Ok... having a few odd symptoms, and trying to track down what is going on. Maybe you guys have seen these things before and have some ideas.
Here's the background on the problems, listed in chronological order of appearance:
0. Car Specifications
1. Intermittent Clunk on Accel
2. Coolant light
3. "Chunky" accel towards secondaries opening (900 to 3400 RPM)
4. CELs
5. Airbag light
6. Needle Sweeps
Tests
-Cleaned battery up a while ago, some new corrosion has formed in past month on positive terminal.
-Coolant light after warm start not on (I think)
-Voltage checks OK on batt when cold or when running.
-Alternator recently replaced due to batt light coming on at high RPMs. Replacement was off a 2000 Cougar with 50,000km on it.
-No batt light coming on ever after replacement, and headlights and guages have expected brightness.
-Checked the plugs, they look good (as far as I know. See pics below).
Theories
I'm thinking that the clunk is unrelated, but I have no idea what is causing it. It's not reproducible without load (i.e. when I'm manually operating the TB) so can't really watch what's happening. Ignoring the clunk, I'm wondering if the battery is dying and causing the other symptoms. This is the stock battery -- it has never been changed. I'm thinking that maybe the coolant sensor is very sensitive to low voltage, and maybe the airbag light too. When starting cold, the lack of power in the batt is causing the needle sweeps, random CELs (maybe), and maybe ignition issues. I'm wondering if the chunky accel could be due to the battery having very little amperage or voltage, and the spark plugs aren't getting strong enough juice to ignite the mixture well. As the RPMs rise, the alternator generates enough to compensate for this, and the power smooths out instantaneously past a certain point. This is NOT the fuel pump issue. I've had that, and this is different. Power is still linear, and revs still increase, but it feels... uneven until a certain point.
Other than this... no ideas! Thought maybe my plugs were worn, and thus it took a lot of power to get a good spark (NGK Iridiums I put in in the spring, ~25,000km+ on them). Check the pics below for the front-bank plugs. Someone correct me if I'm wrong, but they look textbook perfect.
Anyone seen these problems before? Is this just a bad battery acting up and causing all of this?
Thanks,
Massiv.
Cylinder 4
Cylinder 5
Cylinder 6
Here's the background on the problems, listed in chronological order of appearance:
0. Car Specifications
- 1999 Mercury Cougar V6
- 5spd Manual
- Modifications listed in signature
- 125,000km [78,000mi]
1. Intermittent Clunk on Accel
- Changed both roll restrictors under the car with SVT units + inserts
- Clunk still present
- Investigated upper mounts (only visual inspection with no removal) and can't _see_ anything wrong
- Manually operating TB plate to rev engine shows no rocking motion at all
- When starting from a stop, there feels like no power till clunk, then goes.
- Could be my perception, but after some clunks, the car feels like a rocket, and after others, like a dud
- Had place that changes my oil double-check my work. They said the bottom mounts were totally solid, and their brief investigation didn't show anything.
2. Coolant light
- Was coming on sporadically, I thought when I parked on slopes
- Figured it was time for a coolant flush anyway, so did that, and coolant light still on
- Had coolant topped right up to MAX line, and maybe a millimeter or two over, still on intermittent.
- No overheating or coolant circulation problems that I can detect thus far.
3. "Chunky" accel towards secondaries opening (900 to 3400 RPM)
- This is a weird one... feels like not all cylinders are firing down low.
- Pretty mild problem, not severe like fuel delivery cut-out due to fuel-pump problem.
- Probably intermittent as well. Maybe temperature dependent, but can't see a pattern yet.
- At point in accel, it suddenly goes perfectly smooth
- Not too much power during "chunky" accel, but pulls really smooth and hard from 3000+
- Part throttle may be smoother, possibly even faster accell, then full throttle down low.
4. CELs
- Had a couple of codes. Scanned them, got P0402 EGR Flo Exces Flow Excessive Detected and P0340 Camshaft Position Sensor A
- Reset the codes, they have not returned.
5. Airbag light
- Saw this flash for the first time just recently.
- This happened as it started to get really cold out here (-20 C / 0 F)
- Restarted car, and no problem. Haven't seen it since.
6. Needle Sweeps
- When I start the car cold, like in the morning, or after work, the speedo and tach sweep smoothly to max vals then back
- If I start it warm, they do not do this.
- Just started happening very recently
Tests
-Cleaned battery up a while ago, some new corrosion has formed in past month on positive terminal.
-Coolant light after warm start not on (I think)
-Voltage checks OK on batt when cold or when running.
-Alternator recently replaced due to batt light coming on at high RPMs. Replacement was off a 2000 Cougar with 50,000km on it.
-No batt light coming on ever after replacement, and headlights and guages have expected brightness.
-Checked the plugs, they look good (as far as I know. See pics below).
Theories
I'm thinking that the clunk is unrelated, but I have no idea what is causing it. It's not reproducible without load (i.e. when I'm manually operating the TB) so can't really watch what's happening. Ignoring the clunk, I'm wondering if the battery is dying and causing the other symptoms. This is the stock battery -- it has never been changed. I'm thinking that maybe the coolant sensor is very sensitive to low voltage, and maybe the airbag light too. When starting cold, the lack of power in the batt is causing the needle sweeps, random CELs (maybe), and maybe ignition issues. I'm wondering if the chunky accel could be due to the battery having very little amperage or voltage, and the spark plugs aren't getting strong enough juice to ignite the mixture well. As the RPMs rise, the alternator generates enough to compensate for this, and the power smooths out instantaneously past a certain point. This is NOT the fuel pump issue. I've had that, and this is different. Power is still linear, and revs still increase, but it feels... uneven until a certain point.
Other than this... no ideas! Thought maybe my plugs were worn, and thus it took a lot of power to get a good spark (NGK Iridiums I put in in the spring, ~25,000km+ on them). Check the pics below for the front-bank plugs. Someone correct me if I'm wrong, but they look textbook perfect.
Anyone seen these problems before? Is this just a bad battery acting up and causing all of this?
Thanks,
Massiv.
Cylinder 4
Cylinder 5
Cylinder 6