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Dodge Dakota Engine and Underhood Questions



  • bpeeblesbpeebles Posts: 4,080
    Which engine do you have in that 94 Dak?
  • it a 6 cyl 3.9 :blush:
  • ok well we replaced the PCV valve it was majorly blocked and a friend showed me how when i shake it back and forth it should make a noise so since he replaced this plus a new hose since the hose totally cracked my pump is staying off tomorrow ill change the oil and filter and hope the synthetic oil i put will wake up my oil pump if not guess well have to put a new pump in thanks for the advice yall gave without it i wouldnt have made it easier to explain the help i needed from my girlfriends brother.
  • bpeeblesbpeebles Posts: 4,080
    I am glad that I was able to diagnose the plugged PCV valve for you from your description.

    I would suggest AGAINST trying synthetic oil to "wake up" a weak oil-pump. This is because synthetic oil is less-viscous (thinner) than dyno-oil and harder to build-up pressure.

    Instead, change oil/filter using dyno-oil and add a can of STP Oil Treatment. This will add viscosity-improvers (thickeners) to your oil and some xtra detergent. You may find that the oil-pump is able to built-up pressure with the thickeners in the oil

    It is a LOT cheaper to try STP Oil Treatment instead of tearing-apart engine to replace oil-filter.

    In fact.... one time I used STP Oil Treatment to 'assist' a weak oil-pump and to my surprise, the problem never came back over the next 2 years. (without adding STP Oil Treatment again!!) I suspect that the xtra detergents cleaned the cr@p out of the oil-passagways.
  • I NEED SOME HELP!!!! i have a 2000 dodge dakota 3.9L V6. here recently, i had to pull the engine out. due to the freeze plugs leaking very badly in the back of the block and next to the oil filter. i figured that it would be way to fix the problem. I got the engine out with no issues at all. replaced all the freeze plugs and checked for leaks. thank the lord no leaking!!!while the engine was out, i replaced the valve cover gasket, water pump and bypass tube, and replaced rotor cap ,distributor and wires. placed engine back into truck and replaced all wiring and vacuum hoses to there approperate locations. filled up coolant and completed all hook- up to the engine. Now is where i am having the issues. i am now trying to start up the engine... it has taken me a few tries since i have to get fuel flowing back into the injectors. i can get the engine to turn over, but i cannot keep it running. whenever i take my foot off the gas it dies. i have heard that when retiming, you have to rev up the engine to 1500 RPM for 5 minutes and that is supposed to retime. its not working? Anyone have any suggestions that will help me? i forgot to mention that i also replaced the PCV valve and just over the summer replaced throttle position module. thanks for anyones suggestions! i also have the issue where i have tried to keep my foot on the gas and tried to place into gear and died right now. HELP PLEASE!!!!!!!!
  • I have a 92 Dakota 4x4 5.2l with about 140,000 on it. The truck is getting spark, fuel, and has about 140 lbs of compression in every cylinder. The truck will crank and fire, run for about a second, and then blow pressure through the throttle body. After doing this for some time I noticed a lot of fuel mixed with the oil, which led me to believe that it was flooding or had poor spark. Replaced, Crank sensor, distributor pickup, cap, rotor, plug wires, plugs, coil, Engine coolant sensor, Air temp sensor. New Egr valve (old one was missing parts). And a used Ecm. I checked the distributor time, with number 1 at TDC the rotor lines up with the pickup coil mark and the number 1 terminal on the cap. I also removed the under hood fuse box and repaired any wires that looked corroded. Still nothing. if one spark plug is completely removed from the engine (in order to test for spark) while cranking the engine it will run for five seconds or so, but obviously very bad. I have totally ran out of ideas. If any one has any suggestions, they would be greatly appreciated.
  • srs_49srs_49 Posts: 1,394
    It sounds like either timing or a stuck/leaking valve to me. But, since the compression test went OK, that sort of rules out a bad valve. Could a really bad valve lash adjustment cause this?

    Looks like you replaced the major components that would lead to a timing problem.

    Don't have much else to suggest. Let us know what turns up.
  • jyrojyro Posts: 4
    Hey bud, as much logical stuff as you have done, and based on the compression, I would have to question if you've got water in your gas. Or maybe a clogged / clogging injector. Just my $0.02 worth.
  • Looks like I have found it, the timing chain has not jumped, but has excessive slack, The crank will almost turn 1 tooth before the cam will start to turn.... Hopefully a new timing set and I will be good to go.
  • I have a 2000 dodge dakota 3.9L V6 and i am asking if anyone knows how to time the engine back to the computer settings? battery was removed and now spits and sputters.
  • Do you have any engine mods, like cold air injection or throttle body spacer? I had an 2002 s10, if the battery was unhooked for to long it would reset the computer. The truck would run poorly until I drove it for about a half an hour in order to give the computer time to relearn how the truck ran. I dunno just an idea.
  • srs_49srs_49 Posts: 1,394
    Just disconnecting the battery should not cause those problems. The ECU defaults to some basic factory settings (spark and fuel injector timing and duration, etc) when the battery has been disconnected for some period of time. The truck should still run, though maybe not optimally until, as dirtyharrys said, the ECU has some time to "re-learn" the engine and driving habits of the driver.

    Is that all you did - just disconnect the battery?
  • no..... i had to take motor out to fix very badly leaking freeze plugs........
  • Well, that is a whole different story. I would start by rechecking all of the vacuum lines and plugs to make sure everything is plugged in properly. Also, may sound stupid, but make sure all of the plug wires are on the correct plugs.
  • I have a 2000 dakota with a 3.9L magnum engine. Each time I star it either warm or cold it idles up between 1500 or more RPM. After looking through the different posts it seems the IAC motor may be the culprit. Is there any way of correcting this other than replacing the motor completely? Thanks for any suggestions.
  • bpeeblesbpeebles Posts: 4,080
    On my 2000 Dak, I would pull the IAC and clean it and the seating surfaces about once a year. It is amazing how much black crud builds up on the surfaces which are used to modulate idle-air.

    It is very easy to do with Torx driver, some Qtips and can of carb cleaner. While I was at it, I cleaned the entire throttlebody.

    The only thing to remember.... AFTER removing/replacing the IAC, you need to "recalibrate" it. Do this by turning ignition key to run (dont start engine) and wait about 10 seconds for computer to recalibrate it. Then, when you start engine, the idle may "hunt" for a few moments before it settles out. (It has to relearn how to idle the enigne with CLEAN air passageways)

    Remember, it is the COMPUTER that sets the idle-speed using the IAC to modulate airflow around the butterfly valve. NEVER EVER try to adjust the throttlebody to set the idle. (You wont change the idle and you WILL mess up the calibration.)
  • Thanks for the input. I have the shop manual which tells in detail how the IAC motor works so that helped me understand the operation of it. I did remove it and clean with some acetone and q-tip. It wasn't too bad. I even pushed down the spring loaded collar around the motor shaft and shot a little WD40 in it to help in case it was sticking. I turned the key on for a brief second and the piston retracted into the motor slighty. So I put it back on the throttle body and started it. I didn't go through the steps you mentioned to re-teach the computer. The first time I started the engine it only went up to a little over 1000 rpm. But noticed a few times afterward it still goes up to around 1500 then drifts down. My main concern is when the engine is cold and it does it. I feel it is harder on the engine to start it when it's cold and have it run so fast. I might even try disconnecting the battery and then reconnecting it to see if that changes anything. Will let you know.
  • Johnny005, I have a 2000 Dakota 3.9L and I need to replace both freeze plugs. Was wondering if you or anybody else knows of a way to replace plugs without pulling the engine? Doesn't look good because of where the plugs are located.
  • :confuse: ok guys heres a real kicker for over a month now my 94 dakota has been trying to tell me something at times my oil pump will shut down then turns on when i drive or actually when i accelerate it shuts off i can let off the gas and it turns on and this happens most trips but at times it shuts down and i end up either stopping shut off the motor turn turn it on or pop it in neutral shut off and turn on i know im gonna mess up my starter but what can ya do ;) is the truck telling me to put a new pump or is the sensor sayin change me :P im sure yall prob say do both but another kicker is when i get under 1/4 tank this is when it happens mostly over 1/4 tank the gage stays in middle and she runs perfect :confuse:
  • Well, finally got around to replacing the timing set.... Guess what,,,,, No help, the truck is still doing the exact same thing. Fires, but wont run. Any one have any other ideas???
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