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General Dakota Board
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olscout
Dodge Dakota
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10/02/2008
11:36:27
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 Subject: 94 Dakota, barely runs
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OK, I've checked and rechecked and started replacing parts with no luck.....maybe somebody else has had this problem before. Truck is a 94 Dakota 4x4 extend cab, 3.9 V6 automatic, 160,000 miles. Truck has had a new timing chain/gears, and normally runs great and gets decent MPG. But for the last five hundred miles or so, it's been going downhill, the point where now it will hardly run- the last trip I made with it, I had to limp it home at 40 mph the last ten miles. The engine acts like it has a rev limiter on it, and at any RPM at or approaching 2000 rpm it starts to cut out. It's also running rich most times, to the point of blowing black smoke out of the exhaust, not all the time, but quite a bit. What I've done so far- suspected plugged cat, removed cat for a 'test tube'- no change. Cleaned IAC and throttle body, then replaced with good take off IAC- no change. Plugs, cap, rotor and wires- no change. TPS, no change, MAP sensor, no change. Picked up a used computer from Ebay, ran better at idle than it had, but no change in the problems at 2000 rpm. Pulled all engine and component grounds loose, cleaned connectors, cleaned the ground point, and reattached- no change. My buddy is a mechanic, and he put a Snap On scanner on it, everything seemed to be reading in the OK range except it showed no cam sensor. Since the cam sensor is the pickup in the distributor, bought one of those, plugged it in, fired it up, and it showed up that we had a cam sensor. Speeded up the engine RPM's, and then it showed no cam sensor again?? I've heard about the distributor problems, so we checked the distributor manually (no excess play) and with the scanner, and it's not bouncing 'sync' all over the place, and the pickup plate 'glue points' are still intact and in good shape. I'm about to throw an O2 sensor at it, because of the running rich.....but I don't know how much problems the O2 sensor could cause, especially because on the scanner it's showing the right voltage range when it's operating. I'd drive this thing off of a cliff, but it doesn't have enough guts to climb the hill to get to the top.....help! Anybody, Bueller, Bueller????
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dakota49
Gen I
10/04/2008
23:04:35
| RE: 94 Dakota, barely runs
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olscout, I think you are looking in the wrong place, I think it has a "Cam Position Sensor" and that is where your problem really is, not just the dist. I think the cam pos. sensor is at the front of the engine.
The 02 can cause a lot of problems as well, but if you aren't getting an 02 sensor problem code, I wouldn't just replace it just yet. Try the Cam Pos. Sensor first then if it runs better but still smokes bad, or gives you a code for the 02 then replace it. I'm thinking if it was just the 02 causing it to smoke so bad it would give a code for it. I think you also have a "Crankshaft Position Sensor as well, but you didn't say you were getting a code for that, so again I would go with the Cam Pos. Sensor.
Good Luck
Dakota49
dakota49
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olscout
Dodge Dakota
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10/04/2008
23:25:02
| RE: 94 Dakota, barely runs
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Thanks for the reply. The part in the distributor is supposed to be the cam position sensor- it plugs into something, I'm guessing the actual probe that does the sensing, but the cam sensor is the part inside the distributor from what I can find out. And it's not showing ANY codes, none at all, we're having to try to hunt this down by using the scanner and going on what my buddy recognizes as OK readings and out of whack readings, and they all seem to be OK, that's what's frustrating. When we scanned it, he said the O2 sensor looked to have about the right voltage readings; since then, he's tried to scare up another O2 sensor (he found one off of a V8 that was nearly new, but it was three wire and mine is four) to save me some money, but so far no luck. Might have to explore that actual sensor or whatever the cam sensor plugs into at the back of the block.....I have no idea of what it is, but I guess I can find one in the JY and see. Any other ideas, keep em coming!
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verdesardog
Dodge Dakota
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10/04/2008
23:40:22
| RE: 94 Dakota, barely runs
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checked fuel pressure?? could be a fuel pump or filter
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olscout
Dodge Dakota
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10/04/2008
23:56:43
| RE: 94 Dakota, barely runs
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Sorry, should have noted that, new fuel pump/filter assembly right after I noticed the original problem, which was the truck was cutting out on hard acceleration (like when you're getting onto an interstate from an off ramp). It would crap out, I assumed fuel pump (160K miles, made sense) so I put in a new one, no change whatsoever. And it's getting plenty of fuel, you could just about light the fumes coming out of the tailpipe......
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olscout
Dodge Dakota
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10/08/2008
11:16:27
|  RE: 94 Dakota, barely runs
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Problem solved, unfortunately more money later than I like. Took it into the shop where my buddy works, and they spent hours on it, dug into the harnesses and all the splices- no luck. Checked all the sensor references for correct voltage, it all looked fine. Finally somebody suggested to pull the crank sensor- bingo. The OEM crank sensor is all plastic, and apparently when the trans was rebuilt (30K miles ago, before I got it) they had cracked the mounting for the crank sensor while installing the new trans. It apparently finished breaking sometime recently, and the actual crank sensor was rubbing against the flywheel and bouncing around, which caused the problems- sometimes it was where it was supposed to be, and it ran OK, rev it up and it would bounce around and cause the engine to cut out and run rough. Since the normal 'fail mode' for a crank sensor is 'go/no go', and it ran with no codes linking to the crank sensor, we didn't think to check it. Something to keep in mind for anybody else having problems.....
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