Fails to start first time

[philboo]

Thank you Kaz. I’ll look into answering all of these when I get chance.

The quick ones.

it’s a UK 3.0 96 NSX T so I assume DBW.

No electrical changes or work apart from you repairing my climate control a few years ago.

It’s all standard. It had an original alarm which I don’t use but also doesn’t seem to cause issues.

Just standard services, nothing electrical related.

Thanks for taking the trouble to reply.

Phil

What is the spec of your NSX?
From the gauge design, looked to be DBW so must be 95+ MT.

Year model, country spec, any modifications, aftermarket security devices, etc?
Anything done around the ECU connectors, behind the seat, ICE devices, etc?
Anything done inside the Eng bay when this started happening? For example, DBW motor connector, sensor connectors, etc?

Please read the error code first.
http://www.nsxcb.co.uk/showthread.php?9229-How-to-read-the-error-code

If you set the clock, does it keep the correct time?


In your video, after in P2 ON, the CEL stayed On for about 2sec for the bulb check mode (normal) but it immediately came back On again (00:05 - 00:06) and stayed On for at least another 2+sec (not normal).

Possibly triggered the CEL before starting the engine due to open/short circuit on sensor/device/etc or loss of Vcc or Vref.

It actually stayed On for about 3sec but then you cranked the engine so it could have stayed On forever (not normal).

The engine stalled fairly fast so not conclusive but your TCS light also stayed On after the engine started.
Normally, it will switch itself Off as soon as the engine starts.
However, because it stalled so fast that it may not be able to complete the cycle and could be nothing wrong and not related.


Just before the 2nd attempt when you turned the IGSW into P2 ON, the CEL DID switch itself Off after the 2sec bulb check mode and stayed Off (00:16 - 00:19, this is how it should be).
Then, the engine started successfully and the TCS light switched Off.


From what you wrote, there are several question marks on the IGSW and you could have multiple issues resulting in just one phenomenon so another question mark (but lower priority than the IGSW) on the Fuel Pump Relay, Fuel pump, fuel pump resistor but I'll wait for your answer to the spec of your NSX and the report on the error code first.


Kaz

[philboo]

Hi

i assume this is the correct information for engine diagnostics http://www.nsxcb.co.uk/showthread.ph...the-error-code

Thank you Kaz. I’ll look into answering all of these when I get chance.

The quick ones.

it’s a UK 3.0 96 NSX T so I assume DBW.

No electrical changes or work apart from you repairing my climate control a few years ago.

It’s all standard. It had an original alarm which I don’t use but also doesn’t seem to cause issues.

Just standard services, nothing electrical related.

Thanks for taking the trouble to reply.

Phil

[Kaz-kzukNA1]

Yes.
Can be used for both OBD1 and OBD2 spec.
Yours is OBD1 and DBW spec.
If not sure about the actual code, please take a video from IGSW in P0 Off position and try to include all readings including the volt gauge.

Even without triggering the warning light, it's worth reading the error code at least once a year.

Some of the error codes require two consecutive drive cycles or two detection within the same drive cycle before triggering the warning light.
Therefore, even without any warning lights, still, you may have error code stored on certain controllers.


Kaz

[philboo]

Hi Kaz

I've done the following today.

Inserted diagnostic loop


Car still in my garage, not been started since I previously since put away. See video here: https://www.dropbox.com/s/ii1gm0f6hx...%2012.mov?dl=0

Next I removed diagnostic loop and started car (without the issue as if had the ignition on and off a few times for the diagnostic video), drove it for 30 mins


Stopped. Inserted loop and did this video: https://www.dropbox.com/s/zchwvyk0ex...%2003.mov?dl=0


Then I removed the diagnostic loop


Tried to start car (from warm having been stopped about 5 mins), it failed with same issue. See video here: https://www.dropbox.com/s/ar93k7gw4p...%2048.mov?dl=0


Inserted the diagnostics loop. See final video here: https://www.dropbox.com/s/68viuzeyqw...%2034.mov?dl=0

Looking at the diagnostic pdf I think this is showing just the one error code of 4, is that correct ?

Thanks

Phil

Yes.
Can be used for both OBD1 and OBD2 spec.
Yours is OBD1 and DBW spec.
If not sure about the actual code, please take a video from IGSW in P0 Off position and try to include all readings including the volt gauge.

Even without triggering the warning light, it's worth reading the error code at least once a year.

Some of the error codes require two consecutive drive cycles or two detection within the same drive cycle before triggering the warning light.
Therefore, even without any warning lights, still, you may have error code stored on certain controllers.


Kaz

[Kaz-kzukNA1]

That's CEL #40, DBW motor circuit or TH butterfly target/actual positon deviation.
It's not conclusive whether this error was stored in the past or indeed happening at the moment.
If the latter case, very likely to be related to the cause of the engine stall.

Voltage reading seemed to be consistent even during cranking so at this stage, I'll leave power supply related cause out of the scope.


Still, from your latest video, whenever the CEL came back On after the light bulb check mode, the engine stalled so there must be a relationship.


Now that you read the code, the next step is to reset the ECU but please don't do it if you are close to the MOT (6 months extension only applies if renewal date before 01/Aug) or away from your home as there is a chance the ECU may not be able to re-learn all of the co-efficient figures if there is a problem (including loose connector, etc) with the DBW.


Please note that the followings are not the standard reset procedure and only applies to your specific situation.


1. In preparation for the reset process, locate the 7.5A CLOCK fuse inside the pentagonal/octagonal black box under the bonnet/hood.

2. Fully warm up the engine.
Just go out for a short driving or combine the process on your return from outing.

3. Before stopping the engine, switch off the A/C, audio head unit, head light, etc.
Basically, create no load condition in preparation for the next fireup.

4. Stop the engine.

5. Remove CLOCK fuse for 10sec and then place it back.
This will erase all of the error codes from any controllers on the car except for the latest one body ABS brain.

6. Turn IGSW into P2 ON and wait for at least 2sec while keeping eye on the CEL.
Do not start the engine and keep no load condition.
Do not touch the TH pedal.

7. If the CEL came back On after 2sec of light bulb check mode, put IGSW back into P0 Off and then back into P2 On. Otherwise, go to step #8.
Repeat this a few times if the CEL doesn't switch itself Off after every bulb check mode.
This is just to simulate some of your video as the engine always stalled if cranked with the CEL On but then if power cycled, the CEL switched itself Off after the bulb check mode and the following engine fireup was fine.

8. Now start the engine without touching the TH pedal and keep no load condition.
On first attempt, if the engine stalled like before because the CEL stayed On in step #7, go back to P0 and re-start the engine again.

9. Keep running the engine under no load condition and without touching the TH peal for 10 - 15min.
Don't worry about the electrical load increase because of the radiator fan.

10. Stop the engine, wait for a few sec, put IGSW into P2 On and wait for at least 2sec.

11. If CEL came back On after 2sec, repeat #7 and #8 but no need keep running the engine for 10 - 15min. Just short fireup like 10sec is enough.
If CEL stayed Off after 2sec, just start the engine for about 10sec.
Unlike in step #8, the engine rpm should drop to 800rpm almost immediately after the fireup.

12. Stop the engine.

13. Read error code.
If new code or CEL #40 stored, you will need further diagnosis but most likely, loose connector, etc.

14. If no code stored, go out for several outings and remember to read the error code at some point even if you didn't trigger the CEL.
From now on, try waiting for at least 2sec after every IGSW P2 and keep eye on CEL.
On first occurrence of CEL coming back On after 2sec, ideally, do not start the engine and read the error code immediately.


Kaz

[philboo]

Kaz, you're great. My MOT is booked for the 14th July so I'll pause this now until after that. I'll then do the process as you advise.

Many thanks.

Phil

That's CEL #40, DBW motor circuit or TH butterfly target/actual positon deviation.
It's not conclusive whether this error was stored in the past or indeed happening at the moment.
If the latter case, very likely to be related to the cause of the engine stall.

Voltage reading seemed to be consistent even during cranking so at this stage, I'll leave power supply related cause out of the scope.


Still, from your latest video, whenever the CEL came back On after the light bulb check mode, the engine stalled so there must be a relationship.


Now that you read the code, the next step is to reset the ECU but please don't do it if you are close to the MOT (6 months extension only applies if renewal date before 01/Aug) or away from your home as there is a chance the ECU may not be able to re-learn all of the co-efficient figures if there is a problem (including loose connector, etc) with the DBW.


Please note that the followings are not the standard reset procedure and only applies to your specific situation.


1. In preparation for the reset process, locate the 7.5A CLOCK fuse inside the pentagonal/octagonal black box under the bonnet/hood.

2. Fully warm up the engine.
Just go out for a short driving or combine the process on your return from outing.

3. Before stopping the engine, switch off the A/C, audio head unit, head light, etc.
Basically, create no load condition in preparation for the next fireup.

4. Stop the engine.

5. Remove CLOCK fuse for 10sec and then place it back.
This will erase all of the error codes from any controllers on the car except for the latest one body ABS brain.

6. Turn IGSW into P2 ON and wait for at least 2sec while keeping eye on the CEL.
Do not start the engine and keep no load condition.
Do not touch the TH pedal.

7. If the CEL came back On after 2sec of light bulb check mode, put IGSW back into P0 Off and then back into P2 On. Otherwise, go to step #8.
Repeat this a few times if the CEL doesn't switch itself Off after every bulb check mode.
This is just to simulate some of your video as the engine always stalled if cranked with the CEL On but then if power cycled, the CEL switched itself Off after the bulb check mode and the following engine fireup was fine.

8. Now start the engine without touching the TH pedal and keep no load condition.
On first attempt, if the engine stalled like before because the CEL stayed On in step #7, go back to P0 and re-start the engine again.

9. Keep running the engine under no load condition and without touching the TH peal for 10 - 15min.
Don't worry about the electrical load increase because of the radiator fan.

10. Stop the engine, wait for a few sec, put IGSW into P2 On and wait for at least 2sec.

11. If CEL came back On after 2sec, repeat #7 and #8 but no need keep running the engine for 10 - 15min. Just short fireup like 10sec is enough.
If CEL stayed Off after 2sec, just start the engine for about 10sec.
Unlike in step #8, the engine rpm should drop to 800rpm almost immediately after the fireup.

12. Stop the engine.

13. Read error code.
If new code or CEL #40 stored, you will need further diagnosis but most likely, loose connector, etc.

14. If no code stored, go out for several outings and remember to read the error code at some point even if you didn't trigger the CEL.
From now on, try waiting for at least 2sec after every IGSW P2 and keep eye on CEL.
On first occurrence of CEL coming back On after 2sec, ideally, do not start the engine and read the error code immediately.


Kaz

[Kaz-kzukNA1]

Nothing wrong taking the MOT now and as I don't know your circumstances that it may not apply to your case but you could be eligible for the automatic 6 months extension;

Coronavirus: MOTs due from 30 March 2020
Your car, van or motorcycle’s MOT expiry date will be extended by 6 months if it’s due between 30 March 2020 and 31 July 2020.

https://www.gov.uk/guidance/coronavi...-30-march-2020

Please note the latter part of the above link especially the following sections;

If you take your vehicle for its MOT and it fails;

and

If your vehicle tax and MOT run out in July

Kaz