07 tahoe AFM removed now it will not start

[tex96]

my wife's 07 Tahoe gave us a service message about a month ago as we were driving. It said service stablitrack and traction control off. We stopped the car as soon as we could and it had a very rough idle. I started by changing the plugs and wires but nothing helped. Towed the car home and it sat for about a week until i had time to mess with it. After removed parts and replacing a few sensors, I finally found the problem. We had a collapsed lifter. I did some research and found that the AFM system was a nightmare. I decided to the remove the AFM parts. The car sat for about 3 weeks. Last week I was off from work so I started the process of tearing down the motor to remove and replace the AFM parts and some general parts that due to the age and mileage on the car. The parts that we replaced are the following. Head gaskets, head bolts, valley cover plate, lifters, timing cover gasket, lifter guides, cam thrust plate, cam shaft, water pump, oil pump, timing chains and gears, tensioner, exh manifold, and intake manifold gaskets, belts, and had the ECM reprogrammed. I got all of this changed out and put oil and water back in the car the ECM was installed and when I went to crank the car nothing happened. I have dash lights, headlights, door locks work, rear windshield wiper works but the front wipers do not. I took the starter back off and used the jumper cables to tell if the solenoid would work and it does. When I reinstalled it on the car the purple wire has no power running through it. I'm read a few things about the BCM going bad but not really sure that is my problem. I finally got a code on it and it was U0102 which is lost communication with transfer case control module. any help would be great appreciated.

2007 Chevrolet tahoe
5.3 L Vortec
z71 4 wheel drive
flex fuel
U0102 Lost Communication with Transfer Case Control Module (TCCM)

Read more at: https://www.obd-codes.com/u0102
Copyright OBD-Codes.com
U0102 Lost Communication with Transfer Case Control Module (TCCM)

 

[Rocket Man]

I would pull the ECM back out and double check the connectors for a bent pin or corrosion. Who did the programming? Can you take the ECM back to have it checked for problems?

 

[swathdiver]

Welcome Charlie, definitely double and then triple check all of your electrical connections and grounds. An advanced scan tool like the Tech2 is indespensable in solving these kinds of problems, more important than a wrench.

What camshaft did you go with?

 

[kbuskill]

Check starter fuse 62... 40Amp. If it's good proceed.

Check the YEL/BLK wire going into the underhood fuse block for the starter relay pin 86 for power. If it has power, swap with a different relay and try again. If no power on pin 86 proceed.

Check the ORG/BLK wire from the Park/Neutral safety switch for continuity to ground.

If all these check ok then my guess would be bad BCM.

 

[tex96]

went back through all the connections and everything looks good. Only thing is I do not have power to the starter wire. The place where I got the ECM reprogrammed at is think it is a bad BCM. The battery was unhooked for a week, could we have lost programming to the BCM? If so how do I fix it.

 

[kbuskill]

went back through all the connections and everything looks good. Only thing is I do not have power to the starter wire. The place where I got the ECM reprogrammed at is think it is a bad BCM. The battery was unhooked for a week, could we have lost programming to the BCM? If so how do I fix it.

Check everything I posted above before condemning the BCM.

 

[sfc_jones]

You really need a Tech2 to see if it can communicate with the bcm and the ecm for that matter

 

[smokymtn65]

Need some Ideas. AFM delete and tuned by reputable tuner, hard start, delay start issue. cranks but no fire and smells flooded. Will start by 2nd or 3rd attempt. Unloaded tune and reloaded, tweaked it but still has issue. normally after 10-20 sit time its the worst. He is going to try a different "operating system" in ECM today. Anyone else experienced this? A wire short? senor ? Any help would be appreciated.
Thanks

 

[kbuskill]

Need some Ideas. AFM delete and tuned by reputable tuner, hard start, delay start issue. cranks but no fire and smells flooded. Will start by 2nd or 3rd attempt. Unloaded tune and reloaded, tweaked it but still has issue. normally after 10-20 sit time its the worst. He is going to try a different "operating system" in ECM today. Anyone else experienced this? A wire short? senor ? Any help would be appreciated.
Thanks

When you say "no fire" are you saying that there is no spark at the plugs or are you just saying that the engine doesn't start???

If it doesn't want to crank after sitting, I would check the EVAP Purge solenoid on the side of the intake.

You said it smells flooded. When the solenoid gets stuck open it allows the fuel vapors from the charcoal canister to "flood" the intake and then when you try to start the truck it adds even more fuel, making it worse.

Try holding the accelerator pedal to the floor, WOT, while cranking the truck. This puts the ECM in "clear flood" mode and will shut off the injectors while cranking.

You could also unplug the line from the purge solenoid and cap the side going to the intake, as a test, and see if that fixes your problem. If it does, replace the solenoid. Don't drive around with the line going back to the charcoal canister disconnected and uncapped as the fuel vapors could collect under the hood and cause a problem.

 

[smokymtn65]

First thanks for the response, I am saying (or should have) it just doesn't start. I do not know if it actually has spark or not. I will check the EVAP Purge Solenoid

 

[kbuskill]

First thanks for the response, I am saying (or should have) it just doesn't start. I do not know if it actually has spark or not. I will check the EVAP Purge Solenoid

Please keep us posted as to what you find.

 

[smokymtn65]

I will , Thanks

 

[smokymtn65]

As per tuner, re-flashed again, it's better but not totally happy with it, I asked about EVAP purge sol. he says it appears to be working fine, I did not ask how he determined that though. .LOL

 

[kbuskill]

As per tuner, re-flashed again, it's better but not totally happy with it, I asked about EVAP purge sol. he says it appears to be working fine, I did not ask how he determined that though. .LOL

They can leak without throwing a code for a while.

 

[smokymtn65]

And it gets worse.. The start issue is still there, 95 percent of the time it is when engine is warm and has sat for at least 10 minutes. I will always start may take 2 try's. To make matters worse the oil pump bypass stuck open 2 days after i went and picked it up. Put in a HV Melling it seems ok however OP is a lot lower that before. Hot idle around 15ish but I do not have a quality gauge on it to verify at this time. So if it will remain consistent for a little while I will try to figure out the start issue. The main problem is it is my wife's daily driver.

 

[smokymtn65]

They can leak without throwing a code for a while.

Been some other developments, have a misfire on cylinder 4 , had a bent intake valve. Was getting the code that day then had the valve issue. Pulled head replaced valve could see no other damage. Back together still misfire on 4, swapped coil, injector, plug, plug wire still on 4. Compression tested 150 exactly the same as cylinder 2. Any ideas?

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[kbuskill]

Refresh my memory.

You said AFM delete and custom tune.

Did you have someone disable the AFM in a custom tune OR did you physically remove the AFM cam and lifters and associated hardware and then have the AFM turned off in the tune?

 

[smokymtn65]

Refresh my memory.

You said AFM delete and custom tune.

Did you have someone disable the AFM in a custom tune OR did you physically remove the AFM cam and lifters and associated hardware and then have the AFM turned off in the tune?

The latter, btr stage 2 cam , then tuned


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[kbuskill]

The latter, btr stage 2 cam , then tuned


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Have you checked for power at the coil and fuel injector on cylinder 4 with a test light?

You could also check for spark on cylinder 4 just as easily.

Perhaps it is a broken wire in the harness and therefore swapping coils and injectors wouldn't move the problem.

 

[smokymtn65]

Have you checked for power at the coil and fuel injector on cylinder 4 with a test light?

You could also check for spark on cylinder 4 just as easily.

Perhaps it is a broken wire in the harness and therefore swapping coils and injectors wouldn't move the problem.

I have not checked for power at injector or coil yet, however i did put my "spark tester" in line of wire and plug and it show a steady spark, so process of elimination would be power to injector. I did notice the face shall we say, of injector was very clean looking compared to the others were a little sootier . Question, in tuning can the fuel rate be changed in each injector or only as a whole? I don't know what tune program my tuner uses.

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