Major cutting out at 6000 RPM

[angus]

The car is a '91 manual trans. When accelerating full throttle in 1st gear the car hits 6k rpm and VERY abruply cuts out, throws you forward in the seat - it is not like a rev limiter, it is WAY more abrupt - when this happens the TCS MIL comes on and stays on

- I unplugged the TCS unit and the problem still exists.

I was thinking igniter? The problem is allegedly intermittent.

There is no check engine light on at all, it does work but it is not on.

Anyone care to venture a guess?

 

[NONSENSE]

Does it cut out in other gears, or just 1st? A single bad igniter would not cause this; the symptoms you describe would require the loss of all igniters.

 

[EdinKali]

Isn't that the exact RPM that the ignition gets cut if the engine isn't up to operating temp? If the engine is warm(ie. thermostat not stuck open) when it happens I would suspect a bad coolant temp sensor.

 

[docjohn]

check oil level,maybe vtec is not engaging due to insuficient oil pressure/ solinoids

 

[ChopsJazz]

Isn't that the exact RPM that the ignition gets cut if the engine isn't up to operating temp? If the engine is warm(ie. thermostat not stuck open) when it happens I would suspect a bad coolant temp sensor.

IIRC, that cut-out is at 7K rpm.

 

[Cody@LoveFab]

Do you have an error code to read?

I've had issues with a few cars having intermittent signal from the coolant temp sensor which results in a COLD temperature reading on the ECU side. Perhaps this is an issue and the computer is cold-limiting the engine?

Or there are major issues with the VTEC system. Offering food for thought, good luck!

 

[EdinKali]

IIRC, that cut-out is at 7K rpm.

You could be right on that. Let me see if I can find the wiki entry.

Ahh, here it is:

http://www.nsxprime.com/wiki/Rev_Limit_Breakin

[EBK] The engine will stop climbing according to engine temp. It will cut even below 6000rpm if your engine is real cold


So we are probably both right. It probably cuts in at 6 or 7K rpm depending on how cold the engine is or how cold the ECU thinks the engine is.

 

[Daedalus]

I do not think it's the same thing. Even when cold the engine bounces off a rev limiter--not as violent as what Wil is describing. FWIW when I bought the car it had a bad temp sensor where the car thought it was -35* out, and it still revved to 7000.

You should still be able to read a TCS code.

 

[EdinKali]

I do not think it's the same thing. Even when cold the engine bounces off a rev limiter--not as violent as what Wil is describing. FWIW when I bought the car it had a bad temp sensor where the car thought it was -35* out, and it still revved to 7000.

You should still be able to read a TCS code.

Could be although the temp sensor you are describing is an ambient air temp sensor not a coolant temp sensor. Totally different animal.

 

[Daedalus]

Could be although the temp sensor you are describing is an ambient air temp sensor not a coolant temp sensor. Totally different animal.

No, it was the coolant temp sensor.

 

[peiserg]

I know what it is angus. Same thing used to happen to me.

6000 rpm is approx when vtec kicks in (yo!!).

The accelleration of the nsx is so fast at 6001 rpm and up that you actually exceed the speed of light, whereupon a time travel type of phenomenon is encountered. What ends up happening in this scenario is you accellerate into some unknown point in the future where you hit the brakes. when this happens, the car drops below the 6000rpm point, and you come back to "the present," where your foot is still firmly on the gas.

It happens so quickly, you don't even realize you just time traveled.

Simple physics.

 

[angus]

I know what it is angus. Same thing used to happen to me.

6000 rpm is approx when vtec kicks in (yo!!).

The accelleration of the nsx is so fast at 6001 rpm and up that you actually exceed the speed of light, whereupon a time travel type of phenomenon is encountered. What ends up happening in this scenario is you accellerate into some unknown point in the future where you hit the brakes. when this happens, the car drops below the 6000rpm point, and you come back to "the present," where your foot is still firmly on the gas.

It happens so quickly, you don't even realize you just time traveled.

Simple physics.

So the solution is to get a Delorean and a puffy red vest?

 

[angus]

I do not think it's the same thing. Even when cold the engine bounces off a rev limiter--not as violent as what Wil is describing. FWIW when I bought the car it had a bad temp sensor where the car thought it was -35* out, and it still revved to 7000.

You should still be able to read a TCS code.

I think you are on to something here - since the TCS MIL is on after each event and only goes out if you re-start teh ignition, there should be a code right?

How do I extract the code?

 

[angus]

The "cold" rev limiter is very smooth, just like a normal limiter - I have felt that before. Even if the TW sensor was faulty it would still provide a smooth limit, not like this.

This is very violent as I said, it throws you forward!

I am leaning towards a VTEC malfunction, the only thing is that there is no CEL, and even on cars with low oil level I sometimes see a code for VTEC oil press or something like that.

 

[Daedalus]

Reading the TCS code is the same as reading the CEL code. Jump the diagnostic connector, turn the key to ON and count the flashes. 19-84 in the '91 manual has codes; not sure if they've changed over the years.

 

[nsxtasy]

The "cold" rev limiter is very smooth, just like a normal limiter - I have felt that before. Even if the TW sensor was faulty it would still provide a smooth limit, not like this.

This is very violent as I said, it throws you forward!

Is it happening when the car is fully warmed up, or only when it is cold?

I know this has been mentioned already, but you haven't confirmed when it is (or isn't) happening.

 

[DRIFTER]

Could it be a fuel pump Issue w/ Computer sensing a lean burn and cutting power?

 

[angus]

Is it happening when the car is fully warmed up, or only when it is cold?

I know this has been mentioned already, but you haven't confirmed when it is (or isn't) happening.

Happens when the car is fully warm.

 

[angus]

Could it be a fuel pump Issue w/ Computer sensing a lean burn and cutting power?

This may be, I am going to check the fuel press.

 

[angus]

No one has ru into this problem before?

 

[Larry Bastanza]

For sure get the code, but since this still happens when you unplug the TCS system, I am not sure what the data will tell you.

Do you also get an ABS light?

When you get the cutout does it backfire at all? (lack of spark)

If it does not, most likely lack of fuel, get a gauge on it for the test drive.

mmm....I am assuming this is a stock setup, yes?

Just my $.02,
LarryB

 

[DDozier]

Does anyone know what RPM or load point the fuel relay for the fuel ressistor is active?

I am wondering if there could be a problem with the fuel pump relay cutting power to the fuel pump when the ressistor is normally being removed.

Dave

 

[pgilliam1]

I think the resistor for 2nd stage on the fuel pump kicks in around 4500rpm. I have had a spool valve stick and not let VTEC engage and it is not violent, it just bogs the engine down. It almost sounds like when the engine hits VTEC, 6000 rpm, the TCS engages and stops wheel rotation. I'd try resetting the ECU by pulling the clock fuse first.