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Discussion Starter #1
Looking for help here
I have the 06 3.3 Van
about a month ago it would misfire cold for 20 second & then pick up & run great .then it would not pick up cylinder #6 so I checked everything & it seemed to be a bad coil pack so I swapped it out & it ran perfectly again for about 3 weeks now it will not fire #6 again at times , sometimes it runs perfect others it misfires randomly .
I am getting 4 codes
P-0420 -cat problem
P-0456 - evap problem
P-0300 - random misfire
P-0306 - #6 misfire
I changed spark plugs & wires , I have replaced to coil twice
I did a compression test & it is 185 on all front 3 cylinders
SO I am thinking maybe leaking injectors causing excess fuel & causing the faulty Cat code , or wiring although the wiring visually looks perfect or ECM
I am trying not to just throw $$ at it as I don't have much $$ to spare right now .
Thoughts ?
Thanks for the help !
Neil
 

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Drivin' Maniac
2002 Grand Caravan ES 3.8L
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You could swap injectors between cylinders, see if the misfire follows the injector.

Hopefully your cat con isn't damaged.
 

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Yeah, swapping injectors is not really that much work or expense. You should be able to re-use all the gaskets and putting it all back together is pretty straight forward.

Did you read the spark plugs? sometimes that can give you an indication of what is going on.

I was thinking an intermittent valve sticking if everything else checked out. Maybe do the compression test again...

Good luck and let us know what you find and how you repair your minivan.
Regards,

another thing, before I buy an electronic part, I try to simply unplug, inspect, and then reinstall that plug. Many times that mere action will 'refresh' the electrical contacts (which could give you the same results of installing a new part, but because it was the connector, it may go bad again) So look at those connectors on the coil and injectors very closely.
cheers
 

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Discussion Starter #4
Plugs are brown / not normal so either misfire or rich has darkened them so it could be bad injector or the coil not firing .
I will try the ECU plug , good thought !
 

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fix it if you can
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How many miles (on the 'clock')? Any sign of rodent activity? (droppings, nut shells, etc under hood - chewed wires?)

Since you pulled 2, 4 & 6 - was only #6 plug discolored or all 3?
If all 3, what brand O2 sensor in in front of the cat? and does it still have OEM Champion plugs in it?
 

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Discussion Starter #6
270,000 miles , no rodents , it never sits still long enough !!
2 & 6 were discolored 4 was white , I can't remember the O2 make , replaced it 3 years back .
yes I still run the factory Champion plugs
 

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fix it if you can
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2 & 6 are on different coils, so something big is up.
Dreaded cracked flexplate comes to mind :(
It's not fun, but I'd pull the inspection cover and take a peek with mirror and flashlight or scope if you have one (and take a good look at the pics posted on here so you know what signs to look for).
 

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fix it if you can
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You may need to rotate the engine and if you don't want to pull the plugs and belt to do it manually, you can pull the ASD relay and use the starter (just keep your fingers away from the opening)
 

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Discussion Starter #10 (Edited)
Well that was not hard to check , the flexplate is good , tougher to get the cover back on than anything !! I just pryed the flexplate around with a screwdriver tooth by tooth .which takes a couple of minutes but that way you are sure to see every part of the flexplate ..

I also pulled the ECU from the front of the fuse block / power center , everything looked great. clean & dry . no corrosion & I didn't coat the terminals with dielectric grease . So I am still thinking maybe crank sensor not reading right but that should have its own code I believe , or the ECU is the problem , it runs better cold , & is totally intermittent , it will run perfect one moment & misfire multiple cylinders the next .

You don't know me but I am competant as a mechanic but more old school , I have no fear of electronics & I tend not to blame them as the first response but instead I ask myself if there was no computer what would the problem be & generally I can find the answer !
This has me stumped as either the computer is misfiring the coils or the injectors are not functioning correctly .
I am thinking I will order 2-3 injectors maybe a crank sensor & another intake gasket & tear into it , I was going to do it today but I cannot locate the intake gasket right now .
 

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fix it if you can
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I also pulled the ECU from the front of the fuse block / power center
Hold your horses, that little 'box' mounted on front side of fuse box is Front Control Module.
PCM is located in one of the worst possible places - in front of LH front wheel under the wheel well splash shield and is a combined ECU & TCM (unlike early 4th gen where TCM was in that spot and ECU next to the battery).

Good to hear flexplate is OK.
 

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Looking for help here
I have the 06 3.3 Van

SO I am thinking maybe leaking injectors causing excess fuel & causing the faulty Cat code , or wiring although the wiring visually looks perfect or ECM
I am trying not to just throw $$ at it as I don't have much $$ to spare right now .
Thoughts ?
Thanks for the help !
Neil
Let me ask Neil, do you ever experience a situation where it seems like there is one cylinder that is stuck when trying to crank the engine. Then once it gets over the 'hump' it seems to crank fine?

I have experienced that on a different vehicle as a result of leaking injector. It would bleed off the fuel pressure through that leaking injector and then cause hydraulic lock on that cylinder. As soon as the engine tried to squeeze that fuel and got past it, then it would continue to crank as usual AND it only happened occasionally.

Beware the aftermarket injectors. They are relatively inexpensive and I've heard tell of the plastic crumbling after a few short years.
 

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The top of the plenum comes off easily with 10 bolts as does the throttle body. All of those silicon gaskets should be able to be re-used. At least for troubleshooting / testing. Removing the top of the plenum give you great access to the injectors and even enough room to change rear spark plugs and the rear valve cover gasket.

(I removed the plenum to change the rear valve gasket, the spark plugs and even the o2 sensor before I learned how superior it was to simply remove the wiper cowl) (<~~ dummy)(hindsight is usually 20/20 vision)
 

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Discussion Starter #15
Never had a hydraulic lock situation , it cranks & starts just fine then after 15 seconds idles down & starts to misfire
I have had the upper intake off before , I realize it is not that hard to remove it .
I was looking at getting refurbished Bosch injectors , I just feel more like it is an ECU issue , just a hunch though
 

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I don't know what resources you have in Panama? Noid lights are a diagnostic tool for the wiring. I can 'borrow a set here at AutoZone lend a tool program.

For my 2002 3.8 I had Siemans-Dekka injectors. I ordered some refurbished for a 3.8 on Amazon and learned that there are other variations. Mine were black with a gray band where what I got from Amazon were black with a brown band (higher fuel flow specification) I ended up having my originals serviced/cleaned/flow checked by mail order while I ran for a week on the fueley ones. She was certainly running rich beyond the ECM's ability to trim it.
So, keep that in mind.
 

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Discussion Starter #17
Well I spent a couple more hours on it today
I rechecked the plugs , 2 & 4 are white again after changing the coil , 6 is light orange , the codes I get mostly are P-0300 & P-0306 , twice I had P 0302 . When I pull the ign wire off of # 6 terminal is is shooting a spark 5" to ground .as I said often it runs perfect , lift off the throttle or come to a stop & get back on the throttle & 1-2 cylinder are misfiring & I am not sure it is the same cylinders as the P-0300 is random misfire . Frustrating for sure .

I pulled the front wheel & the liner , the ECU is easy to access , I pulled all 4 plugs , everything is in good shape , the wiring is undamaged , the , the plugs are tight & clean , no corrosion or evidence of rodents
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I pulled the upper plenum off the intake , everything seems fine there as well , wiring is wrapped & undamaged , no wear , the connectors are tight on the injectors & no evidence of rodents .

What you may not realize is this van is like new , we have no harsh conditions here at all , 365 days of summer no salt , no rust , everything still works perfectly on the van , I was averaging 250 miles + / day mostly highway , I have done oil changes every 5000 miles which most of the times was every 3 weeks , I have serviced the trans regularly , I do front struts approx every year , & have done front brakes 3 times & rear once , I have changed a couple of window motors & door lock actuators , an alternator . the worst part is the paint fade in the tropical sun !!
This van has been fantastic & I really believe I could add another 200,000 miles to this van yet !!
I used to run Ice roads in northern Canaduh in temps as low as -58 *C or -78*F , this is so much better !
 

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Discussion Starter #18
All the part stores are just independent family run stores & most do not carry parts for American vehicles , there are 3-4 in the city that cater to north American vehicles & 1 Napa store that I am aware of but I have never heard of any tool rentals here so no noid lights unless I buy them ,
My injectors are green Bosch ones , Rock Auto shows the Bosch Green injectors , Rock has done me very well here , the only time they have sent me a wrong part is 1 time when they sent me someone elses order included in mine .
 

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Will it misfire as before if you unplug the front O2 sensor? (and cause it to run "open loop" - pre-set fuel map instead of rich/lean feedback from sensor)
 

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Will it misfire as before if you unplug the front O2 sensor? (and cause it to run "open loop" - pre-set fuel map instead of rich/lean feedback from sensor)
Is there a o2 sensor up front on the 2006 3.3, the upstream?

Neil, do that.... and then tell us what the results.
 
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