tschangrx7

Have PFS purple computer + other basic upgrades. Just noticed, on highway, downshifting from 5th to 4th, accelerating hard, car will not go past 5200RPM in 4th as if something, somewhere is putting some type of limit. When 5200RPM is hit, I can hear extremely loud exhaust sound as if it's been clogged.
Recently installed N-Tech high flow catalytic converter which increased the power noticeably, it also increased the boost climb up from 15, PFS set on high, to about 15.5. No reprogramming of the computer was done.

Any ideas?

ronarndt

Had the same problem. After installing the PFS PMC there was a period of about a month where everything worked as expected. Then I had intermittant episodes where the engine would cut out at approx 5000-5500 rpm, as if the rev limiter had activated. I changed the max boost on menu 900 to 14 psi, since it was set at 33. System worked OK again. However, last night on the way home, the same thing happened. Several people have suggested that the PMC sometimes does not properly mask the boost setting from the stock computer, which has a high limit of 12 psi. I have the software package on order to see wtf is going on. Probably just as well that I don't do any full throttle passes now any way. I smoked the clutch pretty good a week ago, and now it's giving all the signs of being on its last legs. I'll be interested to see if anyone has a solution, since others have had the same problem.

tschangrx7

Thanks for the info, keep me updated. Gonna contact Peter Farrell to see if he has the answer.

Trexthe3rd

Ummm guys, when was the last time you changed out your spark plugs?? Try it, you'll like it.

tschangrx7

Replaced by Peter farrell, less that 5k miles ago.

Trexthe3rd

5K on a rich fuel mixture (I am assuming you run rich, if not then this is not your problem)? I run my A/F **** rich and I get into that situation @~3K. I put in a new set of plugs every other oil change (1500mi) and never have the hesitation problem since.

tschangrx7

it does not at all go past 5200RPM in 4th gear.

ronarndt

tschangrx7- I somehow missed that you stated in your original post that you installed a high flow cat. PFS has info in their tech sheets which strongly advises keeping the cat in place to create enough back pressure to keep boost below 15 psi. The max boost cutout is probably kicking in. In the lower gears it probably does not kick in, since there is a delay built in and you probably shift into the next gear before the time delay. I noticed that I only have a problem in 3rd gear and higher, again probably because it never maxxes out long enough in the lower gears for the time delay to activate the boost cutout. In pre-set position 1, there is no problem, since the boost never exceeds 12 psi. If my PFS software package ever gets here, I should be able to pinpoint the problem. I PM'ed you some additional comments.

bbr1

Three suggestions for tschangrx7:

- Go into Menu 900 on setting 3 and check your boost level for fuel cut. Raise that number to atleast 17 psi.

- Check your redline setting, also in menu 900 I believe. Set it to anything above 8k rpm (doesn't make a difference - it won't be able to raise it above 8k).

- Reset your stock ECU by disconnecting the battery, waiting a minute, holding down the brake pedal for a few seconds and reconnecting the battery.

I had a problem with my PMS soon after I installed it - my car would run into fuel cut at 7k rpm in every gear. After resetting the ECU, it worked just fine!

Try these suggestions and post back on how you did!

ronarndt

bbr1- I changed the menu 900 settings a while back but forgot the magic battery disconnect, brake step. Duh. Guess I better complete the job by re-setting the ECU. Thanks for the reminder. Ron A.