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Looks like a grounding strap to me.
What the F&*$ is this?
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The truck was running a little rough today; think the cats may be ready to go from teh sounds of it. But anyway I got under the truck and saw a wire or strap hanging down, obviously burnt through. But I have no idea what it is and if its important. Looks like it could be a grounding strap????????? On the first and third picture you can see it hanging down from a screw into the frame. On the second picture, it hangs dwon from close to the muffler pipes and the driver side cataltic converter.
Anyways, can anyone tell me what it is and what purpose it serves? Also, should I stay away from driving it while this is hanging down?
Thanks in advance,
Shawn
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Anyways, can anyone tell me what it is and what purpose it serves? Also, should I stay away from driving it while this is hanging down?
Thanks in advance,
Shawn
1 - 17 of 17 Posts
Is it necessary or should I not be worried about it? Where does the frayed end connect?
Thanks,
Shawn
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DMM and measure resistance between chassis ground and exhaust with and w/o ground strap. My thinking is that it does nada.
Exhaust manifolds are bolted to grounded block with conductive studs & nut (and perhaps conductive gasket). B-pipes are bolted to manifolds with conductive fasteners and probably conductive metal leaf gasket.
PS: you can see the end of the connector on the exhaust stud in your first pic where the ground strap was formerly connected. I don't think you will get that nut off too easily.
Exhaust manifolds are bolted to grounded block with conductive studs & nut (and perhaps conductive gasket). B-pipes are bolted to manifolds with conductive fasteners and probably conductive metal leaf gasket.
PS: you can see the end of the connector on the exhaust stud in your first pic where the ground strap was formerly connected. I don't think you will get that nut off too easily.
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6,413 Posts
Just do a hose clamp around the exhaust to hold the ground strap. Electronics Sensors create a need for extra grounding throughout the vehicle. Minute variations cause misreadings. This is likely not a critical one, but better to reestablish it.
There were reports on early Titans of a ticking exhaust noise that subsided with Grounding.
Also, maybe overlooked by most of us... Heating creates a voltage, I had this proven to me in my kids science project last year. We heated a wire and measured voltage at cold end to a center point, and heated end to same point. We got several tenths DC. Thus, Grounds are needed on Exhaust for various sensors to read accurately.
UPDATE: Read next post. Good to know this issue is negated by the sensor being a 4 wire design.
There were reports on early Titans of a ticking exhaust noise that subsided with Grounding.
Also, maybe overlooked by most of us... Heating creates a voltage, I had this proven to me in my kids science project last year. We heated a wire and measured voltage at cold end to a center point, and heated end to same point. We got several tenths DC. Thus, Grounds are needed on Exhaust for various sensors to read accurately.
UPDATE: Read next post. Good to know this issue is negated by the sensor being a 4 wire design.
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17,244 Posts
4 wire exhaust sensors use harness ground. Does nada.
"Four Wires - One wire is the sensor signal, one is the isolated sensor signal ground and the remaining two are used to supply a voltage to the internal heater. Also referred to as an ISO - HEGO Sensor (Isolated Heated Exhaust Gas Oxygen Sensor).
The sensor signal wire is directly connected to one of the platinum electrodes on the ceramic element. The sensor output is immune to ground loop voltages and also to large resistances in the vehicle ground return, caused by corroded connections. No NTK four wire sensor is case grounded. Case grounded sensors have the ground wire physically attached to the sensor body. It is not recommended to replace isolated ground sensors with case ground types."
"Four Wires - One wire is the sensor signal, one is the isolated sensor signal ground and the remaining two are used to supply a voltage to the internal heater. Also referred to as an ISO - HEGO Sensor (Isolated Heated Exhaust Gas Oxygen Sensor).
The sensor signal wire is directly connected to one of the platinum electrodes on the ceramic element. The sensor output is immune to ground loop voltages and also to large resistances in the vehicle ground return, caused by corroded connections. No NTK four wire sensor is case grounded. Case grounded sensors have the ground wire physically attached to the sensor body. It is not recommended to replace isolated ground sensors with case ground types."
So basically that means that I shouldnt worry about reconnecting it, correct? If it doesn't do anything, why is it there in the first place? :huh:
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You can find extensive debates on this topic in forums all over the net, even going to the point of suggesting dynos and data logging. I subscribe to the "not needed" theory for 4 wire sensors where the entire exhaust system is grounded via its connection to the block. There is one thread where people with 3 wire sensors replaced with 4 wire sensors to solve exhaust ground problems affecting sensors. Various theories for the exhaust ground strap include:
to make the exhaust quieter due to some mystery action on exhaust particles
to diminish static electricity
to improve cat function
to improve O2 sensor function
to minimize corrosion of exhaust system
to minimize RF interference
When I was installing headers, B-pipe, and exhaust, I noticed that my strap was also hanging, broken from the end of the ring terminal in exactly the same place. I had apparently been running w/o for a long period of time w/o problems. There are probably a lot of trucks in this condition, but I have not seen any threads about O2 sensor malfunction corrected by re-attachment of exhaust ground strap.
When I extended an aft O2 sensor harness, I noticed they were 4 wire. There are two heater wires, one signal wire, and one signal ground wire. In looking in the manual section ec.pdf I was unable to find any reference to the exhaust ground strap. The troubleshooting for the sensors advises to check the harness ground, but says nothing about the exhaust ground strap.
Nonetheless, I dutifully crimped and soldered a new ring terminal on the end of the strap and re-connected. It doesn't hurt anything and only takes a few minutes. The hose clamp would be fine also, I dunno if rust on the pipe makes any difference or not, but it could be sanded prior to attaching hose clamp.
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But now, what about the real problem? His truck is running rough! No, I don't think the ground has anything to do with that, not with a 4 wire circuit, and propensity of those straps to fail - insignificant. How is the truck running today? Miles on Spark Plugs? MAF? Air Filter?
Wife didn't like how our lawnmower was running this week, so turned it off. No IPDM, MAF or ECU issues, so I checked the Air Filter and found it had gotten soaked with Gasoline. Removed to test and it ran perfect! Picked up new filter, off now to mow.
Wife didn't like how our lawnmower was running this week, so turned it off. No IPDM, MAF or ECU issues, so I checked the Air Filter and found it had gotten soaked with Gasoline. Removed to test and it ran perfect! Picked up new filter, off now to mow.
Hahahaha.....i almost forgot! I had the brakes and rotors replaced last month and it was running great.
I haven't driven it today. Basically the problem for the last week or two is it felt like some hesitation under acceleration with some "hiccups" (best way I can explain it). Louder exhaust under the cab, but no leaks that I can tell. I have a magnaflow dual out bolt on that is loud as it is but sounds more airy instead of throaty if that makes sense. There is also an audible ticking from the passenger side (sounds like it is under the wheel well or passenger side door. It never stops but speeds up with acceleration and slows with deceleration. It is annoying as ****! My SLIP light was on for a day, scanned it and didn't get a code. It has gone off and stayed off. Sometimes it smells bad when first starting if it has been sitting for a long time. I just changed the Air Filter. Haven't cleaned the MAF since I installed the AEM Brute Force a couple years ago. Original spark plugs (65K on the truck now).
I think it could be the cataytic converters (with everything else that has gone wrong with the truck, it wouldn't surprise me). But I know if I take it to the dealer they will cahrge me the $75 diagnostic fee and say nothing is wrong with it.
Suggestions or thoughts are welcome. I can certainly clean the MAF and do minor diagnostics and repairs, but anything other than that, it is going to the shop.
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There was a problem with passenger side ticking that varied with RPM on early model trucks caused by a bad engine block ground. The bad ground related ticking on mine had a more defined, distinct "tick" sound versus my cracked manifold "pfit" sound. The cracked manifold noise was also loudest on cold start and diminished as the manifold heated up.
http://www.titantalk.com/forums/tit...rvice/16678-fix-tick-passenger-side-area.html
http://www.titantalk.com/forums/tit...rvice/16678-fix-tick-passenger-side-area.html
It is definitely a ticking sound that matches rpm: sounds like it could be the engine ground. I will check it out and give it a try. Thanks everyone for all the help.
Shawn
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