Well here’s my two cents. If you’re seeing that nut heat up more than anything else, it is heating up because there’s resistance in the connection (loose or corroded) and it is limiting the current flow. That’s what creates heat. current flows on the outside of the wire. It doesn’t flow through the center of the wire and when you Solder all the wires together you make potentially a better electrical connection if the Solder flows between the surface of the wire and the surface of the lug that’s joining and you get good wetting. Problem with solder is that it likes to melt when it gets hot. and it likes to crack when it’s under vibration or stress. So that’s why you don’t see soldered connections much in wiring harnesses on cars. A good solid crimp that pushes all the air out of the available space in the forms to copper to mesh to the lug perfectly is your best connection believe it or not.

Now here’s where I’ve got some confusion. Yes that cable is getting hot while you are driving, Current is flowing through that cable and there’s a lot of it and that’s why it’s getting hot. But why is there a lot of current flowing to or from the battery while you’re driving? The battery should provide A hefty bit of current to turn the car over to get it running but after it’s running the alternator should be putting out sufficient current to not only run the car but also all it’s accessories and lights and everything else as well as charge the battery. Now I can see a large flow of current when you first start the car is the current turns the starter over, and then for a short time afterwards in the reverse direction as the alternator recharges the battery but then there should not be much or any current flow between the two after running a good long while as the battery should be charged and not demanding any current.

So your options here is that you have a horrible battery That’s sucking power like it’s going out of style. Or you have crappy output from your alternator so everything’s running off your battery. Or you hsve really crappy connections limiting the current. Or a combination of all three. you could have crappy output from your alternator so everything‘s running off your battery. Or maybe it looses power after it gets hot?

So the question is which one is the current flowing at the time of the misfires. Is it flowing into the battery charging it as it should be? Remember it really shouldn’t be charging at that high of a rate if you’ve been driving for a while unless you’ve got a bad battery or poor connections. Maybe the alternator goes whompy and its output drop so current is the flowing out of the battery to run the car which would suggest your alternator is bad.

 

Aarcuda, current flows through the whole wire with the exception of high frequency signals (ie, 100 Mhz and up type stuff). This is called the skinning effect. For stuff in a car, that is not much of an issue.

As for current flow to/from the battery when the engine is running, there is some because the alternator puts out a pulsating DC (stems from the fact that the alternator is truely an AC generator that has the output on half of the signal reversed to make everything positive). This pulsating voltage causes the battery to attempt to fill in the gaps when the voltage drops below the battery voltage and when it goes above the battery voltage, the battery will suck in that power to restore itself. This is why running a modern day car on a weak battery is a problem. When the voltage drops, hte battery doesn't output enough voltage and the voltage in the car starts moving around too much. This confuses the computers (they need a rock solid voltage) and therefore, they will start seeing "problems" (not that they really exist, but what they are referencing is moving around, making it seem like the parameter is moving).

 

Just for clarification, the high temperatures I measured on the positive battery cable were at idle in the driveway to see if I had a bad battery cable. That may or may not be related to this car misfiring all the time when it warms up. I think it is related because changing the cable got me from running for 10 -15 minutes before misfiring to today when I can go 30 or even 45 minutes before it misfires.

I have to assume the battery connections are good on the car, it has new cables from battery positive to starter, alternator, and fuse box. When I changed the cables I wire brushed or sanded all the connection points. I also pulled and cleaned the main ground to the body and cleaned up a few other ground connections that I could see.

I could see the battery being toast since it was running with that bad cable and the positive terminal was cooking for who knows how long. But in my experience batteries go bad when they are cold and not when they warm up. I think I will run a volt meter to the battery and see if the voltage gets wonky when the misfires start.

 

I should probably start a new thread but I'll try adding on here. Misfires on cylinder 2 or 4, I forget at this point because it has been so many problems ago. I swapped coils with another cylinder and the ECU reported the problem stayed with the coil not the particular cylinder. Replaced the coil. Problem solved for a few hundred miles. Then misfire problem reappears as loss of power and CEL telling me misfires on cylinder 1. I take the intake manifold off and replace coils on cylinders 1, 3, and 5 so I don't have to take the intake manifold off again. Spark plugs are all under 5,000 miles old, all six plugs are clean and dry, no oil pooling in the spark plug wells. Car now drives 15 minutes before it starts misfiring and leaves me stranded with the code for misfire on cylinder 3.

I try the route of bad battery cable here in this thread. After replacing positive battery cable to fuse box and positive to starter and alternator I can drive 30 minutes before the engine misfires so badly I lose so much power I can't drive. I get general misfires (code P0300, P1313, P1316). Towed home at $200 for the 2nd time in the last 100 miles driven. Not good.

Just before loss of power I get warning lights for ABS and for air bags, then the engine starts running rough and I suddenly get the misfire codes (P0300, P0303, P1313, P1316,... again). Seems electrical to me.

I left the car alone for a week and then tried again. Car runs like crap from the moment it starts, but it keeps running. After it warms up I realize the upper radiator hose on the passenger side is collapsed. After 3 or 4 more minutes the upper hose on the driver's side is collapsed. I let the engine cool off for 5 minutes and the upper driver's side hose looks much better but the upper passenger side hose is still collapsed.

After the engine is off for an hour the radiator hoses look fine. I run the car at idle for 10 or 12 minutes and the radiator hoses are some how sucked flat again. When I turn off the engine and wait an hour the hoses are fine.

So I am somehow pulling a vacuum inside the coolant lines? The hoses are fine when the engine is cold but are collapsed when the engine is running and warm...

I keep thinking I found "the" problem only to realize I found "a" problem. Is whatever causing the collapsed coolant lines related to random misfires and complete lack of power??

 

hey, the collapsed hose is probably from a bad radiator cap.

 

Thanks, I did read about the bad/sticking reservoir caps so I ordered a new one. Just wondering what that problem with the cap does ultimately... could it in any way be related to all my misfire problems??

 

dh53, atleast for the moment, try removing the radiator cap and then running the engine. This will remove any effect from cap potentially drawing a vacuum on the system. Granted, I find what you are experiencing rather interesting as normally the hoses should balloon because the coolant system builds up pressure, not draws a vacuum (hot gases expanding, water expanding as it gets warm, etc). As for it being related to the misfires, I am not thinking so unless you are also seeing an overheating issue (ie, temp gauge reading high). Letting the car idle with the radiator cap off should allow the coolant system to remain at normal pressure and if the hoses collapse now, then we know those hoses are seeing a vacuum created by the water pump. I would need to research which hoses are on the output of the water pump and which are on the suction of the water pump. From what you are describing, my mind is going towards a blockage somewhere. But, I don't want to run down that rabbit hole quite yet as it is just a feeling that I have.

 

Chris,
Appreciate your help very much. I ran the car 15 minutes with the radiator/reservoir cap off. The radiator hoses are fine under that condition, they do not collapse. As you know it was quite cold here in Maryland today so not the same conditions I have had problems with recently but I did run the car until I could see steam from the open reservoir. While it was warming up I squeezed all the hoses hoping to burp the system but didn't get any air out.

Temp gauge is normal. Through all of my misfire problems the temperature gauge has never shown a problem.

New reservoir cap will be here tomorrow, will give that a shot.

I borrowed a thermal camera and the recirc lines to the reservoir look really hot after just a few minutes. On the left side of this picture but also the bright orange (meaning hot) line you can see by the strut tower. I don't know what normal is so maybe this is fine? Just seems really hot for only a few minutes of the engine running. Over 100F on a 35 F day.

 

dh53, thatis what I would expect. You have a small amount of coolant flowing from a high spot in the engine, straight to the overflow bottle. This is what allows the engine to self vent. This is an interesting problem. I need to look at how the coolant system flows to see if I can figure anything out.

 

Previously the car was misfiring after 15 or more minutes of driving, when everything gets hot. Today I cleared the codes, started the car and pulled out of the driveway...boom...misfiring badly and flashing check engine light, codes P0303, P1313. Total travel distance of about 100 feet before it failed now. Tomorrow the intake manifold comes off for the 3rd time in the last few weeks, see if I can spot anything. At a minimum swap coils.

Edit to add: new reservoir cap was not on, but obviously not related since the engine wasn't even warm yet.

 

May well be a bad coil and if it is you'll see nothing of any help.

Well worth checking wiring, for water, etc. Also, maybe swap the coil with another & see if the fault moves.

 

Pulled the upper intake manifold and checked plugs and coils. Again, all spark plugs replaced with new parts within the last thousand miles. All rear coils (cyl 1, 3, 5) replaced in the last 100 miles.

Getting misfiring on cylinder 3. Swap coil and plug between cylinder 3 and cylinder 2, still get misfires on cylinder 3. Take upper intake off for the 10th time in weeks and realize the green wire to the coil on cylinder 3 is missing some insulation. The wire looks corroded but OK and it is not in contact with anything it can ground out on but I cut out the suspect 1/4" of wire and twist and solder in a new piece of wire and cover with heat shrink.

Put everything back together and...P0303 !!! Still misfiring on cylinder 3.

Cylinder 3 has new coil, new spark plug, new wiring on the 1 suspect pin.... where else do I go to try and find why cylinder 3 is misfiring??