02-12-2008, 12:15 PM
Hi,
Trying to get some suggestions.
This is what's going on, as I accelerate there seems to be several 'flat spots' on the way up and after 5500 power flattens out. Had a dyno test late last fall which showed this, rising torque til about 3500 rpm then falling til 4000 rpm, rising again til 4500, falling til 5000, then a slight rise to 5500 then falling, HP curve goes flat. The torque curve is a regular roller coaster. The HP curve has pronounced steps in it. The car is, of course, running an after market chip, though the problem didn't seem to start immediately after putting it in, but seems to have developed over time. The chip is from Transaxle in germany, was made for the 24hr Nurburgring race, so it's a little different from the usual.
Looking for possible causes. Talked to Pete and he suggested that the MAF might need some cleaning, this didn't seem to change anything. He also mentioned the hall sensor, which I'll look at next and setting up the cam timing very carefully. The cams were changed before the chip went in, could poorly timed cams cause some of this behavior? Of course the next thing is to put in the old chip and see if the problem goes away. Doesn't seem to lack power at the low end, actually pulls pretty good, it's the stumbling and the missing high end.
Thanks for any help,
Tore
Trying to get some suggestions.
This is what's going on, as I accelerate there seems to be several 'flat spots' on the way up and after 5500 power flattens out. Had a dyno test late last fall which showed this, rising torque til about 3500 rpm then falling til 4000 rpm, rising again til 4500, falling til 5000, then a slight rise to 5500 then falling, HP curve goes flat. The torque curve is a regular roller coaster. The HP curve has pronounced steps in it. The car is, of course, running an after market chip, though the problem didn't seem to start immediately after putting it in, but seems to have developed over time. The chip is from Transaxle in germany, was made for the 24hr Nurburgring race, so it's a little different from the usual.
Looking for possible causes. Talked to Pete and he suggested that the MAF might need some cleaning, this didn't seem to change anything. He also mentioned the hall sensor, which I'll look at next and setting up the cam timing very carefully. The cams were changed before the chip went in, could poorly timed cams cause some of this behavior? Of course the next thing is to put in the old chip and see if the problem goes away. Doesn't seem to lack power at the low end, actually pulls pretty good, it's the stumbling and the missing high end.
Thanks for any help,
Tore
