| From | Message |
Chris
GenI
 
8/29/2009
09:21:42
|
 Subject: ANOTHER Rough Idle Issue 3.9
IP: Logged
Message:
Hi everyone - new to the forum. Glad to be here. Please take time to weigh in on this issue as I am out of easy answers.
Couple weeks ago I stumbled onto a 92 dakota 3.9 magnum extended cab truck....with 98kmiles on it...owned by some older folks...bought it...paid only a grand for it. Truck is in pretty much immaculate shape. The owner said it had a small engine noise (before I bought it) but I looked at it and chalked that up to a bad water pump.
I changed the water pump out which made the engine noise disappear - did a complete tune up on the motor which consisted of:
-clean and inspect IAC (works now)
-shake PCV valve (works)
-replace cap, rotor, and spark plug wires
-replace spark plugs
-clean and inspect crank case ventilator (don't know exactly what it's called on this truck)
-cleaned throttle body
-replaced air filter
-replaced egr valve and vacuum controller
I have inspected all the vacuum hoses that lead to and from the engine and all 'appear' to be fine...in addition...I sprayed carb cleaner all over each and every vacuum point to see if I could get the motor to stumble...no stumble. Throttle body bolts are tight and all the intake manifold bolts are tight. No hissing.
All cylinders register right around 150lbs EXCEPT #4. #4 cylinder is 120lbs.
I have NOT taken off the throttle position sensor and looked at it or replaced it. I have not taken off the map sensor and looked at it either. I have not looked at the PCV grommet or the CCV grommet...but...the motor doesn't stumble when I spray them either. There is no check engine light on (I don't even know if this model has one).
I don't have a borescope so I can't look at the piston on number 4 or the valves for that matter.
The engine will run like a top when you are the accelerator...but when you stop at a light and the truck is in gear...it will 'lope' real hard. Shakes the whole truck. I don't think this is electrical. No light shows at night.
Can someone recommend something I might have overlooked?
Thanks folks!
Chris
|
well
Dodge Dakota
JOIN HERE
8/29/2009
10:14:43
| RE: ANOTHER Rough Idle Issue 3.9
IP: Logged
Message:
Hi Chris
Welcome to dodgedakotas.com
and Congrats on the Dak
OK as for "All cylinders register right around 150lbs EXCEPT #4. #4 cylinder is 120lbs. "
The 30lb dif. is a bit high
Try retesting the cyl. dry then with a squirt of oil in it. Mileage is pretty low I can't imagine it would be rings. Unless sat awhile an compression rings are gummed up an stuck.
Moving right along, Get a fuel pressure gauge on the schrader valve (located on fuel rail near TB)
If you don't have one try a tool loaner program at a local auto parts chain store.
Post results of pressure with just key on then with motor at idle.
|
Chris
GenI
8/29/2009
11:59:51
| RE: ANOTHER Rough Idle Issue 3.9
IP: Logged
Message:
Thanks for the input. Actually the truck did sit for a while. From somewhere in 2005 until the middle of August this year it had less than 3kmiles put on it. I've run an entire tank of 93 octane with a bottle of Seafoam thru the motor. Still no change.
I haven't checked the fuel pressure. If that's low it would mean the fuel sending unit is not operating correctly, as I just changed the fuel filter. I'll get right on that.
|
Bob Lincoln
Dodge Dakota
JOIN HERE
8/31/2009
08:02:52
| RE: ANOTHER Rough Idle Issue 3.9
IP: Logged
Message:
And it does have a Check Engine light, so you can check fault codes:
http://www.allpar.com/fix/codes/index.html
|
| | P 1 |
|
Post a reply to this message:
Username Registration: Optional
All visitors are allowed to post messages
|
