Fuel/Ignition/Starting problem

SparkyNZ · 2021-09-12T04:09:34+00:00

Im sure @VolvoMike can help but to read codes and reset anything you need VIDA and Dice , the software and unit to plug into the OBD / CANbus network , can b...

SparkyNZ

nh2868
Interesting. Oxygen sensors switch between 0 and 1V. They should be cycling between these a few times per second. (Some sensors are A/F (air/fuel or Lambda) which work slightly differently but cycling quickly between 0-1V sounds normal)
You can see that as time goes on, the long term fuel trims BOTH decrease to -18. So it's not just bank 1 with the problem - both banks have the same issue and it just happens that bank 1 happened to trip first.
So it's unlikely that both sensors have failed the same, and the engine thinks it's running rich. Usually we'd be chasing a lean code caused by a vacuum leak, but you have the opposite problem.
In your case, the computer may think it's getting less air than it thinks it is - ie the MAF (Mass Air Flow) sensor may be causing the issue. See if you can find a value for air flow (in g/sec) at idle... conveniently when warmed up you should get around 3.2 g/sec for a 3.2L engine. (3.2 to 3.8 shouldn't be a problem, but if it's around 5 or 6 then the engine "thinks" it has a lot of air to add fuel to, then the oxygen sensors BOTH find that the fuel was too much.)
The MAF sensor is the only single component I can think of (apart from the temperature sensor) which would make a large enough difference to the fuel trim that it's set a code.

I let it idle for a while. Hoping it got warm enough - I've included the temperature values as well to give an idea:

Frame 12/12:

Engine coolant temperature ----- 83°C

Intake air temperature ----- 33°C

Air mass ----- 3.98g/s

When it started the Air Mass was around 4.5 but it dropped to just under 4 when it warmed up.

Here's a snapshot at 78degrees C:

Frame 78/78:

Outside temperature ----- 22°C

Engine control module (ECM), temperature ----- 41.88°C

Engine coolant temperature ----- 78°C

Ambient air pressure ----- 1010hPa

Intake air temperature ----- 32°C

Intake air pressure ----- 300hPa

Air mass ----- 4.05g/s

Fuel temperature ----- 51.99°C

Fuel pressure ----- 487.92kPa

Fuel rail pressure (rel) ----- 373.98kPa

Fuel pump, duty cycle ----- 44.70%

Engine speed ----- 652.25rpm

Front long term fuel trim, bank 1 ----- -17.97%

Front long term fuel trim, bank 2 ----- -17.97%

nh2868

Not an expert by any means, but I suspect your MAF is a little high. If you rev the engine, of course the air flow should increase. Do the fuel trims improve at all at higher revs, or stay around the -18 value ?

You could try cleaning the MAF sensor - they tend to get dirty but you need to be very careful and only use MAF sensor cleaner - and don't tough the components inside. Youtube should have a number of videos showing how to do it.

SparkyNZ

nh2868
Not an expert by any means, but I suspect your MAF is a little high. If you rev the engine, of course the air flow should increase. Do the fuel trims improve at all at higher revs, or stay around the -18 value ?
You could try cleaning the MAF sensor - they tend to get dirty but you need to be very careful and only use MAF sensor cleaner - and don't tough the components inside. Youtube should have a number of videos showing how to do it.

I can take a look. I do have something stupid wrong with the air filter cover. The torx screws holding that down are stripped so the damn thing won't sit down snug and may be letting more air in than it should. That would cause it to run leaner if anything though wouldn't it?

Here's some more stats at higher revs:

Frame 7/49:

Engine coolant temperature ----- 75°C

Intake air pressure ----- 270hPa

Air mass ----- 6.22g/s

Fuel pressure ----- 479.81kPa

Fuel rail pressure (rel) ----- 377.46kPa

Fuel pump, duty cycle ----- 44.93%

Engine speed ----- 1100rpm

Front long term fuel trim, bank 1 ----- -21.88%

Front long term fuel trim, bank 2 ----- -20.31%

Frame 28/49:

Engine coolant temperature ----- 78°C

Intake air pressure ----- 330hPa

Air mass ----- 9.64g/s

Fuel pressure ----- 478.65kPa

Fuel rail pressure (rel) ----- 378.71kPa

Fuel pump, duty cycle ----- 45.19%

Engine speed ----- 1813rpm

Front long term fuel trim, bank 1 ----- -17.97%

Front long term fuel trim, bank 2 ----- -17.19%

Frame 30/49:

Engine coolant temperature ----- 78°C

Intake air pressure ----- 290hPa

Air mass ----- 9.12g/s

Fuel pressure ----- 477.49kPa

Fuel rail pressure (rel) ----- 378.62kPa

Fuel pump, duty cycle ----- 45.18%

Engine speed ----- 1741.75rpm

Front long term fuel trim, bank 1 ----- -18.75%

Front long term fuel trim, bank 2 ----- -17.97%

Frame 39/49:

Engine coolant temperature ----- 80°C

Intake air pressure ----- 280hPa

Air mass ----- 8.82g/s

Fuel pressure ----- 478.65kPa

Fuel rail pressure (rel) ----- 382.09kPa

Fuel pump, duty cycle ----- 44.98%

Engine speed ----- 1261.75rpm

Front long term fuel trim, bank 1 ----- -21.88%

Front long term fuel trim, bank 2 ----- -17.97%

Frame 49/49:

Engine coolant temperature ----- 81°C

Intake air pressure ----- 300hPa

Air mass ----- 3.45g/s

Fuel pressure ----- 480.97kPa

Fuel rail pressure (rel) ----- 384.41kPa

Fuel pump, duty cycle ----- 44.66%

Engine speed ----- 654rpm

Front long term fuel trim, bank 1 ----- -18.75%

Front long term fuel trim, bank 2 ----- -18.75%

nh2868

My air filter (XC90) has a few stripped screws as well. The air filter is before the MAF, so leaks around the air filter won't affect anything (apart from premature engine wear !) Yes air leaks AFTER the sensor will produce a lean condition.

None of your values look out of place to me - except the LTFT values.

Were you waiting on cam position sensors ? The engine is just an air pump - and if the camshaft timing is off then you could get weird things happening here.

You replaced the fuel pressure sensor, right ? If the fuel pressure is too high, then more fuel will be added than the ECU is expecting (for the injector opening time it calculates) and you'd get a rich O2 result. Do you still have the old fuel pressure switch ?

I know the value you have around 380kPa should be about right (approx 60psi) but we can't assume that's an accurate value at this stage - if the old sensor gave similar results then we can be a bit more certain that the value is correct. Usually you'd connect an analogue gauge to verify but I don't recall the 3.2 having a pressure port - you'd have to tee into the fuel rail supply somehow.

SparkyNZ

nh2868
My air filter (XC90) has a few stripped screws as well. The air filter is before the MAF, so leaks around the air filter won't affect anything (apart from premature engine wear !) Yes air leaks AFTER the sensor will produce a lean condition.
None of your values look out of place to me - except the LTFT values.
Were you waiting on cam position sensors ? The engine is just an air pump - and if the camshaft timing is off then you could get weird things happening here.
You replaced the fuel pressure sensor, right ? If the fuel pressure is too high, then more fuel will be added than the ECU is expecting (for the injector opening time it calculates) and you'd get a rich O2 result. Do you still have the old fuel pressure switch ?
I know the value you have around 380kPa should be about right (approx 60psi) but we can't assume that's an accurate value at this stage - if the old sensor gave similar results then we can be a bit more certain that the value is correct. Usually you'd connect an analogue gauge to verify but I don't recall the 3.2 having a pressure port - you'd have to tee into the fuel rail supply somehow.

Yeah I have one new camshaft sensor sitting here and I'm waiting for the second one to arrive.

To be honest, I put the old fuel pressure sensor back. When I put the new one in, fuel began to leak out of the end of the fuel rail. I didn't put any grease or anything around the new O-ring when I fitted it so I don't know if the sensor was just a dodgy cheap Bosch imitation or not - but my priority at the time was to stop the leak. It didn't make any difference to the symptoms I had on the car so I never bothered putting the new one back in.

But yes, unfortunately there's no Schrader valve on my fuel rail so I didn't have anywhere to connect a real pressure sensor.

Maybe I just wait for the other camshaft sensor and see if the situation changes? Those camshaft error codes haven't reappeared but the car has been sitting in my garage since I got my little Corolla. I just haven't been able to depend on the XC70 so it's had to take a back seat. :-(

nh2868

It would be interesting to see if the "new" fuel pressure sender gave you different results on the fuel trims - now that you can measure those. Yes the sensor needs some lube to install without leaks. It's still a good idea to clean the MAF, although your last report at 3.45 g/sec at idle looks just about perfect.

Your engine temperature of 81 fairly consistently is strange - my S40 and XC90 run 88-91 consistently, but a few degrees shouldn't matter that much. (Usually reading very cold would effectively keep injecting more fuel, but that's more like 30 degrees...)

If the cam position was wrong, the engine would certainly trip a code straight away. They're very fussy about that.

The only factors which would result in too much fuel should be:

Engine coolant temperature reading too low

Inlet air temp reading too low (inbuilt with the MAF I think)

fuel pressure too high

MAF reading too high

The engine thinks it's getting too much fuel. Either it actually IS, or it's just getting the feedback that it is.

I'd have a look at a spark plug tip. If the engine is running consistently rich, the plug will be black and sooty by now. If they look normal (light grey / tan) or lean, I guess it's possible that both oxygen sensors are mis-reading. Has anyone worked on the car recently, maybe connecting the wrong oxygen sensors to the wrong plugs ?

SparkyNZ

nh2868
It would be interesting to see if the "new" fuel pressure sender gave you different results on the fuel trims - now that you can measure those. Yes the sensor needs some lube to install without leaks. It's still a good idea to clean the MAF, although your last report at 3.45 g/sec at idle looks just about perfect.
Your engine temperature of 81 fairly consistently is strange - my S40 and XC90 run 88-91 consistently, but a few degrees shouldn't matter that much. (Usually reading very cold would effectively keep injecting more fuel, but that's more like 30 degrees...)
If the cam position was wrong, the engine would certainly trip a code straight away. They're very fussy about that.
The only factors which would result in too much fuel should be:
Engine coolant temperature reading too low
Inlet air temp reading too low (inbuilt with the MAF I think)
fuel pressure too high
MAF reading too high
The engine thinks it's getting too much fuel. Either it actually IS, or it's just getting the feedback that it is.
I'd have a look at a spark plug tip. If the engine is running consistently rich, the plug will be black and sooty by now. If they look normal (light grey / tan) or lean, I guess it's possible that both oxygen sensors are mis-reading. Has anyone worked on the car recently, maybe connecting the wrong oxygen sensors to the wrong plugs ?

I bought some MAF cleaner this morning - I removed the sensor, gave it a few cleans and let it dry in the sun for an hour or so before refitting (I made sure both the brown bulb and the 2 or 3 little wires inside were all sprayed). I let the car warm up - only to 73C. It looks as though the Air Mass values are less now so that must have had some effect. Unfortunately the P017200 DTC keeps coming back. I forgot to record the LTFT but it still seemed about the same at around -17.85%.

Frame 30/30:

Engine coolant temperature ----- 73°C

Ambient air pressure ----- 1010hPa

Intake air temperature ----- 24°C

Air mass ----- 3.03g/s

Fuel temperature ----- 26.98°C

Fuel pressure ----- 482.13kPa

Hmm. Well maybe I can go and change the fuel pressure sensor back to the new one and see what difference that makes, if any.

SparkyNZ

Just wondering about the new injectors I fitted.. and wondering if they're cheap crap.. Which 3 injectors would correlate to bank 1? Looking at the engine (with torque rod on the left and airfilter on the right), which injectors relate to bank 1 and bank 2?

Indeed, which cylinder is #1? Is it the one on the left or right?

I was just wondering whether I should try swapping out 3 injectors for the old ones to see if it gets rid of that error code. I've had this hard start problem since before I installed the new injectors though. First time I noticed it was when I installed new plugs and coils.

Recently I put the old plugs back (to see if that made any difference to the hard start) and I did notice one of the plugs looked dirtier than the others - but I can't remember if that was before or after the injector replacement.

nh2868

Traditionally bank 1 is the bank with cylinder 1, which once again would be the cylinder closest to the drive belt end of the engine.

From another site:

Cyl #1 is at the upper engine torque mount and cyl #6 is at the chaincase/READ unit next to the transmission.

Bank 1 is cylinders 1-3 and Bank 2 is cylinders 4-6

Of course if the replacement injectors are a larger size than standard they'll flow more fuel and cause your rich condition !

Your original injectors shouldn't be worn out at your kms. Maybe reinstall them and try cleaning them the easy way...

https://www.youtube.com/watch?v=aDvtzg-ThZs

I've done this manually out of the car powering the injectors with a 9V battery, but this looks much easier and I'll try it this way next time !

Nothing to lose: I'd reinstall and clean the old injectors, then see how your fuel trims are after warming up again.

SparkyNZ

nh2868
Traditionally bank 1 is the bank with cylinder 1, which once again would be the cylinder closest to the drive belt end of the engine.
From another site:
Cyl #1 is at the upper engine torque mount and cyl #6 is at the chaincase/READ unit next to the transmission.
Bank 1 is cylinders 1-3 and Bank 2 is cylinders 4-6
Of course if the replacement injectors are a larger size than standard they'll flow more fuel and cause your rich condition !
Your original injectors shouldn't be worn out at your kms. Maybe reinstall them and try cleaning them the easy way...
https://www.youtube.com/watch?v=aDvtzg-ThZs
I've done this manually out of the car powering the injectors with a 9V battery, but this looks much easier and I'll try it this way next time !
Nothing to lose: I'd reinstall and clean the old injectors, then see how your fuel trims are after warming up again.

So if I buy a can of this: https://www.supercheapauto.co.nz/p/crc-crc-clean-r-carb---400g/1074.html

So any aerosol carb cleaner should do the trick?

I should be able to somehow connect it to the intake of each injector and just pulse 9V across the 2 pins? The bit I couldn't understand in the video was how he adapted the pipes of different sizes. I tried to downsize some pipes on my water bottle some time ago with little success. He glues some sort of spacer ring inside the larger pipe.. no idea what that is.

Shame the engine mount needs to come off to get the fuel rail off.. but I've done it twice already I guess.

SparkyNZ

https://www.youtube.com/watch?v=8rk0tKtiVic

This looks pretty helpful!

nh2868

He just pushes a washer down the hose then installed the small house through the washer. Another version used hot melt glue without the washer, I've used the uncut nozzle of a silicone gun tube which has a taper the injectors fit in to. Whatever works. Yes a 9V battery works to open the injectors...doesn't matter about polarity, just click on and off a few times. Permanently on not so good for a long time. Usually they'll clear in second or two and like the videos you'll notice the difference.

SparkyNZ

nh2868
He just pushes a washer down the hose then installed the small house through the washer. Another version used hot melt glue without the washer, I've used the uncut nozzle of a silicone gun tube which has a taper the injectors fit in to. Whatever works. Yes a 9V battery works to open the injectors...doesn't matter about polarity, just click on and off a few times. Permanently on not so good for a long time. Usually they'll clear in second or two and like the videos you'll notice the difference.

Well.. that wasn't a very productive afternoon. I cleaned the old injectors and replaced the new ones with the old ones. Also fitted the new fuel pressure sensor again.

The new fuel pressure sensor began to leak again so I had to remove it. I'm still getting the "Bank 1 too rich" DTC and LTFT is still -18.85%.

The only thing I did notice when watching the live data was that the Bank 1 rear oxygen sensor kept dropping to a low value close to zero when the Bank 2 rear sensor seemed to remain more constant.

Could it be that the rear Bank 1 oxygen sensor is just dodgy perhaps?

nh2868

The rear oxygen sensors are really only there to monitor the efficiency of the catalysts. The upstream sensors are what the engine uses to adjust the fuel trims...usually.

It could be that the upstream oxygen sensor is faulty - which is not all that unusual at the 150,000km mark.

SparkyNZ

nh2868
The rear oxygen sensors are really only there to monitor the efficiency of the catalysts. The upstream sensors are what the engine uses to adjust the fuel trims...usually.
It could be that the upstream oxygen sensor is faulty - which is not all that unusual at the 150,000km mark.

I just wish the sensor seemed to be returning different values from the bank 2 one. I'm going to put the old coils back on the car tomorrow and inspect the sparkplugs again.

I doubt this is causing my hardstart problem though. I mean.. the engine has to have started for the O2 sensors to be registering feedback, doesn't it? Berry Motor Group were suggesting my fuel pump may be on the way out. If it won't start it has to be lack of fuel or no spark at the right time. Wouldn't a weak spark cause a rich fuel level if it didn't ignite? I'm not seeing any misfires on my diag tool though. What fires the ignition coil? Is there an ignition amplifier of sorts between the ECU and coils?

SparkyNZ

nh2868
The rear oxygen sensors are really only there to monitor the efficiency of the catalysts. The upstream sensors are what the engine uses to adjust the fuel trims...usually.
It could be that the upstream oxygen sensor is faulty - which is not all that unusual at the 150,000km mark.

Hmm.. So I put the original coils back in.. The DTC hasn't come back yet and LTFT has dropped from -18.75% to -16.45%. Is this this a significant difference?

It'll be interesting to see how it starts when warm again. I'm letting it warm up now.. I'll take it for a drive soon and stop/start a few times to see what happens.

nh2868

Yes the oxygen sensors are completely ignored for startup, so they're not your problem. (Engine starts in open loop - no feedback from the oxygen sensors for the first few minutes whilst the engine and oxygen sensors warm up. Both of them indicate rich running too, so it's unlikely both have failed at the same time.

Your injectors are powered by the relay (top left), and each grounded by the ECM (right) to fire them. Coils are powered by the same relay, have 2 separate grounds but are also triggered directly by the ECM. No separate amplifier like there used to be on some cars.

Were your replacement coils genuine / OEM or "aftermarket" ? I guess it's possible to have weak spark which would certainly produce rich mixture and hard starting but I would have thought that you would have misfires if that was the case also.

I thought that you had replaced the coils in an attempt to cure your hard starting ?

SparkyNZ

nh2868
Yes the oxygen sensors are completely ignored for startup, so they're not your problem. (Engine starts in open loop - no feedback from the oxygen sensors for the first few minutes whilst the engine and oxygen sensors warm up. Both of them indicate rich running too, so it's unlikely both have failed at the same time.
https://cdn.ozvolvo.org/uploads/S4O39TWQL06U/fullscreen-capture-9102021-74010-am-bmp.jpg
Your injectors are powered by the relay (top left), and each grounded by the ECM (right) to fire them. Coils are powered by the same relay, have 2 separate grounds but are also triggered directly by the ECM. No separate amplifier like there used to be on some cars.
Were your replacement coils genuine / OEM or "aftermarket" ? I guess it's possible to have weak spark which would certainly produce rich mixture and hard starting but I would have thought that you would have misfires if that was the case also.
I thought that you had replaced the coils in an attempt to cure your hard starting ?

The reason I'd replaced the coils was because of the juddering I was getting going up hill. I wanted to put new plugs in the car when I bought it (something I usually do with all cars when I buy them) and because of this juddering I thought I'd get some new coils as well. I don't think they'd be OEM coils.

Anyway I'll pop into the garage and swap out the coils and see if it affects my starting at all.

I'm also thinking about swapping the rear O2 sensors to see if my problem moves from Bank 1 to Bank 2 (if I can get them out easily enough without a special tool). If the problem moves with the sensor, then that would pinpoint a faulty sensor wouldn't it?

timbo

Ideally the ecu wants less than +-10% fuel trims. Long term fuel trims are a stored value based on short term fuel trims, so can take longer to return to normal once you fixed the issue. Ideally you want to look at short term fuel trims to see instant data.

Some repairs that fix a large fuel trim issue, like replacement MAF, need the adaptive fuel trim data reset (possible in Vida, not always possible with aftermarket scan tool) after replacement or a decent drive to reset

Worth checking the evap purge valve (block off fuel tank line) and the pcv (check for excessive vacuum at oil cap.

SparkyNZ

The PCV seems to be OK.

I also spoke too soon - the DTC Bank 1 too rich error is back. We took it out for a spin and will remove plugs soon and see what they look like. I'm still thinking about swapping the O2 sensors over to see if the error moves to Bank 2 or not.

« Previous Page Next Page »