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FMXguy
Dodge Dakota
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1/29/2005
01:29:26
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 Subject: 3.9 no solutions...please help!
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I have a '97 3.9 4x4 automatic with an unsolvable disease. At completely random times (usually if I'm running late) the motor runs as if there isn't enough spark for the gas it's getting, there is a popping sound (backfiring maybe?) under the hood. Diagnostic machines show no codes (there's no check engine light on) and everyone I've taken it to is baffled. I've replaced; plugs, wires (correct gap), dist. cap, rotor button, coil...I've checked; fuel pressure, injectors, gaskets, gas tank for water. Premium gas makes no difference. I can go for days with no problem, and then go for days with the problem, or just have a brief "misfiring." The only thing I can think of might be the ignition module going bad, but wouldn't that cause a consistent problem or throw a code? Someone please help b4 i waste $400 on an ignition and it's not the prob.
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EverWiser
Dodge Dakota
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1/29/2005
05:11:02
|  RE: 3.9 no solutions...please help!
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Have you changed the hall-effect pickup in the distributor yet? I didn't see it listed in what you've looked at and/or changed. They can cause some flaky things when they start going bad. Just a thought.
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93dak4x4
Dodge Dakota
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1/29/2005
09:32:40
| RE: 3.9 no solutions...please help!
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it almost sounds to me like a wiring issue as if its not making connection all the time. as for it being the computer i really doubt it, when they go back the truck runs like crap permanently (usually. but i could be wrong.
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gloomygoblin
Dodge Dakota
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1/29/2005
17:32:47
|  RE: 3.9 no solutions...please help!
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I recently had a simular problem.. Turned out 2 be that the #1 cylender fuel injector had needed some wiggling.. Try "with engine running" wiggling your injectors and insure proper electrical connection, keep an eye out for vacume leaks at the O rings. Listen for any RPM change if you come accross one that changes your RPM that might be the root of your problem.. Good luck =)
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J and J Auto
GenII
1/29/2005
18:21:15
| RE: 3.9 no solutions...please help!
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I would also suspect the pickup in dist it tells
the injectors when to pulse check that the trigger
is not lose in dist the small metal peice
sometimes comes lose also wore dist bushings
And the crank sensor it provides the base timing
for the comp and they will work eradicly without
throwing a troubble code
Larry
J&J Auto
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92azdakota
Dodge Dakota
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2/01/2005
14:21:25
|  RE: 3.9 no solutions...please help!
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I had the same symptoms on my 92 3.9 auto and replaced the crank position sensor as advised above. Seems to be the fix! Good luck
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daddio
Dodge Dakota
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2/01/2005
15:18:47
| RE: 3.9 no solutions...please help!
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just a thought, but could it possibly be the TPS?
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broke3000gt
Dodge Dakota
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2/01/2005
18:10:54
|  RE: 3.9 no solutions...please help!
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i recently had a problem ith my 98 3.9l dakota sport randomly freaking out on me. I would hear a backfire sound and a ticking under the hood, and the rpm would jump around. the truck bucked back and forth like crzy too, dont know if thats happening to you, but it ended up being the crank position sensor.
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fmxguy
Dodge Dakota
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2/02/2005
01:25:03
| RE: 3.9 no solutions...please help!
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Well it wasn't the hall-effect pickup either, so 2morrow's job is the crank pos. sensor. Does anybody else think 30 bucks for a hall-effect is a little crazy? I could only afford a six pack after that!
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CampBell
Dodge Dakota
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2/03/2005
15:15:38
| RE: 3.9 no solutions...please help!
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Hey man there is Crank sensor that the pcm syncs with to help in controling the fireing order and the pulse of the injectors. maybee the connection is bad or the sensor is starting to die. You can check it by plugging a volt meter into the pos side and grounding the other out and have somebody try to start the truck and watch to see if it puts out a constant voltage. Not bouncing around it should at least stay within a volt.
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fmxguy
Dodge Dakota
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2/07/2005
00:36:30
| RE: 3.9 no solutions...please help!
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well, it definitely was NOT the crank position sensor. Also, a note on that thing, go to auto zone before you take the fender wells off, the plastic plugs that come standard in the fender wells are impossible to put back in, get something simpler. I guess it's the TPS tomorrow...(i am sick of spending money on this biotch...I wish my local dealer could tell me something but they can only figure out what the computers tell them...)
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hanzlik
Dodge Dakota
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2/07/2005
12:38:09
| RE: 3.9 no solutions...please help!
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I have a 92 3.9 and I have had similar problems . It turned out to be the distibutor gear bushing . If you take the dist. cap off , twist the rotor a bit and see how much slop you have . If it appears to be excessive , take the distributor out and look at the gear that it rides in . A large magnet should lift it up out of the hole, but mark it first . Mine wore out at 75,000 miles and now again at 155,000 . Mine was very obvious when I pulled the gear out . The teeth on the gear were half way wore through. The root cause was the bushing that the gear rides in . It wears out and causes the gear to get sloppy , causing the teeth to wear , and in turn , causes the timing to bounce around . Some symtoms I had were an erratic idle , backfiring , loss of power . NAPA carries the shaft for about $31 and I had to get the bushing from the dealer for $13 . It is supposed to take some special tools to replace the bushing . I used some makeshift tools the first time , but I am going to see if I can get the right tools this time.
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bsasteve
Dodge Dakota
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2/13/2005
07:46:43
| RE: 3.9 no solutions...please help!
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Still having problems?
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dakman
Dodge Dakota
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2/13/2005
12:14:09
| RE: 3.9 no solutions...please help!
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i have the same problem and have found no fix yet... please help!
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bsasteve
Dodge Dakota
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2/14/2005
11:07:53
| RE: 3.9 no solutions...please help!
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Sorry about the delay e-mail problems. What have you checked so far and what have you found? it definitely sounds electrical like a auto shut down relay or possibly fuel pump relay do yourself a favor and get onto alldata.com and check tsbs/technical service bullitens. Two main things to check are one pull the distributor out and physicaly check for exessive play and also check for loose,corroded damaged wiring including battery cables and ALL grounds. I don't know about new mopars but one thing that used to go all the time on the older ones is a fusable link inside the wiring loome located near the master cylinder open this thing up and thier might be two large red leads with fusable links disconnect the battery and look at these they corrode and break all the time on the older mopars. One more thing when was the last time you cleaned the throttle body and iac carbon does funny things after a while. Good luck 88 4x4 with 380,000
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jake
Dodge Dakota
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2/15/2005
23:45:28
| RE: 3.9 no solutions...please help!
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still no fix, BUT after I replaced the TPS, the problem has been significantly reduced! Maybe that means the problem is relative...????
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jake
Dodge Dakota
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2/16/2005
00:06:41
| RE: 3.9 no solutions...please help!
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could my damn 160* thermostat have had a negative long term effect? (ie carbon buildup somewhere I can't see?) I just read another post saying that the 160* t-stat is too cold for the engine, but it sounded like a good idea living in FL, I replaced that bad boy about 6 months ago...I'm freaking out...My truck has automotive AIDS, no cure.
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bsasteve
Dodge Dakota
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2/16/2005
10:56:32
| RE: 3.9 no solutions...please help!
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Okay hear's what i think you should do first disconnect the battery and whilst the computors forget what they have learned yes you want this to happen take out the 160 and install the stock thermistat. After that then hook the battery back up. BEFORE you start the truck dial in the tps and spray the tb butterflys and iac pintLe valve area with a high grade tb cleaner like 3M. whilst you are adjusting the tps is the ideal time to clean you're tb after this go ahead and let the tb air out butterflys open. Finish purging air out of cooling system and take it out for nice test drive note any problems with truck also gather as much info as you can about the problem temp. rpm. load no load idle part or full throttle ect. ect. information is critical. As far as the adjustment on the tps is concerned thier are some threads on how to do this i cannot recall off the top of my head. Good luck ole88with380000+
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340dak
Dodge Dakota
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2/16/2005
19:24:11
| RE: 3.9 no solutions...please help!
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Please help me. My 93 dak 3.9 is being a pain too.It takes about 20 minutes to warm up. Untill it does it want's to die out unless I keep my foot on the gas. And yes, untill it warms up it too makes the backfire noise. Even when it warms up and I am able to get the rpm's above 2,000 it will still die out if I let it run below roughly 1200 rpm's. What a pain. Any suggestions? And I already have the new map/crank/and thermo sensors.Thanks!!
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dakota92
Dodge Dakota
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2/17/2005
22:00:28
| RE: 3.9 no solutions...please help!
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had the same problems replacing the EGR worked for me
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jake
Dodge Dakota
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2/17/2005
23:20:13
| RE: 3.9 no solutions...please help!
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well the 195* thermostat didn't help at all...dakota92 are you saying replacing the EGR will help me, or 340dak's problem of taking 20 minutes to warm up? By the way everyone, I checked the distributor bearings and cleaned the throttle body etc...every idea on here (except the EGR) has been tried but still no fix. Next step= drive down the road and crash into the ocean. OOPS! (i just noticed I'm posting under names 'fmxguy' and 'jake'....what an idiot)
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