in my case, was the missing signal to the PCM from the ICM telling them to get ready.

EDIT - actually, i should have asked you the million dollar question first.... Did you figure it out ??

 

I have a set of noid lights. I confirmed that I’m getting signal to all six of the injectors. 3 of them were intermittent but I cleaned the contacts and solved that issue. So, to recap: I have strong spark, good compression, firing injectors and 60psi of low side fuel pressure and still no start. What am I missing?

 

Seems like you're so close!

Do you know what input the MAF is sending to the PCM? How about the MAP? I think an Engine has one or the other ... so maybe no MAP on your Engine (since you said you cleaned the MAF)? If the MAF input is bad ... maybe that could be causing the ECM to flood the Engine (??) ... although you'd think it'd be smarter than that, right? Also, along these lines ... do you know if the Throttle Body Butterfly is even opening? Maybe it's closed and there's no air getting in? These values are in the OBD-2 data list, and it's possible a Reader's "logging" functionality might be able to capture them during a "Cold" Start.

What about the O2 Sensors? They're typically only used once the Engine goes to "Closed Loop" ... which occurs after it heats up ... so not during "Cold" Start (which is where you're stuck) ... but they also have "heaters" on them ... which means they might be getting referenced during a "Cold" Start?

Of course ... the other "elephant in the room" is the Timing of all these Signals. What you really need is a Display showing all the pertinent signals superimposed on a single Trend ... so you can verify the Timing of all of this (i.e. ... you have Injectors firing, but not when the Fuel is being Injected ... or when the Plugs are Firing ... if that's even possible). What if the Cam Sensors (or Crank Sensor) are "working" but not reporting accurately because what they're "watching for" isn't accurately mounted itself (is this the "Reluctors" at the end of the CamShafts ... can those get "spun" ... or what is the Crank Sensor watching ... some piece on the back of the Crank Balancer ... but you didn't touch that, right)?

I'm sure the Dealer could just crank your Engine for a few seconds ... while running his Data Logger ... then have all these input data points (Crank Sensor, Cam Sensors, Plug and Injector Firing signals, MAF sensor, Throttle Position, O2 Sensors ... appear on a Graph with their square waves... then look at how they "marry up" ... and say ... "Oh yeah ... here's the problem right here ... ".

Should really only take them a few minutes ...

 

Thank you guys for staying with me through all of this! I understand that even new parts can fail but all cam and crank position sensors are new AC Delco parts as is the harmonic balancer. Each of the sensors are made to install in a specific orientation so I don’t think I messed those up. Both the MAF, MAP sensors and Cannister Purge Valve are all new AC Delco pieces. I have not replaced the Throttle Position Sensor as you mentioned. I am presently replacing both high and low pressure fuel pumps, fuel pump control module and the fuel rail and EFI pressure sensors with (you guessed it!) AC Delco units. If this engine ever restarts, just about every wear item will have been replaced. Considering it’s my daughter’s car that I need to be completely reliable, that’s a good thing…and very expensive!

 

@2014ImpalaLTZ : You might be better off buying yourself a good handheld scanner for the OBD-2 Port. I know my Harbor Fake handheld can log data ... I've used it that way before ... but I'm not sure if it can plot these signals on a graph/trend ... and I'm fairly sure that even if it can ... it would only be a single signal (or two). I'll have to check when I get home.

Does anybody on this Forum know of a semi-professional Scanner that could plot multiple signals on a graph/Trend Display? Even the (prohibitively expensive) SnapOp handhelds you see people using in some of the YouTube videos only say, "Live Data Graphing of 1, 2, or 4 graphs" ... not sure what that even means!

There's a Member on the Equinox Forum who vouches for Auto-Enginuity, which is sort of a mid-priced package ... but I've read the information they present at their Website, and it doesn't really say much. I don't think it can Display a multi-point graph/Trend.