Car: 2006 C6 base Built LS2 tuned with HP tuners. Keep in mind car hasnt moved the entire time (on jackstands)

After car has been sitting for a little over two weeks and killed my factory replacement GM ACDelco battery I decide to swap a known good battery into the car to start it to get the fluids moving and the seals lubricated. Car started perfectly. Another two weeks goes by (today) and I go buy Optima Red Top today (multimeter measured 12.6 volts) and put it in the car. Car turns over very strong but doesnt start. Mind you I havent changed anything. I get a friend to come over and take a look and he starts playing with the fuses in the bay. He tells me to hold the Accessory button for 10 sec until the car turns to the "on mode" and unplugs the fuel pump and injector fuses and plugs them back in and the car starts. I have checked all the grounds going to and from the battery terminals down to the starter and the grounds on the heads and eveything is tight. I Also noticed after successfully starting the car after performing the above reset procedure that the volt meter guage on the dash fluctuates from 13.6v down to 12.3 and then car throws "service charging system" light on display. I will mention that the "SCS" light was making its appearance well before the car sat for weeks at a time and was running strong. I noticed the volt guage fluxing then too but car ran fine so I did nothing about it.

So it's come down to two separate issues:

1. The volt meter fluctuates when car is running and car reads "Service Charging System" **Could this be a bad altenator?

2. You have to reset the FUEL PUMP fuse and/or the INJECTOR fuse while car is in the "ON" position before car will start. If performed car starts immediately otherwise it wont start at all. Just continues to turn over.

So far I have tried two different known good batteries and have the same results with each. Car cranks very strong but will not run unless the above reset procedure is accomplished. After reset, car runs like a champ. It's almost like the cars security system is purposely hindering the car from starting until it see's a reset for the pump and injectors or almost like it cant read that they are plugged in and working. I have swapped the ignition relay with another known good relay and I get the same result.
I have checked fuel and ignition for spark and I have both. I have been told be a reputable source that I may have partially lost certain options of the tune that may control the PCM into allowing the pump and/or injectors to work properly each time I go to start the car. Is that possible? Thoughts?

 

The possibility of it being the tune would prompt me to return it back to the stock tune using the HP tuner, and see if the problem goes away. Do these "HP" tuners maintain your stock tune in memory like the hyper-tech tuners do?

 

sounds like the alternator was going out in the beginning so I would start there.

 

I remember reading a post about hard starting issues, ,and it turned out to be the fuel pump, or lack of voltage to it. The end result and repair was that the bulkhead connection from the engine harness to the inside cockpit had corroded pins connectors. I believe this connector is in the area of the ECM, behind the right front tire. Also read about leaky batteries dripping on that same harness, and causing all kinds of weird problems.
These problems always seem to be electrical issues with ground or connector, or shorted circuits.

FYI

 

I do not have access to the tune nor do I own HP tuners with any credits. The car was tuned at Speed Inc in Illinois. I am in Oklahoma.

Been told it could be this or it could be the starter solinoid or b+ wire going to the starter (either burnt or loose) I just checked that wire and it looks fine and wasnt loose. How should I check the altenator with a multi-meter?

I have no idea how to even start going about troubleshooting this. I am terrible when it comes to anything electrical. I only know the basic. When you tell me to chase this and that wire im instantly become clueless. I need someone with more experience to assist me or walk me through it. BTW: doing all this on jack stands sucks *****!

 

The fluctuating of the voltage at the alternator would be easy to check. Using the volt meter, measure the voltage off the alternator hot lead, it will be the largest one, to see if the fluctuating is present there also (while engine running). If it shows no fluctuations, something is going on to the point to the dash, that's why I mentioned the hardness connector. Voltage at the alternator should be around 13.8 - 14.5v.
Electrical issue do suck, but looking for the obvious things like a wire laying against something sharp cutting the wire and creating a short, pins inside the connector with corrosion, are easier to look for.

 

I agree. I haven't yet checked the alternator while the car is running. I've heard it should have an output of 13.3-13.5v while car is running. Is it possible, if the alternator is bad, that it could be causing my fuel pump issue. Isn't there a live feed wire coming from the alternator to the injectors and or fuel pump telling it to operate correctly?

 

The alternator is easy to check,

Just pull it and take it down to an auto parts store so they can machine spin it and get output readings. If it turn out to the be the altinator, then you can rebuild them way on the cheap side since it most often that the brushes are worn out, and they cost less then $10 at any alitnator/electronics shop. If the alternator checks out good, at least you have pulled the wire plugs to check and clean then (which may be the problem as well.


As for the fuel problem, two parts here. Have the tuner email you the stock and tune files so you have them. HP tuner has a demo version that you can download to see the files, and here, start by checking under fuel system to make sure that the prime time is set for 2 seconds and the pump is fixed rate. The give the system enough time to pressurize the line before the engine kick over.

Also, could be the amp draw if the battery is weak/not a clean cable connection that is causing the problem, and between pulling the alternator to check and clean the cables, and double checking the battery cables for problems as well, should at least weed out any problems at least in that part of the system.

To add, since there is a TB out for a fix on some of the under hood fuse blocks for the early C6's. if your car is not part of this recall, might be a good idea to do this low beam head light wire update yourself. When you have the fuse block apart to replace the wire and add in a second jumper wire across that path, it will allow you to clean the other fuse connections/wire connections at the same time (read you unplugging and plugging the fuse back in may be correcting the connection problem at the fuse connector to wire in the middle of the block.

Go to post #85
http://forums.corvetteforum.com/c6-c...dlights-5.html

 

The part about the alternator I understand already and you dont need to take it off of the car to test it. The rest of what you were saying is jiberish to me. I dont have access to the tune and the old owner doesnt either so that's not an option for now. Also even if I did have a copy of the tune I have no way of loading it to the car incase the car did somehow forget the HPtuners tune it originally had. I am going to start with measuring the alternator voltage and go from there to start.

 

The next time the engine doesn't start, check for voltage at the fuel pump fuse, should have voltage at both fuse ends with the ignition in the on position, assuming the fuse is good. If you don't, change the fuel pump relay, , (it's not a fuse) with another one in the fuse panel, I believe there is another one in the fuse panel that is the same, just swap them, and see if you get the voltage at the fuel pump fuse. The fuses have a small spot right on the tops; you can see the small exposed metal part on the top. See image of the 10 amp. fuse. May have just a pump relay not working all the time. It sound like there is enough voltage to trigger the relay. Other possibility; bad connection right at the fuse connection. There had been bad fuse boxes with broken wire connections inside the box, but I think that was related to earlier C6's. This is what Dano was referring to.
Go to post #85
http://forums.corvetteforum.com/c6-c...dlights-5.html

 

Update:
After tinkering around a little we found that the female side connector where the fuel pump fuse plugs into has a loose pin. While car is in on position I had a friend go see if it had any play. Upon touching the fuel pump fuse we noticed it was arching blue sparks on the outboard most side where the prong plugs into. So we disconnected the entire harness going to the fuse block and took a bright light to that particular plug-in and notice the one of the pins was tight (close tolerance bt both pins) and the other was wider almost as if someone took a mini flat head and stuck it in there and twisted it to pry the pins apart. This explains the arcing I was getting and maybe the ms4 cam was just enough to wiggle the fuse loose to where it wouldn't supply the car with fuel on startup. When we had the car running we did check the voltage coming from the alternator and it did fluctuate from 13.5 up to 14.3 back down to 11.2. At the time of reading this flux I went inside and looked at the volt Guage and it wasn't moving at all. Looked to read right at 14 as normal operation should provide. My goal is to tear into the fuse box tomorrow and see if I can find anything melted (fuse was burning hot when we pulled it out probably due to the arcing). If all looks good then I will try to close the gap of on the loose side of the fuse block for that particular fuse on the inside of the block to see if that fixes my intermittent starting issue. If not I'll likely have to buy another fuse box. :-( heard there not cheap and that they go bad a lot.

 

Looks like your on to something. Might find a used fuse block through auto salvage people, much cheaper, just find a low mile one if possible, and maybe a later model, if the part number is the same. Like I said, early ones had some issues.
Good luck

 

After you repair that harness I would still check to see if any codes thrown? This would be the first thing to check in any hard start situation.

 

Update:
Car is GTG!!!!!
After rebuilding the fuse box and ohming out each wire inside, I polished and cleaned up each pin on both top and bottom ensuring good contact and the least amount of resistance for each fuse to feed off of. After reassembly and installation she fired up right away with no more charging issues. I think the arcing from the fuse pump was kicking the pump on and off rapidly causing a draw from the altenator, which is why I was seeing a flux in volatge while measuring the altenator output voltage. Needless to say my fuse box and altenator were both good and no more "SCS" light coming up. Car is now holding a solid 14.4-14.6v. Super happy We got this figured out and that it ended up being a fairly easy fix.







Notice the burnt and widened pin located center screen. That was the pin the fuel pump fuse was plugged into causing the arc from poor contact

 

"Fairly Easy", yea, after finding the problem, usually are, but just trying to figure the problem is the brain teaser.

Good for you.

Cheez-It always helps too.

 

Well After taking the car for a short drive, I notice the Service Charging System light on the dash again. The fuel pump fuse issue is no doubt fixed but I am beside myself about this charging system issue. Voltage coming from the altenator is still 14.4-14.6V but if I measure the voltage from the positive battry terminal to the fuse box ground the multimeter reads 0.15 +/- 0.3v, So I must have a wiring issue somewhere in between the fuse box and the battery. Thoughts?

 

Your losing me on the ground terminal at the fuse block.





The negative battery wire smaller loop gets bolted to the frame straight down from the inner, front corner of the battery, and the larger cable end down below.

Positive battery wire, loop at the fuse block terminal, then the other part of the positive wire to the starter.

The fuse box just has the positive terminal that the cable loop bolts to, and the bolts that bolt the fuse block down are not good ground termination points.

As for bad battery wires, could be the problem. Might want to start by checking them to make sure that is not just a loose connection/ground connections are all good at the chassis, and worse case, new set of cables is only around $70.

 

What I meant by that was the fuse box ground located on the outside of the fuse box in the bay. I had a very good friend who is also a forum member on here stop by to run a diagnostics test on the car and he pulled a code p0621 which is the generator L circuit. It was showing intermittent signals meaning there is a short on the generator (altenator) plug somewhere. We did find a wire to be damaged and when wiggled or pulled while car was running the volt meter read erratic spikes (anywhere b/t 11.9-14.6v). I will be ordering a new pigtail from GM tomorrow to see if this is going to be an adequate fix. Wish me luck and more to come!

 

UPDATE:

Replaced the pigtail coming off of the alternator and still failed to fix the issue. Although it did not fix the SCS light it did level off the voltage fluctuation (running a steady 11.6-11.7 in all places tested with multimeter). Now time to remove the alternator and check it for proper operation along with a voltage regulator test. I will continue to update as I do more tourbleshooting. Signing off!

 

I hope that was not your charging voltage 13.8-14.5 normal
Did you try clearing the code?
Keep us updated.