A oxygen sensor issue?

[89berlina]

What are the symptoms of a stuffed oxygen sensor? Could it cause the car to cut out or run rough? My 89 VN has had almost every sensor and valve replaced but still runs rough at idle and cuts out when driving. Here is what Ive replaced/checked:

• IAC valve
• Crank Angle Sensor
• Fuel pump + new fuel filter
• Leads + plugs
• Checked coil pack resistance and earth - all good
• Checked alternator output - all good
• New battery
• Checked fuel regulator - all good
• Tested fuel injector resistance's - all good

Any help would really be appreciated
Cheers Rhyan

[89berlina]

UPDATE: Took the car for a drive and once again it died on me. The car would have a hiccup and then just die So close to giving up on this car!!! Changed and checked almost everything!

One thing I noted after I struggled to get the car home and have a look at, was that one of the connections to the ECU looked abit fried. Do I need a new ECU? Also cleaned the O2 sensor and its no longer coming up as an error on the ECU so dont think thats the problem. I have no idea whats going on with it???

[aussieghostrider]

does it do it more so when its warmed up ?

could be alot of things ... Earth cable loose , stuffed coilpack/module

also cleaning the O2 sensor wont help it , I would replace it just to be sure..

I do know the o2 sensor can cause issues you are having but usually you just use alot of fuel as the car still goes.

try reseting ecu take out engine fuse or disconnect battery for 5 mins.

[88GreenVN]

I had to replace my ECU in the wagon after replacing most sensors.

They dont cost much from the wreckers.

[89berlina]

aussieghostrider:
Ive done all of what you've mentioned besides replacing the Oxygen sensor. It came up as a error code on the computer as an intermittent fault but no longer comes up after the Oxy sensor was cleaned and the computer reset. But as you said the car should still run so not worrying about it for now. The car does being to play up as it heats up. Around the first notch on the temp gauge. Could only possibly be the Coil pack or ECU. Originally thought it may be a dodgey connection to the fuel pump, so removed the connector and hard-wired the connection but didnt do anything

88GreenVN:
Yeah got myself a ECU for free off a neighbour today who has three. What symptoms did your car show?

[aussieghostrider]

could it be **** in your fuel tank that is interfering with swirlpot ?

but you said it does it more so when warm so has to be electrical ...

the coolant temp sensor can cause the engine to stall. , if the sensor isn't working right, it can tell the computer the engine is cold when it is actually hot, and the computer will send the wrong air/fuel mixture to the hot engine, and cause it to stall & also running rich all the time will foul up your 02 sensor as well creating another problem.The car needs properly troubleshooted to be sure so auto electrician..



It might not even be the sensor anyhow, it could be the wires and connections to/from the sensor.

[88GreenVN]

88GreenVN:
Yeah got myself a ECU for free off a neighbour today who has three. What symptoms did your car show?

Car would just quit - die. It started by jolting on the expressway @ 100 kph.

But at slow speed it would stall. Most of the time would fire up first time. But got harder and harder. Replaced the CAS - but the car still stalled.

Plugged in the laptop and the car stalled when the fan was called into action by the ECU. Replaced the ECU and no more stalling. (the car had a major meltdown one night and ended up replacing most things).

If the ECU replaced has no effect and you have a new CAS - I'd be looking at the DFI or Coils.

[Nevyn]

yup...this all sounds a lot like how my VN has been since Friday....I just changed the ecu and memcal then and its running fine again...apart from the air leak I had before.

[89berlina]

could it be **** in your fuel tank that is interfering with swirlpot ?

but you said it does it more so when warm so has to be electrical ...

the coolant temp sensor can cause the engine to stall. , if the sensor isn't working right, it can tell the computer the engine is cold when it is actually hot, and the computer will send the wrong air/fuel mixture to the hot engine, and cause it to stall & also running rich all the time will foul up your 02 sensor as well creating another problem.The car needs properly troubleshooted to be sure so auto electrician..



It might not even be the sensor anyhow, it could be the wires and connections to/from the sensor.

Just recently I pulled out the fuel tank and thoroughly cleaned it, so its spotless and cant be the issue. Also tested the coolant temp sensor and its working perfectly

Car would just quit - die. It started by jolting on the expressway @ 100 kph.

But at slow speed it would stall. Most of the time would fire up first time. But got harder and harder. Replaced the CAS - but the car still stalled.

Plugged in the laptop and the car stalled when the fan was called into action by the ECU. Replaced the ECU and no more stalling. (the car had a major meltdown one night and ended up replacing most things).

If the ECU replaced has no effect and you have a new CAS - I'd be looking at the DFI or Coils.

Sounds very much the same story. Also assumed it was a CAS problem and replaced it but made no difference. Still stalls - especially at low speeds and just randomly when cruising at 80-100km/h. Thanks 88GreenVN

yup...this all sounds a lot like how my VN has been since Friday....I just changed the ecu and memcal then and its running fine again...apart from the air leak I had before.

Good to hear Im on the right track Really hope this is the end to me forking out dollars. Thankfully I have a neighbour giving me the ECU.

Will keep you updated on the situation. Thanks for the help guys

[89berlina]

UPDATE: Changed the ECU but no go. She still died on me It definetly happens when the car heats up. So im hoping its the coil pack... if not dont know whats going to happen

[88GreenVN]

UPDATE: Changed the ECU but no go. She still died on me It definetly happens when the car heats up. So im hoping its the coil pack... if not dont know whats going to happen

Coils/DFI is a good bet if you have already replaced the CAS. Do you know anyone with a VN? or live ner a wrecker - they may let you test it on the car. Also have you closed all the connectors on the DFI plug - 1 may just be open too far and when hot loses contact.

[needwork2-4fillhabbit]

My misses vp has the same sorta issue at the moment, has a big miss thats causing a noise like a broken cat or exhaust slapping against something...really sucks. Im going to change the o2 sensor saturday to see if its that then ill try injectors. But similar simptoms car started normally with new plugs in then quickly the noise came back after 20 seconds, i to have changed memcals over ecu and plugs and leads and even the coil pack. Ill be interested to see how you fix it.

[89berlina]

Coils/DFI is a good bet if you have already replaced the CAS. Do you know anyone with a VN? or live ner a wrecker - they may let you test it on the car. Also have you closed all the connectors on the DFI plug - 1 may just be open too far and when hot loses contact.

Yeah, the connectors on the DFI plug are fine. Managed to borrow a Coilpack off my next door neighbour, so I'll see how it goes.

My misses vp has the same sorta issue at the moment, has a big miss thats causing a noise like a broken cat or exhaust slapping against something...really sucks. Im going to change the o2 sensor saturday to see if its that then ill try injectors. But similar simptoms car started normally with new plugs in then quickly the noise came back after 20 seconds, i to have changed memcals over ecu and plugs and leads and even the coil pack. Ill be interested to see how you fix it.

Cant say mine makes noises. It just shuts off. When you go to start it again the starter motor just winds the engine but the cylinders dont seem to fire. Dies around the first notch on the temp gauge. Dont know if this helps? Hope you figure out your problem

If I sort it out I will definietly let you know, unlike many of the threads on the site where some people have a issue but dont end up explaining how they fixed it.

[88GreenVN]

My misses vp has the same sorta issue at the moment, has a big miss thats causing a noise like a broken cat or exhaust slapping against something...really sucks. Im going to change the o2 sensor saturday to see if its that then ill try injectors. But similar simptoms car started normally with new plugs in then quickly the noise came back after 20 seconds, i to have changed memcals over ecu and plugs and leads and even the coil pack. Ill be interested to see how you fix it.

A big miss in the engine if you have changed plugs and leads would point to the coils.

The coils are the most common fault. (after leads) the injectors are no where near as common in going kuput.

[Nevyn]

when u changed the ecu were u using the same memcal?

[89berlina]

No just swapped them over. Does this make a difference? The symptoms were exactly the same

[Nevyn]

could be the memcal itself then

[89berlina]

A big miss in the engine if you have changed plugs and leads would point to the coils.

The coils are the most common fault. (after leads) the injectors are no where near as common in going kuput.

Yep definetly a big miss in the engine. Hopefully changing the coilpack ends my spending spree's

[88GreenVN]

Yep definetly a big miss in the engine. Hopefully changing the coilpack ends my spending spree's

Real pain spending on fix it up bits. AND not make the problem go away. Only good thing is your not paying 40 per hour for some one else to test and replace bits.

[needwork2-4fillhabbit]

I changed the coil and still has the miss, doing me in might just scrap it and use the vp parts on my vn project.

[89berlina]

Real pain spending on fix it up bits. AND not make the problem go away. Only good thing is your not paying 40 per hour for some one else to test and replace bits.

Yep it sure is Well thats true. At least Im not spending anything on a mechanic. My car would be a nightmare for the 'average jo' who might not know much about cars! lol

I changed the coil and still has the miss, doing me in might just scrap it and use the vp parts on my vn project.

Try checking the following:

• IAC valve - make sure its clean
• Leads and plugs - test resistance on leads and check each of the plugs to see how well they're burning (they will be a tan colour if burning properly)
• Earths - check earths on your ECU and ignition module/coil pack
• Coil pack - make sure you didnt buy a 'dud' pack by testing a mates or a friends pack on the car
• Fuel pump - how old is it? May be worth your while checking your fuel pressure.
• Fuel tank - make sure your fuel is clean and they're is no gunge or rust in the tank. This could cause bad detonation and a miss

You may have already done all of this, but thought it may be worth your while knowing

[89berlina]

Changed the coil pack and ignition module with a Series 2 unit... and GUESS WHAT! Died AGAIN and wouldn't start. For a 18 year old working a casual job with not much of a income, this car is becoming a nightmare! Checked over every (and I mean EVERY) sensor... but everything is 'fine'. No computer code either. Just says its workinog fine (code 12). I have now tried almost everything. If someone can help me, I'd be so thankful!

One thing I noted however is that symptoms were a little different. Such as the fact that the car heated up quite abit but didnt die for awhile and when it did, at times, it started immediately. Also noted that the car struggles to keep idle when coming to a stand still. Oh and YES, I did reset the IAC valve

Would appreciate any advice. Thanks so far

[88GreenVN]

Changed the coil pack and ignition module with a Series 2 unit... and GUESS WHAT! Died AGAIN and wouldn't start. For a 18 year old working a casual job with not much of a income, this car is becoming a nightmare! Checked over every (and I mean EVERY) sensor... but everything is 'fine'. No computer code either. Just says its workinog fine (code 12). I have now tried almost everything. If someone can help me, I'd be so thankful!

One thing I noted however is that symptoms were a little different. Such as the fact that the car heated up quite abit but didnt die for awhile and when it did, at times, it started immediately. Also noted that the car struggles to keep idle when coming to a stand still. Oh and YES, I did reset the IAC valve

Would appreciate any advice. Thanks so far

When you changed the ECU did still die or just run rough?

[89berlina]

When you changed the ECU did still die or just run rough?

When I changed the ECU, the car wouldnt die until you came to a stand still and when it attempted to keep idle. When cruising it didnt die anymore. I changed both ECU's around when testing to see if it made a difference. I noticed when I put the orignal ECU in however, that the car would die and take awhile to start. When the other ECU was put in the car would die but start straight away. Could this be a coincidence or could I just have two faulty ECU's by chance? How can I definitely know the ECU is stuffed?

[88GreenVN]

When I changed the ECU, the car wouldnt die until you came to a stand still and when it attempted to keep idle. When cruising it didnt die anymore. I changed both ECU's around when testing to see if it made a difference. I noticed when I put the orignal ECU in however, that the car would die and take awhile to start. When the other ECU was put in the car would die but start straight away. Could this be a coincidence or could I just have two faulty ECU's by chance? How can I definitely know the ECU is stuffed?

Took me ages to find the fault - I ended up driving around with the laptop hooked up waiting for death to occur. When the car wamed up and the fan was called into action (by the ECU) the car would quit. The thing was I had changed the ecu some time (running rough) before as a test and the still ran rough - so I thought the ecu was not the problem.

The chances of 2 faulty ecu's would be rare - but the spare ecu is not in a car for some reason.

I would also make a bet that your ecu is dead and when you put the spare in a second issue is comming to light. (So you have 2 problems)

Often when these VN's have a fizzy fit they take out a few parts at the same time of which some die slowly over the next few months - I guess some parts are weakened by the electrical surge but dont die there and then.

I'd go with the new ECU for a while.