O2 Sensor supplier in UK?

[WhyOne?]

Another part under suspicion of causing my misfire is (are) the O2 sensor(s).

I am reluctant to pay silly Honda UK prices for these, but don't have time to wait for delivery from the US.

Can anyone recommend a company in the UK who can be relied on to supply decent quality parts which will fit the NSX please?

[vtecdirect]

I can always beat HUK prices by a country mile, although delivery from Japan around 7 days. Thats for Gen Honda part.

Or can do an OEM replacement (denso usually);

1. Front pre cat sensor £165.80 delivered (each)
2. Post cat Sensor £ 83.60 delivered (each)

regards
Andy

[simonprelude]

Who has advised the O2 sensor? Seems strange to link that to a misfire, especially if only on a single cylinder (do you have a fault code?)

[WhyOne?]

Hi Simon. Yes, it is a funny one. Initially I was getting a non-specific P1399 code. Then I managed to register a P1201 (cylinder 1 misfire) - easy, sorted I thought - plug or ignition coil!

I took the car to my Honda dealer & they switched the suspect coil to cy. #2, then #3, expecting to see the code change accordingly.

It didn't.

Misfire prevailed & codes ranged from non-specific to occasionally misfires across all cylinders.

A new ignition coil is on its way, and will replace the initially suspect one on Monday.

If this doesn't work, I am borrowing an ignitor unit from (the other!) Simon to swap with mine.

If that doesn't work, I have been given an O2 Sensor test procedure for them to try. There are instances documented on Prime of O2 sensors causing this sort of problem. I also have it on extremely good authority more locally that this could be this issue. ;)

I am under pressure from my son - he has his school leaving ball this coming Thursday. All the students try to arrive in something a bit special - mainly stretch limo's, but also a smattering of exotica (and tanks plus the odd helicopter!!!) Having been brought up watching F1 & travelling in my S2000 & NSX, he is desperate for me to take him in the NSX.

I am equally keen not to let him down. :(

[vtecdirect]

Cant beat the sound of a 5 Cyl NSX .:D
I have seen coil packs not work on cyl 1 but once switched work ok for a while and again randomly fail but not enough to be a constant misfire. It is an expensive fix but a new set of coil packs could be a good way of discounting them from the fault issue, although a new set of O2 sensors not a cheap fix either.

[Kaz-kzukNA1]

Who has advised the O2 sensor? Seems strange to link that to a misfire, especially if only on a single cylinder (do you have a fault code?)
It was me who asked WhyOne to carry out ECU open loop mode test as well as swapping the Ignitor unit for misfire diagnosis.

After receiving lots of info from WhyOne with initial error code P1399 (which is the multiple random misfire for Honda), I suggested to check the water inside the rear bank IGN coil/spark plug area. Then, he reported another error code for CYL#1 misfire so I also asked him to swap the #1 IGN coil to other CYL to see whether the error code will follow the same IGN coil or not.

His NSX was at his local garage and seemed that the test they carried out on moving the #1 IGN Coil to other CYL was not conclusive as they were still getting P1399 multiple random misfire or even all six cyl misfire so I also recommended to swap the Ignitor unit with known good one and also try the ECU Open Loop mode by disconnecting the Pre-CATs O2 sensor.

There were several misfire cases reported with bad O2 sensor without triggering the ECL or OBD-II error code. I also recommended other points to be checked as well but it will get too long so will leave them for now.

Seems like the visual inspection of IGN Coil at the garage was fine with no corrosion or water and they also checked the resistance.

However, this method is not conclusive as you need to put it on the spark bench using the 3 point gap under compression to test it while monitoring the signal. Temperature is also the factor to be considered when testing IGN Coil and SPark Plug.

If it is getting multiple misfire, it is very unlikely to have lots of IGN Coils to fail at the same time. Same for the Spark plugs. It is very unlikely to have many spark plugs to fail at the same time.

So, if a certain owner visit my place with multiple random misfire on his/her NSX, then I will carry out the above Ignitor and ECU Open Loop test after looking at the IGN Coil and Spark Plug conditions as these two methods doesn’t require any new parts. I can use my Ignitor and for O2 sensor, you just need to disconnect the two pre-CATs ones to trigger the ECL and put ECU into Open Loop mode. I can also use my known good IGN Coils and Spark Plugs from my NSX as well....

Hope he can sort this issue out very soon as I now know why he was pushing very hard and even asked about the source of O2 sensor even before carrying out the ECU Open Loop mode test.

The price from Andy at Vteccirect seems very attractive compared to the ones from USA so I sent you an email, Andy.
I want to keep some stock as I don't want to touch the front header during service work without having spare O2 sensors...


Regards,
Kaz

[Nick Graves]

You might want to do a search on S2Ki - I seem to remember that O2 sensors are pretty generic and someone there found a good source of one which matched Honda spec.

[WhyOne?]

Thanks Nick, I'll go and have a rummage now.

[AR]

I bought a cheap generic one and had to splice the plug. Worked well until the SOS NGK ones arrived.

[Nick Graves]

Man for the king?

http://cgi.ebay.co.uk/Lambda-Sensor-Honda-Civic-FR-V-NSX-Prelude-Stream-/180499750548?cmd=ViewItem&pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2a069f9e94

[AR]

http://cgi.ebay.co.uk/Honda-Universal-4-Wire-oxygen-lambda-sensor-probe-/140400867310?cmd=ViewItem&pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item20b08b37ee

ymmv etc.

[Kaz-kzukNA1]

Hi, all.

As I get similar questions through PM and email regarding O2 sensors, I would like to share the following especially for those who are planning to place an order in the near future.

First, please double check the spec of your NSX.

Pre OBD-II model will require just two sensors before the CAT.
Both sensor has 4 pin male connector.
Sensor spec is the same between the two and the loom length is similar so some of the manufactures will use longer loom to cover both sensor position with single parts number.

If you are installing aftermarket header and if your OEM O2 sensor loom is not long enough, try using the OEM Front sensor at the rear position.
Front one has longer loom length.
You just need one extension loom connecting it to the Rear sensor and install it at the front side.
Saves your time and cost by not building two extension cables.

For OBD-II model, please note that you have two sensors before the CAT and another two after the CAT.
Although all four sensors use 4 pin connector, one of them is different (male/female) from others.
You must connect the sensors to the correct ports otherwise, ECU will get confused.
Sensor spec is different between before/after CAT sensors so when placing an order, please make sure to check this point.
The sensor before the CAT is more expensive than the one after the CAT.

For example, the sensor mentioned in one of the link posted here is the one after the CAT and thus it is cheap.

Personally, I will use the ones from Denso or NGK/NTK with OEM connector fitted. From the information gathered, they seem to have better protection against contamination and thus, lasts longer than others.

These ones will also come with the protection rubber for fixing the loom to the OEM bracket.

Generic/Universal model won’t have these connector or protection rubber and thus, you will need to crimp the wires of replacement sensor to the original loom.
Please do not solder the joint as it will crack with vibration.

Regards,
Kaz

[WhyOne?]

With the pre-cat o2 sensors disconnected / ecu in open loop mode, am I correct in my understanding that if the engine runs without misfire on test drive, there is a problem with one or both of the disconnected sensors?

If this is the case, is there a way to determine which is faulty or is it good practice to replace both?

Thanks.

[Kaz-kzukNA1]

Hi, WhyOne.

I think you are just planning ahead and not actually performed the Open Loop mode yet.

Presuming that you are no longer experiencing the misfire by disconnecting both Pre-CAT O2 sensors, then you can identify the failed sensor(s) by re-connecting them one at a time, reset the ECU every time when you change the connection and then carry out the test driving session with similar condition of which you experienced the misfire previously.

Although it is very unlikely to have both sensors to fail at the same time, you need to connect only one sensor at any time to determine whether it is single or both sensor failure.

As your NSX is OBD-II, your garage should be able to monitor the state of open/close mode control, the signal output from all four O2 sensors, rpm and so on through the OBD-II monitor.

It all depends on the performance of the OBD-II monitor and since it’s using the CAN bus, the timing of the realtime data is not guaranteed but at least, you can watch what’s happening with the A/F trace of each sensors.

Not sure at what rpm the misfire happens so you may struggle to monitor the signal trace if it doesn’t have enough sampling rate performance.

If you are installing aftermarket header, then it is a good idea to replace both sensors at the same time as you could have damaged them during the removal process but this is just my policy of not touching the header area without spare sensors.

For your case, as it is an OBD-II car, I won’t replace the O2 sensors unless they are faulty or they were used for about 100K miles.

Due to the strict emission control, I’m not sure about the UK market but some countries offer quite long term/mileage warranty on emission related parts including the O2 sensors and CATs.
Best to ask your local Honda garage for the condition of warranty if your O2 sensor is faulty and/or if you have OBD-II car.

Regards,
Kaz

[NoelWatson]

As your NSX is OBD-II, your garage should be able to monitor the state of open/close mode control, the signal output from all four O2 sensors, rpm and so on through the OBD-II monitor.



Might be worth buying a reader from EBay. I borrowed Ewan's when we were having problems with the CEL after hi flow cats were fitted and you can see the voltage from all four sensors in near real time.

[WhyOne?]

Hi, WhyOne.

I think you are just planning ahead and not actually performed the Open Loop mode yet.



Yes, you are quire right Kaz....I am probably getting ahead of myself in my eagerness to anticipate the next step.

The garage will today perform the Open Loop test & swap out the ignitor unit with a known good one from Simon's (NSXGB's) car.

They had a little time to look at the car on Saturday & monitored the spark activity using an oscilloscope.

They saw no misfire whilst the engine was cold.

Once it warmed up, there was no misfire at idle or up to about 1800rpm.

At 2000rpm+ they could see random 'misses' across all cylinders.

From this they deduce it is likely to be an electronically derived problem and were grateful that I dropped in the ingnitor unit & details of the open loop test.

Hopefully more information later today.

Ian

Edit...PS - the car has standard factory headers.