Nissan Terrano II
Submitted: Sunday, Oct 12, 2003 at 13:29
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Pepper
Hy everyone,
Just came across the
forum while looking for some answers with an over-fueling problem in my 97 Terrano diesel. In the 4WD Monthly mag, some reader talked about cleaning the oxygen sensor to improve performance. He was very specific but failed to talk about its location. I spoke to Nissan and a
well established mechanic who both said that this vehicle does not have one. I do not know what to believe now and hope somebody can help me. I found out that I had a problem after taking the Intercooler off and looked down the intake manifold. It was covered in about 1/2 an inch of black muck.
Reply By: awill4x4 - Sunday, Oct 12, 2003 at 15:31
Sunday, Oct 12, 2003 at 15:31
Pepper, if the crud accumalation is in the intake manifold it won't be from over-fueling because the diesel is injected under pressure either into the combustion chamber in the case of direct injection or pre-combustion chamber in the case of indirect injection.
The only thing in theory which is supposed to enter the intake manifold is clean filtered air compressed by the turbo.
What I suspect you're seeing is oil, either drawn through the oil seal on the turbo or from the rocker cover breather tube where it enters the air intake system upstream of the turbo. I don't know if these engines have a PCV valve but that could also be a problem if it's stuck open.
Your best way to
check is to remove the tubing from the rocker cover and PCV tubing if it has one at the end where they enter the air intake and
check if there has been any obvious signs of oil going through the tubing.
Any oil in your intake manifold has to have gone through your intercooler and it will also be very badly contaminated and need to be cleaned out. To clean the intercooler you should pour some petrol in it and just shake it around then drain it. Keep on doing this until it runs through fairly cleanly then set it aside in a warm dry space outside if possible and allow the petrol to evaporate. If you're concerned about the petrol fumes you can use methylated spirits after the petrol as it has a less combustible nature.
At no stage should you install the intercooler unless it completely dry of fuel!!!!
Regards Andrew.
AnswerID:
33483
Follow Up By: Pepper - Monday, Oct 13, 2003 at 18:53
Monday, Oct 13, 2003 at 18:53
Hey awill4x4
Looks you were right. the breather tube as
well as the air intake hose between the filter and the turbo are full of black soot. I can clean that stuff up as you suggested, but that would not fix the problem. I don't know if the turbo leaks oil or what else is wrong. I only picked all this up since the idle is continiously surging. Sometimes to the point where the car snuffs. I checked for air in the fuel and bleeded the system, no better. Nissan had it on the diagnostic and confirmed all is
well.
Some more thoughts from your end?
Cheers
FollowupID:
24139
Follow Up By: awill4x4 - Monday, Oct 13, 2003 at 22:10
Monday, Oct 13, 2003 at 22:10
Pepper, from your description it sounds either like pressure blow by where the turbo is boosting past the rings and pressurising the crankcase/rocker cover which then vents oil through the breather tube back to the inlet to be burnt. Or a damaged oil seal on the turbo itself. I suspect the former as the oil/crud is upstream of the turbo.
Probably your best and cheapest alternative is to install an oil/air separator between your breather tubes and the air intake.
In this the breather tubes are redirected to the oil/air separator (also known as oil catch can) here the oil is separated from the air and the clean air is then redirected back to the intake without any residual oil contaminating the intake system.
Do not get a catch can which vents to the atmosphere via a small air filter instead use a sealed system which simply redirects cleaned air back to the original air intake positions.
Be aware the catch can needs to be checked regularly so it can be emptied of oil/crud accumulation.
These catch cans can either be custom built or bought from a speed store. I've struck this same problem on turbo Toyota motors and the catch can has made a lot of difference.
Regards Andrew.
FollowupID:
24175
Follow Up By: Pepper - Tuesday, Oct 14, 2003 at 08:53
Tuesday, Oct 14, 2003 at 08:53
Thanks mate,
I'll give that a go. I went back to my mechanic today and he confirmed your suggestions, however, the evidence would be excessive oil use and that is one thing the car does not do. So I guess the catch tank is it.
Cheers for now
FollowupID:
24208
Reply By: Member - DOZER- Sunday, Oct 12, 2003 at 19:42
Sunday, Oct 12, 2003 at 19:42
Oxygen sensor can mean a few things. In a petrol, it is on the exhaust manifold and reports to the computer whats happening, on a electronic injected diesel, it could be in the intake down from the filter and measure temperature or flow, not sure, but with some new cruisers, you cant use an oil/foam filter in them or it will coat this sensor with oil mist and shut down the motor.
What you are seeing in the intake is normal for a turbo diesel. When you say overfuelling, what do you mean? tell us whether it is using too much fuel, down on power, starting cold runs erratic, smoking, colour of.. etc etc.
Andrew wheredayathinkwer mike?
AnswerID:
33492
Follow Up By: Pepper - Monday, Oct 13, 2003 at 18:57
Monday, Oct 13, 2003 at 18:57
Hey DOZER,
Seems like there is no sensor just a air flow meter between the air filter box and the turbo. I thought it might be broken and called Nissan for a price on a new one. They quoted $995.00 so I guess I 'm stuck with the old one. The smoke is more black than white or blue and only excessive beyond 3000 RPM so I don't know if that is an indicator for anything.
Cheers
FollowupID:
24140
Reply By: awill4x4 - Sunday, Oct 12, 2003 at 23:55
Sunday, Oct 12, 2003 at 23:55
Dozer, if as Pepper states there is about 1/2 an inch accumulation of muck in the intake, I would be most concerned. It certainly doesn't sound like normal wear & tear.
Pepper, when you say over-fueling. Is it blowing smoke, either blue or white? Or is the engine running on after shut down. If it's the latter then you may have a problem with the engine running on its own oil.
Regards Andrew.
AnswerID:
33532
Reply By: hoyks - Thursday, Oct 23, 2003 at 09:00
Thursday, Oct 23, 2003 at 09:00
The air mass meter is located in the duct just down stream from the air filter. The meter can be removed from the duct with a star type screwdriver and given a good spray with contact cleaner.
Mine was totally stuffed, so I went looking for a new one and nearly fell over at the price Ni$$an were asking. BOSCH makes the part, and being good Germans that like to keep track of everything, there is a BOSCH part No. On the side of the duct that the air meter in screwed into (4 bolts hold it onto the air cleaner and a hose clamp to the turbo duct). Take this number to a Bosch auto electrical/fuel injection
shop and you will get the part for around $400, not good, but better.
Nissan say the fuel injectors have to be bought as a complete unit (around $2000 a set), but you can get Bosch nozzles (original part anyway) for fitted and pressure tested for around $300.
AnswerID:
34816
Follow Up By: Pepper - Friday, Oct 24, 2003 at 06:49
Friday, Oct 24, 2003 at 06:49
Thanks hoyks for that info. That price is less than half of the nissan part.
I gave the flow meter a good clean but it was not realy that dirty. However, cleaning out all the muck from the manifold gave me a better fuel economy of 1 liter per 100 km. I will install a bottle to catch the oil from the rocker breeder tube to prevent the build up in the future.
Cheers mate
Pepper
FollowupID:
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Follow Up By: hoyks - Friday, Oct 24, 2003 at 07:43
Friday, Oct 24, 2003 at 07:43
I gave the breather tube a good clean out and that helped stop (
well reduced alot of) oil being sucked into the air intake.
I got a bottle of that "engine flush" stuff that you poor into the oil and it removes the sludge from in the oil galleries of the motor.
I removed the plastic chamber in the crankcase vent (the one on the front of the engine that has the breather tube to the air intake) and gave it a clean and then poored the engine flush down the tube that goes down to the sump. I needed a piece of wire to unclog the bottom of this tube, which may have been the problem in the first place.
About 1L of extra oil and sludge came out when I changed the oil, so it must have done something.
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