Engine misfire? I've been getting the P0301 code?

I have turn the key on and off three times and it is giving me code 1684 can you please let me know what is it , i have little cash and cannot afford to take it to a shop
Thanks

For Chrysler products, P1684 means the battery to the pcm(powertrain control module)has been disconnected within the last 50 start cycles. A cycle is when you start the van, run it, and then shut it.

Was the battery disconnected at any point?

yes the battery was disconnected because i had to change the starter

Is the miss constant?

The van is not missing constantly only when you go over 100 km\hr and i notice that there is steam coming from the radiator cap i change it but it still happening, the gauge is reading normal ,cooling fan is working any suggestion , I kindly appreciate all you help you is giving me because of my financial situation
Once again thank you

Chances are where the overflow tube connects to the radiator may have cracked. Listen, they make a pump that will pressurize the system so you can check for leaks. You may want to try that. Also, you can get a dye to put into the radiator. Drive it from a couple days and check for a leak using a black light. THe dye will glow and you can trace where it is coming from.

I hate to say it, but the tanks they use on the radiators today are plastic. Over time they either crack or where they are crimped together they get loose and come apart. Try one of the methods I mentioned. Let me know where the leak is coming from so I can help you decide if it is repairable or if it needs replaced.

I look forward to hearing from you.

Joe

3.3l engine is misfiring on multiple cylinders. Getting what seems like a weak spark on 1, 3, and 6. get little white sparks only when keeping the wire really close to the spark plug. on other cylinders the spark is arcs quite strong, blue and orange in color. I have changed coil and wires, spark plug look good but reguaged and reinstalled. I can hear injectors clicking using stethoscope. There are no engine codes. Not sure what do to next.

Correction to the message posted. On 2 4 and 5, the spark is bright white and arc goes circularly when holding the wire close to the spark plug

check to see if the boots are cracked or broken as it goes circularly. then check cransk sensor for resistance and connection. check fuses under hood as well.

I changed the wires and was getting the same result so I am thinking boots are ok but will double check again.

what resistance should I see on crank sensor, and are there any particular fuses I should be checking.\

just ecm ign fuse s if there are any. and we have no figures on crank sensor. are you sure you aren' teven getting a P0300 code auto parts do that fro free. also check for vacuum hoses off or any grommet on valve covers or air duct leaks.

I have a 2001 Dodge Caravan with 4 Cylinder 2.4 Liter Motor. I have had a misfire for over 7 months. The code Im getting is P0304 Misfire Cylinder #4. I have Replaced: Coil Pack, plugs, wires, injectors, egr valve, injector wiring harness, fuel rail. Still have the misfire. I have spark in the coil, plugs and wires so I think that it is safe to rule out ignition. I checked the compression and I have 180Psi in all 4 cylinders, so I think it is safe to rule out compression or internal damage. Im thinking maybe the injectors arent getting power, maybe the harness is bad? Im gonna pick up a noid light and check the power to the injectors. Until then, does anyone have any tips or suggestions on what to try next?
My van runs extremely rough and I get bad gas mileage.

If engine running rough check if coil firing cylinder #4 and noid light should also check if PCM pulsing the cylinder too
Wiring harness and or PCM maybe the cause of it

100% no cylinder misfire codes. Drove 30 miles hoping it would set some code but it didn't. It had set a large evap leak code a few months ago but the car ran fine and after resetting that code, it hasn't come back since. The misfire started couple of months after that.

when I say arcs are going circular, its not when boots are on the plug (that would be cracked boots), its when I removed the boots and held close to the spark plug to see if I was getting spark (others might hold it close to the engine block), and that's when on the 3 cylinders spark flew arcing across the engine bore around the plugs in a circular motion. On the other three cylinders the arcs are really small flying from wire to the tip of the spark plug.

anyway checking your recommendations now

JMac101, I am interested in the final outcome of your situation with the misfire in you 2001. I have a 2000 with 115,000 miles and am having the exact problems. I am afraid it is the pcm.

there is a fuse labeld ign which is good.

if there are no figures for crankshaft resistance then how do I know if my readings are for good or bad sensor.

check against a new one at auto parts. I don't know if I said or not but check for a vacuum leak as well with choke cleaner and look for hoses rotted split holes etc.

you had mentioned vacuum leak and I don't see any. why would vacuum leak cause unevevn spark. I can understand erratic idling but not weak spark

misfires are extremely hard to diagnose even for a pro so you have to eleimnate everything first. because to a pro it may seem ok about the spark you are talking about.

thanks. would large evap leak code that I mentioned before might be causing this even though it hasn't come back again

yes I have no further suggestions without doing tests myself.

the coil you replaced with, was it a dealer coil, or aftermarket??? ive seen new coils that were bad out of the box.... your complaint is weak spark on some, good on others.... verify its good out of coil 1st... take a known good wire, and connect an inline spark tester (one that u can adjust the gap on) so u can check for a healthy blue spark.... if still no good spark, we will need to further diag.

ive been stewing on this for a while.... you said you drove it for a while, and still no check engine light??? if you dont have spark, it would set a flashing CEL for whatever cylinder is misfiring (it flashes because its performing damage) the firing order on this, are you certain its correct??? you may have crossed wires, so it runs, but wont set a misfire code....

Thank you for the follow up madmike1735.

I had replaced the original coil pack with an aftermarket couple of years ago as a "routine maintenance". The original coil was working fine so I had kept it as spare. When misfire started, I first swaped with the original coil that I had kept and then got another brand new one. Both swaps didn't fix the problem.

Regarding spark check, I used an inline spark tester that flashes and things looked ok. I then decided to do an alternate check by pulling the wires and holding them close to the spark plug tip. My plugs sit between exhaust manifold and what I noticed was that bright white sparks arced to the manifold in a circulation on each fire on cylinder 2 4 and 5. On the other three cylinders I saw small bright white arc going between wire and spark plug tip. When I turned the a/c on (this is when misfire is most obvious) and reved the engine, sparks on 1 and 6 disappeared. I didn't check 3, but I think its safe to say that it lost the spark. as well.

I have checked and rechecked for cross wiring. My wires and coil have numbers on them so its difficult to make mistake.

I was considering replacing crankshaft position sensor but something tells me that's not the problem. Mostly when crank sensor fails, there is no spark on all cylinders.

The van shudders badly over 40; you can't drive the thing so I am baffled why its not setting at least some code.

yea, the crank sensor will cause a loss of spark to all cylinders.... an inline spark tester will give false readings- as you found out by checking for a healthy spark by pulling wires, and checking for the spark to jump.... im confused as all hell on this... your coil takes voltage it recieves, and through "coiling" very fine wire inside, it amplifies your voltage, and thats why you get a good spark... its increasing for example a 12v signal, but multiplies it to an output of maybe 20,000 volts.... (some cars go up to 60,000 volts) what bothers me, is your coil is giving the symptom of not working.... its getting a signal to it, but not multiplying it for say, and is giving a lousy spark on 1,3, and 5 cylinders.... is this making sense???

It makes sense but I don't know where to go from here and what to eliminate besides throwing parts.

id hate to see you waste money, and time also.... but the evidence here is pointing towards the coil.... i hate aftermarket coils (been burned by them-new out of box, and no good) i would buy a new coil from the dealer.... i know its not the answer your looking for, but we need to eliminate it.... i understand you have the one that came out... but coils do break down over time.... start with a new one... or if you know anybody with the same vehicle- see if you can borrow their coil just to verify it will correct the problem.... coils are most common, and my gut is saying go with it....

Wanted to post the find for others. The coil wasn't the problem. In the end, it turned out to be a bad spark plug. Still don't know why no misfire code was being set but then I am no expert on how the computer system works.

Thanks Madmike1735 for trying.

im very glad you found the problem!! give your self a pat on the back, you earned it! wierd a single plug caused this.... usually it will set a misfire code fast.... without access to a good scan tool, we couldnt have told you to gain access to Mode $6.... this is the easiest way to verify a misfire in a cylinder.... however these scan tools cost atleast 2500$ (thats what i paid for my OTC genisys)

My van has been misfiring randomly for a while now. I have changed the EGR valve, crank sensor, oil pressure sensor, gaskets (intake and valve covers), coil, wires, spark plugs, oil and oil filter. It idled real bad until I changed the PCV valve then it ran perfect for about fifty miles and all the sudden the oil light came on, engine light came on and the engine shut off. That is when I changed the oil pressure sensor and I was able to turn the engine over. But not it is misfiring very badly and once put into drive it shut off once given gas.
Does anyone have a solution?

The first thing and easiest to do is check trouble codes to see if there is something that is related to the misfire. If it is missing, you will have those codes. However, see of there are others that may be leading to the problem.

I have checked the codes multiple time. I only receive the generic code P-03000 Cylinders 1-10. I only have six cylinders and it shows up 1-6 times. It never gives me a cylinder exactly.
The van sat for four years but was turned over regularly to keep fluids flowing and the battery normal.
Does anyone think I could have a clog in my fuel system (even though I am getting fuel but most of it is being spit out of the tail pipe unburned due to misfire)?
It rough idles now in park or neutral but in gear it stalls nearly moments after shifted into gear or reverse.
Also, I have an inkling that it might be internal. Can anyone confirm my ideas?

It could be several things. The coolant temp sensor could even be playing a role in the problem. If the sensor malfunctions and tells the computer that it is extremely cold, the computer compensates by making the fuel mixture richer. With your scanner, check to see what the sensor is reading. NOTE: If it is reading an extremely cold temp, it will not set a code because the computer things it is working.

Next, check to make sure the fuel pressure regulator is working properly. If there is too much pressure, that can cause issues. Finally, when you say internal problems, I think of a compression issue. If it is too low, it won't fire the cylinder or create a misfire.

Thank you for that. I didn’t think to check the coolant sensor. That does make sense it would burn richer if it was thinking it was colder. I also am going to do a compression test on the motor to see if it is an internal issue because I think there might be a spring broken or a rod bent maybe. Also I’m gonna check the fuel pump as well as the oil pump. It seemed odd the oil pressure light turned on moments before the motor died. I’m also in the process of replacing most if not all sensors sense I found a lot of corrosion and brittleness to a lot of the sensors. I am in Las Vegas so the heat could have just eroded the sensors sitting in the desert sun for 4 yrs.
I will post an update once I have completed said obstacles.
Thank you again.

Update: so it turns out it was the very first thing I thought it was. My ECU fried out. Ordered a new one and placed it in and the van started up and now drives like new. Thanks you for the advice and support.

Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help

Cheers, Ken