1999 Auto V70 Engine Runs Like a Pile of Rocks

[mikealder]

Where did you get the replacement Lambda probe from, was a genuine Bosch or Denso or a generic - Mike

[Pozzouk]

Originally Posted by mikealder

Where did you get the replacement Lambda probe from - Mike

Just been and checked the box - Genuine "Denso Lambda", supplied by Camberley Auto Factors. Considered one of the Chinese jobs but all the advice seemed to suggest they were a waste of money.

Pozzouk.

[Pozzouk]

Originally Posted by TXC

Is this issue the running of the engine? as in, if you get it up to temp it runs awful even when stationary in Neutral?

Disconnecting Temp Sensor resolves issue virtually entirely?

I'm just thinking, by disconnecting the sensor, the car sees infinite resistance or open circuit, so therefore thinks -35 C, yes, you already know that. You are 'telling' the car it's colder, and it is, so....

The car never reaches 'closed loop' because it never sees the correct figure, lets say 65 C for fun.

Without 'closed loop' , it'll never listen to the H02 sensor (Lambda, whatever name you prefer).

I'm thinking if this sensor is stuck 'lean' for example, as soon as we hit 65 C, ECU starts to listen, finds it lean, winds the fuel right up to try and get the sensor to switch correctly, it never switches or responds so the ECU just keeps the fuel additive on max.

Same principles would apply if the sensor is stuck rich, so it would try leaning it off etc Same result, rough running.

A convoluted way of explaining that I don't think its hitting closed loop with the Coolant sensor off, and a duff HO2 sensor would give all these rough running symptoms.

Will not always leave a code, however you can test the HO2 sensor (I'll assume it's a four wire for now), either back-probe the signal wire and get it up to temp, monitor it.
Or if you have live data on your Autel, use that to give you feedback.

Cruising at 70mph may well mask a stuck rich/lean sensor, in fact at higher engine speeds the sensor may begin to switch nicely, then fail miserably with lower gas content to sniff.

Best of all, it's free to test.

Although it would throw a code (which you can clear of course), there's nothing to stop you just disconnecting the HO2 sensor so that signal never gets back to ECU, it may not run perfect like this, but it may prove the point crudely but effectively.


Sorry for essay, but i had to explain as best as poss without confusion, dunno if it worked though lol.

I know you are also concerned about the Autobox, but the crank speed will be slowing down and speeding up randomly on misfire, affecting the shaft speeds, and confusing the box what's being asked of it.

In answer to the above - "Yes" awful when stationary in neutral or in drive once up to temperature but was ok once above idle.

And "Yes" disconnection of TSU virtually solved the problem but i found that sometimes as the throttle was depressed it was threatening to stall initially.

Here's a clip from a test i did a few days back - i presume the -40 is referring to the lack of the TSU being connected? But was wondering if there was anything else interesting in the rest of the data???

Maybe i need to let it warm up to problem level and test again when the idle goes to pot????

------------1------------
DTC_CNT 1
FUELSYS1 CL
FUELSYS2 --
LOAD_PCT(%) 27.1
ECT(°C) -40
SHRTFT1(%) 3.9
LONGFT1(%) -2.3
MAP(kPa) 56
RPM(rpm) 926
VSS(km/h) 0
SPARKADV(°) 18.5
IAT(°C) 39
MAF(g/s) 4.08
TP(%) 2.7
O2SLOC B1S12--B2S----
O2B1S1(V) 0.545
SHRTFTB1S1(%) 5.5
O2B1S2(V) 0.870
SHRTFTB1S2(%) 2.3
OBDSUP OBD&OBDII

Thanks Guys for all your help.

[TXC]

Nothing on the intake side looks too amiss there considering its sat at nearly 1000rpm, was this stone cold (i realise it wasnt -40, but was this after first start up?)?

It does indicate it's in closed loop, but that could be in reaction to open circuit CTS. Plug CTS back in, clear codes and run it up again watching the live data, your're watching for:

Coolant temp starting at a realisistc value, so approx 20C if you're working from cold engine, watch it climb steadily with engine on time.

The (Bank 1 Sensor 1)B1S1, voltage, once warmed up should be ranging from approx 0.2v to 0.8 v at idle (switching between the two), your Autel may be a little slow in computing these values too often, but expect to see it change voltage every second to three seconds.

The idle should settle to around 650/750rpm once warmed up. If it doesn't and you you're running at near 1000rpm with the values below, you likely have an air leak/or poorly ETM.

If that .545V on the B1S1 is hardly moving, and the B1S2 is moving plenty, then consider if you have misplugged the 02 Sensors.

You can do this all from idle stationary if you like.

[Pozzouk]

TXC - that all looks very helpful.

Only i just went and took all the air intake kit apart to check out the state of the input sensor to the gearbox! As it is, i wanted to pop the sensor out to see what state it was in having had the P0716 & P0717 codes but it seems pretty awkward (yes i have undone the securing bolt) and I'm in danger of pulling off the wires.

Yes, she was cold at the time of me gathering the test info.

As soon as i have back together i will run that live data test you suggest.

[mikealder]

I would go back to basics and start by pulling the TCS put it in a pan with cooking oil and heat it up with a thermometer in the oil and a digital voltmeter set to read resistance connected to the two electrical connection on the TCS plug, check the readings against the graph I posted earlier in this thread - At least this way you will know whether the TCS is working correctly or not.

Also double check the engine bay wiring to make sure some previous idiot hasn't added a "power increase" mod to the wiring between the TCS and the ECU, these work by tricking the ECU in to thinking the engine is cooler than it actually is and therefore the ECU throws more fuel in that it should do. These so called Power Enhancers don't work and really screw up an engines fuel metering ability - Mike

[Pozzouk]

Originally Posted by TXC

The (Bank 1 Sensor 1)B1S1, voltage, once warmed up should be ranging from approx 0.2v to 0.8 v at idle (switching between the two).

The idle should settle to around 650/750rpm once warmed up. If it doesn't and you you're running at near 1000rpm with the values below, you likely have an air leak/or poorly ETM.

If that .545V on the B1S1 is hardly moving, and the B1S2 is moving plenty, then consider if you have misplugged the 02 Sensors.

You can do this all from idle stationary if you like.

Hmmm, Bank 1 seems to stay pretty much rooted to .500V this was the sensor recently replaced.

Sensor 2 however is far more erratic it seems to range anywhere between .065V upto .700V and occasionally beyond.

Is that right?????

PS. Incidentally the temperature sender now reconnected was registering around 95C while idling for half an hour on the drive tonight (i hear you Mike).

With Revs around 850.

For a moment i thought i had it sorted - BUT - took her 300 yards down the road and the first corner stop had her back in limp mode - Just to make matters worse Disaster strikes............While i'm out testing, the other half was making room on the Autel as it was running outa memory and she only went and wiped it's brain of it's ability to read OBDII codes!!!

Someone tell me this ain't happening.

Thanks as always Pozzouk.

[TXC]

If you're sure you've read and and interpreted it right, then those sensors are mis-plugged.

Front sensor B1S1 - Bank 1 Sensor 1 should fluctuate under idle and cruise conditions 0.2Volts to 0.8 Volts approx, a little more or less is fine.

Rear Sensor B1S2 - Bank 1 Sensor 2 should remain within a narrow band of around 0.4Volts and 0.6 volts, the less fluctuation, the better.

Are they both 4 wire sensors? Are the plugs located next to each other? Are they identically shaped?

Wether it would cause this level of running/driveability issue without throwing more fault codes is up for debate, but you have nothing to loose by swapping the connectors over assuming they're physically identical.


In fact disconnect em both for now if you don't have the live data anymore *points at wife* you can reset the codes later.

[mikealder]

Originally Posted by Pozzouk

Incidentally the temperature sender now reconnected was registering around 95C while idling for half an hour on the drive tonight (i hear you Mike)

That isn't right, after 30 minutes the cooling fan should have kicked in which requires a temperature about 10 deg C above what you are reading, check the TCS before you start looking in to other issues as it looks like it is reading low, did the rad fan kick in at all when you had it at idle? - Mike

[Chris_Rogers]

I wouldn't read too much into the front sensor not switching.

On these cars the front sensor is a wideband type, OBDII live data will often not display anything useful with this type of sensor.

The important fuel trim figures look OK.

I'd look at the known problem you have with the gearbox, the fact the problem happens when the engine is up to temperature also applies to the gearbox fluid. This is the point when the gearbox ECU will allow lock up.
If the input speed is missing or erratic then lock up can't be detected and a DTC will be set and a 'safe mode' selected to protect the box. This maybe what you are experiencing.