NSX Health Check Service

[goldnsx]

We normally do this o-ring too and if the car is more than 15 years old do the injector o-rings

1 91212-PR7-A01 OIL SEAL (41X56X7)
6 91301-PM7-003 O-RING (7.3X2.2)
6 16472-PH7-003 SEAL RING, INJECTOR
6 16473-P10-A01 RUBBER RING, INJECTOR
1 16741-PG7-005 O-RING, PRESSURE REGULATOR (12.1X1.9) (HONDA KIKAKI)

[nobby]

Hi Kaz

I am somewhat concerned re your post (see below). My car is currently going through Refresh with Sudesh (as you know). prior to getting the car, i had arranged with the garage i bought the car off to do the whole timing belt and water pump replacement done there. also recently, Sudesh has completed the crank pulley replacement etc. In relation to the oil pump replacement below, should this have been done at time of the belt being replaced?

Is this part easily got at or is it inside the engine and should have been sorted at the time of TB service?

bit concerned now re this as my car is 16yr old and since getting her, i have been playing about in her i.e. high revs etc. also is this total pump replacement, i have read about gear replacements etc, but assuming you are saying a full replacement is required.

do i need to get this looked at ASAP?

You wrote:

Please make sure to replace the Oil pump if you have ever over-revved the engine in the past.
In Japan, I saw at least three NSX engine failures due to the cracked oil pump.
Just over 8,000rpm, there is a resonance vibration point on the internal oil pump parts.
The crack could happen immediately at the time of over-rev or sometimes, at later date.

[Sudesh]

Andrew the pump is basically inside the engine, to the side.

Basically in short.

Drain Engine oil
Remove Timing Belt
Remove Oil filter Assembly
Remove Oil Pan
Remove Oil Screen
Remove Baffle Plate
Remove Oil Pass Pipe
Remove mounting bolts and then the pump




You can read some more here: http://www.nsxprime.com/FAQ/Performa...p_upgrades.htm

[Kaz-kzukNA1]

Hi, Sudesh.
Thank you for the follow up. I didn’t even know Prime had such a nice photo.

Hi, nobby.
As in my post, unless you over-revved the engine, you are very unlikely needing to replace the oil pump during your ownership. I know there are lots of NSX in Japan with their original oil pump still being used and running happily. I knew some of the NSX covered more than 300k miles with their original pump.
I covered over 127k miles in 16 years on my NSX and I replaced my oil pump just once at very early stage for R&D purpose and still running it without any issues.

The only parts at the oil pump that I can think of is the oil seal.
As goldnsx suggested, I heard that people replaces this seal at the time of TB service but in Japan, it is very rare and thus, I have never done it. I have one spare just in case.

So, if you are just driving on the street using the high rpm upto 8,000rpm, you are fine. Car manufactures have their own endurance test cycle and you’ll never know how they carry it out and how extensively they do this unless you are very close to the actual dyno and the test facility setup.

The problem was, during early 90’s, there were several aftermarket ECUs claiming that they can increase the rev limit higher than 8,000rpm without knowing the engine spec and other parts used inside/outside of the engine. They just wanted the easy quick profits.

So, some of the owners bought this expensive ECU and used a few 100’s extra rpm frequently believing that they gained something and eventually, bang, the oil pump cracked.

The other time when the oil pump could get damaged is the over-rev by the missed downshift.

If you are just driving on the street using high rpm and hit the rev limit, the ECU will cut the fuel and thus, rpm will drop.
I have never tried hitting the rev limit continuously so can’t comment on this but I presume, it won’t be good for the engine and other parts.

Unfortunately, for the missed downshift, the ECU fuel cut won’t save you…. The gear ratio and the speed will force the engine rpm to where you don’t want to be.

So, although I don’t know the history of your NSX, the way you drive your NSX, how often you track your NSX, number of missed downshift, etc, it sounded like you don't need to worry too much from what you wrote but as always, the final decision maker will be the owner.

Kaz

[goldnsx]

Kaz,
what would you consider over-rev? 8500, 9000 or 9500 rpm?
I've a 8300 rpm chip but don't use the 8k+ range. I ran only about three times into the limiter by mistake.

[nobby]

thank you kaz for clearing this up ... welcome relief for sure! I spoke to Sudesh briefly about it yesterday, and he thought i/my car was Ok but just wanted to make sure after your post that i was fine

Kaz, i am enjoying the NSX so enjoying the VTEC range however I am not over-reving ... i change when i hit the 8k rpm mark. This is not done on a daily basis, its just that i am enjoying my new ownership with the car. i do not intend to do this type of driving throughout course of ownership. I had an ATR before and like everything else you settle down after a bit

I have an extensive service history with the car so will review past receipts to see if anything has been done in this area. but as for history of the car in terms of ownership i have no idea how it has been treated etc.

I don't plan to track the car albeit i am heading to Nurburg as part of my summer hols so i plan to go round the ring but i dont plan to do timed laps or anything so will take it reasonably handy round here. dont plan to do anymore than 4-5 laps anyway.

As for missed down shifts i have never had this problem, long may it continue, but defo something i will ensure that this does not happen longer term.

Thank you for clarifying these issues with the pump, Sudesh thought it should not be so much of an issue for me, but as he refers to you as 'the master' ... thought i would still get your advice

I will now try to reduce my concern (use this term loosely more just a big question mark) around this area

many thanks for clearing this up for me

regards

andrew

Hi, Sudesh.
Thank you for the follow up. I didn’t even know Prime had such a nice photo.

Hi, nobby.
As in my post, unless you over-revved the engine, you are very unlikely needing to replace the oil pump during your ownership. I know there are lots of NSX in Japan with their original oil pump still being used and running happily. I knew some of the NSX covered more than 300k miles with their original pump.
I covered over 127k miles in 16 years on my NSX and I replaced my oil pump just once at very early stage for R&D purpose and still running it without any issues.

The only parts at the oil pump that I can think of is the oil seal.
As goldnsx suggested, I heard that people replaces this seal at the time of TB service but in Japan, it is very rare and thus, I have never done it. I have one spare just in case.

So, if you are just driving on the street using the high rpm upto 8,000rpm, you are fine. Car manufactures have their own endurance test cycle and you’ll never know how they carry it out and how extensively they do this unless you are very close to the actual dyno and the test facility setup.

The problem was, during early 90’s, there were several aftermarket ECUs claiming that they can increase the rev limit higher than 8,000rpm without knowing the engine spec and other parts used inside/outside of the engine. They just wanted the easy quick profits.

So, some of the owners bought this expensive ECU and used a few 100’s extra rpm frequently believing that they gained something and eventually, bang, the oil pump cracked.

The other time when the oil pump could get damaged is the over-rev by the missed downshift.

If you are just driving on the street using high rpm and hit the rev limit, the ECU will cut the fuel and thus, rpm will drop.
I have never tried hitting the rev limit continuously so can’t comment on this but I presume, it won’t be good for the engine and other parts.

Unfortunately, for the missed downshift, the ECU fuel cut won’t save you…. The gear ratio and the speed will force the engine rpm to where you don’t want to be.

So, although I don’t know the history of your NSX, the way you drive your NSX, how often you track your NSX, number of missed downshift, etc, it sounded like you don't need to worry too much from what you wrote but as always, the final decision maker will be the owner.

Kaz

[Timage24]

Back to the Yellow Targa NSX....


Now look for a small black box behind the left shoulder of the right side seat with the label as ‘RELAY ASSY, MAIN RZ-0101’ on it.
It is next to the big silver box (EFI ECU).

If you can’t find it, your NSX is DBW model and requires extra panel to be removed.

If you found the Main Relay, you can replace it with new one by removing just one fixing bolt on the bracket and two connectors at the bottom. You may struggle to access the connectors but if you remove the fixing bolt, it will provide you with extra space allowing you to access the connectors.

I am hopeing to clear something up before taking my car apart, i contacted Lings Honda, no reason other than top of the google list, and asked them for a price for a DBW main relay but they say that my car has the other relay
http://www.hondaoriginalparts.com/ho...block_03=21787
as shown in the diagran as number 11 but i've been in that part of my CAR and the relay is not their.

The man on the phone said it has to be but i'm sure its not, before i remove the other panels, as i am poor at DIY, is their another way to confirm which one i need.

Mine is a '97 manual 3.0 if that helps.

any help would be appreciated, i have a photo but cannot work out how to add it to the post, sorry.

Tim

[Kaz-kzukNA1]

Hi, Tim.
The answer is simple.

The parts list/diagram doesn't always show the actual shape/location of each parts for all Year models.

As you experienced, there is only one diagram on the parts list for the two different shape/location of Main relays for DBW and non-DBW models.

Presuming that you have RHD model and if you want to be sure, please have a look at under the bonnet or inside the engine bay.


DBW model

You need Main Relay #39400-SL0-A01

You will see LOOPED black cable surrounding the brake fluid reservoir and connected to the black plastic cube box inside the front compartment under the bonnet.

Also, at the right side of the engine bay, you will see thick black hose with red text on it. This is the fuel line from the fuel filter.
On DBW model, you WON'T see thick cable running in parallel to the fuel line like the one on non-DBW model below.


non-DBW model

You need Main Relay #39400-SL0-003

There is no looped black cable surrounding the brake fluid reservoir but still, you will see black plastic cube box nearby so don't get confused.

At the right side of the engine bay, you will see thick black hose with red text on it. This is the fuel line from the fuel filter.
On non-DBW model, you WILL see thick cable running in parallel to the fuel line. This is the TH cable running all the way from the front to the TH body at the left side of the engine and hence, non-DriveByWire.

I'm not a fan of Year model as sometimes, people get confused with registered year against Year model.
You may have 97 registered NSX but not necessarily 97 Year model NSX.

The best is to check against the VIN but if you check the above photos and 100% sure that your NSX is DBW, then your Main Relay is located around the right shoulder of your driver seat for RHD model.

Wow, more than GBP109 for the Main Relay.....
I'm quite sure if you ask Andy at vtecdirect, he would be able to source it much cheaper.
I always keep one each in stock at my place for owners.
Depending on the exchange rate and delivery charge from Japan/US, I would assume it would be about GBP50.00.

Regards,
Kaz

[Kaz-kzukNA1]

Now back to the TB/WP service on the facelifted Silver NSX.

Originally, we were planning to carry out the TB/WP service together with the Coolant system refurbishment before Japfest. However, I only managed to finish the Coolant system and Crank Pulley services in time due to my personal reason. Thus, some of the parts and Type-2 coolant were wasted by carrying out TB/WP service after the event but I covered these as it was my personal matter causing the changes in plan.

Also, the owner had to drive his NSX all the way to my place again using his precious time and fuel. I offered the owner something but he was a very generous man and gently declined it so instead, I carried out the A/C CCU service and cleaning of A/C cabin temperature sensor for free. Once again, I always feel I’m very lucky to be able to work and meet these generous owners.

So, the service started by talking to the owner.

The owner told me that this would be the first TB/WP service on this NSX but the valve cover was removed by the main dealer in the past for valve clearance adjustment.
So far, he didn’t feel any strange vibration at idling but still got some chattering noise even after the valve clearance was adjusted.


During the last service before Japfest, I noticed unusual amount of oil leakage for such a low mileage NSX so I was also interested to find the cause of this issue.


The engine area was inspected again.
Last time, I cleaned as much as possible the oil leakage and the oil pan area was quite clean even after the track session and long mileage driving so there was no need to replace the oil pan gasket.

I already had the parts but it was not clear last time whether it was leaking from the oil pan gasket or not due to the excessive oil leakage from the upper area of the engine and leaking down to the oil pan.

[Kaz-kzukNA1]

The spool valve and Oil Press sender unit area were clean apart from the usual leakage from camshaft black cap area so the filter at the spool valve and O-rings for the sender unit were not replaced.
This NSX already got the latest design Lost Motion Assy so there was no need to replace them at this low mileage.

I always carry out the compression check on the engine before opening the engine.

This will provide me with some idea on the condition of the engine by comparing it to the data from lots of other engines measured in the past. NA1 and NA2 engines will show different range and tendency depending on the engine status and measuring conditions.


Removing the injector terminal block at the right side of the engine to disable the fuel injection during the compression check. On earlier models, you will have injector resistor unit instead.

While preparing for the compression test, I noticed that there were lots of leaves around the intake chamber. Not sure how they managed to get in there but had to be cleaned before I can go any further. After cleaning them, the IGN Coils and Spark plugs were removed.

In order to re-install them at the same location, they were marked with the cyl #.

As seen on many other NSX, the IGN coil #1 (rear bank) was showing rust at the fixing tab due to the moisture getting inside. Another reason why it is best to replace IGN Coil cover seal at the time of TB service and regularly apply silicone grease until next service.

The rust was smoothed out and silicon grease was applied to prevent future corrosion.
Spark plugs looked fine and burnt in nice light brown colour at the insulator.

One of them showed a little extra oil at the thread so probably not torqued to the spec when it was removed in the past. As it was still at very low mileage, they were not replaced at this point.