Why Can’t I Get Full Throttle?

Hose blocking throttle plate (on pre-drive-by-wire cars)

[AW] The ~1/2" diameter coolant hose that runs from the engine to the top of the coolant recovery bottle was draped in such a way that it prevent the last 1/2" of travel (15 degrees or so) of the throttle plate. Since the throttle pedal has this very cute little spring-loaded strain relief arrangement, all this produced was a stiffening of pedal effort near full throttle (which I *had* noticed) and my missing out on a small but noticeable amount of torque, especially up high.

So, take a look at your throttle mechanism while a cohort floors and releases the pedal (do this with the engine off, please <g>) and make sure the throttle plate travels through a full 90 degrees to its stop, and that nothing is interfering with its motion.

Slack in throttle cable (on pre-drive-by-wire cars)

[DNG – 98/8/24] There was some significant play in mine. I simply tighten it about a 1/4" and the throttle response is now very responsive and sharp! I figure there would be some slacking as the cable gets stretched over time. It’s a really easy procedure to perform and only takes a couple of minutes. All that’s involved is unscrewing/adjusting 2×12 mm nut.

Just make sure you don’t over stretch the cable or else the engine will rev high at idle. At warm idle you want around 800 RPM +/- 50.

Look at your throttle body from the left side of the car. On the bottom left of the throttle body, there’s a bunch of coil springs. Attached to the springs is a cable that goes all the way into the intake manifold cover ("DOHC VTEC") and back out through the other side. That’s your throttle cable.

Near the throttle body, the cable is routed through this long hollow rod secured by 2 nuts. You’ll also see this rubber ribbed boot protecting the exposed cable. Check your slack here.

1998 Throttle Computer Problem

Technical Service Bulletin #98-026 – Product Update: NSX Engine Control Module

(TSB issued October 19, 1998)

Background: When the engine speed is above 5,000 rpm the engine and vehicle may slow down more rapidly than expected if the accelerator pedal is released.

Customer Notification: All owners of affected vehicles will be mailed a notification of this campaign. An example of the customer letter is at the end of this service bulletin. VIN – JH4NA…..WT000239

Corrective Action: Replace the engine control module.

 [RBO - 98/08/20] Small update on the drive-by-wire issue I had with my new '98. It appears  Acura did change something in the '98 NSX with relation to acceleration. Several previous  NSX owners, including myself, that are "sensitive" to the car's feel have  complained about the issue. 

According to my dealer’s service guy, who has heard this information third hand (from Acura->his NSX guy->him), Acura changed the flywheel in the ’98. They have determined a problem with the manner in which the chip is handling this, and are in the process of redesigning the chip. They will be installing a test unit in my car tomorrow (hopefully).

I’m not standing by any of the accuracy of the above statement, as it has been passed through too many individuals to be totally accurate. I’m also not sure if Acura will consider this a recall or not.. I’m still waiting to get more information. But it does appear as if I’m not crazy and there was a problem AND it wasn’t a defect limited to just my car.

[UPDATE – 98/08/24] The new chip seems to have completely fixed the problem..

[RJL – 99/2/10] I had the repair done today at keyes acura in Van Nuys, CA and it took half an hour and it was successful. The problem is gone and the car is that much happier.

Troubleshooting