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moparman
Dodge Dakota
JOIN HERE
5/10/2006
19:30:59
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 Subject: engine trouble
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Message:
92 3.9 wont run but kicks and backfires when trying,is showing trouble code 12. what is this code truck is mpfi.
please guys bear with me iam not knowlageable about computer controlled vehicles.thanks in advance.
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cuzindoug
GenIII
5/10/2006
20:05:55
|  RE: engine trouble
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Message:
All that 12 means is that the power to your PCM was disconnected in the past 50 or so key cycles. If you have removed or replaced that battery recently it will so up. Don't worry about it. As to your problem, check the easy stuff first (i.e. wires, plugs, cap, rotor, spark at coil) then check fuel pressure and quick check your distributor for free play (indicates worn bushing). Keep in mind that you cannot adjust your IGNITION timing with the distributor, adjusting your dist. will screw with your INJECTOR timing.
If it doesn't fit, you're using the wrong hammer!
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moparman
Dodge Dakota
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5/10/2006
21:23:03
| RE: engine trouble
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Message:
ok i have disconected the battery many times recently so that is explained. it has started but runs only at a very low idle any throtle at all causes much back firing and then it dies.
and i did try to adjust the timming via turning the dist.
so now how do i fix what i messed up so that i can find the other problem? this truck was purchased as is not running has 215000km on the odometer and was used to pull a trailer.
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moparman
Dodge Dakota
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5/10/2006
21:40:05
| RE: engine trouble
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Message:
i have also changed the oil as it was way over the full line and full of gas.i have also checked the fuel pressure and it never dropped below 37 psi.once again thanks in advance.
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Engineman
Dodge Dakota
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5/10/2006
22:21:25
|  RE: engine trouble
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Message:
Sounds like it is running rich. Try pulling out the spark plugs and seeing if they are wet, indication of to much fuel or leaking head gasket. If they are wet pull them all out for a day or so and let the cylinder dry out, good chance to regap the plugs. With the turning the dist. turn it back to the center. Take off the intake and look it over to see if anything is impeding air flow ccausing it to run rich clean the tb if needed. good luck hope it helps
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cuzindoug
GenIII
5/10/2006
22:41:53
| RE: engine trouble
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Message:
To get a quick estimate of where your injector timing was set before, rotate your engine to #1 at TDC, notate were the #1 plug wire is on you dist cap'housing body (also notched on the dist housing), and align it were the rotor is "pointing" to. While you are doing this do the quick check on the dist bushing.
If it doesn't fit, you're using the wrong hammer!
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J and J Auto
GenII
5/11/2006
02:46:37
| RE: engine trouble
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Message:
tdc rotor at #1 wire center rotor button over cyl
line in pickup plate that is 0 the button just
behind the line looking from front is aprox +3
that is where it will run the best
put a timming light right on the coil wire and see
how its fireing almost sounds like a bad wire or
coil
even if the o2 sensor is unpluged the motor will
still run on the default tables it will not cause
it not to rev
posible jumped timming chain check base timing
#1 drivers side pull fuel pump relay should be
at 10 if not the chain jumped
Larry
J&J Auto
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J and J Auto
GenII
5/11/2006
02:48:30
| RE: engine trouble
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Message:
the old brain is slipping again
are the plugs wet or dry could also be fuel pump
Larry
J&J Auto
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moparman
Dodge Dakota
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5/11/2006
18:58:00
| RE: engine trouble
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Message:
thanks guys the plugs are very wet with fuel,i replaced them but could not get wires but they should be here for the weekend.i will reset the dist as per the instructions(to set it at +3 is that to the engine side of the line or towards the firewall?)
i was thinking coil as well as it has spark but very weak but would that cause backfiring?
thanks again guys i really appreciate your help.
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Engineman
Dodge Dakota
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5/11/2006
19:39:36
| RE: engine trouble
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Message:
If your spark plugs were wet ant the coil couldn't produce enough energy. There would be to much resistance, and the spark would find a different (easier) way to ground. But the way the spark plug is designed it would have to jump a gap no matter what and produce some kinda spark, so if there was just enough spark to ignite some but not all the fuel it would back fire. So if it was up to me I would replace the coil. I think advance is towards the engine side but im not positive, it would be 3 deg of advance. Make sure you let the cylinders dry out GOOD.
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Mike A
Dodge Dakota
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5/11/2006
23:50:54
| RE: engine trouble
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Message:
With the backfiring, sputtering, and wet plugs I'm thinking the chain slipped.
Mike
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moparman
Dodge Dakota
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5/13/2006
12:43:47
|  RE: engine trouble
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Message:
well i reset the dist and changed the coil but it still does the same thing just sputtering and backfiring.
have to turn the crank pretty far before the rotor moves so i guess i need a timming chain.
whats the chances that a valve didnt hit a piston??
well i was at it i redid all the splices in the engine bay harness although they looked ok i wont have to worry about them in the future.
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shatto
Dodge Dakota
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5/13/2006
15:45:17
| RE: engine trouble
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Message:
Down n dirty.
Put the code reader and other electronic tools away.
Blow off the dirt, remove the valve cover for #1 cylinder. Hand turn the engine to TDC, paying attention to the valve opperation. Exhaust will open then close-immediately intake will open and close. turn to TDC and you are set. Stick a screwdriver in the plug hole to confirm the piston is there.
Now check that your rotor is at #1.
Your distributor should be the same as the 98, so, under the end of the rotor will be a notch in the metal housing. If it is, your ignition/injector timing is set. NOWHERE ELSE. You cannot adjust timing at the distributor.
Make sure the wires actually go to the cylinder with the tag on the injector with the number on it. Check inside each end of the boot to be sure it isn't corroded to death.
Now double check your work. Take a break. Check it again.
My 98 3.9's timing chain, along with the rest of the engine, except valves, has gone 500,000 miles. I do not understand the concept of slipping timing chains. But, that is my experience.
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moparman
Dodge Dakota
JOIN HERE
5/27/2006
18:44:42
| RE: engine trouble
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Message:
ok guys just replaced the timming chain and added a tensioner(the old chain was shot)and it is still doing the exact same thing!
where should i start looking now?? crank sensor,cam sensor,dist. the check engine light has not come on but it has also not run.
i'm starting to remeber why i dont like computer engines!! please help me get this thing running..
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cuzindoug
GenIII
5/27/2006
19:43:43
| RE: engine trouble
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Message:
HE coil, crank sensor or possibly dist bushing come to mind. I would rule out the cam sensor if you have wet plugs.
If it doesn't fit, force it. If it breaks....well, it needed to be replaced anyway!!
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moparman
Dodge Dakota
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5/27/2006
20:43:34
| RE: engine trouble
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Message:
what is the dist bushing and how do i change it??
the coil is new. thanks for the reply.
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Joe M.
Dodge Dakota
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5/28/2006
01:32:33
| RE: engine trouble
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Message:
moparman
you said you replaced the chain "it was shot"
did it slip/jump teeth?
(how far off were the timing marks on the old chain?)
try to nail this down b4 you keep throwing money at it
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moparman
Dodge Dakota
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5/28/2006
09:39:08
| RE: engine trouble
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Message:
it didnt jump any teeth yet but it wasnt going to be long before it did. the crank position sensor looks like it was recently replaced(the mounting bracked is fairly clean)not that that rules it out though. think i will line it back up on tdc mark it and pull the dist today and see what i can see.
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Shatto
Dodge Dakota
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5/28/2006
12:33:59
| RE: engine trouble
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Message:
Ok, Guys, help me understand, cauz I don't; what are the reasons to need to replace the timing chain?
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cuzindoug
GenIII
5/28/2006
15:54:16
| RE: engine trouble
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Message:
dist bushing is a brass bushing that the dist shaft slips though inside the engine. When it goes bad or becomes too worn, you can "wiggle" the dist back and forth with no effort what so ever. I recall a gal on here a couple of months ago that was having problems similiar to yours, were she dropped a 1000 or so into the vehicle and it turned out to be a worn bushing. They are fairly strainght forward to remove/replace providing you have removed the oil pan and oil pump.
If it doesn't fit, force it. If it breaks....well, it needed to be replaced anyway!!
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moparman
Dodge Dakota
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5/28/2006
17:03:31
| RE: engine trouble
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Message:
thanks cuzindoug for the explaination. my dist is tight but the rotor can be turned quite a bit does the 3.9 have the same dist drive setup as a 5.2/5.9 ? with the shaft that drives the oil pump and meshes with the cam and then the dist aligns with a slot in the top of it?
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