Alright gents, I've been having a very odd electrical gremlin that is getting pretty serious.

A few weeks back, I was in a parking lot and rolling very slowly over a speed bump. As the bump passed below the middle of the car, it felt like it hit something underneath; immediately, the motor died, and the coolant temp sensor went to 0. I tried to restart, and the starter was turning her over very fast but she wouldn't go.

We pushed her to an empty parking space and I was about to post a 911 post on the forum asking for help, including codes from the DIC, when my wife tried to start the car and, after a couple seconds of cranking, she started up. The coolant temp sensor bounced between 0 and 200ish and back again for a couple minutes then went back to normal. Car drove fine for a while after that. The codes from the DIC I didn't write down and got lost with the unsaved post, but the funny thing is none seemed relevant; RDCM & LDCM history codes, and that's it.

We went into a touchless car wash later and the exact same symptoms after the undercarriage spray hit the car; coolant temp 0, engine dies, won't restart for about 10 minutes, no codes at all (I had cleared them after prior issue).

So, my wife has been driving it to work for about two weeks with no issues. We drive to dinner tonight, and on the way the car shudders (seemed like the engine stopped firing for just an instant), coolant temp 0, engine still running but something feels odd. I push in the clutch and the motor revs to 2500 and stays there. Release the clutch and sure enough, in 6th gear the car wanted to go past 75MPH with no pressure on the go pedal. Also, at this point the HVAC started blowing only hot hot hot air.

As we continue down the wet freeway the car would shudder and everything was back to normal; shuddered again, back to 2500 RPM "idle" and hot HVAC, with the temp sensor at 0. I tried to pull the codes via the DIC again, but there were none.

We get the car home and just as I pull into the garage the idle dropped from 2500 to 1000 (still high) and the HVAC blower was varying in speed even though it was set to the lowest speed.

I left the car running and tried jumpering from the frame rail to the engine thinking I'd likely lost a ground; no change. Frame to negative battery, no change. Multimeter showed zero resistance or so close it makes no difference between these locations also.

During a prior electrical issue (door harness) I had packed the ground connections behind the headlights with dielectric grease to prevent corrosion; I received a lot of flack on the forum for it saying that it would degrade the connection, so again with the car still running I undid the contacts and sprayed them clean with electrical contact cleaner. Reassembled and no change.

I was just grasping at straws and touched a jumper from the frame rail to the fuel line above the drivers fuel rail cover (braided ss line), and suddenly the idle dropped to 700 or so and my wife reported the coolant temp was reading 218, which is about what I'd expect idling in my garage after a trip. Removed that jumper and everything stayed fine. Shut her off, started her up, revved her up, nothing could change the perfectly fine situation.

Still no codes. None. Please, car, just give me a damn code so I know where to start!!!

Alright, if you've read this book then I'm sure your interested in the ending; so am I. If you'd like to help me move the plot along I'm all ears as to where to troubleshoot from here.

Thanks in advance.

 

Sort of sounds like more than one problem at the same time. First, you need to identify this "wire" that you touched, to us so we can help there. Secondly, the starter not engaging the flywheel is a serious problem. I'm hoping you don't have a broken starter mount as happened to Bill Curlee. You really need to get under there and take a good look at things. I would suspect there is more than just a lose starter there.

 

What jumper?

 

Sorry if this was confusing, but the starter is definitely engaging the flywheel; the motor turns over, she just wasn't starting. I haven't had any trouble with the starter per se, more with a lack of fuel or spark when the car was refusing to start.

The jumper was a piece of wire with two alligator clips on the end that I happened to have in my garage. I clipped one end to the frame rail and the other to bare metal on the engine to see if that additional ground path fixed anything. The instant I touched my jumper wire from the frame to the fuel line everything evened out and stayed that way even with the jumper removed. That being said, I'm not really sure that my jumpering was doing a damned thing; yesterday it just seemed to be doing different things at random.

My wife drove the car to work today (it's her DD and our backup vehicle is..well, out of commission also) and it was fine. I think the car just loves her and hates me.

 

Sounds like you snapped a ground wire somewhere.

 

A code, a code, my kingdom for a code...never thought I'd be begging my car to throw codes at me.

Throw me a friggin code here.

Alright, so lets back up a step. If there were to be something, anything, under the middle of the car that would get jolted by a speed bump passing under, what would it be? I will try and get the car in the air in the next couple days and take a look but it'd be great to have a starting point. Or a code. Damned car.

 

Ground strap has come off/loose. I don't have a schematic on where they are located. Maybe Lucky or Bill will post one.

 

Have you been under the car to inspect?

 

Main battery ground cable, should bolt directly to the engine block.

 

Are you SURE that you seeing ALL the symptoms. Are there aly other gage symptoms. You could have an ignition switch issue and its shutting off and you not seeing it. NO DTCs meand that the car thinks it was shut off normally OR when it glitches, it clears aht ever DTC that you need to see.

Do you have a big clump of keys hanging on your key chain???

There are ONLY TWO engine grounds. G106 (above the starter on the engine block) Just follow the neg battery lead down to the engine. The other eng ground (G-105) is on the drivers side in the exact same place.



BC

 

I am not sure, no. There could easily be other things I'm missing that I just aren't seeing from the driver's seat. I did notice the oil temp gauge was going in and out of failure, and it seemed it was opposite of the coolant gauge; coolant was working sometimes when oil wasn't, oil was and coolant wasn't, and sometimes both worked fine. Never did they both not work though, always one or the other. No, just the car key, house key, and the fob. I'd heard of many keys being a problem after reading on here so after only about a month of owning the car both my wife's and my keychains got trimmed down to 2 keys + fob. I will absolutely try wiggling the ignition switch somewhat to see if that changes anything. For some reason I hadn't even thought of the ignition switch, but it seems like a likely culprit.I will take a look at these engine grounds tonight when the car comes back home from work (hopefully with my wife in it). I won't be able to get under the car to look at things until Sunday though, just not enough time after she gets home to get it up on jackstands and get a thorough look.

 

A bad G105 can be the source of a handfull of probs. BC knows how I know.


Thanks again Bill.

 

Well, I'm pretty sure I found and solved the problem. I was finally able to get under the car tonight, and just took a cursory look around. I wasn't finding anything major until I got to the driver's side engine ground, but it wasn't an issue with the ground:



So, that big black wire goes directly to the driver's side engine ground, and the small green and black wires go to what I believe to be the oil temp sensor (directly above the oil filter). They were, as the picture says, a melted mess. I have no idea how they got that way, but evidently something got very hot right there as even the sleeving was melted and brittle.

I was able to pull the wires apart, and they're now covered in liquid electrical tape to seal them back up. I can't imagine what caused this but hopefully with them separated and insulated I won't have this problem recur.



I also found this on the starter side of the block. Obviously I need to seal that yellow/orange wire near where it lands on the solenoid, but is this splice configuration normal? Looks like fusible links but I want to be sure.



That black spot on the red wire is just that; a black spot. It looks like a cut in the insulation but it isn't. Is the wire that starts pink at the top and turns grey after a splice supposed to be that way also? The grey part of the wire is a much lighter gauge than the pink before the splice.

Thanks for the help folks.

 

You have some serious wire issues!!! That green corrosion on the main cable isnt good if its coming out of the crimped joint on that eyelet

That is a fuse link and it looks like its in poor condition. When the insulation is open, the wire inside will corrode and turn to a GREEN DUST!

At a minimum, I would disassemble all the wires and carefully inspect eash one. Check for corrosion and copper wire damage under the exposed areas.

BC

 

Yeah, those connections are getting cleaned today, and then after reassembly I'll put something on them to prevent that. Damned Washington...if you drive to and from work 5 days a week, 8 out of 10 trips will be at least damp.

 

Welllllllll,,,,,,,,,,,,, If thats the case,, you better be up on your chassie ground cleaning preventive maintenance!!!!!!!! Yours may just look like mine did on my 98 Coupe:

 

Actually, I looked at those when I was having a serial bus failure that you helped me with a few months back; they were clean as a whistle, though I got a lot of flak from Lucky and others for putting dielectric grease on the connector before I reassembled it. I pulled them apart to clean that grease out as part of the troubleshooting for this problem; now I'm thinking about applying it again.

 

Well, I started the car to roll it off the blocks and the friggin thing went nuts again; no coolant temp reading, then there was one, then the motor died, etc etc. So, Bill, I went through your ignition switch test procedure laid out here, and I found I was losing about 0.25 volts at the interior fuses. Doesn't seem like a lot of loss to me; underhood fuses were all reading battery voltage or close enough as makes no difference. At what level should a guy get concerned about voltage drop across the switch?

 

This problem seems to be getting worse. I went for a drive just to see if the problem would recur, and they did; it was again stuttering and the coolant temp swinging wildly, oil temp was reading LOW, and no codes. Then, as I figured it was time to head home, the motor stuttered so badly it felt like the whole car was bucking, 2-3 times, and then it would mellow out for a few seconds, then bucking 2-3 times again. After I got her in the garage I took a short video of the panel as it was being odd. Watch the coolant gauge, especially around 0:50, and the little bump you hear at :54 is the engine stutter (a very minor one in that case, I can't make her buck on command...).



I've checked the main grounds behind the headlights, the grounds to the block, the battery connections, done BC's ignition switch test and I believe it passed, cleaned the wires at the starter solenoid...there has to be SOMETHING causing this? Help me Obi-Wan Kenobi, you're my only hope.

 

Negative, the floor and BCM/fuse area is completely dry. I had my whole upper body crammed in there doing fuse tests earlier today.