Killing O2's?
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Thanks guys 
, I had my headers re-ceramic coated over the winter and I think I have double coat on the outside plus a coat on the inside.
I will do some ground check Tuesday, I am travelling on business today and tomorrow till late afternnon, then I can do some tests!
The Corvette forum is awesome and I thank you all for your input! :
, I had my headers re-ceramic coated over the winter and I think I have double coat on the outside plus a coat on the inside.I will do some ground check Tuesday, I am travelling on business today and tomorrow till late afternnon, then I can do some tests!
The Corvette forum is awesome and I thank you all for your input! :
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Originally Posted by LD85
EDIT:Oh yeah, when I touch my multi meter to the driver side header pipe and the cross brace above the battery, it reads @ 1.5 volts
Is there a hot wire touching somewhere?
Jake
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
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From: Indianapolis IN
So the braided ground starps are OK or should I go with a heavy 02 gauge?
Jake: Thats what thought too, but everyone say its a ground issue.
I will pick the cables up today and do this tonight.
My negative cable goes to the bell housing and the ground strap goes from the battery to the frame. My harness grounds attatch to the back of the driver side head.
I will jumper from the large negative bell housing cable up to the back of the head and jumper from the same point bell housing over to the frame.
Jake: Thats what thought too, but everyone say its a ground issue.
I will pick the cables up today and do this tonight.
My negative cable goes to the bell housing and the ground strap goes from the battery to the frame. My harness grounds attatch to the back of the driver side head.
I will jumper from the large negative bell housing cable up to the back of the head and jumper from the same point bell housing over to the frame.
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
Originally Posted by LD85
So the braided ground starps are OK or should I go with a heavy 02 gauge?
Jake: Thats what thought too, but everyone say its a ground issue.
I will pick the cables up today and do this tonight.
My negative cable goes to the bell housing and the ground strap goes from the battery to the frame. My harness grounds attatch to the back of the driver side head.
I will jumper from the large negative bell housing cable up to the back of the head and jumper from the same point bell housing over to the frame.
Jake: Thats what thought too, but everyone say its a ground issue.
I will pick the cables up today and do this tonight.
My negative cable goes to the bell housing and the ground strap goes from the battery to the frame. My harness grounds attatch to the back of the driver side head.
I will jumper from the large negative bell housing cable up to the back of the head and jumper from the same point bell housing over to the frame.
You have aluminum heads now - I would NOT run any ground wires to the heads anymore.
Move them down to the block and I bet you find that you are then fine
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Originally Posted by ninetyfivevette
Out of curiosity, why?
In checking on a digital dash problem I've been having I learned, among other things, that GM changed the actual grounding location to different spots in different years. Gordon listed the years and where the grounding location was moved to, but off the top of my head I can recall which years had it where.
I can look it up if you need to know though.
My main grounding location is on the lower, driver's side of the block into a tapped hole, I believe it's 1/2" or 5/8", coarse. The braided strap runs from that location outboard to the chassis.
Over the years, I've seen that some guys have eliminated or failed to reconnect that braided strap, but I understand that it's important to have it remain installed.
Electrical problems are one of my weakest links, so I'm learning here too.
Jake
Last edited by JAKE; Apr 26, 2005 at 01:22 PM. Reason: Edit: the word "checked" to "changed"
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
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From: Indianapolis IN
Originally Posted by ski_dwn_it
You may have just mentioned what your problem truely is.
You have aluminum heads now - I would NOT run any ground wires to the heads anymore.
Move them down to the block and I bet you find that you are then fine
You have aluminum heads now - I would NOT run any ground wires to the heads anymore.
Move them down to the block and I bet you find that you are then fine
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Melting Slicks
Joined: Nov 1999
Posts: 2,281
Likes: 129
From: NOVA
St. Jude Donor '05-'06-'07
I think the engine maybe be grounded correctly but not the headers. I think the coating is acting like an insulator between the bolts and the heads.
Sounds like the easiest bet is to solder wires to the O2 sensor casing and ground them if possible.
Sounds like the easiest bet is to solder wires to the O2 sensor casing and ground them if possible.
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Nope it is a short to ground, not a ground problem
I am getting 12 volts from the header to the negative on the battery, intake etc now with the battery negative disconnected so I will look over the etnire harness this weekend.
I am getting 12 volts from the header to the negative on the battery, intake etc now with the battery negative disconnected so I will look over the etnire harness this weekend.
Melting Slicks
Joined: Nov 1999
Posts: 2,281
Likes: 129
From: NOVA
St. Jude Donor '05-'06-'07
Originally Posted by LD85
Nope it is a short to ground, not a ground problem
I am getting 12 volts from the header to the negative on the battery, intake etc now with the battery negative disconnected so I will look over the etnire harness this weekend.
I am getting 12 volts from the header to the negative on the battery, intake etc now with the battery negative disconnected so I will look over the etnire harness this weekend.
Last edited by Chris_G; Apr 26, 2005 at 08:39 PM.
Melting Slicks
Joined: Oct 2000
Posts: 3,426
Likes: 4
From: Heidelberg PA
Cruise-In V Veteran
Da*n, I feel your pain. Went through many troubleshooting efforts to end up with a good running engine. Hang in there, it is worth the effort.
I will be waiting to here how bad as@ed it is.
I will be waiting to here how bad as@ed it is.
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
Originally Posted by XFIRED
Actually, it is a ground problem. If the header were grounded, it would have depleted your battery or blown a fuse. Therfore, the header must be floating.You may have 12 volts shorted to the header but, not to ground.
Mine runs right across the brake booster, just under the master cylinder - then back over #7s primary tube. Its a very heavy gage wire to supply power to the starter. MIght be a good place to check, and would not be real obvious.
Easy way to locate the source is to hook up your meter and watch the screen while you move wires around. It should go to zero when you move the right wire. THen you can search in that specific area.
Gotta love electrical problems...
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Originally Posted by LD85
I have 12 volts shorted to somewhere , but nothing actually touching the header.
Friday I will slay this problem at all cost, so I can drive my blasted car!
Friday I will slay this problem at all cost, so I can drive my blasted car!
No matter though, in either case the cause has to be found and, as they say in England, sorted out.
Do you get the voltage reading with the ignition key both "On" and "Off"?
Jiggling the harness while the meter is connected is a good idea to point you in the right direction.
I remember having the same concern that Jesse posted about. I had to secure my starter wires up and out of the way to prevent them from touching the header. I moved them in such a way to give the greatest clearance I could get and then secured them in two or three different places to prevent them from dropping down over time.
Keep us posted.
Jake
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
Originally Posted by ninetyfivevette
I don't think aluminum is the problem. Al is almost as good as Cu in terms of conductivity, and Al is a better conductor than Fe.
15 yr Journeyman electrician weighing in here. But wouldn't the head gaskets insulate the heads to the block somewhat? Especially if a thread sealant was used on the bolts.I believe it should still make contact somewhere though just a thought.
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
Originally Posted by JAKE
I remember having the same concern that Jesse posted about. I had to secure my starter wires up and out of the way to prevent them from touching the header. I moved them in such a way to give the greatest clearance I could get and then secured them in two or three different places to prevent them from dropping down over time.
Keep us posted.
Jake
Keep us posted.
Jake
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Update:
Last night and early this morning I pulled the harness to the lower firewall plug out and looked it all over and re-wrapped it, no problems there.
Tonight I pulled the ECM harness out and looked it all over and re-wrapped it, nothing obvious or suspicious that I could see.
I did get the firewall harness and the ECM harness back in place and then connected the battery, by Friday I should have it all back up and ready to test, Thursday I coach Little Leauge,,, so mid Friday I should know more.
I will say that with the ECM, MSD 6AL and several connectors disconnected like the IAC, TPS, MAT etc,,,,, that I now have .000 voltage on my meter, with the positive and negative cables on the battery. I cant be sure,,, so Friday I will know more!
Many thanks for all of the brainstorming, you guys are fantastic!
Last night and early this morning I pulled the harness to the lower firewall plug out and looked it all over and re-wrapped it, no problems there.
Tonight I pulled the ECM harness out and looked it all over and re-wrapped it, nothing obvious or suspicious that I could see.
I did get the firewall harness and the ECM harness back in place and then connected the battery, by Friday I should have it all back up and ready to test, Thursday I coach Little Leauge,,, so mid Friday I should know more.
I will say that with the ECM, MSD 6AL and several connectors disconnected like the IAC, TPS, MAT etc,,,,, that I now have .000 voltage on my meter, with the positive and negative cables on the battery. I cant be sure,,, so Friday I will know more!
Many thanks for all of the brainstorming, you guys are fantastic!
Burning Brakes
Joined: Jan 2002
Posts: 1,228
Likes: 1
From: Dallas Texas
Originally Posted by LD85
I will say that with the ECM, MSD 6AL and several connectors disconnected like the IAC, TPS, MAT etc,,,,, that I now have .000 voltage on my meter, with the positive and negative cables on the battery.
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Well the problem is gone, but I am not positve why,
I think I may have missed connnecting a ground from the harness to the back of the head. When I put the two harnesses back in, it seemed that had one more to attatch than I remembered. So I may have just missed bolting one ot the head. I did not find any wiring issues while I had the harness's out so this must have been it
I still put a #4-gauge negative battery wire from the head/ground wires to the chassis where the battery ground is attatched.
Anyway, I will put the O2 in today and should be able to get the car off the ramps, been there since October!
I think I may have missed connnecting a ground from the harness to the back of the head. When I put the two harnesses back in, it seemed that had one more to attatch than I remembered. So I may have just missed bolting one ot the head. I did not find any wiring issues while I had the harness's out so this must have been it
I still put a #4-gauge negative battery wire from the head/ground wires to the chassis where the battery ground is attatched.
Anyway, I will put the O2 in today and should be able to get the car off the ramps, been there since October!