Should my car be blowing black smoke?

4sfed5 · Postby **4sfed5** » Mon Aug 14, 2006 4:54 pm

Well you said..\"open exhaust\" That to me means no cat and no mufflers.....if youd said \"cat back\" exhaust then that is a different story

93_Clubman · Postby **93_Clubman** » Thu Aug 17, 2006 12:19 am

adam, mine's also white & gets a similar sootiness but not as concentrated or quickly. your exhaust tip doesn't seem to protrude as far as most which might be contributing to the discolouring. similar to slugoid & others, i get a black sooty condensation in the mornings which has left a long black mark on the concrete where i park. fwiw, from a richness perspective, i get 42mpg with a dyno-tuned piggyback unichip on interstate trips sitting just under 4k rpm & the exhaust tip's still really black. btw, the clubman's looking good...

Adam_NAclubman · Postby **Adam_NAclubman** » Thu Aug 17, 2006 2:18 am

It was definitely dumping fuel on hard acceleration the other day though

You can't see all the scratches and chips in the paint from going through a wire fence in that photo. I wish my cousin would hurry up and get a job so I can get my car sprayed.

sab · Postby **sab** » Thu Aug 24, 2006 2:17 am

I think I have a similar problem.....

Picture was taken after 2000km of mainly highway driving. :shock:

Any sugestions as to the cause and cure would be appreciated.

rodent · Postby **rodent** » Thu Aug 24, 2006 2:27 am

Of all the possible suspects, I think the O2 sensor might be worth checking out first...

Astroboysoup · Postby **Astroboysoup** » Thu Aug 24, 2006 8:44 am

to fix my fuel dumping problems i returned the car back to stock timing and it was fine.

I use to get alot of the symptoms posted here.

at start up there would be fuel dripping from the exhaust.

black smoke under hard acceleration.

I sanded back the black stains on my bumper and resprayed it to get rid of it all.

Once I get off my ass and install the ECU i think it will come back again but probally in a more contorlled manner

sab · Postby **sab** » Fri Aug 25, 2006 12:05 am

O2 sensor was replaced not too long ago.

Might drop the timing back a little and see what happens.

How common is it for the cam belt to jump and skip a tooth? Is there an easy way to tell???

JBT · Postby **JBT** » Fri Aug 25, 2006 6:48 am

sab wrote:How common is it for the cam belt to jump and skip a tooth? Is there an easy way to tell???

I doubt that it could jump teeth unless the tensioner was loose - there would be many poor running problems. The only way to tell is to visually check with the cam cover and cam belt front covers off.

We found Boags' belt to be out one tooth on the inlet cam but he had hot running problems and unsettable ignition timing (1600 engine) as symptoms. It had been put there by the mechanic who changed the belt before he bought it.

How was/is your fuel economy? If it's blowing out excess fuel you could have a suspect injector or two. It could also be the coolant temp sensor which may think the coolant is still cold and thus running the system richer.

How is the oil consumption? Could be burning oil. Are there any visible signs to you whilst driving the car.

sab · Postby **sab** » Fri Aug 25, 2006 10:06 am

Fuel injectors were replaced with new ones at the same time as the o2 sensor.

Fuel economy wasn't too bad at around 550 k's per tank (hwy driving).

Doesn't seem to burn oil. Never needs topping up between services.

What's the story with the temp sensor? Are they expensive to replace?

devolutio · Postby **devolutio** » Fri Aug 25, 2006 10:44 am

kitkat wrote:could the TPS position be causing the problems with Adam's clubman?

ive played around with the TPS on our 5 in the past and noticed with the changes came farting on deceleration and higher fuel consumption and vice versa.

why did you play around with it? there's only one spot for a tps to be set. a farting on deceleration might have been caused by your foot off the throttle, and the computer thinking you still had it on a little (there is an idle contact for when the throttle is closed).

my advice to anyone thinking about 'tuning' their tps to see if anything changes, don't. unless it's been taken off, consult a workshop manual and get out some feeler guages and a multimeter. it's a pain in the arse.

JBT · Postby **JBT** » Fri Aug 25, 2006 11:33 am

sab wrote:Fuel economy wasn't too bad at around 550 k's per tank (hwy driving).

That's about 8.3lt/100km (depending on how much was still in the tank). I get under 8lt/100km cruising at 100-110km/hr, so yours could be running a bit rich by comparison.

sab wrote:What's the story with the temp sensor? Are they expensive to replace?

A bitch to get at because it is on the back of the motor. See this thread and look at the response by Bill Strohm. You may be able to test it using his figures.

sab · Postby **sab** » Fri Aug 25, 2006 8:27 pm

Steve 818 wrote:MX's have two coolant temp sensors. The one at the back of the engine is for the temp guage, and the one at the thermostat housing is for the ECU.

Thanks Steve. Guage is working fine. Bonus with the ECU sensor being at the front and easier to access, provided that's the problem.....

Russellb · Postby **Russellb** » Fri Aug 25, 2006 8:39 pm

sab wrote:
Steve 818 wrote:MX's have two coolant temp sensors. The one at the back of the engine is for the temp guage, and the one at the thermostat housing is for the ECU.

Thanks Steve. Guage is working fine. Bonus with the ECU sensor being at the front and easier to access, provided that's the problem.....

NA6's have Three Sensor two in the back off the head One for gauge and one for ECU And then one on the Thermastat housing for the fan
NA8 had Two both in the back of the Head and none in the thermastat housing