Acura TL Engine Grounding for $20





Introduction: Acura TL Engine Grounding for $20

Search popular car performance websites and you'll probably uncover discussions on improving the grounding of a car's engine and associated parts.

There are wild claims about the results from doing this. Some people claims this does nothing. Others claim 5 horsepower and 19 foot pounds of torque. As with most things, the truth is probably in between.

However, there is a degree of logic that the modification can help the car run somewhat "better". Newer cars have a lot of electronics on them - lots of sensors to provide information to the car's ECU. If there's electrical noise in these signals, then the ECU *might* make poor decisions while adjusting things like fuel/air ratios, timing, etc. The ECU is the Engine Control Unit or a "computer" that's dedicated to making your car's engine run correctly.

In theory, improving the grounding reduces the resistance of the electrical path, and makes it more likely that the sensors, etc. will return clean information.

So, for $20 and a little wrench time, it's an easy mod to perform even if you don't really notice much difference in performance.

On my TL, I chose to "daisy-chain" the chassis, alternator, engine, throttle body and battery negative post together. You may decide to add or remove some of these locations.

Step 1: Obtain the Cables

I used four (4), 19" 4 gauge "switch to starter" cables for my grounding kit. I obtained these from Pep Boys for $4.50 each. Less than $20 including tax.

These cables come in a variety of lengths. Nineteen inches was the shortest I found, and forty the longest. These cables have plain terminals on both ends. These cables were only available in the ultra-sexy "Henry Ford" black. Doesn't really matter - you'll pretty much never see them - another reason not to spend lots of bucks for 'primo' cables.

Step 2: Remove Covers

Before you can do anything much on a TL, you need to remove the covers. The left and right covers simply pull off with an upward motion. The engine cover has 3 locks. These locks are rotated about 60 degrees counterclockwise to unlock them. The cover then lifts off.

Step 3: Safety First - Disconnect the Battery

You DO NOT want to short your car battery. Car batteries are capable of delivering hundreds of amps of current. While there is very little danger in being shocked - 12 volts is just not enough to overcome the electrical resistance of human skin - there is a VERY REAL danger of welding your favorite wrench to your car or otherwise damaging the car, tool or battery.

Be smart and disconnect the battery first!' This is another 10mm bolt.

Reminder: If you have a radio or other equipment that uses anti-theft codes, make sure you have them BEFORE disconnecting the battery! This TL has anti-theft codes for the radio and navigation system.

Step 4: Chassis Ground

I started with the chassis ground on the passenger side of the vehicle. If you look at the engine bay near the windshield washer fill, you will find a spot where Acura ran a ground cable from the engine to the body. This ground is secured with a 10mm bolt. Remove the bolt and add one end of one of the cables to the connection. Depending on how big the hole is in your cable terminal, you may want to add a washer to the stack.

Step 5: Alternator Ground

The chassis ground cable is run to the top of the alternator where a lovely bracket awaits an additional purpose in life. Remove this 10mm bolt and insert the 'other' end of the cable you just bolted to the chassis. You will also attach the engine cable here - so you have a stack of two cables you've added to the bracket bolt.

Routing of the cable from the chassis is not too critical, just run it so it doesn't rub hoses and is away from the belt.

Routing of the engine ground cable is "up", that is towards the rear of the engine compartment.

Don't tighten this bolt up yet, you may need to wiggle the cables around some for the best fit.

Add a washer to the stack if needed.

Step 6: Engine Ground

The engine ground cable that you just attached to the alternator is bent at a 90 degree angle to the right and run along bracket, under the coil wires. It easily reached the last bracket bolt on the driver's side of the engine. Again a 10mm bolt and the next cable leading to the throttle body is stacked. You can tighten this bolt up now - nothing much to adjust here.

Once this is in place, go back and tighten up the alternator bolt stack.

Step 7: Throttle Body

The throttle body cable continues its run from the engine toward the driver's side. It's then bend "90ish" degrees to the rear of the engine compartment toward the throttle body. The lower front throttle body bolt (12mm this time) is removed and the throttle body ground cable and final ground cable to the battery is attached. Be careful tightening this up as it is a steel bolt threaded into the aluminum manifold - no need to strip this out!

Again, route the cables sensibly and neatly!

Step 8: Battery Ground - the Final Link

The final link in the daisy chain is from the throttle body to the battery negative terminal. I removed the nut from the cable clamp and added the final cable terminal plus a washer (battery nut is fairly small). Once assembled but not tightened, put the battery terminal back on the battery (it will probably spark a little, don't freak) and tighten the assembly up. Again, run the cable neatly. The OEM battery ground cable runs about 6" to the chassis off the driver's side of the battery.

Step 9: Replace Covers and Crank Her Up!

Replace the covers and you're done. Crank up the car, enter your radio codes and any others and take it for a spin to enjoy... well, who knows what. If you think you get a real boost from this mod, I'd love to hear about it in the comments.





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    21 Discussions

    I did this on my 02 accord with some knukonceptz 1/0 wire

    Great idea, just the reassurance I needed for my problematic alternator and battery. I will "mod" it slightly and connect one cable directly to the alternators armature.
    Your mod should improve the current flow and possibly extend the life of BOTH alternator and battery, and that is priceless! Thanks

    Looks like you just double grounded most of the components. If you were to get the wiring diagrams for you vehicle, there are usually a page or two dedicated to grounds. By referencing the grounds and grounding sensors that are only grounded by a chassis connection aka not by a wire, I think you would have accomplished more. By grounding things just by assuming, your probably just wasting your time. Not only that you can sometimes introduce more problem than doing good.

    Thanks for the write-up.  I just joined and went through the posts.  I guess some just don't get the point.  When you've replaced 5 PCMs on a Ford F-250, an article like this really clarifies the problem with grounding and what an educated owner needs to do.  Thanks again.

    1 reply


    Really a properly designed and constructed vehicle *shouldn't* need or benefit from additional grounding.  However, you can start a "holy war" over the subject.

    My effort was to demonstrate how to perform additional grounding without spending an absurd amount of money.  Of course people still buy Monster Cables for their sound systems too ;-)  If you got the bucks, then more power to you!

    Hope your 250 benefits ;-)


    Yeah, some people pull the covers to keep engine heat down.  Does tend to keep things clean though.

    Good point made.  Grounds are often the source of trouble for many ailments.  By the looks of your vehicle, you live in a salt free area.  It would be good to note that if you live in a salty, wet area you should check and clean ground straps once a year.  They seem to corrode very quickly and can cause all sorts of problems.

    1 reply

    Thanks.  Yeah I live in Florida - no road salt here ;-)

    Awesome, thank you so much for this write up. I did this on my 2006 TL and have noticed steadier voltage, slightly better starting, and crisper sound. Although it could all be in my head.Once fact is true, I have gain 0.1V. Either way it looks cool for shows and was fun installing.

    I went to NAPA since it was in my neighborhood, and I paid more like $60. My fault, too lazy to drive further to Pep Boys. I did the mod, and am ecstatic about the performance, maybe it's in my head, but the car definitely feels faster, and if I could stop racing it from every dead stop, I'd be able to check the mileage. In my mind that will be the best objective test. The steps are amazingly well documented (thanks TL Ground man!!), and I recommend anybody with a TL do it. I feel it can make the car last longer also. A couple of "lessons learned" doing it; 1. The first nut is in an odd angle, and small, need to have the right tool to break this one loose. 2. I had to make a couple of slits in the battery cover panel for the new ground wire. TL Ground man's photo shows it like I did it, but had to make the slits with a box cutter. 3. Careful when turning the 3 nuts on the engine cover shroud. I "tightened" vs. half turned them, and I broke 2 of the 3. The dealer gave me the little plastic females, so all set. If you are thinking of doing this mod, I say DO IT! -DD

    1 reply

    So, to help me understand. What you are doing is isolating the alternator, engine, throttle body from the rest of the car's electrical system? Also, if that is true, you are really not grounding them, only isolating. To ground means that everything has the same reference for a return path.

    1 reply

    No, they are not isolated. The grounding kit parallels the existing ground and in theory would be a preferred path due to lower resistance. The new cables act more like a buss bar for the DC negative pole ("ground" in modern cars) of the battery. Make sense?

    i don't think you'll ever make up the $20... the weight of the cables might actually just cost you a $1 in gas over the car's lifetime /: there's already enough excess electrons built up in your engine block, they have no problem going through the spark plug and back to the battery. cleaning your spark plugs off would do more.

    3 replies

    It could save you gas as well though. Better grounding means a better curret which means slightly less strain on the alternator. It also puts less strain on the original grounding cables. FIAT's have terrible grounding, this would help them out.

    Ummm, pretty much everyone suggesting this mod does it for performance, not fuel savings. I'm certainly not concerned about recovering my $20.