Black soot / blobs out of exhaust on startup / cold start

[stevex]

Hi Guys,

I've got other issues with the car to sort but, on cold start I noticed black soot firing out of the exhaust on to my driveway, little blobs of it that come out with the condensation.

The car does smell rich on cold start, once warm it seems to be ok, could this be a sign of an over-rich condition?

I've cleaned the MAF only recently, maybe it needs to clear the exhaust out, not sure.


Thanks,


Steve

[Essex2Visuvesi]

Probanly needs an Italian Tune up  s:) s:)

[m1tch]

Are the O2 sensors showing ok voltages etc?

[The Other Stu]

Are the O2 sensors genuine denso or cheap chinese crap? Juries out on the chinese ones right now.

[stevex]

Thanks for the replies.

Lol it probably does need a good run, I haven't really used it much since buying as I haven't had chance and have been worried about the oil issue.

Previous owner fitted a new genuine Denso on bank 1, bank 2 and 3 are the original old ones. I pulled bank two and wire brushed, TBH didn't 'look' bad. Haven't checked the post cat. does anyone know what voltages they should show and at what time? I did take a look at live data on the car but wasn't sure what the banks should show.

[stevex]

I took the car out and warmed it up to do a diagnostic test on it. It's still randomly hesitant before 3k RPM on part throttle.

It smells way too rich, I've noticed this since I got the car, if I sit still in it with it running and the roof down it just smells of fuel (as if I didn't already have enough problems to deal with).

Here are the stats I collected when at running temperature:

Short Trim 1 > 0 to -2ish
Short Trim 2 > 0 to -2ish
Long Trim 1 > -18.8 pretty solid
Long Trim 2 > -23.4 pretty solid

Not sure why the long trims are telling the ECU the car is running so rich? If I am right, this shouldn't be anywhere near this, especially as ST's are only 0 to -2ish?

O2B1S1 > 0.04 jumping to 0.8 and back to .04ish quickly (this sensor looks new and I have a denso packet so must be the one changed, assume seller was trying to fix it running rich)
O2B2S1 > 0.04 jumping to 0.8 and back to .04ish quickly (this sensor looks old, I cleaned it up with a wire brush)
O2B1S2 > 0.04 to 0.10 > looks like the cat is doing it's job at a guess, so hopefully not blocked (not investigated this sensor, as AFAIK the ECU shouldn't really use this to fuel)

So the above roughly tells me everything checks out.

Short Trim Bank 1 Sensor 1 > 2 to 3
Short Trim Bank 2 Sensor 1 > 0.8 to 4.7
Short Trim Bank 1 Sensor 2 > 99.2 constant (post cat so assume it doesn't measure or effect fuelling and just reports the default value)

MAF on tickover shows 2.46 to 3 or so, so it's varying from 2.46 up the range to 3 and back down. I am not familiar with the MAF value on this car, however, this reading seems a little low, I'd have normally thought it should be around 5 or so. That might tell me the MAF is weak or on it's way out I guess (if that number is not normal for an MR2 MAF).

Seems to me like my Long Trims are waaaaay too low. And from these results I am not sure what is causing it. I'd have expected them to be in the -5 range max. The ECU obviously thinks the car is running super rich and trying to trim back, but still not working.

So what the hell could it be? Other than some monkey remapped the ECU.

[SteveJ]

I guess you haven't fixed the oil drinking problem yet? Guess where it's going! Effectively its unmetered fuel that the O2's are trying to compensate for.

[stevex]

Ok, so the TPS isn't very responsive, and *could* be an issue, if I tap the throttle no change in reading (11 same as idle), if I blip the throttle half way, it doubles, WOT, it goes to the same figure as just tapping the throttle.

It could be my reader, but I am pretty sure it updates pretty speedily, on other cars.

[SteveJ]

The other alarm bell that's ringing for me is reading the other thread you've been active on, the car was over-boosting due to a faulty pressure reducing valve in the waste gate line.

I can't help but think the engine has suffered some very serious abuse.

[stevex]

I guess you haven't fixed the oil drinking problem yet? Guess where it's going! Effectively its unmetered fuel that the O2's are trying to compensate for.

I haven't had chance to pull the engine and rebuild it in the past few days no   s:D s:D  

But that doesn't make sense, why would that make the engine run rich? It should run lean if that were the case, as it's pulling the fuel back when extra fuel isn't going in. And why would the exhaust smell of fuel and be very sooty? It would smell of oil and be smoking all the time even on tickover.

RE the oil usage, I really haven't used the car any length of time to determine how much it is using in my ownership, something I can check now I've reset the counter and done an oil change.

[SteveJ]

Ok, so the TPS isn't very responsive, and *could* be an issue, if I tap the throttle no change in reading (11 same as idle), if I blip the throttle half way, it doubles, WOT, it goes to the same figure as just tapping the throttle.

It could be my reader, but I am pretty sure it updates pretty speedily, on other cars.

 The TPS is intercepted by the TTE piggy-back and feeds a false figure to the stock ECU which you are seeing on your OBDII reader.

[stevex]

Aha got it thanks.

[SteveJ]

I guess you haven't fixed the oil drinking problem yet? Guess where it's going! Effectively its unmetered fuel that the O2's are trying to compensate for.

I haven't had chance to pull the engine and rebuild it in the past few days no   s:D s:D  

But that doesn't make sense, why would that make the engine run rich? It should run lean if that were the case, as it's pulling the fuel back when extra fuel isn't going in. And why would the exhaust smell of fuel and be very sooty? It would smell of oil and be smoking all the time even on tickover.

RE the oil usage, I really haven't used the car any length of time to determine how much it is using in my ownership, something I can check now I've reset the counter and done an oil change.

Do you know what fully-synth oil that's burned in the engine and then fed through a catalytic converter smells like? Guess what!

[stevex]

The other alarm bell that's ringing for me is reading the other thread you've been active on, the car was over-boosting due to a faulty pressure reducing valve in the waste gate line.

I can't help but think the engine has suffered some very serious abuse.

Yep, something the previous owner neglected to tell me when I asked specifically about /sigh, but we've been there, done that.

[stevex]

I guess you haven't fixed the oil drinking problem yet? Guess where it's going! Effectively its unmetered fuel that the O2's are trying to compensate for.

I haven't had chance to pull the engine and rebuild it in the past few days no   s:D s:D  

But that doesn't make sense, why would that make the engine run rich? It should run lean if that were the case, as it's pulling the fuel back when extra fuel isn't going in. And why would the exhaust smell of fuel and be very sooty? It would smell of oil and be smoking all the time even on tickover.

RE the oil usage, I really haven't used the car any length of time to determine how much it is using in my ownership, something I can check now I've reset the counter and done an oil change.

Do you know what fully-synth oil that's burned in the engine and then fed through a catalytic converter smells like? Guess what!

Hmm, never experienced that, just smells like neat fuel, a bit like when I started up my track car with no cat on it.

[m1tch]

Reset the ECU and see what happens - might be the engine has gone to richen up the mixture due to bad O2 sensors on the long term trim but its not been reset etc - ECU fuse out for 20 minutes should do it.

[stevex]

Reset the ECU and see what happens - might be the engine has gone to richen up the mixture due to bad O2 sensors on the long term trim but its not been reset etc - ECU fuse out for 20 minutes should do it.

Thanks I'll give it a try.

Also looking at the MAF, I am used to a 5.5 litre, which shows from experience 5+ at idle. Of course this is a 1.8, so perhaps this should be metering more like 2 grams per second at idle rather than it's 2.4-3. All the readings were at idle, and with the engine at running temp.

[ilovejapcrap]

mine was doing this

 m https://www.youtube.com/watch?v=SE2Ae1Ym-Qo m

so I'm doing this

 m http://mr2roc.org/phpBB3/viewtopic.php? ... 11307f8ca1 m

[stevex]

mine was doing this

 m https://www.youtube.com/watch?v=SE2Ae1Ym-Qo m

so I'm doing this

 m http://mr2roc.org/phpBB3/viewtopic.php? ... 11307f8ca1 m

Bloody hell now that is smoke! Nice progress by the way  s:) s:)

That's the weird thing, this car doesn't smoke at startup, idle, under load, on rundown, only a puff if the car is warmed up and you rev it to about 4k and let off.

The previous owners claim of 1 litre per 250 miles of driving just seems odd. I've seen oil burning cars before, and hence I bought this one as there was no obvious sign of burning oil. The more interesting thing however is that the oil return feed to the sump is leaking, it's soaked down there so I am going to replace it when I can get my hands on some pipe and time to get it up and change it (probably at the weekend when I drop the oil again). Also there is misting I noticed near the oil filler car, had a look around the back and can't see where it's coming from.

When I spoke to Matthew at Rogue, he said all 1zz's burn oil and have oil misting on the tops of the pistons, he's yet to see one that doesn't. Maybe I will get lucky and fix these other issues that will help the consumption (again need to use it really to test it myself). But it is loosing oil for sure.

Anyhow, the rich thing is definitely fuel, the small puff that comes out when hot, at idle and reving smells like burning oil not fuel.

It's entirely likely that the car has been running rich for ages, and no one has sorted it, that in itself has probably led to premature ring wear.

Whether or not I rebuild or how I move forward, there is absolutely no point in fitting another motor with the same ancillaries and running rich, so if possible I'd like to troubleshoot it now and come to a conclusion.


Cheers.

[ilovejapcrap]

mine was doing this

 m https://www.youtube.com/watch?v=SE2Ae1Ym-Qo m

so I'm doing this

 m http://mr2roc.org/phpBB3/viewtopic.php? ... 11307f8ca1 m

Bloody hell now that is smoke! Nice progress by the way  s:) s:)

That's the weird thing, this car doesn't smoke at startup, idle, under load, on rundown, only a puff if the car is warmed up and you rev it to about 4k and let off.

The previous owners claim of 1 litre per 250 miles of driving just seems odd. I've seen oil burning cars before, and hence I bought this one as there was no obvious sign of burning oil. The more interesting thing however is that the oil return feed to the sump is leaking, it's soaked down there so I am going to replace it when I can get my hands on some pipe and time to get it up and change it (probably at the weekend when I drop the oil again). Also there is misting I noticed near the oil filler car, had a look around the back and can't see where it's coming from.

When I spoke to Matthew at Rogue, he said all 1zz's burn oil and have oil misting on the tops of the pistons, he's yet to see one that doesn't. Maybe I will get lucky and fix these other issues that will help the consumption (again need to use it really to test it myself). But it is loosing oil for sure.

Anyhow, the rich thing is definitely fuel, the small puff that comes out when hot, at idle and reving smells like burning oil not fuel.

It's entirely likely that the car has been running rich for ages, and no one has sorted it, that in itself has probably led to premature ring wear.

Whether or not I rebuild or how I move forward, there is absolutely no point in fitting another motor with the same ancillaries and running rich, so if possible I'd like to troubleshoot it now and come to a conclusion.


Cheers.

well when I stripped mine one thing I did find is the intake when it connects to the engine, the rubber gasket was rock solid, I suspect may have been letting in a very small amount of air? (very very small) maybe replace with a new one that still feels like rubber and a good seal ?

[stevex]

Thanks for the info, that sure is an option. I went out and let it warm up again, I don't have any fault codes, but interestingly I checked pending codes and it has P0172 - Bank1 too rich.

The MAF seems possibly suspect. On tickover at 770RPM, which was pretty solid give or take 20rpm, the MAF was showing 2.4-3.2 gp/s.

I added MAF and RPM to a custom data set and followed it on the graph, when the RPM increased a little at tickover the MAF didn't follow suit, sometimes went down, when RPM was say ticking around 770, the MAF spiked to 3.2 or sometimes more.

Again, could be accuracy of the reporting or could be an issue. I don't have time to play with it any more as I have other things to take car of, but, I will attempt to reset the ECU at some point to see if the long term FT's come down, but with that code pending I suspect it won't and a sensor is likely at fault.

[shnazzle]

The car is indeed massively overfueling, with LTFT of -23 the added stft of -2 makes that -25 total trim which sets off P0172.

Resetting the ecu will stop the overfueling until it catches up and it'll be back to how it is within 20 mins of driving .

Smoke on overrun points to valves, so there's some evidence to suggest the seals weren't done as stated.

Idle speed is spot on.

TTE uses stock maf and airbox so can't imagine the MAF readings are being altered by the piggyback. Also not sure why the piggyback would adjust the tps signal either.
Unless Toyota built in their own open look trick in the TTE piggyback  s:) s:)  

Piggyback will be adding fuel, but not at idle. So it's not (just) that.

I'd remove the boost controller anyway at this point.

Injectors could be leaking. Or one. You said one bore was particularly washed.

[stevex]

That's interesting, thanks for the info and help - it's appreciated.

The MAF was fouled when I cleaned it, the AIT sensor was gunked up on the back, that'll be the backwash from the turbo when it vents back to the filter area I guess. Also one of the wires and resistors had a grey appearance. They looked clean when I refitted, but maybe I didn't leave the battery off enough to reset the LTFT. It's only ran 10 miles since the clean. One other thing, the backwash from the turbo and venting that air back past the MAF, would that cause it to meter more air and dump fuel in when letting off creating an over rich condition before fully letting off the throttle? I assume Toyota had a solution for this, likely when the throttle is closed / based on TPS input. I also find it odd that the intake charge pipe connects to the engine breather, so the turbo recirculates gasses and sucks air in through the engine breather. Perhaps another thing is to pull the PCV on the rocker cover and check it - I'm going off on one now.

That pending code makes sense, if it's rich mostly at idle or tickover, perhaps that's why it's still pending - hasn't hit that 25% enough time yet, although I haven't driven the car enough time for it to become permanent, I think it's 40 times perhaps to become a current code? That bank appears to be the sensor that has been changed, it looks fairly recent. Also there is an MOT missing, the current MOT I was provided states pass with no advisories. Yet online it failed one week prior to that on emissions! Seems I wasn't provided a paper copy for that one, so seems it is was running rich then a few months back.

There may be hope yet then, perhaps pull the cover, replace the seals and gaskets, if I can figure out the rich running, replace the turbo oil feed return and sort out whatever seems to be misting oil near the filler cap I could be in a much better place with this car. I'd have to be VERY lucky though I would think...

Also found the oil feed pipe to the turbo to have traces of oil around it, best replace that one too.

I'm definitely wanting to remove that controller, I hate it being there. Not sure how to remove it though, I guess get underneath to see where the vacuum pipe has been spliced to the waste gate and just replace it from it's original source and destination?

Injectors seem fairly straight forward to get to, if I only I had better diagnostic equipment for Toyota, I could see what they were doing.

Your guess is as good as mine at the moment, O2 sensors seem within limits and no crazy figures or spikes going on. One new one and the old one reading similar show they should both be ok, so it has to be somewhere else. I guess MAF, injectors as you say or a dodgy remap are the first suspects?

[stevex]

Oh another interesting point, TPS reads buttery with engine off and ignition on, perhaps the piggyback is doing something odd with it, or the signal once being sent to the piggyback is accurate but the info reported to the scanner is not as suggested once it's running.

[Carolyn]

mine was doing this

 m https://www.youtube.com/watch?v=SE2Ae1Ym-Qo m

so I'm doing this

 l viewtopic.php?f=88&t=62697 l

My engine removal method.