Smokes Liek a steam Engine

[OptimisticRed]

Hi Folks,

My MR2 now smokes like a steam engine. The link on Youtube perfectly shows it:

 m http://youtu.be/T0FBBLZdMGQ m

My post cat O2 sensor has gone, could this be the reason?

Thanks

[onion86]

My post cat O2 sensor has gone, could this be the reason?

Nope wouldn't be caused by that. I'm not too knowledgeable with smoking engines but I'm sure someone else will be along to help, doesn't look good though  s:? :? s:?

[AndyM]

Hi,

No idea either I'm afraid but the same video was referenced in this thread...
 l viewtopic.php?f=11&t=44340 l

Andy

[Jay67]

could be running rich because of the faulty sensor

[onion86]

could be running rich because of the faulty sensor

Not a post cat one.

[Jay67]

could be running rich because of the faulty sensor

Not a post cat one.

oops, misread it, ignore me   s:oops: :oops: s:oops:

[shnazzle]

That's mine...
Can't say I have a resolution.

It's not running nicely though. It ran beautifully on our trip to Hartside though. Can't put my finger on it.

It's definitely running rich a lot, and then other times it seems fine. When it runs rich it smells of petrol and when cold the car idles real low and stutters until it gets going a bit.

Open to suggestions because I'm sick of it too.

My bank 1 sensor1 (right side) heater element is kaput. I know that.

[Jon_G]

Running rich might mean the MAF sensor is faulty or in need of cleaning.

[shnazzle]

Running rich might mean the MAF sensor is faulty or in need of cleaning.

Anybody know if I can test the MAF with a multimeter? What values would I be looking at?

[GSB]

Water temperature sensor? Been a reeeeaaaaalllly long time since I've looked at a BGB, but running really rich when its supposed to be in closed loop fuel control? The ECU may well be reading a low / non-existant water temperature reading, and running the start up rich mixture program.

If its intermittent, it may not bring up a CEL on the dash.

Edit: actually, it says as much in the notes on the video...  s:roll: :roll: s:roll:

[Wabbitkilla]

Hi Folks,

My MR2 now smokes like a steam engine. The link on Youtube perfectly shows it:

 m http://youtu.be/T0FBBLZdMGQ m

My post cat O2 sensor has gone, could this be the reason?

Thanks

How long had your engine been running when you took this?
Was it cold?
What rpms?

Listening it sounded like it was in high idle state, therefore not warmed up. When cold it's normal for engines to pass a bit of steam, though I admit I haven't checked my own as I normally just get in and drive off   s:lol: :lol: s:lol:   I did notice when we were driving around Hartside you passed a bit of smoke, not sure if they were puffs of oil smoke or being rich. Mafs aren't that straight forward to test as any measurements taken it idle bear little relationship to when you're flying along the road. I would definitely recommend a regular clean (every 6 or 12 months) and maybe try getting a spare one and see if it makes a difference.

[GSB]

Last time I came across a car with a knackered MAF. It had very different symptoms to this. It wouldn't rev properly for a start, anything over 4000rpm was not possible.

It's still worth trying, but I don't think its the flow sensor that's causing this (unless of course this could be caused by a defective air temperature sensor, also included in the MAF).

[shnazzle]

That video was indeed taken at cold startup. But it did the smoking for a good while. Took it for a drive afterwards and still saw smoke in my rear view, which I've never had on a petrol before. I'm disappointed when I don't see smoke come out of my soot chucker  s:) s:)

I don't think it's puffs of oil, as its brown/yellow in colour from the looks of it.
Seeing as I got that P0125 error I'm tempted to think it may be the temp sensor.

The car really struggles around idle and cold starts are horrible.

[Wabbitkilla]

Looks like a normal cold start to me then, steam is a sign of efficient combustion   s:wink: :wink: s:wink:  
The exhaust is relatively short on the 2 so could explain it appearing more than a regular car, plus you're closer to the exhaust tips.

Just give the mad a clean and reset the ECU, worth either replacing the sensor or putting a resistor in. It's not a heat sensor, it's a heater to warm up the sensor so it's reading accurately quicker. It can over a long time result in an inaccurate fuel trim but nobody's complained about it being noticeable before.

[shnazzle]

Looks like a normal cold start to me then, steam is a sign of efficient combustion   s:wink: :wink: s:wink:  
The exhaust is relatively short on the 2 so could explain it appearing more than a regular car, plus you're closer to the exhaust tips.

Just give the mad a clean and reset the ECU, worth either replacing the sensor or putting a resistor in. It's not a heat sensor, it's a heater to warm up the sensor so it's reading accurately quicker. It can over a long time result in an inaccurate fuel trim but nobody's complained about it being noticeable before.

I cleaned the MAF not long ago. Few weeks ago. And reset the ECU at David's soon after.

By temperature sensor I meant the coolant temp sensor on the left. Not the heater element, which I know has gone.

[Wabbitkilla]

Not sure but if the coolant sensor wasn't working you would mean your idle wouldn't change whether the engine was warm or not. A more complicated obdii reader would show live readings from all sensors, I had one with me at Hartside. The sensor is surprisingly expensive, so worth finding a way of testing it.

Of course the maf can go faulty, cleaning is only maintenance. Best to see if you can borrow one from somewhere as it's easier to swap out than the coolant temp sensor.

[GSB]

Unbelievably, its been 6 years since I owned an MR2, so I'm a bit rusty. However, recent annoyingly similar problems on a Peugeot have led me down a similar path to this, and modern engines use very similar control philosophies now, since the advent of standardisation and OBD capabilities.

So here's a few pointers that might help.

My research thus far seems to indicate that if the coolant sensor is defective, it will first cause the engine to run rich, whether its cold and needs it, or hot and it then massively overfuels. The over fuelling will cause odd emmisions and fouling of spark plugs, and because the ECU uses the signal for so many other functions, limitation of power, limiting of VVTi, poor idle, rough running and poor starting may also be evident.

Steam out the exhausts can be related to head gasket failure, but dont panic, its not automatically that bad. Water vapour/steam is also generated in the catalysts and can be more evident when the fuel has a high moisture content, and if there is high humidity in the air. Given the right weather conditions, all modern petrol engines will emit huge plumes of steam when they are running a cold start program.

Modern engines use multiple sensors, so the reading on the dash doesn't nessesarily come from the same sensor the engine uses for control. The fact that your temperature gauge works doesn't mean the ECU can see how hot things are.

Depending upon which resource you read, failure of the coolant sensor seems to result in the engine running open loop all the time, in which case the MAF & O2 sensors aren't used anyway. Checking seems a fairly simple procedure though

Lastly, dont let the massive compexity of modern engines fool you. After all your research, you might find that the problem can be traced back to a the perennial favourite of old cars, £4's worth of knackered thermostat. When stuck open, the engine will rarely get to full operating temperature, resulting in many of the problems you've already described.

Check your sensor using this guide;
 m http://www.autozone.com/autozone/repair ... 3f803801b1 m

[shnazzle]

That's helpful. Thanks!
From what I gather from your post, it has all the symptoms of that temperature sensor being faulty.

I'll see if its passing anything.

The only thing is...logs do show that the ECU is responding to lean/rich conditions as reported by the O2. When O2 voltage reads on the rich side, the short term fuel trim shows this inversely.

[shnazzle]

So yeah today the car stalled while driving.

SICK of these issues. Had just started, was slowing down for a light at about 20mph when it died. Spent the rest of the drive to work hauling ass and it hauled nicely.

This cars seems to only want to go fast!!!

Upon stopping at work, I got out and noticed the car smelled like it was on fire  s:) s:)  This could be normal due to the way it had just been treated, or....mucho oil burno.
Will check oil when I get home.

[Wabbitkilla]

CHECK THE OIL AT WORK BEFORE YOU SET OFF!   s:evil: :evil: s:evil:

[shnazzle]

CHECK THE OIL AT WORK BEFORE YOU SET OFF!   s:evil: :evil: s:evil:

I suppose that is the wise decision. Didn't sound like it was out of oil though. And I did check after last time I drove it and the oil was still full

[Wabbitkilla]

Better safe than sorry mate   s:wink: :wink: s:wink:  
It's cheaper to replace the pistons and re-hone than it is to replace the whole engine   s:? :? s:?

[shnazzle]

Yup oil down significantly.

...list of expletives...

Could all be coming out of that leaky tensioner...hopefully...right??

Argh

[shnazzle]

Double post

[shnazzle]

Some more symptoms noticed today.

Popped off the oil filler cap and gave it a sniff.....petrol.

Am I hoping for something as innocent as missing spark?

In any case I guess I best not run it until I can drain it.