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ArizonaBob
Dodge Dakota
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1/07/2010
22:00:43
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 Subject: 00 4.7L Rev problem
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I have a 00 Dakota 4.7L auto that I bought and rebuilt the motor. The compression is fine and even, it runs really well. But, it wont rev over 4K RPM and I now have 1100 miles on it. I've checked the MAP sensor, replaced the TPS and IAC and cleaned the TB. I have no vacuum leaks and a nice even vacuum at the manifold. I checked the fuel pressure tonight and it's right at 50psi as the factory manual states,.. I'm at the end of my rope chasing this,.. Any help is appreciated.
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ArizonaBob
Dodge Dakota
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1/28/2010
16:17:27
|  RE: 00 4.7L Rev problem
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So far I've scoped the engine and I have ensured the following: MAP, TPS, IAC, IAT, coolant temp, CKP, CMP.
What I see is that at WOT the timing drops to 12 degrees! OUCH,..
I have access to the MAC Mentor scan tool so wathing these PID's isn't an issue. This one is hard to figure out,.. :(
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daddio
Dodge Dakota
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1/28/2010
17:31:32
| RE: 00 4.7L Rev problem
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Do you have some kind of Flash or Programmer other than stock on the PCM?
Also, I thought the 4.7's used knock sensors? I could be wrong about that but if it does, that could explain where your timing is going.
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moderator
Dodge Dakota
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1/30/2010
13:17:05
|  RE: 00 4.7L Rev problem
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No knock sensors in 4.7 except for the HO versions.
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02dak4x4
Dodge Dakota
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1/30/2010
15:02:55
| RE: 00 4.7L Rev problem
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What happens at 4000 rpm? is it like a rev limiter or does it just stumble? Lets start with some detail so we can help nail this down.
I would first check the crank position sensor, that can have issues if its not working right at higher rpm. (I have seen this behavior with loose bolts on the sensor in a 3.9 ltr). Other then that you could have a restricted exhaust, maybe your cat is plugged up...that happens too.
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ArizonaBob
Dodge Dakota
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2/17/2010
16:59:15
| RE: 00 4.7L Rev problem
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I've dropped the exhaust off of the manifolds and no change.
The MAC Mentor scan tool shows 12 degrees of timing and fixed
at anything over 80% throttle angle,.. WOT. I will have the
transmission checked to make sure the input and output sensors
are functioning correctly.
I've not changed the crank position sensor but even at WOT the
scan tool does show input from the sensor and it is in sync with
the cam position sensor, so I think that's correct.
I don't know if this PCM has some custom programming done. I
do expect that to be possible. I do see junk yard markings on
the PCM itself. Don't these PCM's need to be set to the same
VIN as the TCM and BCM?
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ArizonaBob
Dodge Dakota
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4/27/2010
14:03:12
| RE: 00 4.7L Rev problem
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OK. I have found out what this problem really is,.. When the engine went bad before there were "things" in the oil pan. One of those "things" was part of a tooth from the tone wheel on the crankshaft. The problem happens when the engine reaches an RPM that it requires all of those teeth to be registering on the Crank Position Sensor. The Sensor is throwing the required output at or below 4K RPM,.. but above that the output begins to die off slowly. The downside here is that replacing the tone wheel will require an engine removal and crankshaft pull,. OUCH!
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Dennis
Dodge Dakota
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8/06/2010
12:38:13
| RE: 00 4.7L Rev problem
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I have a similar problem on my '03 Dakota SLT 4.7, but the
computer is showing PC353 - ignition C 3 malfunction, and the
engine is midfiring at idle as well as cutting out at 3000 RPM.
Question - did you truck have the same code, and was it misfiring
at idle too?
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ArizonaBob
Dodge Dakota
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9/27/2010
15:29:54
| RE: 00 4.7L Rev problem
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No,.. the truck threw no codes. Even when the problem manifests itself there are no codes. I still haven't pulled the motor to fix this, but I do have another tone wheel. Incidentally, I did put a new Crank Position sensor in it and it made better top end RPM for a while, so I will put some Dielectric grease in the plug. That's what had to be done for all the other plugs to get the voltage working correctly.
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ArizonaBob
Dodge Dakota
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1/06/2011
11:55:54
| RE: 00 4.7L Rev problem
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I wanted to post a follow up on this. I pulled the motor again and the crankshaft, leaving the pistons and heads on the block. The tone wheel was certainly bad, had been filed and had multiple nicks in it (large chunks gone). I found a bad short block at a wrecking yard and got the owners to agree to let me have the tone wheel off the crank for $50! WOW!
As fate would have it, I used a Haynes manual to assemble the motor the first time. The plan was to extract the motor, replace the tone wheel and reassemble in one day. My plans went terribly off course. The tone wheel screws on the crankshaft were seized! Not a bad thing if you want the tone wheel to stay in place, but not so good if you need to get them off. Drilling them out wasn't really working nicely so I ended up getting the whole crankshaft from the wrecking yard motor and had that converted into a complete crank kit. Not the most economical way to end up, but the best way. I reassembled the motor and to my surprise it's super fast, even in a 4WD truck!
When I had the block and heads done, in order to clean everything up they had to deck the block and heads. Nothing major, but about .005 to .010. The end result with fresh pistons and rings turned out to be about 10:1 compression, a very nice side effect.
I found one other problem when I removed the cam chains. The left side cam wheel had actually sheared the alignment pin off the camshaft and rotated about 15 degrees (read 3 teeth). I put a new stake in the camshaft as well to ensure the alignment and was very careful to ensure correct installation this time.
The end result is a motor that runs great! Runs hard to it's shift points, has very good oil pressure, seems to get OK mileage for what it is and should run for a very long time!
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ArizonaBob
Dodge Dakota
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1/06/2011
11:58:04
| RE: 00 4.7L Rev problem
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Oh! and DO NOT USE a Haynes manual for ANYTHING 4.7L related! IT IS ALL WRONG! Torque specs, clearances, everything is different in the Factory Service Manual.
I've used Haynes manuals for years and never found one to be that far off.
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aab
Dodge Dakota
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11/10/2011
14:10:05
| RE: 00 4.7L Rev problem
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hey, the magnums have rev limiters on it, i have a
durango, it only revs to 4000, but when you drive it
and slam on the gas, i get up to 6-6500 rpm, so
yeah, they put the rev limiter so you dont rev it
higher than you need so that you dont ruin your
engine.
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mike niday
Dodge Dakota
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3/03/2016
18:00:17
| RE: 00 4.7L Rev problem
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Message:
I have a 2003 dodge Dakota, it will not rev over
3200 rpm's, doesn't matter if it's in park, or
going down road and kicking it in to passing
gear, it just starts sputtering and jumping, other
than this problem , truck starts and runs fine,
what is wrong with my truck?
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