Iwan

G'day from Germany,

I dont post much on this forum, but visit it on regular basis. I performed a search to find a possible solution to my problem but without success.

About my problem.

My car is a Jap. Spec RX-7 Bathurst, 1996 model, with following mods:
- 80mm exhaust systmen with no cat
- Apexi PFC
- Blitz intake

My boost is set to 1.05 BAR wich is about 15PSI.
I experience boost spikes on secondary above 5k PRM on WOT.

I can not say, when the problem starts, just one day it was there but not before. The car spikes only on secondary from 5k on till 8k redline only on WOT, flooding car hardly. Car spikes from 1.05 bar down to 0.7 than up again, than down, than up and so on. On primary I see adjusted 1.05 BAR boost without any problems. Spikes are happen only on secondary and only at WOT.
Accelerating gently going 1.0 BAR of boost permanently, will not cause this issue. So this shows me, that this is not the actuator or WG issue. All the hoses must be right as well.
I have performed a check on my fuel system running UEGO with some free road test. The system shows rich values 11.0:1 AFR at WOT. You can see some spikes on UEGO just going to about 11.5:1 as maximum. Looks OK to me, but maybe I?m wrong and the fuel pump is not able to deliver the adjusted amount of fuel? Fuel filter was replaced about 2000 miles ago. Note sure it this issue is really depend on my fuel pump. This can also be caused by something else, any ideas?
They is a filter on the fuel pump neck inside the gasoline tank, maybe it?s clogged or something, I will check this as next, but AFR looks OK to me when the filter is clogged, the car should run lean, but the car runs just fine. I did not performed a fuel pressure test, but it is on my task list to do next. But once again, I don?t think it is fuel issue.
Sparks where changed about 2000 miles ago as well.
Maybe this is caused by actuator flapping? Why only at WOT?
Maybe solenoid stuck? Same question as before, why only at WOT?

Any ideas and help is much appreciated.

REgards
Iwan

Iwan

G'day from Germany,

I have found the reason for my issue.....

REgards
Iwan

cruiser

And the reason were injectors ?

cruiser

BTW. did you do left-hand-drive conversion or do you drive with your wheel on the right ?

Iwan

G'day.

no this was not injector issue.

I did not perfomed the conversation. You can check my car at: www.rotary-power.de

REgards
Iwan

Scrapiron7

Nice looking car you got there. I found this pic interesting, since the PFC Commander looks so much different:

cruiser

Then what was it ?

Balance setting on Profec set to too sharp ?

wiblergt

nice car!
let us know how you fixed your problem!

william

BLKTOPTRVL

My car went from running fine to spiking overnight. I had made no changes. After installing a Profec B, I was still getting spikes, but was able to keep the boost under 10PSI by tuning the profec low.

I had to live with a 10,5,10 pattern to keep the spike under control.

Finally, I did the hose job and found that two of the hoses were not correct. One had expanded and was passing air at the connection point (to the rack) and another was flattened and probably not passing enough air.

When I replaced the hoses, the boost pattern came back to 10-8-10 (this is still with the profec tuned low.)

Note:
I got all kinds of wild suggestions as to how to fix it - and I ignored most because they involved radically changing this or that part. Mostly people suggested I port the hell out of the wastegates. (I concluded that many of the advisors had no idea what they were talking about).