Can my XJ really not have a ground from the battery to the engine block? long story..

XJ info: 1999 sport 4.0/AW4/231. So I had this problem yesterday. Keep in mind it rained maybe an 1/8". I swapped my T case Sunday with one that I installed an SYE in. Yesterday I drive to work and all is well. I leave work and as I'm walking up to the Jeep I click the unlock button on my keyless entry(aftermarket not stock) and the lights flash, doors unlock as normal. I get in and turn the key to start but it goes dead and its dead dead, absolutely zero power anywhere no dim lights nothing, black. So next thing I think is OK I must have messed with some wires and maybe my NSS is acting up(I know the rest of the power isnt working, whatever it's worth a shot). I move the t case shifter around and the trans shifter around and voila power comes back starts right up. I drive it exactly one mile to get gas and when I pull up to the pump its idling at about 1500rpms, much higher than a normal cold idle. Knowing better, I shut if off anyway and proceed to fill up with gas. I go to start and its dead again. This time after 30 mins of trying nothing works. I wiggled all the cables under the hood, the wiring in the kick panels, checked fuses and all seems well. I have a friend come jump me and the vehicle acts like a normal dead battery situation, after a few minutes of charging it starts, roughly, then runs and drives. As I'm driving I notice the radio isn't on(also not stock), I push the power button and the vehicle goes dead, at 45mph and its night time, black. So I pull over and jump it again, same thing typical dead battery situation. I drive it about a mile at 45, stereo off, get into another town, speed slows down to 25, idle drops down and it dies. Jump it again, drive 10 miles to the next town keeping the rpms at 1500 minimum, speed slows to 35 let off the gas, dies again. This time im only 2 miles from home, I jump it again put the tranny in 1/2 and drive 20mph at 2000 rpms brake torquing at 2 stoplights until I get home and put it in the garage, it dies again as soon as I let off the gas. So I park it for the night and come back the next day.

I spend the rest of the evening searching for answers. I only find one thread where someone has a situation anywhere close to mine. That thread as well as all other threads I could find were pointing towards a bad ground. I have had two problems prior to this that might also lead to a bad ground. First I have this messed up situation where my passenger front window switch doesnt work but the drivers door switch will control the passenger front window. However occasionally when I try to use the drivers door switch to control the passenger front window but it doesnt control the window, it shuts off the radio. The second problem is; for the last 2 weeks or so the starter has been taking 2-3 times longer than normal to start the engine. Yes its getting colder here in WI but not that cold it has been pretty warm like 40-60's during the day. Naturally when thinking about the slow starter issue I think maybe just maybe the battery or starter is slowly going out. But when this drastic of an event occurs it is hard for me to believe this actually is a battery or starter issue. I have PIAA H4 headlights and an aftermarket stereo system which both draw a lot of power and I have never had a single problem with battery strength. However when I was driving the Jeep at high rpms it would stay running.

So the next morning I go out to start diagnosing and the Jeep has power again WTF!?! I sit inside it for a second thinking what is the deal? I notice the radio isn't on again so I push the power button and everything goes black. So I undo the cables on the battery, reinstall the power, reinstall the ground and it sparks. I look inside and theres power again. OK I definitely have a grounding issue. I start pulling apart all the wires I've touched recently and cleaning them, applying dielectric. I start tracing all the ground wires off the battery and wind up with a ground from the battery to the fender, a ground directly to the alternator and a ground directly to the assembly that powers the distributor. Those three are it and I think nothing of it. Then I start attacking the grounds I found on all my searches here on . Dipstick ground (which goes from the dipstick/block into a wire loom, not to the firewall which, confused me) Valve cover to firewall and PDC, none of which are corroded and are only slightly dirty if dirty at all. I clean all ground bolts, which have the toothed washer things, scrape all metal surfaces down to fresh clean shiny metal, no paint. I reinstall everything and hook the battery back up. I open the door and the dome light comes on, turn the ignition to run and the radio turns on wOOt! I must be getting somewhere. I turn the key and it fires up after barely one turn of the starter, awesome. I continue to trace all the main wires off the battery and clean the connections, alternator, starter and AC compressor, thats it.

I drive the Jeep all day and don't have a single problem. I go back and redo some searches here on as I'm second guessing myself. How could it act, out of nowhere, like a dead battery/bad alternator, and turn into a normally functioning vehicle after cleaning a few grounds that werent even dirty??? I start to notice a trend that involves people saying there should be a ground wire directly from the battery to the engine block. I didn't notice one of these so I go back and check, nothing. I do not have a wire from the battery to the engine block. Is there something about a 99 sport 4.0/aw4/231 that tells me I shouldn't have a ground from the battery to the block? I have seen a few threads saying there might be a ground from the exhaust mani to the frame. I have an aftermarket stainless header and def don't have one of these grounds. I looked all over the engine and can't find any other grounds than I have previously mentioned.

So after that really long story, I have a very very hard time believing my wierd electrical gremlin was solved by cleaning a few grounds that werent corroded and were barely dirty. I don't want this to happen again esp in a sticky situation. I will say after cleaning all these grounds my idle seems to be much steadier and generally it seems to be running better. Could this instead simply be from getting a few good shocks to the battery from a bunch of jump starts in a matter of 2 hours, or was it actually from cleaning the grounds? Should I have a ground from the battery to the block? Could a dying battery or alternator act like this? Does anyone have any other suggestions?

Mike

Myself and many others who have been down this road, or worked on these Jeeps for a living, try to pound this into peoples' heads continually. Many of them ignore us or probably think we're nuts. Ground refreshing is at times free, and at the most costs a few bucks but people like buying new parts I guess. Thank you for your support.

short answer to part of your long question: 99 should have a ground from battery to engine block just beneath the coil.

the "fat" cable off the neg. (-) post of the battery should run to the post that the dipstick mounts to. If it runs to the alternator mounting bracket, you've got a lot more points to clean-- bolt to bracket, bracket to alt, bracket to engine block, etc..

It can work without a direct connection between the battery and the block, but it's far from "the best way" to ground things.

I'm pretty sure my 99 has the original factory cables. On mine, the ground cable has two lines, one to the body (inside fender right near battery) and one to the block just below the coil. There is none to the dipstick tube, and no sign that there ever was one.

I do believe that 97 up stock grounding is post to fender and post to block at the coil mount. There is a flat braid to the firewall at the driver's side rear of the block. I replaced all of my cabling (including the one from the head to the firewall) with 2/0 cables I had made here in town. World of difference...

I also have upgraded my battery cable and grounds in my 00. It made a world of difference, even my lights got brighter!

Grounds are critical and like our health, are one of those things that we take for granted until something is wrong.

They are the cause of many an electrical gremlin and as mentioned, are the reason for many new parts being unnecessarily purchased.

Freshening grounds is NEVER a bad idea.

Though it's apparently not the problem here, I'll throw in my usual mention of that braided line from head to firewall. Here in rust country, that cable tends to deteriorate, but not always visibly. It will turn to powder while still looking all right. Always worth checking carefully.

I don't know how many times I've stated that grounds must be taken off and cleaned, not just inspected and "looks good"

all it takes is a thin film of corrosion to screw them up. Cleaning all the grounds is the first thing I do when confronted with an electrical problem.

Xwhatever. Grounds are somewhat religious, just do it and everything will be better :dunno:

Grounds on the XJ:
* from the firewall to the back driver side of the head (self-destructing braid, as Matthew noted.)
* from the negative battery terminal to the inner fender wall
* from negative battery terminal to the block, just below the coil (as noted. This is where it was on my 96 from the factory.)
* from wiring harness to dipstick mount stud (these are for sensors, ECU, switches, etc. Rather important if you want the engine to run right)
* from the wiring harness to the fender wall, driver side, near the ECU - for a bunch of the HVAC system, dashboard, ECU, transmission control (wtf? no idea why the HVAC/dashboard/TCU stuff is grounded to here, blame Chrysler) this one LOVES to come undone if you have large tires and minimal bumpstopping and bash on it a bit, because your tire will smack the tip of the screw repeatedly till it strips the hole out. Don't ask me how I know :roflmao:
* possibly one somewhere under the dash. Haven't verified this.
* one inside each rear fender in the cargo area for the lights and some other stuff.
* on the MJ, the ground behind one of the taillights also runs the fuel pump. Yeah, WTF?

I am sure there are others I am missing.

kastein said:

Xwhatever. Grounds are somewhat religious, just do it and everything will be better :dunno:

Grounds on the XJ:
* from the firewall to the back driver side of the head (self-destructing braid, as Matthew noted.)
* from the negative battery terminal to the inner fender wall
* from negative battery terminal to the block, just below the coil (as noted. This is where it was on my 96 from the factory.)
* from wiring harness to dipstick mount stud (these are for sensors, ECU, switches, etc. Rather important if you want the engine to run right)
* from the wiring harness to the fender wall, driver side, near the ECU - for a bunch of the HVAC system, dashboard, ECU, transmission control (wtf? no idea why the HVAC/dashboard/TCU stuff is grounded to here, blame Chrysler) this one LOVES to come undone if you have large tires and minimal bumpstopping and bash on it a bit, because your tire will smack the tip of the screw repeatedly till it strips the hole out. Don't ask me how I know :roflmao:
* possibly one somewhere under the dash. Haven't verified this.
* one inside each rear fender in the cargo area for the lights and some other stuff.
* on the MJ, the ground behind one of the taillights also runs the fuel pump. Yeah, WTF?

I am sure there are others I am missing.

Click to expand...

Nice list. Thank you.