So I've been chasing a stall problem that was somewhat intermittant that has become an almost daily occurence. Vehicle is a 2006 Dodge Ram 1500 SLT QC SB 5.7L Hemi MDS 545RFE 4x2 3.55 gears 137K miles.
Changed most of the plugs (12 of 16) last Sunday. Will do the remaing 4 (the toughest to access) this Saturday. See the Spark Plug thread in the Ram forum (http://www.allpar.com/forums/topic/139430-spark-plugs/).
Thought that might cure the stalling problem which usually only happens on cool/cold mornings. It'll stall or nearly stall at the first stop within a mile or so of the house. Refires with no problems. Could actually feel the engine stumble as I slow to a stop. Changing the plugs made no difference. Even though the CEL was not on, I stopped at Advance Auto last night to have them check for any fault codes that may be stored, but not triggering the CEL. I was inclined to think the EGR was going bad (replaced at 83K).
Imagine my surprise when the code reader found this:
P1521 - Incorrect engine oil.
As I had the last oil change done by the local Firestone shop, I checked the service invoice and it says they used 5W-20 which is the recommended weight for the Hemi with MDS. Hmmmmmm...... The more I thought about it, the stalling became more prevalent after the last oil change and has become progressively worse with the cooler weather (ambient temps around 40*F in the morning now).
Since an oil change was due (last done at 133K and the truck has 137K now). Put in Castrol 5W-20 (7 qts) and a Purolator filter. First time in a long time I did an oil change after dark (yes, I do have work lights). Maybe it was just me, but the engine sounded smoother after the change and guess what - it did not stall this morning!
So that brings to mind - what was wrong?
1) Did Firestone use the wrong weight oil (10W-30) even though the service invoice indicates 5W-20?
2) Oil pressure sensor going bad (the gauge has been normal as far as I can tell)?
3) Anti-drain valve in the filter failed?
4) Just a quirk?
I'm inclined to send a sample of the oil to a tester to verify it was the proper grade- if that indeed can be tested for(?). If not, I'm going to have a talk with the Firestone manager.
I know the proper grade is critical for the MDS (Multiple Displacement Service) to operate correctly so I generally do oil changes myself or at the dealer. I've never seen this code come up before nor did I have stalling issues like this (EGR issue aside) - it did not stall everyday when the EGR was bad (P0406) though it did eventually set the CEL.
Googling the web I found a P1521 could be two different issues depending on the vehicle:
1) Incorrect Engine oil or
2) Transmission Engaged at High Throttle Angle
Get more discussion results
Thoughts anyone?
Changed most of the plugs (12 of 16) last Sunday. Will do the remaing 4 (the toughest to access) this Saturday. See the Spark Plug thread in the Ram forum (http://www.allpar.com/forums/topic/139430-spark-plugs/).
Thought that might cure the stalling problem which usually only happens on cool/cold mornings. It'll stall or nearly stall at the first stop within a mile or so of the house. Refires with no problems. Could actually feel the engine stumble as I slow to a stop. Changing the plugs made no difference. Even though the CEL was not on, I stopped at Advance Auto last night to have them check for any fault codes that may be stored, but not triggering the CEL. I was inclined to think the EGR was going bad (replaced at 83K).
Imagine my surprise when the code reader found this:
P1521 - Incorrect engine oil.
As I had the last oil change done by the local Firestone shop, I checked the service invoice and it says they used 5W-20 which is the recommended weight for the Hemi with MDS. Hmmmmmm...... The more I thought about it, the stalling became more prevalent after the last oil change and has become progressively worse with the cooler weather (ambient temps around 40*F in the morning now).
Since an oil change was due (last done at 133K and the truck has 137K now). Put in Castrol 5W-20 (7 qts) and a Purolator filter. First time in a long time I did an oil change after dark (yes, I do have work lights). Maybe it was just me, but the engine sounded smoother after the change and guess what - it did not stall this morning!
So that brings to mind - what was wrong?
1) Did Firestone use the wrong weight oil (10W-30) even though the service invoice indicates 5W-20?
2) Oil pressure sensor going bad (the gauge has been normal as far as I can tell)?
3) Anti-drain valve in the filter failed?
4) Just a quirk?
I'm inclined to send a sample of the oil to a tester to verify it was the proper grade- if that indeed can be tested for(?). If not, I'm going to have a talk with the Firestone manager.
I know the proper grade is critical for the MDS (Multiple Displacement Service) to operate correctly so I generally do oil changes myself or at the dealer. I've never seen this code come up before nor did I have stalling issues like this (EGR issue aside) - it did not stall everyday when the EGR was bad (P0406) though it did eventually set the CEL.
Googling the web I found a P1521 could be two different issues depending on the vehicle:
1) Incorrect Engine oil or
2) Transmission Engaged at High Throttle Angle
Get more discussion results
Thoughts anyone?