Engine misfiring bad?

Tiny
COURTNEYW
  • MEMBER
  • 2000 DODGE CARAVAN
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 10,400 MILES
Diagnostic test says cylinder 2 is misfiring need to know what to do?
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Monday, July 28th, 2008 AT 3:01 PM

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Tiny
DOCFIXIT
  • MECHANIC
  • 18,828 POSTS
Could be plug, wire or fuel injector. Is the miss constant or intermittent?

This guide can help us fix it

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Please run down this guide and report back.
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Monday, July 28th, 2008 AT 3:33 PM
Tiny
2CP-ARCHIVES
  • MEMBER
  • 4,544 POSTS
  • 1999 DODGE CARAVAN
  • 140,000 MILES
I have done a tune up from the rotar to the plugs. I have a miss in #4 and #5. I also have white steam coming from the exhaust. With a smell I cant describe. But the tricky part is im not losing any coolant. I have been chasing this problem for weeks and I am stumped. Please help. Also there is enough condensation from the exhaust it will run down the drive way.
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Monday, July 27th, 2020 AT 9:48 AM (Merged)
Tiny
FREEMBA
  • MECHANIC
  • 1,152 POSTS
Before goiing through too much trouble, double check your spark plug wires to be sure they are on the proper terminal on the distributor cap. I have attached a picture of the diagram for the spark plugs. (Not sure which engine you have--let me know if your engine isn't on the diagram)

If the spark plugs wires are correct then it sounds like a blown head gasket. Have a compression check done on those two cylinder (all cylinders actually). You can sometimes rent a compression gauge from a local auto part store. (They will fully refund you money when you return the tool).

If possible, have a shop to do a cylinder leakage test on those cylinders if the compression test shows low compression. This test forces compressed air into the cylinder. In your case if the air comes out of the ajacent cylinder, it would indicate a blown head gasket, warped or cracked head.
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Monday, July 27th, 2020 AT 9:48 AM (Merged)
Tiny
GODIAM
  • MEMBER
  • 1 POST
  • 1999 DODGE CARAVAN
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 163,800 MILES
My caravan has a slight miss when sitting at a idle and when on the highway. I changed out the plugs, wires, coil, fuel filter, pcv, airfilter and it keeps kicking on the service engine soon light so I hooked up my obd2 reader and it says that cylinder one is missfiring still my local mech shop told me to take it into dodge but I figured id ask you guys before I go spend hundreds at dodge for something that might be small that I missed? The battery was getting weak so I put a new one in and thats when the miss started but I couldnt see that making a difference but maybe?
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Monday, July 27th, 2020 AT 9:48 AM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
My obd2 reader and it says that cylinder one is missfiring : equates to P0301

Check the spark plug, fuel injector and compression for cyl no. 1

Misfires can be caused by worn or fouled spark plugs, a weak spark (weak coil, bad spark plug wire), loss of compression, vacuum leaks, anything that causes an unusually lean fuel mixture (lean misfire), an EGR valve that is stuck open, dirty fuel injectors, low fuel pressure, or even bad fuel.
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Monday, July 27th, 2020 AT 9:48 AM (Merged)
Tiny
JNOVACK
  • MECHANIC
  • 723 POSTS
Sounds like #1 wire is bad but do the following test


https://www.2carpros.com/forum/automotive_pictures/52960_misfire_2.jpg

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Monday, July 27th, 2020 AT 9:48 AM (Merged)
Tiny
DALEEN
  • MEMBER
  • 1 POST
  • 1999 DODGE CARAVAN
Engine Mechanical problem
1999 Dodge Caravan 4 cyl Two Wheel Drive Automatic

miss firing on 4th cylinder changed wires and plugs
put new coil box what else could the problem be could it be somrthing serious?
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Monday, July 27th, 2020 AT 9:48 AM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,938 POSTS
Hi there,

best check compression next, also injection pulse and injector, also check for a vacuum leak around the manifold near that cylinder, start here.

Mark (mhpautos)
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Monday, July 27th, 2020 AT 9:48 AM (Merged)
Tiny
DNSTILKE
  • MEMBER
  • 3 POSTS
  • 1998 DODGE CARAVAN
My 98 Dodge Grand Caravan has been acting up, missing and back firing. I took it in and had it put on a computer, the results came back misfire on #3 cylinder. So I changed all the spark plugs and plug wires. The problem was not fixed. My brother in law said that the same thing happened to his parents van and it was something in the computer sending the wrong signals to the engine. Any ideas?
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Monday, July 27th, 2020 AT 9:48 AM (Merged)
Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
More likely a bad injector. First do compression test to be sure it is ok. Then, since the plugs are new, remove #3 and any other and compare the color. Does that engine have just one coil?
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Monday, July 27th, 2020 AT 9:48 AM (Merged)
Tiny
DNSTILKE
  • MEMBER
  • 3 POSTS
To be honest I am not sure how many coils there are. The engine is a 3.8L if that is any help. The #3 spark plug is the back middle one and they are impossible to get to without having to remove part of the engine so taking it out is not really an option.
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Monday, July 27th, 2020 AT 9:48 AM (Merged)
Tiny
2CARPRO JACK
  • MECHANIC
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If you arent willing to remove the plug and check it, then im not sure how much help I can be to you. You wouldnt believe some of the things that have to be done to get access to areas, but it helps make a more accurate diagnosis.
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Monday, July 27th, 2020 AT 9:48 AM (Merged)
Tiny
DNSTILKE
  • MEMBER
  • 3 POSTS
I guess if that is the only way, I will look into having it done. The thing is I just paid someone (a professional) to put the spark plugs in a week ago. I had to problem before and after the plugs and wires were replaced. And it has only been a week since I did that.
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Monday, July 27th, 2020 AT 9:48 AM (Merged)
Tiny
RUSTYFORD
  • MEMBER
  • 14 POSTS
  • 1998 DODGE CARAVAN
Engine Performance problem
1998 Dodge Caravan 6 cyl Front Wheel Drive Automatic

Keep getting random cylinder misfire codes. It is burning some oil. Since the bottom end was done.I beleive I need valve seals done. If these were real bad. Would it cause the misfire codes? Or should I look else where?
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Monday, July 27th, 2020 AT 9:48 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,005 POSTS
When was the last tune up?
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Monday, July 27th, 2020 AT 9:48 AM (Merged)
Tiny
DENNIS MCLINN
  • MEMBER
  • 1 POST
Your main power wire has a bad connection on the dash cluster, you can google the repair. Fixed mine in a afternoon.
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Monday, July 27th, 2020 AT 9:48 AM (Merged)
Tiny
RUSTYFORD
  • MEMBER
  • 14 POSTS
Tuned up 6 months ago.I do beleive I might have my answer. It also has a high pitch sqeal.I now suspect the belt tensioner. Could it be that easy?
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Monday, July 27th, 2020 AT 9:48 AM (Merged)
Tiny
CARADIODOC
  • MECHANIC
  • 33,699 POSTS
If I may add a few tidbits of information, forget the injectors. Chrysler buys their injectors from Bosch in flow-matched sets, and has extremely little trouble with them. Since 1990, I've read about one bad one. If you were to suspect a bad injector or spark plug, swap that one with one from a different cylinder. Erase the fault code, then see if a code sets for the cylinder you moved the suspect part to.

When you have a running problem, you need to list the engine size right away. There can be four or five, and some of them have wildly different ignition systems from the others. You also need to list the mileage and transmission type. We make generalizations based on that when deciding the order of things to check. It's not fair to make us guess, or to waste time dragging that top secret information out.

You're right that number 3 is the rear, center cylinder. It is easy to get to from underneath when the van is on a hoist. If you try to do it from the top, the long black bucket holding the wiper system can be removed to improve access.

The 3.8L uses three ignition coils in a coil pack, or assembly. The easiest is to get a good used one from a salvage yard to try as a test. While it's not real common, a partially-shorted coil can fail to develop sufficient voltage to fire the pair of spark plugs under all conditions. What you hear as a backfire could be the unburned fuel from a misfire going into the exhaust system where it fires and creates the sound of a backfire.

A deteriorated spark plug wire can cause the same symptom as a weak coil. A better suspect is a failing crankshaft position sensor or one that was installed improperly without the spacer needed to set its critical air gap. If the history of that sensor is unknown, your mechanic can use a scanner with graphing capabilities to record the sensor's signal while the problem occurs. If you see the signal pulses drop out completely, intermittently, suspect the sensor is failing. If you see the signal voltage drop just a little, but it's enough for the computer to be unable to read it, resulting in a momentary misfire, suspect the air gap is too big.

You don't have to run to your mechanic to have diagnostic fault codes read. Chrysler makes doing that yourself much easier than any other manufacturer. Cycle the ignition switch from "off" to "run" three times within five seconds, without cranking the engine, leave it in "run", then watch the code numbers appear in the odometer display. You may only get a code indicating which cylinder is misfiring, but if you're lucky, one will set related to the crankshaft position sensor. Remember that fault codes never say to replace a part or that one is bad. They only indicate the circuit or system that needs further diagnosis, or the unacceptable operating condition. When a part is referenced in a fault code, it is actually the cause of that code about half of the time. First we rule out wiring and connector terminal problems, and mechanical problems associated with that system.

Also be aware a lot of people, including some mechanics, still believe there is no fault code to be read if the Check Engine light isn't on. That is absolutely not true. There can be over 2,000 potential problems detected. About half of them refer to something that could adversely affect emissions. Those are the codes that turn on the Check Engine light. A fault code related to a crankshaft position sensor or camshaft position sensor will usually not turn on the Check Engine light. That is because with a totally-failed sensor, the engine won't run, and a non-running engine can't create excessive emissions.
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Monday, July 27th, 2020 AT 9:48 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,005 POSTS
No, a tensioner won't cause that. As far as the oil burning, when valve seals are bad, usually you will get blue smoke when you first start it and wide open. Is that what is happening?

As far as the noise, the tensionier could cause it. Remove the belt and start the car to see if the sound is gone. Only let it run a few seconds, just long enough to see if the sound is gone.

Let me know what you find.
Joe
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Monday, July 27th, 2020 AT 9:49 AM (Merged)
Tiny
RUSTYFORD
  • MEMBER
  • 14 POSTS
Hi Joe:
Turned out dis. Cap was cracked. Tensioner bearing was shot. Thanks for the advice. Rusty
P.S. As to the last question, yes its blue smoke on start-up only. Thanks, again
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Monday, July 27th, 2020 AT 9:49 AM (Merged)

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