2000 Dodge Grand Caravan backfires, Help Please

Rob Hartman · Jun 14, 2010

I need some help. I have a 2000 Dodge Grand Caravan w/ 3.8 engine. I have replaced: coil pack, plugs, wires, crank sensor, cam sensor, fuel pump, fuel filter, and air filter. When you go to start it up it pop,pop,pops then starts. It stumbles and coughs when you go to pass or get after it. It gets really bad gas milage if you don't run premium fuel in it. I've sprayed carb cleaner around the intake with no results, I check the timing chain be taking the front valve cover off and turning the engine back and forth, doesn't seem to be any slack. I did notice there was some oil on the cam sensor but I think there is sappose to be. I've also taken off the cat. converter and put new manifolds on it. The check engine light is on and the only code it throws is crank or cam sensor interminent siginal. Any suggestions?? Help would really be appreciated as I have put $1200 in this van and I haven't got it to run right yet. Thank you in advance.

Kevin2 · Jun 14, 2010

All I can say is I had a '96 T&C 3.8 and it developed a backfire and would die, even going down the hiway. Had to walk once. After 30 minutes it might start up and be good for a week or more. Local yokel could not figure it out. Plugs, wires, fuel pump, filter. Still died. Took it to the Chrysler dealer and he called up and said misfire in #5, the plugs installed were not the exact OEM called for. I called BS and told him to fix it and give it to the delivery boy for 400 miles so he could walk when it died again. I got it back and although it tried to act up once in a great while, it never died again in the next 65k miles. Moral of story: Put the EXACT OEM plugs in it, not what the desk jockey at the local store tells you to put in.

Rob Hartman · Jun 14, 2010

I crossed the Champions over to Auto Lite. I will not use Champions in anything I own.

Patsdeere · Jun 14, 2010

You already dumped a bunch of money into it. If it only took $15 of plugs to get rid of it I would be willing to do it.

Anonymous-0 · Jun 14, 2010

Have you checked fuel pressure and volume ? I know ,,,new pump,,but new means new ,not always good . Also ,ever had injectors cleaned ? Not dumping stuff in tank, but hooking into fuel rail and pressure cleaned ? I have ran into some wiring trouble with a few of these . Wiring near connector to coilpack looses insulation , wires short, intermittant missfire . One more big issue with these is Broken flex plate. Will usually cause a no start . I have seen them spin and catch where the engine will run but be out of time , backfire , miss , throw cam/crank sync codes . Only way to find it is pull trans and remove flex plate , The center where it bolts to the crankshaft breaks out . Real pain !

rockyhawaii · Jun 14, 2010

Try the EGR valve, and also check your battery's condition with a GOOD meter, like NAPA uses. It will tell the condition of each cell. My 1999 Caravan 3.8 had the same problem as yours.

Brian Jasper co. Ia · Jun 14, 2010

Crank or Cam signial intermittant? Are you saying there is a dtc for each one? One dtc cannot indicate both. So far all that you've done is throw parts at it. Gonna have to do some detective work. Get a schematic for it and look at the wires for the CKP and CMP sensors. I would pay close attention to the reference voltage wire. If the sensors are loosing reference voltage, the signals will stop.

ASEguy · Jun 14, 2010

Rob, You need to deal with what the controller (PCM) sees. The controller sees an intermittant cam/ crank sensor signal. Two things that can be checked without a scan tool are: 1) Did you put the green dot on the end of the crank sensor when you installed it? Chrysler crank sensors on the 3.8 engines have green spacer dots to properly space the sensor from the tone ring on the flexplate. I'm sure aftermarket ones have spacer dots too. We used them all the time when we rebuilt their 4 spd automatics. 2) Intermittant could mean a loose cam gear. I ran into that on a 3.3 Intrepid years ago when I worked at a Dodge dealership. Pull out the cam sensor, look in the hole to see if the cam gear is physically loose. If not then just put it back in. Other than that examine wiring for obvious defects and check crank and cam sensor plugs for missing weatherpacks or corrosion. Hope this helps. Let me know... Gerard

Kevin2 · Jun 14, 2010

He asked, I replied, the rest is his problem. Wants advice, but won't take it.
I once bought a Skidoo snowmobile a guy couldn't keep running. Hot plugs, cold plugs, plugs, plugs plugs. Most expensive NGK racing plugs were even tried as recommended by the counter jockey as a last resort. Fouled em dead in 20 miles. Went to shop three times to check carbs. I screwed cheap Champions into it and ran it hundreds of miles...

ASEguy · Jun 14, 2010

Rob, Brian Jasper has a good point. If you loose your 5 volt reference the same thing can happen. They don't run several reference voltages from the controller to various sensors, but rather "tee" off of them to go to other sensors. You can use a DVOM to probe the three wire connector at the cam sensor to find if one wire is open at 5 volts. Remember-with key on this WILL set another code for the cam sensor. Also, what are the p codes?

Anonymous-0 · Jun 14, 2010

Dodges only run on Champion plugs. don;t ask why but they don't like anything else.every time i used some other brand they would not run

Anonymous-0 · Jun 14, 2010

it will never run right if you don't get Champions in it

rockyhawaii · Jun 14, 2010

Never mind my post, it was a 3.0 and I guess I got brain-freeze.

RusselAZ · Jun 14, 2010

You have either rodent damage to the wiring or a broken center of the flex plate.

It is going pop when cranking because it is trying to find #1. when it fires close enough to spin faster the ecm sees the speed and turns on everything.

As long as it is seeing a bad cam/crank relationship it will not have sequential injection.

Spark plugs won't cause your problem.

Rob Hartman · Jun 15, 2010

The only P code is P1391 - intermittent loss of either cam or crank sensor. I checked the wiring pins for corrosion and even sraped them I guess I check for the voltage and continuity and see whats going on.

circus · Jun 15, 2010

Had a crack in the rubber tube on the intake manifold. Exceleration opened the crack killing the engine which rocked forward closing the crack starting the engine which rocked backward killing the engine. Bucking bronc, what a ride. Won't tell you what I spent figuring it out.

Hobo,NC · Jun 15, 2010

If you are sure all your replaced parts are of good quality and the work has been completed as suggested then it may be a cracked flywheel,,, its something you will not see till its been removed...

I had a 90 Plymouth Voyager with 300K on it I parked cuzz I could not fix a sudden stall at times,,, well maybe it was it did not owe me nuttin and I was not going to spend money on it...

Replaced it with a 2000 Plymouth voyager,,, at 100K same problem,,, actually more problems but will not go into that,,,, it had a cracked flywheel,,, I was lucky it rattled so it made it a no brainier...

Plugs,,,, brosh are junk,,,, autolites are junk now,,, thank the chinese for this...

plug wires,,, Belden (napa) are all I use 99% of the time,,,, cheap low end wires are a big problem....

crank sensor,,, recheck as sugested,,, that litte paper spacer is important....

One other thang,,, check crank shaft endplay....

BTDT

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Rob Hartman · Jun 15, 2010

I buy all my parts a NAPA, I guess one could still be bad though.

ASEguy · Jun 15, 2010

The problem with intermittant problems is they don't always show up when you are testing them. If not wiggle the wires when testing along their length. Remember with reference voltage the signal (voltage)is regulated at 5.00 volts. Less than that will cause a corrupted input to the PCM via the sensor return wire. Ground wire needs to be less than 5 ohms. I think sensor ground is blk w/blue tracer if I remember correctly. Chrysler did have some issues at their splices especially the 5 volt reference wire. They didn't always solder wire splices. The reason you are seeing a loss of cam or crank sensor is the PCM can't see which one is falling out due to using a common reference voltage wire going to the splice for individual sensors. Great idea huh. Gerard

ASEguy · Jun 15, 2010

Hey Hobo where's the front pump? Brings back many memories...The ole 604 and out of a 3.0 to boot. I've got a 3 spd in my wife's 3.0 Caravan good engine and trans. combination.

Hobo,NC · Jun 15, 2010

(quoted from post at 23:41:28 06/15/10) Hey Hobo where's the front pump? Brings back many memories...The ole 604 and out of a 3.0 to boot. I've got a 3 spd in my wife's 3.0 Caravan good engine and trans. combination.

It got a seal and pump bush'n while the trans was out,,,, piece of cake,,,, the top trans adapter came off a older snap-off jack,,, jack was junk from the get go but the adjustable top is the best I have ever used so I adapted it to a Chinese jack,,, I have owned Chrysler mini vans since 1990,,, cuzz they are the only ones i like to work on,,, but the electronics and wire'n are junk always has been on Chrysler long as I can remember....

The 3.0 mitts is as good a engine that have ever been built,,,, bullet proof,,, tho they do like lifers and valve seals

,,, it will get 24MPG loaded down trucking along at 80MPH 8)

I agree it could be another sensor,,,, if it were a GM I would bet if it gave a crank code it would be the cam sensor are if a cam code a crank sensor are a reference voltage wire short'n that would affect both...

2000 Dodge Grand Caravan backfires, Help Please

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