HELP! Black Smoke Question + P5 Road Trip Prep

[sgryzko]

So my girlfriend and I are heading down to vegas in August, which will be around a 5000 km round trip. We are taking my P5 with 140,000 km on it, and it has not been behaving lately.

Every time I start it in the morning, it puffs out a dense cloud of black smoke. It seems worse on cold mornings. It seems to run fine other than that though. I took it to the dealership and they said it might be the timing belt, but it would cost me $500 for them to even look at the timing belt. I don't know too much about cars, but I really don't think it's the timing belt.

Have you guys heard of this problem with P5s before? What should I do??

Also, do you have any tips for road trip preparations? I'm obviously planning on checking the tire pressure and changing the oil, but what type of oil is best for a long trip like this? Is there anything else I should do?

Please help!

 

[slavrenz]

Have you noticed a drop in gas mileage lately. Black cluds of smoke usually indicate that your vehicle is running rich, which may be caused by one or more faulty sensors. Do you have a CEL on?

 

[sgryzko]

Have you noticed a drop in gas mileage lately. Black cluds of smoke usually indicate that your vehicle is running rich, which may be caused by one or more faulty sensors. Do you have a CEL on?

Actually, I've noticed an improvement in mileage lately- ever since I put in new ignition coil packs. My current mileage is in the 8.1-8.4 L/100km range (28-29 mpg)

And yes, I do have a CEL on.

 

[slavrenz]

Actually, I've noticed an improvement in mileage lately- ever since I put in new ignition coil packs. My current mileage is in the 8.1-8.4 L/100km range (28-29 mpg)

And yes, I do have a CEL on.

Go to Autozone, Oreilly Auto, Advanced Auto, etc., and have them read this code with their scanner (they'll do it for free). Post the code here - this is really the only way to accurately diagnose your problem.

 

[sgryzko]

Go to Autozone, Oreilly Auto, Advanced Auto, etc., and have them read this code with their scanner (they'll do it for free). Post the code here - this is really the only way to accurately diagnose your problem.

Thanks. I'll do that in the next couple of days and I'll post it on here.

 

[sgryzko]

No luck on the code scanner- everyone wants $110 just to scan the car. I'll keep looking though, and maybe just buy a scanner.

 

[JDMJNKY]

um autozone scan's your car for free.

 

[sgryzko]

We don't have autozones up here in Canada though

 

[JDMJNKY]

humm well that suck's.Anyhow I bought an obdII scanner for like 60 buck's I think might wanna think about doing that.

 

[slavrenz]

We don't have autozones up here in Canada though

You don't have O'Reilly's, Advanced Auto, etc.?

You can get a simple code scanner on eBay for like $30. Those codes are gonna be the key to solving your issue.

 

[bucksatan]

Canadian tire sells many scanners for under $110. Well worth your time to grab one. There is also likely a mazda club of some sort in Calgary, someone would probably be happy to run the code for you. Try posting in the local area of this section, or googling calgary or edmonton mazda club.

Best of luck finding the problem.

 

[RockerPro5]

Dude, just go to Auto Value. They read codes for free (I've had codes read from them before, and they were quite helpful). You could also try Part Source (don't know if they read codes though).

 

[sgryzko]

Dude, just go to Auto Value. They read codes for free (I've had codes read from them before, and they were quite helpful). You could also try Part Source (don't know if they read codes though).

I found a friend that could scan mine. I will definitely try Auto Value next time though- I didn't think about them. I tried NAPA, and apparently they don't read codes period.

Anyway, it came up as:

P0421 Warm Up Catalyst Efficiency Below Threshold (Bank 1)

I had my catalytic converter replaced back in December. Ugh.

 

[thecrash91]

3 possibilities

The catalytic converter is no longer functioning properly
An oxygen sensor is not reading (functioning) properly
A sparkplug is fouled up

or if you have headers spark plug non fouler trick should do it for ya

 

[slavrenz]

Actually, the most likely culprits for this code are:

- Bad catalytic converter (the one near the exhaust manifold, not the one underneath the car)
- Bad front O2 sensor
- Loose front or rear O2 sensor
- Other exhaust gas leakage.

The first thing you should do is contact the dealer. In the U.S., all emission related stuff (like the catalytic converter) is warranted by law for 8 years or 80,000 miles. I'm not sure if they have something similar in Canada, but it may be worth checking into.

Otherwise, if you're the DIY type, clear the code and check for exhaust leaks and make sure that your O2 sensors are tight. If the code comes back on (it may take up to several weeks since the catalytic converter isn't monitored continuously), you will either have to find a scan tool that has live data capabilities or take it to a mechanic who can test to see whether your catalytic converter is bad. I would suggest the second option, since it can get kind of complicated trying to explain how catalytic converter efficiency is measured and what to look for when diagnosing a problem such as this.

My initial guess on all of this is that your front cat is shot. If this is the case, you have several options:

- New OEM catalytic converter (will likely run you close to $1000 after installation)
- New aftermarket catalytic converter (Walker makes a good quality direct fit, which is about a third of the cost of the OEM part)
- CEL Non-Fouler trick (search the forum for this - it basically fools your O2 sensor into thinking that your cat is working)
- Just live with the CEL (not recommended, as you could miss another problem that might also trigger the CEL).

The point is that for a road trip, this code does not mean that your car is going to fall apart or anything. Sure, you'll be polluting a little bit more, but you've said that your gas mileage hasn't suffered, so I think you'll be fine.

P.S. - Maybe go to a different dealer than the one you first contacted. There's no way it would cost them $500 just to look at the timing belt - all they have to do is pop the valve cover off. $80-100 max. Also, since you said that you have had black clouds of smoke, I'm guessing that your front O2 sensor is malfunctioning, and causing too much fuel to be dumped into your engine. This in turn likely caused your front cat to have to work overtime to process all that fuel, and it probably just died because of it. But, since you said your gas mileage is good, this isn't a foolproof theory...

 

[sgryzko]

...for a road trip, this code does not mean that your car is going to fall apart or anything. Sure, you'll be polluting a little bit more, but you've said that your gas mileage hasn't suffered, so I think you'll be fine...

Thanks for the replies everyone. I agree with you, slavrenz. For my road trip, I am not going to worry too much about this, because my performance still seems to be decent.