stormrider

Bill, I have recently been experiencing intermittent starting problems and while I haven’t been left stranded YET, I wanted to go ahead and get this issue fixed before it happens. First I removed the starter and took it to an auto parts store to be benched tested. The starter passed with flying colors so I went on to CF and saw your posts about failing starter switches and tested my fuses per your post (http://forums.corvetteforum.com/1568186703-post64.html) and below are the results (I checked each fuse twice)

The fuses I checked with the "HOT in ACC and ON":

Under Hood Fuse Center
ENG ING1 FUSE# 19: 6.6-5.9

INJR 2 FUSE# 18: 0.1

THROTCONT FUSE# 17: 0.3

INJR 1 FUSE# 22: 0.1

PCM FUSE# 16: 1.2-1.1

F/PMP FUSE# 13: 0.0

Instrument Panel Fuse block

BTSI BU Fuse# 21: 0.0

BCM 13 Fuse# 22: 0.0

IPC Fuse# 19: 5.3

Notes: After taking a 100+ mile road trip I pulled into my driveway and washed the car afterwards the car would not start so I charged the battery but the car still would not start until the following morning. Today, thirty six hours after the charging, my battery read between 12-12.14 volts with the key in the off position. Furthermore, prior to my road trip I installed a LMC5-R steering column lock bypass and been getting a “pull the key and wait 10 second” on my DIC the first time I try to start the car. Upon pulling the key I don’t get the “pull key” message again unless I let the car sit for several hours. I don't think the LMC5-R is causing the issue because 3-5 days prior to the installing the LMC5-R I had several bouts with intermittent starting issues but I wanted to give you as much info as possible

Do you think my ignition switch is going bad? Of course all opinions are not only welcomed but appreciated. If you all think I need to replace my switch I have a couple of questions regarding the removal of the switch per the instructions on this post: http://forums.corvetteforum.com/1571067145-post107.html

Thank you!
Mark

Bill Curlee

WHEW!! Unless you are measuring those voltages wrong,, they sure are hosed up. Are you reading from the test point on top of the fuse to CHASSIS GROUND????????

Is the meter set up to read DC Volts?? 0-20 Volt scale

With the ignition switch ON, you chould see battery voltage at each fuse.

Bill

stormrider

Bill, thanks for chiming in! I turned the **** of the meter to "Battery Load Test 12V" (link to pic of meter: http://www.amazon.com/gp/customer-me...e=UTF8&index=1), turned the ignition to ACC then put the meter's probes in each of the small openings on top of the fuses you listed. Did I do something wrong?

Mark

Bill Curlee

NO! You should be using the DCV in the RED block

BC

stormrider

Damn, I will re measure the fuses using the correct setting and report my findings. Thanks a million Bill!

stormrider

I must still be doing something wrong as I am basically getting the same readings as the first time (I only re-measured the fuses under the hood). I have the meter switch pointing to the "10 megOhm input DCV" section of the dial, the black probe in the "com" input jack and the red probe in the Volts, mA, HHMS, BAT, Diode and Continuity input jack. I am placing the tips of both probes in the small openings at the top of each fuse. What am I doing wrong??? On a side note, I am getting a reading of 10.2 even when both probes are just laying on the windshield cowl, is that normal?

chaase

I would've expected that you put the red into the fuse opening and the black end to ground. The voltage should be flowing through the fuse, there isn't a positive end and a negative end.

lionelhutz

Did it read 10.2V or 10.2mV???? You gotta watch the auto scaling because when it shows 10.2mV that means it's reading 0.0102V which is quite normal for a meter with leads not connected to anything. In your link, the meter is showing 66.3mV or 0.663V. See the mV in the top right of the display?

You don't measure with both probes on the fuse unless you're looking for a blown fuse. You normally put the black lead on a good known chassis ground point and then use the red wire to each side of the fuse.

stormrider

chaase and lionelhutz, thank you for your input. When I get back from the gym I will re-measure the fuses by placing the back probe on the fuse box grounding bolt and post my results. lionelhutz, I will also pay more attention the auto scaling as well.

Mark

lionelhutz

In the above, I should have wrote the meter you linked to was reading 0.0663V. I missed the 0 when typing and didn't proof read very well.

stormrider

Okay here are the new numbers. There was fluctuation of around a volt on most of the fuses so I made three separate readings and tried to write down the numbers that appeared the most often.

Under Hood Fuse Center
ENG ING1 FUSE# 19: 12.01, 11.87, 11.96

INJR 2 FUSE# 18: 10.3, 11.97, 10.6

THROTCONT FUSE# 17: 12.0, 11.96, 11.95

INJR 1 FUSE# 22: 11.99, 11.95, 11.95

PCM FUSE# 16: 11.94, 11.9, 11.9

F/PMP FUSE# 13: 11.94, 11.9, 11.88

Instrument Panel Fuse block

BTSI BU Fuse# 21: 11.75, 11.75, 11.74

BCM 13 Fuse# 22: 11.73, 11.74, 11.74

IPC Fuse# 19: 10.51, 11.62, 11. 51

Battery was reading between 11.99 - 12.03 V

I also noticed that the Ignition mini relay in the under the hood fuse block (number 42 in the owners manual) was VERY hot to the touch, is this normal and/or could it be the cause of my intermittent starting issues?

Thank you again!

Mark

whisperinsam33

BigGun

You need a new battery or at least a charge and load test.

lionelhutz

See below. The voltages I highlighted in red could be an issue. Those are showing large fluctuations when they should be fairly steady like the other voltages. I don't have time right now but checking the schematics to see what is common to those would be a good idea.

The relay being that hot is a bad thing. I would replace it.

The battery voltage is low, but not that big a deal if you've been testing and cranking the thing for a while without it running. Throw a charger on it for a few hours.

stormrider

I will take the battery to get tested. It is a 2 year old Diehard Gold so I would think it should still be good but hey, it will be a godsend if that is the cause of my starting issues.

stormrider

Unfortunately I am schematic illiterate which is a bad thing since most of the issues I have with my C5 are electrical related

I will replace the relay ASAP!

I charged the battery Sunday night after it wouldn't start upon the completion of a 100 plus mile road trip so maybe I have a bad cell or something. I will get the battery checked tomorrow. Again, I will be if something as easy as getting a new battery solves my starting issues.

Thank you everyone for your input!!!

lionelhutz

What is your starting issue? It won't even try to crank over? A battery reading 12V would not cause that and a battery reading 12V doesn't have a bad cell.

Bill Curlee

It is good to know the output of all those circuits BUT, you also need to compare them to something. That would be the ACTUAL BATTERY OUTPUT.

If you have 12.5 VDC at the battery terminals and 10.2 VDC on one of those fuses, you have a significant voltage drop somewhere.


All of those fuses are supplied by the battery but, the battery HOT WIRE goes through the IGNITION SWITCH.

Any switch or relay has mechanical contacts that make and break the flow of current in the electrical circuit. If the mechanical contacts make POOR CONNECTIONS, the result is HEAT and a drop in output voltage and current. Here is the formula for OHMS LAW E = I X R Where E = Voltage, I = Current and R = Resistance. If you have Two values you can use the formula to figure out the other unknown.

Long story short, If your ignition switch has dirty, burnt or damaged electrical contacts, you will see a significant voltage drop across those contacts and a low reading at the component that needs that voltage. Another problem, when a switch makes poor contact it generates HEAT and causes the CURRENT in that circuit to be reduced. It’s the CURRENT that does the work. If the current gets too low, relays don’t work correctly and can start chattering and eventually stop working.

Any coil of wire in a circuit will get hot. That relay has a coil of wire that makes a magnetic field and pulls the contacts closed. Yes, it does generate some heat. If its abnormally HOT, YES,,, Replace it. You can remove the relay, apply power to the two terminals on the relay that energize the coil and use an ohm meter to read the resistance of the electrical contacts inside the relay. They should read really close to ZERO OHMS. If the resistance reading is high, the relay is BAD.

Its easier to just replace it! But, If you know me, I like to PROVE what caused the issue (SMOKING GUN THEORY)

You already have this Ignition Switch post, correct?




- C5 ignition Switch repair - http://forums.corvetteforum.com/c5-t...ch-repair.html

Bill

lionelhutz

Like this?

stormrider

I took my battery to get checked and here are the results. Keep in mind I fully charged it on Sunday night and other than starting the engine to move the Vette into the middle of the garage and turning the key to the on position to test the fuses, the battery has remained idle.

Voltage: 12.22V
Measured: 500 CCA
Rated: 700 CCA
Ambient Temperature: 80 degrees
"Battery meets of exceeds industry specifications but is low on charge"

I am currently charging the battery outside of the Vette, will measure the voltage prior to installing then I will test the battery each day for the next couple of days to see how much draw I am getting with the car sitting idle in the garage. What is the normal draw for a C5 that is not being driven or turned on?

Bill, do you feel from the readings I posted (my battery was reading between 11.99-12.03 V) last night do you think there is a strong possibility the switch is causing to my issues? I do have the link you posted on the switch repair but I am confused as to the first part of the removal process; up to removing the center console. When you refer to the passenger I/P door are you referring to the fuse compartment in the passenger foot well or the actual door the passenger opens to get in and out of the car? I apologize for being a pain in the you know what but my mind processes information visually better than verbally so I am really confused. If you can walk me through this I will take step by step pictures and post them to help others who think like I do.

Mark