2002 S60 Rough idle but smooth at higher RPM

quietcoolone · Post by **quietcoolone** » 05 Jan 2015, 14:35

draser wrote:If the misfire condition is combined with fuel trim numbers it points to a headgasket, do you lose coolant?

none that i can account for

draser · Post by **draser** » 05 Jan 2015, 19:13

Is the front O2 sensor switching within the second when rich/lean conditions are created, and did you check for air leaks all the way to the sensor, exhaust included? I believe you checked all intake side. Did you ever get an engine light for lean code? And I forgot to ask if all the MAFs showed same signal levels on vida, at idle and 2.5k?

quietcoolone · Post by **quietcoolone** » 06 Jan 2015, 09:08

draser wrote:Is the front O2 sensor switching within the second when rich/lean conditions are created, and did you check for air leaks all the way to the sensor, exhaust included? I believe you checked all intake side. Did you ever get an engine light for lean code? And I forgot to ask if all the MAFs showed same signal levels on vida, at idle and 2.5k?

- Monitored lambda on the 02 sensor : fluctuating between 1.00 and 0.98 (min) and 1.02 (max)
- did not yet check air leaks on the exhaust manifold. There is a shield that needs to be removed before anything so i will try to do that soon.
- have not gotten a lean code
- YES, they 4 sensors are reporting similar numbers both at idle and 2.5K.

I must add:
When the manifold was off, i decided to inspected the PCV system. Both the return and inlet holes on engine were partially blocked. These were cleaned out and i also flushed the trap (box) with carburetor cleaner and put everything back together. Today (while testing the MAF sensors) i pulled the oil stick and oil filler cap and saw a little smoke coming out. I also placed a rubber glove over the oil filler hole and it did not inflate nor get sucked in. I'm not sure this relates to the issue but thought i would mention it.

draser · Post by **draser** » 06 Jan 2015, 10:11

So MAF's out of the equation. What bothers me is the misfire on all cyl. condition, if the mixture is so lean to cause this the plugs should be white and engine cooked. I'd take a step back though, and look at all repairs done and n-ple check pcv system to be air tight, intake gaskets, vac hoses, etc. I'd pull the plugs as well to see what they look like. Can you read intake manifold pressure with Vida?

draser · Post by **draser** » 06 Jan 2015, 10:17

Don't remove the exhaust shield, you should be able to hear exhaust puffs if there's a leak in there.

quietcoolone · Post by **quietcoolone** » 06 Jan 2015, 10:37

draser wrote:So MAF's out of the equation. What bothers me is the misfire on all cyl. condition, if the mixture is so lean to cause this the plugs should be white and engine cooked. I'd take a step back though, and look at all repairs done and n-ple check pcv system to be air tight, intake gaskets, vac hoses, etc. I'd pull the plugs as well to see what they look like. Can you read intake manifold pressure with Vida?

I don't know how to explain this but they are inconsistencies with this engine.
Today for exampled while testing the MFA's, there was no misfire--- (had engine running on and off for about 20 minutes and coolant temperature 100 degrees C )
Rough idle but smooth after rev up to 3K RPM. Put in R or D and the engine acts up again.
The PCV connections to the engine are air tight.. (i double checked the two short hoses to engine block, the top one and the one into the manifold)
I have spayed carburetor fluid on the elbow hose entering to manifold, top hose, air hoses to MPF, brake booster and air box, none of which changed the idle speed. I also sprayed around the gaskets ( engine to manifold and manifold the ETM).
If there is a leak it must be on the back side and i will check later today or tomorrow.
The spark plugs are new (less than a week old), and i took one out yesterday and it was not white or gray.. a bit brown with no oil deposit.
BTW, there is an intake manifold pressure parameter in Vida but nothing shows up so i guess there is no sensor on manifold to provide that info.
I'm also grateful for your help.-- my daughter also says thank you!

draser · Post by **draser** » 06 Jan 2015, 12:33

Can you post fuel trims after using or driving car for a while, best you can in this condition? And can you see schematics of the evaporative/emission system in Vida? I'd look into that for air leaks as well. Was the engine running differently when you bought this car?

Post by **FLXC90** » 06 Jan 2015, 14:40

FWIW how about the low-tech approach, vacuum gauge on manifold to check for leaky valves, engine condition etc. With that mileage, and a previously gummy PCV, it might be sludgy?

quietcoolone · Post by **quietcoolone** » 06 Jan 2015, 15:41

draser wrote:Can you post fuel trims after using or driving car for a while, best you can in this condition? And can you see schematics of the evaporative/emission system in Vida? I'd look into that for air leaks as well. Was the engine running differently when you bought this car?

I got the car with a few issues (large and small ): oil leak, driveshaft seal in tranny, rear door lock, fuel door lock, blower on/off potentiometer, shocks . The car initially was hunting for idle. Ran Vida ETM test and the throttle sensors were off by 78.5 degrees. Replaced ETM part # 8644345 with another (same part number and software number) throttle sensors off by only 2.05 degrees.

Just took a 25 mile run most of which was on hway at 65MPH, and logged scanner data as best i could:
First 5 miles (local street 45MPH)
FuelSys1 CL
Load_pct(%) 29.8
SHRTFT1(%) 8.6
LONGFT1(%) 21.1
ECT 186 degrees

On HWY
10 miles
FuelSys1 CL-Fault
Load_pct(%) 34.1
SHRTFT1(%) -4.6
LONGTFT1(%) 14.8
ECT 186 degrees

15 miles
FuelSys1 CL-Fault
Load_pct(%) 30.6
SHRTFT1(%) 9.4
LONGTFT1(%) 15.6\
ECT 186 degrees

20 Miles
FuelSys1 CL-Fault
Load_pct(%) 38.8
SHRTFT1(%) -4.7
LONGTFT1(%) 15.6
ECT 186 degrees

off hway idling at stop sign:
FuelSys1 CL-Fault
Load_pct(%) 19.2
SHRTFT1(%) 24.2
LONGTFT1(%) 50.0

ECT 186 degrees

parked in garage
FuelSys1 CL-Fault
Load_pct(%) 15.3
SHRTFT1(%) 24.2
LONGTFT1(%) 50.0
MAP(psi) 7.7
RPM 707
SparkADV 7.0
IAT(F) 86
MAF (lb/s) 0.01
TP(%) 2.0
O2B1S1(V) 0.79
SHRTFTB1S1(%) 24.2
O2B1S2(V) 0.005
ECT 186 degrees

once in garage car stared idling erratically, stink exhaust fumes, but no CEL . Turned it off and found 3 pending codes :
P0420 Catalyst System Efficiency Below Threshold (Bank 1)
P0068 MAP/MAF
P0171 Fuel System Too Lean Bank 1
It appears that Fuel trims seem to get better at high RPM with awful at idle but hopefully this information helps and if not i will continue to provide anything that may be helpful.

Post by **FLXC90** » 06 Jan 2015, 17:58

You mentioned that once you were in the garage you could smell stink of exhaust fumes-just exhaust smelly, or rotten egg-catalytic converter dying smelly? Granted you are currently running lean, but misfires and a not-leaned out combo will cook a cat. Also, if there is excessive backpressure at idle, it could possibly cause poor scavenging at idle and a funked-up fuel mixture..