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93dak4x4
Dodge Dakota
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7/23/2004
23:48:56
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 Subject: running to rich to comprehend
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hey guys i got something wrong that i can't find. my dakota is running so rich that you can actually see the carbon in the exhaust, like as it comes out. i have changed every sensor i can think of except the coolant temp sensor. i don't know what to do, and gas mileage is horrible, 10 or less around town. any ideas, i am lost.
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racerX
Dodge Dakota
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7/24/2004
02:44:50
|  RE: running to rich to comprehend
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catalytic converter? belly pan gasket?
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vern
Dodge Dakota
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7/24/2004
07:48:14
| RE: running to rich to comprehend
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egr,o2 and map
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wadak
GenIII
7/24/2004
16:59:28
| RE: running to rich to comprehend
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How many miles on your truck, it could be that a oxygen sensor may need to be changed. I had a 93 Dodge Caravan that had this happen when the O2 sensor went bad.
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93dak4x4
Dodge Dakota
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7/24/2004
20:42:49
| RE: running to rich to comprehend
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all the sensors are new guys, O2, map, tps, you name it ive changed it. cat is clear, thats easy to tell, i don't know why the egr would make it run rich? keep em comin please...all help is appreciated
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Greg
Dodge Dakota
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7/24/2004
22:09:11
| RE: running to rich to comprehend
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Are all of your vaccumm lines going to your map sensor Ok including the rubber elbow that goes into the throttle body... I wound up rerouting some vaccumm lines, because while I was idling you could literally watch the fuel needle moving to the "E"... After rerouting after all of the top end build motor now burns clean while idling and running... All thanks to Larry on that one :)) He's saved me quite a few dollars in gas bills...
How about T-stat... May be stuck open and keeping operating temperature very low for very rich running... How's your temp gage reading???
One thing that is very imparticular to making a Dodge "more than all other makes of vehicles for some reason" loose performance and run richer is the cap, rotor, plug wires, and plugs for some reason...
Bad injector... Stuck open allowing lots of fuel through...
Exhaust leaking before the cat???
Have you done any kind a modifications to the truck or motor???
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93dak4x4
Dodge Dakota
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7/25/2004
00:17:35
| RE: running to rich to comprehend
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ok, here is what i have. since i have owned the truck i have replaced the timing set with a double roller set, all new sensors except temp sensor(temp reads normal by the way), 318 tb, flowmaster muffler (no exhaust leaks).
i havent spent a whole lot of time on looking at the hoses but from what i remember they seem in good repair. but i will check on them tomorrow, since i plan to replace the coolant temp sensor in the morning.
As far as cap and rotor they are about a year old and plugs are new 3923's and wires are brand new as well.....
anything else i might try?
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Greg
Dodge Dakota
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7/25/2004
01:08:00
| RE: running to rich to comprehend
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Try seeing if one of your fuel injectors are leeking... Let it set over night and take your check valve cap off, use something to push in on the ball and see if gas sprays out... Keep in mind "gas spray" so watch out for your eyes...
When you changed out your tps did you preload it??? Of course you probably changed that out to try and fix this problem, so I doubt that's it...
Had a scan tool test run lately???
Where do you buy your gas and what type are you using??? I know it's a long shot but who knows...
Can you remember what the last thing you did was before it started running this way???
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whitedakota2
Dodge Dakota
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7/25/2004
01:35:23
| RE: running to rich to comprehend
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Remeber that the truck may be running rich because the ECM "thinks" that it is lean. The computer will compinsate for a lean condition by adding more fuel. I had this happen a while back due to a crack in the exhaust the allowed air to come in prior to the O2 so it thought that it was lean. Poor gas milage is the result.
How is your gas milage? Has it gone down?
I agree with Greg, a scan tool may be helpfull
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93dak4x4
Dodge Dakota
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7/25/2004
11:24:15
| RE: running to rich to comprehend
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i know i dont have an exhaust leak before the O2 anywhere. ill have to check like you said and see if gas sprays. as far as the scan tool, i know it isnt throwing any codes...
to answer greg, nothing has really brought on this at one time, its been gradually getting worse in the last two years. started out with 13mpg around town and 18-19 on the highway, then slowly deteriorated to 10or less cty, and 16 or less highway. i changed the coil this morning thinking maybe weak spark...but lets see.
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vern
Dodge Dakota
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7/25/2004
13:18:10
| RE: running to rich to comprehend
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a scan tool will tell you more than just the codes,
it will tell you the operating values of each sensor,just because theres NO codes does,nt mean
the sensor is operating correctly
map may have low vaccumm causing the pcm to richin
o2 may not be changing values causing pcm to richin
temp sensor may be giving the pcm a colder reading than what the temp is causing the pcm to richin
the egr can cause bad fuel mileage,not a lot but some 1mi or so
so on and so on
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Greg
Dodge Dakota
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7/25/2004
17:09:23
| RE: running to rich to comprehend
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I'm going to lean back towards racerx now and suggest that maybe your belly pan gasket is going bad??? Esspecially with your fuel mileage going steadily down hill for the last few years... See if you have any oil down inside of your intake manifold or a grimey residue... These are fairly common to fail for some reason...
Another possibility is perhaps the thingy that goes in your valve cover that I really can't think of the name to right now... Possibly stuck open or closed or which ever one it may be causing it to run rich???
How about intake or air filter, isn't clogged or partially stopped up is it???
Butterfly's on tb completely crusted over with gum and dirt???
A scan tool is really the only thing I can think of to really get down to the bottom of this and not the little code reader that they have at auto zone or other auto parts stores... BUT then again you would have to know what your sensor readings are suppost to be too... You might take it by your local auto class at a local highschool or something for a free reading... I think it's what close to $50 or $100 dollars at the dodge dealership???
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93dak4x4
Dodge Dakota
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7/25/2004
22:38:51
| RE: running to rich to comprehend
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i took it to a dodge dealer last year and paid $85 to get it tested....all clear, since then i replaced all the sensors, so none of them should be bad, as for the belly pan gasket, is the under the intake manifold? i am tryin to avoid tearin into it that far, especially if i dont know if it is leaking, but is there another test i can do to find out if it is leaking?
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Frank A.
Dodge Dakota
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7/25/2004
22:42:56
| RE: running to rich to comprehend
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To test belly pan for leaks.
pull both pvc valve, and the hose off from the other valve cover. plug the holes with your thumbs for about 20secs (while engine runs). If there's pressure built up no leaks. If you sense vacuum your belly pan gasket mabe leaking.
FA
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red neck
Dodge Dakota
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7/25/2004
23:17:09
| RE: running to rich to comprehend
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too much egr at wrong time causes eng to run rich for the same reason a misfiring sparkplug does (the egr causes a lean misfire). Now the o2 only sees 02 not the raw gas and assumes the eng is running lean and adds gas causing the eng to run rich
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Greg
Dodge Dakota
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7/26/2004
00:26:53
| RE: running to rich to comprehend
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BUT when the egr goes bad or starts going bad it will also cause the motor to choke out at idle and idle very funny at that... If it has an electronic egr you can actually use the scan tool to open and close it to tell whether or not it is bad... I'm not saying that this is not what's wrong because I'm not ruling anything out yet...
AND if it was the egr it would look like the guys that performed the scan tool test the last time would have seen it causing the engine to run rich...
I'm still leaning toward the belly pan gasket because fuel mileage has ---
gone down hill steadily "leak has gotten worse and worse over time"
will not show up durring scan tool testing because has nothing to do with actual sensors "may show sensor acting funny but will infact be the wolf in sheeps clothing to the so called faulty sensor"
SIDE NOTE ~~~ The belly pan is well as it's name states... The pan at the belly of the intake manifold :)) It is the closer or opening depending on whether or not it is on or off of the intake manifold to allow access to the inside of the intake manifold for machining or any other kind of work... It also has a very thin gasket held down by a very easily flexing metal plate... People who supercharge their dakotas will take their manifolds off for machining and will also replace this very thin flexible plate with a thicker plate, more than likely from hughesengines, to eliminate most of the possibilities of blowing out on the plate "from extra pressure" and in turn blowing out the belly pan gasket... As you can see this would be a very bad thing...
Hope this helps you out a little more...
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Bob Lincoln
Dodge Dakota
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7/26/2004
10:59:01
| RE: running to rich to comprehend
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"the egr can cause bad fuel mileage,not a lot but some 1mi or so"
It can be a LOT worse than 1 mpg. My dad's car had a bad (stuck open) EGR valve that wiped out the O2 sensor. After replacing the O2, he still only got 13 mpg instead of 27. Replaced the EGR and no further problems. There were never any codes thrown. Poor idle, loss of power, black smoke.
Check the EGR if you haven't already. Have someone rev the engine while you watch the valve stem. It should open and close. If not, replace the entire EGR assembly.
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93dak4x4
Dodge Dakota
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7/26/2004
14:02:19
| RE: running to rich to comprehend
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thanks alot guys, ill try a few of these when i get a chance, i appreciate all the input.
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