Rev Limiter or Knock Retard????
Thread Starter
Staging Lane
Joined: Aug 2007
Posts: 61
Likes: 0
From: East Tennessee
Rev Limiter or Knock Retard???? Hopefully someone can help me diagnose a small problem with my 01 Z28. When I go to WOT @ 60mph, the car will throw you in the back seat and shift normally (I'm thinking it's hitting 2nd gear). If I go to WOT @ approx 75 mph, it will still try to hit 2nd (I think), the RPM goes real high, and then the car stalls and as long as I'm @ WOT, the max rpm is 4000. As soon as I let off and get back in, everthing is fine. Does anyone know if I'm hitting the rev limiter or is my timing really dropping off because it is sensing a severe knock?? This is the only speed I've noticed a problem when going to WOT. Thanks so much in advance!!
I know that your car will only let you rev to 4,000 while in park or nuetral. Do you have a custom tune? That would be the first place I would look. If not, then make sure your trans isn't slipping, then i'd go for sensors/electrical. Good luck!
TECH Addict
Joined: Nov 2005
Posts: 2,379
Likes: 2
Is this an auto?
If so, WOT, 3rd gear (1:1 ratio), 4000rpm is only 94mph. Speed Limiter is 162mph for z rated and 115mph for non z rated tires.
Sounds like you may have another problem. Knock retard only reduces the timing causing a loss of power, but not enough to prevent rpm from rising. You'd also HEAR knock bad enough to cause knock retard. It'd sound like popping popcorn coming from your dash and it'd be loud and crazy.
If so, WOT, 3rd gear (1:1 ratio), 4000rpm is only 94mph. Speed Limiter is 162mph for z rated and 115mph for non z rated tires.
Sounds like you may have another problem. Knock retard only reduces the timing causing a loss of power, but not enough to prevent rpm from rising. You'd also HEAR knock bad enough to cause knock retard. It'd sound like popping popcorn coming from your dash and it'd be loud and crazy.
Thread Starter
Staging Lane
Joined: Aug 2007
Posts: 61
Likes: 0
From: East Tennessee
Thanks for the replies.. Yes... It is an automatic. I am tuning right now with HP tuners, but this actually happened before with the stock tune. With the stock tune, it only happened once or twice. Now that I have tuned things and it has better throttle response and power, I can hit it almost every time right at 70 - 75 mph. How can I tell if the transmission is slipping??
