Noise Coming From Engine At Around 2500 Revs

[Erudite]

Hi,

I recently picked up an 04 MR2.

When revving the engine hard, some black smoke comes out of the exhaust. The exhaust is also lined with black soot. The engine smells slightly of petrol at times.

I recently picked up the car, it's been fitted with a stainless steel manifold and a TTE exhaust.

I believe that the previous owner had fitted the new exhaust fairly recently.

I read this thread here where someone had a similar issue after fitting a TTE exhaust: https://www.mr2roc.org/forum/index.php?topic=53476.0

Could it just be an issue with the new exhaust or something more serious like pre cat failure?

I've done around 200 miles in the car now and haven't seen any noticeable drop in the oil level.

Sorry if I've not provided enough information, I'm currently have very little knowledge on cars and am just trying to start to narrow down what the issue may be.

[shnazzle]

It's very likely the car is running very rich.
This can be due to an air leak on your intake, a duff MAF sensor (just behind the airbox), a duff o2 sensor or two, or a leak in your exhaust.

I'm guessing you're doing not much in the way of mpg

[Ardent]

Hello and welcome.

We always like to start with the basics 1st.

What is the state of the air filter?

A simple but full service is a good place to start
Oil n filter less than £30.
Air filter 5-8
Set of plugs sub £10.
Maf clean. Free if you have car cleaner in stock.

[Ardent]

any engine codes eml lights?
Does the eml come on then go off when starting?

[Ardent]

nothing to do the the engine. But if thats not been maintained correctly. Check your tyres. If there cheapo ditch finders, budget for some proper tyres.

But 1st lets sort the smoke out.

[Erudite]

Thanks for all your replies. I'll check the eml and air filter tomorrow morning.

It is an aftermarket K and N air filter. Could this be causing any issues?

If it were the O2 sensors or maf, are these costly to replace?

[shnazzle]

Thanks for all your replies. I'll check the eml and air filter tomorrow morning.

It is an aftermarket K and N air filter. Could this be causing any issues?

If it were the O2 sensors or maf, are these costly to replace?

It can choke the engine if it's dirty or over-oiled. If over-oiled it can also affect the MAF. There's lots of ifs so @Ardent is spot on. Give it a good service and then you've got a clean slate to start with. 


New plugs (12gbp)
https://www.sparkplugs.co.uk/ngk-spark-plug-bkr5eya-11

New air filter (14gbp)
https://www.partsforallcars.com/za001607

Clean the MAF with some carb cleaner 
https://www.eurocarparts.com/p/wynns-air-intake-carb-cleaner-500-ml-555770650?type=shopping&gclid=CjwKCAjw97P5BRBQEiwAGflV6bkFUUD7Mhd4QDXpOjQPG4X4nuoG9J2-lSKsnMUl7e5LE_DsADpZaRoCkK4QAvD_BwE

If you can be bothered, a fresh oil and filter change 

Then reset the ecu, and take stock of where you are. 

If a new o2 is needed; they are about 65 new each. Or 30gbp I'd you don't mind crimping 3 wires of the connector onto the sensor yourself. No soldering needed.

[Gaz mr-s]

From your 1st post it sounds like you haven't dealt with a maf before.  If you don't know exactly what to do ask & someone will oblige.

[Carolyn]

Black smoke, fuel.
Blue smoke, oil.
White smoke, coolant
Pink smoke, too many mushrooms.

[Ardent]

That's a keeper.       

[Ardent]

some black smoke comes out of the exhaust. The exhaust is also lined with black soot. The engine smells slightly of petrol at times.

I recently picked up the car, it's been fitted with a stainless steel manifold and a TTE exhaust.

Could it just be an issue with the new exhaust or something more serious like pre cat failure?

I've done around 200 miles in the car now and haven't seen any noticeable drop in the oil level.

For now, keep a close eye on the oil. (even better after you have change it.)
Pre cat wise. Good, you don't have any. Bad, you don't know what condition they were in.
How much black smoke?
Lets get a service done and go from there.

Does not matter, but dealer or private?

[MRSwede]

Maf Mod with wrong Injectors ?

https://www.mr2roc.org/forum/index.php?topic=51647.0

[Erudite]

Thanks for all the help so far everyone, it's much appreciated!

I think I'm going to start this weekend by checking the kn air filter panel to see if it's dirty or over oiled (I'll probably also order the replacement filter that @shnazzle linked as it seems more straightforward than having to re oil the kn filter), cleaning the maf and resetting the ECU.

These seem to be the most straightforward jobs I can do with the tools I have to hand.

I can then do a service once I can get over to my friend who has some tools I can borrow.

Could there be any detrimental effects in running the car in the short term while it has this issue?

Sorry again for my lack of knowledge, this is the first car I've maintained so I'm trying to learn as much as I can.

@Ardent it was a private sale. An American had bought it with the intention of exporting it to America. Only to find out that you can't export cars under 25 years old. 

[Carolyn]

Thanks for all the help so far everyone, it's much appreciated!

I think I'm going to start this weekend by checking the kn air filter panel to see if it's dirty or over oiled (I'll probably also order the replacement filter that @shnazzle linked as it seems more straightforward than having to re oil the kn filter), cleaning the maf and resetting the ECU.

These seem to be the most straightforward jobs I can do with the tools I have to hand.

I can then do a service once I can get over to my friend who has some tools I can borrow.

Could there be any detrimental effects in running the car in the short term while it has this issue?

Sorry again for my lack of knowledge, this is the first car I've maintained so I'm trying to learn as much as I can.

@Ardent it was a private sale. An American had bought it with the intention of exporting it to America. Only to find out that you can't export cars under 25 years old. 

You're making a good start.  Tip - take the O ring off the MAF before your spray it with carb cleaner, as the solvent will swell and soften it.

I love your username, I do hope you're a pedant also?

[Gregmorse]

Black smoke = too much fuel/too little oil, perhaps fuel injector issues

[Erudite]

Update:

I cleaned the MAF. Along with cleaning and and oiling the k and m air filter.

This seems to have cured the black smoke problem.

However, the car is still running rich. If I have the window down with the roof up and the wind is blowing into the cabin there's a definite smell.

It also looks like there may be a leak on the engine?





I'm thinking the next thing may be to get an OBD scanner and upload the readings. Would this potentially help to narrow down the problem?

[shnazzle]

That is definitely soot deposit where there shouldn't be. 
 Won't take much to find out where it's blowing there. 
Either crack in that manifold runner or the gasket would be first guess. Easy sorted. 

Sucking in air there could very well lead to the car overfueling as it's running fresh air over the o2 sensors.

[Erudite]

That is definitely soot deposit where there shouldn't be.
 Won't take much to find out where it's blowing there.
Either crack in that manifold runner or the gasket would be first guess. Easy sorted.

Sucking in air there could very well lead to the car overfueling as it's running fresh air over the o2 sensors.

Thanks. I went and had another look this morning and took a couple of video's. That whole side of the engine looks pretty sooted up and grimey.


First video:

https://streamable.com/0u1l6g

Second video:

https://streamable.com/8ozpe3

Is there an easy way to check for the manifold/gasket blowing in that area? Do you think it could be more than that looking at the soot deposited on that side of the engine in the video?

[AdamR28]

A blowing exhaust gasket is pretty obvious, even with it idling you will be able to hear where a blow is coming from.

[Erudite]

A blowing exhaust gasket is pretty obvious, even with it idling you will be able to hear where a blow is coming from.

Thanks, I started it up and couldn't detect any sign of blowing.

On checking the oil I noticed a smell of petrol (as though petrol was mixing with the oil). Could this point to an issue with the injectors?

As a side note I also noticed this mastic on the right hand side of the engine:

[AdamR28]

On checking the oil I noticed a smell of petrol (as though petrol was mixing with the oil). Could this point to an issue with the injectors?

This is almost certainly linked to your black smoke issue. From reading up, sounds like you've had too much fuel going in, and this surplus finds its way into your engine oil. It would be worth doing an oil and filter change asap.

I'm not familiar with the 1ZZ yet but that looks like the rocker cover / cam cover? If yes, then I would guess someone a bit over zealous with the mastic on fitment at some point - should be nothing to worry about, unless chunks of it have found it's way into the engine which is unlikely.

How do you know the car is running rich, just by smell?

[Erudite]

On checking the oil I noticed a smell of petrol (as though petrol was mixing with the oil). Could this point to an issue with the injectors?

This is almost certainly linked to your black smoke issue. From reading up, sounds like you've had too much fuel going in, and this surplus finds its way into your engine oil. It would be worth doing an oil and filter change asap.

I'm not familiar with the 1ZZ yet but that looks like the rocker cover / cam cover? If yes, then I would guess someone a bit over zealous with the mastic on fitment at some point - should be nothing to worry about, unless chunks of it have found it's way into the engine which is unlikely.

How do you know the car is running rich, just by smell?

Yes at the moment just by smell. When reversing or if the wind is blowing from the back of the vehicle there's a distinct smell of fuel.

Thanks for the heads up re: the mastic. I'll go ahead and do an oil and filter change.

[AdamR28]

Righto! I don't know enough about the 1ZZ specifically to help any further, without an OBD code anyway, but I'm sure someone else will be along with more info soon.

[MRSwede]

On a daily driver with short distance drives, the oil tends to smell petrol.

The yellow lump ? The previous owner try to fix a broken gasket ?

At the end of second video it looks like water drops, wipe it with one finger and then rub it between two fingers to deicide if its oil or water.

Water maybe not that god, oil maybe the gasket is broken in some more places.

[Erudite]

You're making a good start.  Tip - take the O ring off the MAF before your spray it with carb cleaner, as the solvent will swell and soften it.

I love your username, I do hope you're a pedant also?

Pendant, erudite, luddite, troglodyte, all words that may apply.

That is definitely soot deposit where there shouldn't be.
 Won't take much to find out where it's blowing there.
Either crack in that manifold runner or the gasket would be first guess. Easy sorted.

Sucking in air there could very well lead to the car overfueling as it's running fresh air over the o2 sensors.

I had a look using a feather attached to the end of a pencil and couldn't see any signs of air being sucked in around this area.

I think a lot of the soot in this area might be from an oil leak from the timing chain tensioner.

I picked up a cheap OBD bluetooth scanner and pulled some data from the torque app. I watched a lengthy youtube video on using the data for diagnosis but it only focused on lean rather than rich conditions. It hopefully helped me to understand what some of the readings were though.

This is the data I gathered so far (I was unsure how to take a log, so I took a few screenshots):



Is fuel trim bank 1 sensor 2 completely broken? Bank 1 x 1 and 2 x 1 look to be acceptable? But as can be seen they intermittently take a really rich reading. It will drop and then quickly pull back into range.




When reducing revs STFT runs lean and then when it adjusts it appears that bank 2x1 runs incredibly rich for a short period.

Also, do the O2 sensors look ok? 1x2 has little variance and when idle it sticks at 0.7v.

All readings were taken while stationary. Can anything be ascertained from them?