Traction TCS System won't allow me to accelerate past 40mph

[davidl78]

I ran into a problem today with my new 1991 NSX. The TCS light keeps flashing at random times when I drive, no matter if its straight or on curvy roads.

But the problem is that when I was at a red light I tried to punch it not redline it but to about 6-7k rpms and from 1-2-3 gear the TCS light came on wouldn't allow me to drive faster than 40 even if I pushed the gas to the floor. I tried up shifting and down shifting but it still capped my speed at 40mph.

The problem stops when I stop at a red light and accelerate conservatively but if I can't push whats the point in having an NSX? ANybody else have this problem. Also when I press the TCS button nothing happens (it doesn't light up) so I'm assumming its already deactivated.

Off the subject, to check the transmission number to see if its in snap ring range, can the dealership easily find it or would they have out forth some effort? Thanks guys.

 

[prova4re]

What size rim's and tires do you have? If there not stock they can effect the TCS.
You can't turn off the TCS when it is working, or when your giving it alot of gas. Try turning it off when your stoped.

If you look in the FAQ section, under snap ring, and under TCS
it should tell you eveything you need to know.

 

[nsxtasy]

to check the transmission number to see if its in snap ring range, can the dealership easily find it or would they have out forth some effort?

You should be able to look at it yourself. You don't have to do anything other than opening your engine compartment. The only trick is to look at the correct angle, so other parts aren't in the way. Just follow the instructions in the FAQ (as prov4re suggests).

 

[hlweyl]

David, when you had the inspection at Acura, did they not find anything wrong with the TCS?

 

[NSX2398]

I ran into a problem today ...the TCS light came on wouldn't allow me to drive faster than 40 even if I pushed the gas to the floor. I tried up shifting and down shifting but it still capped my speed at 40mph.

Exactly the same thing happened to me when I was testing some different size tires on the fronts but not the backs. The front wheels have a smaller circumference than the backs and the TCS is aware of this difference. I went to this web site http://www.powerdog.com/tiresize.cgi and for OEM '91 225/50VR15 and 225/50/VR16 front/rear sizes, it tells you the difference is 4.2% So the question is .. how much variance from 1.042 will the TCS tolerate?

If you look in the FAQ, you'll find that someone [KS] made the following comment " The RATIO between front and rear should be within 5 percent of the STOCK RATIO. Based on the '91-93 OEM
sizes, the ratio should be between 2.7 percent and 12.7 percent. Based on the '94-98 sizes, it should be between -0.3 percent and 9.7 percent". I'm not sure I understand his math .. "within 5%" might mean plus or minus 2.5% which would put the range at 1.017 to 1.067. I have no idea how he got the other numbers.

Anyway, put a chalk mark or some tape on the side of the tire and let it roll one revolution and measure the distance on the ground. If the back is not 1.042 times as large as the front, then you may have to change tire sizes

 

[nsxtasy]

I went to this web site http://www.powerdog.com/tiresize.cgi and for OEM '91 225/50VR15 and 225/50/VR16 front/rear sizes, it tells you the difference is 4.2%

If you use the correct stock sizes - which means, 205/50-15 in front, not 225 - the outer diameter of the rear is 7.7 percent larger than the front.

So the question is .. how much variance from 1.042 will the TCS tolerate?

As noted in the FAQ, the variance from the correct figure of 1.077 can be plus or minus 5 percent. Hence the comment that the rears can be anywhere from 2.7 percent larger to 12.7 percent larger.

However, keep in mind that these calculations show a degree of precision that is not exactly how the real world works. For example, the difference in the depth of tire tread between a new tire (10/32") and a tire that is worn to where the treadwear indicator bars are flat across (2/32") is about 2 percent. There are also differences between brands and models of tire, such that one tire of a stated size may be slightly larger or smaller than another. All in all, that 5 percent threshold is an approximation, and it's not uncommon to hear of cases where a difference of 4 percent in stated tire sizes can activate the TCS. Differences of 3 percent almost never do.

I'm not sure I understand his math .. "within 5%" might mean plus or minus 2.5% which would put the range at 1.017 to 1.067.

No, "within 5 percent" means plus or minus 5 percent. It's not a "range of 5 percent"; it's within 5 percent of the nominal sizes, which means plus or minus 5 percent.

Based on the '94-98 sizes, it should be between -0.3 percent and 9.7 percent".
.
.
.
I have no idea how he got the other numbers.

The '94-01 stock sizes are 215/45-16 and 245/40-17. The outer diameter of the stock rear is 4.7 percent larger than the front. Adding and subtracting the 5 percent threshold means that the rear can be anywhere from 0.3 percent smaller to 9.7 percent larger before the TCS activates. Before taking into account the lack of precision, as noted above.

Incidentally, for the '02-05 stock sizes of 215/40-17 and 255/40-17, the outer diameter of the rear is 5.3 percent larger than the front.

davidl78, what are the tire sizes indicated on the sidewalls of your tires?

 

[davidl78]

Thanks for all the help guys, my tires are as follows:

Front: 225/45 ZR 16
Rear: 255/40 ZR 17

I'm not too sure about the calculations you were talking about but I appreciate all the feedback. Thanks

David

 

[nsxtasy]

my tires are as follows:

Front: 225/45 ZR 16
Rear: 255/40 ZR 17

Those sizes are 3.9 percent greater than stock in front, and 0.7 percent greater than stock in the rear. That, by itself, shouldn't cause problems when the tires are new - the 3.2 percent change in the front to rear ratio is within the 5 percent tolerance. But if the rear tires are worn more than the front tires, that extra difference could be enough to cause the TCS to go off.

My guess is that you wouldn't have any problems if you used tires that were closer to the stock outer diameters. You might want to try the OEM tires (Yokohama A022H or Bridgestone RE010) in the 215/45ZR16 and 245/40ZR17 sizes. They're great handling tires, too - definitely worth trying...

 

[MJK]

I'd check the speed sensors too.

 

[hlweyl]

David, try running the TCS diagnostic, this may be helpful to you:
http://www.nsxprime.com/FAQ/DIY/troubleshooting_tcs.htm

Good luck