RotorJoe

Good Luck Dude.

GUITARJUNKIE28

maybe it's boost creeping up to the fuel cut level?

fstfwd

iTrader: (1)

Thanks for all your feedback guys... very much appreciated.

RotorJoe

Did you figure it out? What was it?

fstfwd

iTrader: (1)

Unfortunately not yet... hoping to bring it down to the shop in the next month or so. Till then, I'm gonna be waiting a little. Unless, I meet someone willing to loan me a datalogit, or an injection amp - to test these theories out.

I'll definitely post the final solution... and then I am going to write a book :o) Hehe.

RotorJoe

Sorry man. I would loan you mine and my HKS TP if I were closer.

Good Luck and let us know.

fstfwd

iTrader: (1)

Was just talking to my mechanic... trying to set up a time to go down to the shop. He was wondering if this might be a fuel cut issue. How do I set the fuel cut in my Power FC, so that it will still maintain 15lbs boost... but not cut the fuel off. Also, how does the PFC know went to cut the fuel? Is it related to Boost or the TPS?

Thanks!

RotorJoe

Go to the boost screen in the PFC. You will see settings for boost and duty cycle. The duty cycle changes the waste gate open and closed times, which will control the boost level. If you are using another device to control your boost then this has no effect. If not then the duty cycles will change boost. I think (I use an HKS boost controller) the greater the number in the duty cycles will increase your boost.

The boost number is for fuel cut. The PFC cuts fuel (shitty I know) at .2 of a bar over what the value is in that screen. Your first (#1) two numbers are for your primary boost setting and control your primary and secondary turbo fuel cut (that is if you are still stock twins). The second (#2) is your secondary boost setting for your primary and secondary turbo fuel cut.

Set boost screen to like 1.4 bars for both #1 and #2 on both primary and secondary turbo.
P.S. Check (if you are stock twins still) to make sure you have the PFC to control the twins under the ETC (I think) screen. This should be on (Japanese characters).

You may want to reread the manual on controlling boost and setting boost levels. If it is fuel cut then you are lucky you have not damaged your engine.

fstfwd

iTrader: (1)

(don't scare me like that...hehe)... other than this jerky issue... it runs/idles smooth... and makes 14lbs boost and 25lbs vacuum. So I think or HOPE my engine is fine. I'm looking at the page in the PFC Manual.pdf file I downloaded, for Boost Setting. I will write down my settings at home and repost them tonight. Are you suggesting that I change all the kg/cm2 values to 1.4 (instead of say .8 or .7kg/cm2... and leave my duty cycles (%) where they are?

RotorJoe

Correct.

You may not have to set the kg/cm2 values to 1.4 bars. Just .2 above your target boost. I am running 1.2 bars (which is right at the max that the stock MAP can read) so I set both Pri. and Sec. settings to 1.4 bars. I use an external HKS EVC to control my waste gate, which controls boost.

I still think you have ign break up.

APEXL8T

full throttle bucking and smoothness with acceleration when backing off sounds like a fuel dumping problem which in turn puts your plugs out .(Acts like ignition brake up.)You even say the crappy A/F says its rich.
waste gate just stays open and you dont get more boost..it doesnt buck.
Maybe injector range at full throttle but really sounds like fuel more than mechanical. JMO

fstfwd

iTrader: (1)

So it would seem, in order to avoid the fuel cut, you need a stand alone Boost controller separate from the PFC. Now I'm really pissed that jerk at Mazda disconnected my Manual Boost controller (unknowingly... because they mess with **** they don't understand). That would have been a great opportunity for me to set the MBC at a lower level, and set the PFC to 1.2bar as x605... recommends.

Sheeit.

RotorJoe

It does not matter if you are running an external boost controller or not, the PFC will still cut fuel at .2 of a bar above what you have it set for. And this is the boost setting in the PFC, not the external EVC.

fstfwd

iTrader: (1)

Gotcha... this is a learning process. As you seem experienced with tuning a bit... what would be the settings for 14lbs? Pr: 0.9kg/cm2, Sc: 1.0kg/cm2 - it's the duty cycle percentages that I don't understands. What would be the appropriate percentages for the Primary and Secondary. Thanks!

matty

[QUOTE=x605p747R1] set to like 1.4 bars for both #1 and #2 on both primary and secondary turbo.
QUOTE]

i wouldnt do that....set it to 1.05.

matty

i dont think you make 25 vacuum..that is too high..i never heard of this.

Also i think you are getting some poor advice....you dont want to set the tgt boost to 1.4 that is WAY too high. Set it to the boost level you are trying to achieve. I could show you in the manual and i believe the pfc uses this tgt number when copntrolling the boost. For example, my car is 1.00 and i may see 1.03 but generally the boost is dead perfect. If your setting is .70 and .80...then your issue may be fuel cut. Call me tonight and we can go thru this if u want. I dont know why we didnt look at this on sunday?! This could very well be your problem!

fstfwd

iTrader: (1)

I'm just kind of taking in everyones advice, but haven't done anything yet.

Thanks Matt... I'll give you a call soon.

matty

did you check your tgt number yet? what is it?

RotorJoe

[QUOTE=matty]That was just an example. I run higher boost settings so it works for me.

PS I never want fuel cut to happen.

Also check to make sure you have the box checked to run seq. Turbo control in the ETC section of the PFC.

I have checked in the PFC manual and their duty cycles for the primary turbo is 56% and for the secondary is 64%. I use an HKS EVC so I don't mess with mine and if I did it would control it anyways. It may be a little different for every set up.

I'll shut up now. When you figure it out let us know. I am curious about this.

fstfwd

iTrader: (1)

No need to shut up... hehe... this is all good brainstorming here.

I now recall some of this issues that we had when we first installed the 99 turbos. Dave at KDR was right in saying that because the 99's spool up much faster the stock solinoids + pfc have trouble keeping up with them and I would notice spikes. For instance, if I'm set for .75, I might see .90 or .95. The spikes aren't as dramatic on the higher end... but again, that is where I have had most of the problems. So I've been setting it lower than what I'm expecting to get to try to elminate spikes.

Just fyi... these are my current boost settings.

1. Pr: 75kg/cm2 74%
Sc: .70kg/cm2 78%

2. Pr: .95kg/cm2 78%
Sc: 1.00kg.cm2 82%

Unfortunately the bucking occurs in both presets.

Will keep you guys updated...

RotorJoe

Your target boost is 1 bar, correct?

If it is then set your settings like this:
1. Pr: 1.0 or higher. Don't touch your duty cycle
Sc: 1.0 or higher. Don't touch your duty cycle
2. You can leave these along. Or just highlight this one.

If this has been your problem then it was explained how to correct this on pg two. If not then you now know your boost settings are coming around and the problem is else where.

PS. What part of my advice is poor?

matty

the 1.40 part..seems u cleared up though.

fstfwd

iTrader: (1)

Hey guys... I thought I would update those of you who were following this problem... and pleased to inform you that we have solved it. I recently went down to KDR in PA, and had them attack this issue.

The first thing we did was to replace my engine wire harness... it was a MESS! When Dave showed it to me at the shop, connectors were falling off as we pulled it out of the box. Just replacing the wire harness fixed the TPS voltage readings, idle problems and smoothed out the car significantly. This unfortunately didn't solve the bucking problem, but was a steph in the right direction.

They started troubleshooting the issue by looking at the iginition system. I had recently replaced the plug wires, so we knew that wasn't the issue... so the next step was to check the coil packs. They replaced the front coil pack and the front plugs. This smoothed things out a little, but still didn't solve the bucking.

On the dyno it looked like the car was running really rich at higher boost levels and rpms. So we leaned everything up a bit... and replaced the front plugs which were getting black quickly. Still no go.

The next thing Dave thought was that it could be that I have a clogged main cat. I was running a downpipe... stock cat, and tanabe exhaust. He pulled the main cat off and sure enough, the "honey comb" was a mess... and really deteriorated. We threw a Bonez-Hi Flo cat on that (I'm pretty sure it's a Bonez) and oila! EETS GOOD!

Now it drives like a bat outa hell.

I hope that this post will help someone else out in the future. Thanks to everyone for your input though, I really appreciate it!

Steve