28 replies to this topic

[Detta]

So, in my ongoing saga of trying to identify why my old girl isn't feeling right, leading on from: http://www.vx220.org...m/#entry1692211

 

I bit the bullet and bought a new MAF for ECP. Much to my disappointment, that didn't fix the problem, and after a week or so of having it fitted, a CEL flashed up without any difference in the 'off' feel. I picked up a cheap Bluetooth scanner, and quickly identified it as a P0130 (02 Sensor Circuit Bank 1 Sensor 1). A search here revealed that this points to a Lambda sensor?

 

Could this be the cause of my problems? It's often hesitant on the power, and sometimes stutters under partial throttle and gentle acceleration. By stutter I mean it will, at low RPM and very gentle acceleration build boost to a steady 15 PSI (when, it really shouldn't be trying for/needing 15 PSI), if I hold this throttle position steady it will sound/run rough for a few seconds before dropping to a flat 0 PSI (not negative), exactly where it should be under such gentle acceleration, and run/accelerate smoothly again.

 

I've looked to the best of my limited abilities for a post turbo boost leak and can't find anything. Other than the obvious hesitation situational stutter, according to my boost gauge, it doesn't appear to have any problems holding boost; low or high, positive or a vacuum, the needle holds steady.

 

Having just spent £100 on a MAF that I may very well not have needed, I'm in no hurry to by a Lambda on a gamble. So I would really appreciate any advice that could be offered. Or, perhaps  if anybody local has a spare one for the sake of ruling it out?

 

Many thanks,

 

Damian

Edited by Detta, 03 June 2014 - 07:34 PM.

[P11 COV]

I had this code for a while last summer - bought a new lambda sensor (front one nearest the turbo) and it sorted it. Not too expensive a job. I didn't have any symptoms other than the warning light.

 

http://www.vx220.org...c/124680-p0130/

 

 

Edited by P11 COV, 03 June 2014 - 08:12 PM.

[Detta]

That's the worrying thing, the CEL doesn't bother me, it's the symptoms that I have been trying to fix for a while now that do. Knowing that it's not running smoothly as it should is heartbreaking.

[Detta]

Ok, as an update, I've toyed around with the free app Torque, which is awesome by the way! And being able to see live readouts shows that the Bank 1 O2 sensor is definitely doing funny things!

 

When I first start the car it looks like this, this is the car at idle.
You can see the sensor bouncing around in the bottom right:

 

 

It shows similar behaviour on the move, very slight load in this case:

 

 

This behaviour only continues for a min or so, I then totally lose reading on the O2 sensor (it flatlines), usually loosing a reading on the Fuel Trimmings shortly after. Would this be the ECU deciding to ignore it based on it's erratic behaviour? These reading are lost (not intermittent) until I restart the car.

 

I have tried contact cleaning where the plug meets the loom, and it doesn't seem to make any difference.

Safe bet that the sensor itself needs replacing, or could it be a wiring issue?

If it's of any help the MAF reading seems to be as steady as a rock under various states of load.

 

Edited by Detta, 04 June 2014 - 10:40 AM.

[siztenboots]

the bouncing around is correct normal behaviour, the flat line would suggest loom problem

[Detta]

Thanks Siztenboots, that's a real surprise!  

 

If it's not to much to ask, can you explain why does a Lambda sensor takes reading in such a way? I would have thought that it would have been a far more progressive line like the MAF, load or RPM curve?

[Nev]

FYI, the front lambda sensor on the exhaust downpipe is a narrowband one. It measures roughly 14.1 to 15.5 AFR. It is used primarily for idle control and very low loads. Thus, at a guess this is not the cuase of your problem, though I would not rule it out. You have reached the point where you need to start swapping out all your sensors. Talking about it wont fix it unfortunately, you just need to spend some money or try and swap out known working sensors from other people's cars I'm afraid.

Edited by Nev, 04 June 2014 - 11:40 AM.

[siztenboots]

the sensor is measuring a very narrow range , although the OBD sample speed is quite slow, you should see it alternate with 0.8 and 0.2 volts

 

[Detta]

the sensor is measuring a very narrow range , although the OBD sample speed is quite slow, you should see it alternate with 0.8 and 0.2 volts

 

 

 

 

But should it be THAT slow? Those blips are over a 10 second window, so it's bouncing every 2 seconds or so. Where as the polling interval on other readouts is MUCH quicker.

[siztenboots]

if you edit the gauges, you can change the +/- range so they scale better and you can see the detail more

 

Maf , upto 200g/s

Fuel trims , +/- 20%

Intake upto 100°C

 

 

According to the NGK site , as the sensor only functions correctly once it has reached approximately 350°C it is essential that the vehicle is brought up to normal working temperature before checking the readings. Once the engine and sensor have reached normal working temperature raise the engine speed to around 2000 rev/min, this should produce a fluctuation in voltage from approximately 0.2 volt to 0.8 volt as the sensor switches from fuel lean to fuel rich. This switching should occur in approximately 300 milliseconds.

 

[techieboy]

It looks fine. It should go from slightly rich to slightly lean once a second.

[slindborg]

its called "bang bang" control... lets ignore ignition for a bit.

the base calibration will have an injection quantity based on MAF, MAP, ECT, IAT and some other values, this will then be trimmed by the Lambda reading assuming its in closed loop. If Lambda = lean then the fuel its made richer by a step, next time round if its still lean itll chuck in more fuel until the lambda tips to rich and so on. the extra needed is used to create the open loop fuel trims for use under high load.

 

What might be happening when it flatlines is that the ECU has gone into open loop mode and is ignoring the sensor so the OBD reading is fixed.

Based on the P code you have, get a new lambda sensor in there.

[Detta]

Food for thought. I have to say guys, I really do appreciate the ongoing support this place provide, and each one of you taking the time to chip in and educate me. In terms of the sensor itself, searching ECP by car (VX220 Tubby), it's showing both of these sensors: http://www.eurocarpa...2a4151a5

 

http://www.eurocarpa...f09f6b80

 

Is there any reason that the 2nd is £24 more expensive? They are both showing as BOSH parts. Is there any reason that I shouldn't get the cheaper part? 

[siztenboots]

I have a spare if you want to prove its not that , its just difficult you are not local.

 

I think the lumpy boost control with part throttle is the actuator, or the control solenoid.

[slindborg]

Branded vs non branded..... If you can prove its the sensor then get the Bosch one

[Ormes]

I have a spare if you want to prove its not that , its just difficult you are not local.

 

I think the lumpy boost control with part throttle is the actuator, or the control solenoid.

 

I may have a spare boost control solenoid you could borrow to rule this out if you haven't already... Can't recall if it is the front of rear solenoid I have but will check later.

[Detta]

Branded vs non branded..... If you can prove its the sensor then get the Bosch one

 

I you check the product details, the cheaper one is listed as a Bosh too.

 

The Turbo itself is less than a year old, so I would be surprised if it's the actuator. It's not just lumpy boost on occasion under partial throttle, sometimes if you're at a roundabout, or junction, and need to make a quick entry from standing, it's VERY hesitant to pick up which can be a bit worrying, especially when you're expecting normal delivery and it's suddenly not there! It's the inconsistency that's really bothering me.

 

 

 

I have a spare if you want to prove its not that , its just difficult you are not local.

 

 

I'd be tempted to take you up on that offer Sizten, but by the time I've paid for your postage, and once again to return it, it would probably cost 1/4 of a BOSH replacment! Unless you could be convinced to let me keep it for a charitable price if it sorted the CEL issue?

 

I had another play with the OBDII reader today, and even if it's not causing the problems I'm sure the lambda must be duff, even if I don't touch the throttle, or it never gets moving, I will lose connection after a min or so at idle, if I go into 'system' for O2 readings after it has flatlined, it says it is running open loop due to incificcient operating tempratures, but this never changes, ever when she's well and truly warmed up! I also reset the CEL code this morning and it was back by the end of the day.

 

That's a very kind offer Ormes, but I've had a look at what I believe to be the rear solenoid and that bottom torx bolt looks like a REAL PITA to get to! So it might make sense to rule out the lambda before attempting that?

Edited by Detta, 04 June 2014 - 07:24 PM.

[Ormes]

Bcs is on top of the bracket that fixes the recirc to the turbo. Drop me a pm if and when and I will post it

[Detta]

Hmm, there are two though if I'm not mistaken? The one on my turbo was replaced along with the turbo less than a year ago, so wouldn't that suggest that if one was giving me problems, it's likely to be the one to the left of the inlet manifold? Also, I'm running a VXR turbo over stock, so it may be a different part? Don't get me wrong, I REALLY appreciate the offer, I just don't want to make you go through the trouble if it turns out to be of little use!

[Ormes]

Yes that's right... as you say... the other is on or near the inlet mani. They are different part numbers but apparently identical apart from the diameter of the vac pipe fixings which are larger on the turbo solenoid. Pretty sure the one on the mani works with the recirc and vac box, and the one on the turbo works with the actuator.

Edited by Ormes, 04 June 2014 - 09:27 PM.