What can happen when....

[m3456y]

For starters...this is NOT about my car, but I want to pass on your responses to a new computerless NSX owner I'm helping. He asked me to get him the Prospeed version 2 upgrade - he has intake, headers, and exhaust.

After swapping everything out - the car ran great. You could easily feel the mid-range power change.

He takes the car for a run to Tampa (about 120 miles) and opens it up a few times on the freeway hitting 100+. When he gets back, he tells me the car has a miss, so I have him bring it by. He recently replaced all of the coil packs and plugs...BUT - he filled up with REGULAR gas on the way to Tampa and then refilled with premium. I explained that he should NEVER do that - especially with the new chip which has the timing advanced.

I gave him a tube of dielectric grease (simple solution if coil pack is corroded) but I explained that using the regular may have created even more serious problems with the advanced timing.

If the grease does not cure the problem...next step - compression check.
I'm trying to prepare him for the worst case.

 

[Big_D]

I thought the ECU would retard the timing if it sensed detonation no matter if there was a aftermarket chip in it. I'm sure Brian at ProSpeed can shed some light on this.

 

[davidf]

Yes but how far can it retard it with regular unleaded. Sounds like he pushed it pretty hard with that low octane. Hope all ends well.

 

[nigel]

RATS!
Can you install the old ECU, (or a spare) and see if it has the same miss to verify it's the computer or the gas?

Cheers
nigel

 

[nsxotic911]

For starters...this is NOT about my car, but I want to pass on your responses to a new computerless NSX owner I'm helping. He asked me to get him the Prospeed version 2 upgrade - he has intake, headers, and exhaust.

After swapping everything out - the car ran great. You could easily feel the mid-range power change.

He takes the car for a run to Tampa (about 120 miles) and opens it up a few times on the freeway hitting 100+. When he gets back, he tells me the car has a miss, so I have him bring it by. He recently replaced all of the coil packs and plugs...BUT - he filled up with REGULAR gas on the way to Tampa and then refilled with premium. I explained that he should NEVER do that - especially with the new chip which has the timing advanced.

I gave him a tube of dielectric grease (simple solution if coil pack is corroded) but I explained that using the regular may have created even more serious problems with the advanced timing.

If the grease does not cure the problem...next step - compression check.
I'm trying to prepare him for the worst case.

You sure it's your friend? :wink:

Depends how many "misses." A few, probably fine, if he was at WOT for 30 minutes while "missing," then that could be problematic.

Compression check would help too but only if you knew a baseline to compare it to.

 

[TURBO2GO]

RATS!
Can you install the old ECU, (or a spare) and see if it has the same miss to verify it's the computer or the gas?

Cheers
nigel

I am not sure you are understanding what is going on. When you raise the limits and start playing with A/F ratios and timing to get that last ounce of power, you are putting the engine at greater risk. If you throw in low octane fuel, the engine cannot retard timing enough and you can get detonation which will put a hole right through your piston and damage all sorts of other things. This is not a gas or ECU problem like you are thinking. The owner may well have some engine damage which can be very serious.

Hopefully its just some sort of ignition related problem and nothing else.

 

[m3456y]

I am not sure you are understanding what is going on. When you raise the limits and start playing with A/F ratios and timing to get that last ounce of power, you are putting the engine at greater risk. If you throw in low octane fuel, the engine cannot retard timing enough and you can get detonation which will put a hole right through your piston and damage all sorts of other things. This is not a gas or ECU problem like you are thinking. The owner may well have some engine damage which can be very serious.

Hopefully its just some sort of ignition related problem and nothing else.

Exactly - +1^

...well it appears he dodged a bullet.

A combination of the dilectric grease and disconnecting the battery has fixed the miss. Car runs perfect again. Hopefully a lesson learned!!

 

[Larry Bastanza]

I am not sure you are understanding what is going on. When you raise the limits and start playing with A/F ratios and timing to get that last ounce of power, you are putting the engine at greater risk. If you throw in low octane fuel, the engine cannot retard timing enough and you can get detonation which will put a hole right through your piston and damage all sorts of other things. This is not a gas or ECU problem like you are thinking. The owner may well have some engine damage which can be very serious.

Hopefully its just some sort of ignition related problem and nothing else.

I understand your concept here, but remember the car is NOT FI. You would have to be real hard pressed to burn a ring land,etc on an N/A car just by changing the timing. Could it ping like an SOB, sure, blow a piston, I kind of doubt it.

I also beleive the knock sensors would back the timing off, regardless of the fuel map alteration, but....this is somewhat speculative on my part, since I do not completely understand what the ProSpeed changes are.

Just my opinion, not enougn data here to comment factually.

Bottom line, glad it is fixed.

Regards,
LarryB

 

[Daedalus]

I asked the same question prior to getting the Prospeed chip, and the answer is that knock response by the ECU is not altered.

 

[m3456y]

Excuse my lack of knowledge here, you would think the ECU retarding the timing if it were pinging badly would be noticeable by the driver - knowing this guy - maybe not though.

Also, is it possible that the computer re-set itself after he re-filled the tank with high octane fuel - after he disconnected the battery?

That was really all that was done - the coil packs already were loaded with dilectric grease. He feels like he has a new lease on life with this car now - and will NEVER make that mistake again.

 

[davidf]

A person should notice the pinging. However, those running GTLW, GT-one, especially catless mat have a hard time hearing it.