Jump to content
SAU Community

Power Loss On Downshifts, Bouncing Idle And Slight Hesitation At Specific Rev Point -R34Gtt


Recommended Posts

To properly check tdc you need a dead stop in the plug hole, or a dial indicator with a long plunger. Looking at it isn't good enough.

Does the PFC display what timing it is running? You should look at it , and if says 20 set cas to read 20 etc...

It always says 15 on the commander (after warming up n idling), even when I set it to 20 yesterday (with TPS off), TPS connected it reads 15 at crank AND power fc as well.

Omg did you not read anything?

Irrespective to what is set on the CAS the ECU won't show what's set. It will always think it's 15 even though the CAS has been dialled to 30

To properly check tdc you need a dead stop in the plug hole, or a dial indicator with a long plunger. Looking at it isn't good enough.

Does the PFC display what timing it is running? You should look at it , and if says 20 set cas to read 20 etc...

^^ I do not know what is this. Dead stop/ dial indicator. haha

At some point you need to make a call and take it somewhere to get it sorted.

If all of this is going over your head just save the hassle and pay someone.

If you don't know what a dial indicator or dead stop (also called piston stop) is, Google it! Google how to check tdc. It's not hard.

Edited by Ben C34

Why pay someone with no guarantee of a proper fix?? When its more rewarding and easy to ask, learn, try etc. And spend money buying my own tools/equipment rather than pay a workshop's labour. I would only go to a workshop after I have exhausted all avenues, tried everything and got as desparate as a cheap crack whore..

And I have already mentioned many times that the bov entry/power loss on shifts is a problem that doesn't really bother me anymore - I can live with it. Lets take this out of the equation, it will be my last fix.

Lets fix the timing first! hehe.. at least I discovered it was the timing that was causing power loss after all.

Edited by rondofj

Well so long as you are having fun with what you are doing that's all that matters.

Keep in mind by cranking in heaps of extra timing your risking popping your engine , which would cost more than getting someone to fix your current problem. I'm sure your tuner would freak out if you told him you added 6 degrees to the map and messed with the cas.

And by the way, didn't you cause the power loss by messing with the cas?

Edited by Ben C34

That last sentence makes me actually worried, just reading it on page 17 of this thread..

One does not simply add 6 degrees to the map and mess with the CAS :P

  • Like 1

My guess would be Yavus set timing at 20deg with TPS connected and you have played with it at some point then reset it to what it should be, try setting it to 20deg with TPS connected and see how that goes

And I wouldn't be surprised if that puts the bolt on the CAS back in the middle

Because then you might muck around with something else, make it a bit lean and BANG... For this critical stuff you are paying a workshop for labour that includes knowledge, wisdom, and a system of doing things properly. One of your mistakes might cost you your engine, a good workshop won't make that mistake.

  • Like 1

Well so long as you are having fun with what you are doing that's all that matters.

Keep in mind by cranking in heaps of extra timing your risking popping your engine , which would cost more than getting someone to fix your current problem. I'm sure your tuner would freak out if you told him you added 6 degrees to the map and messed with the cas.

And by the way, didn't you cause the power loss by messing with the cas?

This is a strange one, I thought that as well, but it wasn't immediately too obvious on that day, maybe 2-3 days later, could have been my mind playing games.. I do think its the messing with cas, I keep saying before it was on the centre of the three bolts when i last set timing, and before I took it off to put Wolverines one in, now its almost fully clockwise at the same timing.

Could it be because I messed with the TPS before that and then brought it back to 0.41V @idle which is what it originally was. And thats all I messed with. And lost that white TPS plug cap.

Cranking extra timing on the pfc brought my power back to what it was before, maybe a bit sharper now, and it doesn't ping/knock at this level, does it mean its still unsafe? Dont understand this one. But crank up 1 more degree and it will knock at high rpm in 3rd.

Edited by rondofj

My guess would be Yavus set timing at 20deg with TPS connected and you have played with it at some point then reset it to what it should be, try setting it to 20deg with TPS connected and see how that goes

And I wouldn't be surprised if that puts the bolt on the CAS back in the middle

^^ THIS seems like the most likely thing that has happened. Will be trying that. What do the others think?

Stock ECU has ignition ramp to stabilise idle, thus when TPS is at 0.45v aka throttle off.. closed loop idle/o2 is enabled - this is why on a stock ECU when you're trying to set your base timing you'll notice it jumps all over the shop.

PowerFC I believe does not have ignition ramp to stabilise idle, so there's no need to unplug the TPS to set base idle and/or the base timing.

based on my logging I've found the idle control does.... I don't have 15 degrees set anywhere on my map yet log monitor shows 15 at idle.

I still dont get how cranking up the maps 6+ degrees can be detrimental to my motor as it doesnt knock at that level and goes hard like before?

Because you don't KNOW that it's not knocking. You are trusting very unreliable knock sensors to tell you that it's not knocking. It could well have more knock than is healthy and you can't hear it.

You have arbitrarily advanced the ignition 6 degrees everywhere and you DO NOT know for sure that it was actually retarded by that amount. It may well have NOT been retarded and in fact has some other problem causing your poor performance. The combination of the possible other problem + 6 degrees extra timing might not be real healthy.

Just because it now goes hard again doesn't mean that all is well with the world. It might, but it is not bulletproof by any means. And unless you can do a few of the basic verification checks that have been outlined you are flying very blind.

Edited by GTSBoy
  • Like 1

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • God damnit. The only option I actually have in the software is the one that is screenshotted. I am glad that I at least got it right... for those two points. Would it actually change anything if I chose/used 80C and 120C as the two points instead? My brain wants to imagine the formula put into HPtuners would be the same equation, otherwise none of this makes sense to me, unless: 1) The formula you put into VCM Scanner/HPTuners is always linear 2) The two points/input pairs are only arbitrary to choose (as the documentation implies) IF the actual scaling of the sensor is linear. then 3) If the scaling is not linear, the two points you choose matter a great deal, because the formula will draw a line between those two points only.
    • Nah, that is hella wrong. If I do a simple linear between 150°C (0.407v) and 50°C (2.98v) I get the formula Temperature = -38.8651*voltage + 165.8181 It is perfectly correct at 50 and 150, but it is as much as 20° out in the region of 110°C, because the actual data is significantly non-linear there. It is no more than 4° out down at the lowest temperatures, but is is seriously shit almost everywhere. I cannot believe that the instruction is to do a 2 point linear fit. I would say the method I used previously would have to be better.
    • When I said "wiring diagram", I meant the car's wiring diagram. You need to understand how and when 12V appears on certain wires/terminals, when 0V is allowed to appear on certain wires/terminals (which is the difference between supply side switching, and earth side switching), for the way that the car is supposed to work without the immobiliser. Then you start looking for those voltages in the appropriate places at the appropriate times (ie, relay terminals, ECU terminals, fuel pump terminals, at different ignition switch positions, and at times such as "immediately after switching to ON" and "say, 5-10s after switching to ON". You will find that you are not getting what you need when and where you need it, and because you understand what you need and when, from working through the wiring diagram, you can then likely work out why you're not getting it. And that will lead you to the mess that has been made of the associated wires around the immobiliser. But seriously, there is no way that we will be able to find or lead you to the fault from here. You will have to do it at the car, because it will be something f**ked up, and there are a near infinite number of ways for it to be f**ked up. The wiring diagram will give you wire colours and pin numbers and so you can do continuity testing and voltage/time probing and start to work out what is right and what is wrong. I can only close my eyes and imagine a rat's nest of wiring under the dash. You can actually see and touch it.
    • So I found this: https://www.efihardware.com/temperature-sensor-voltage-calculator I didn't know what the pullup resistor is. So I thought if I used my table of known values I could estimate it by putting a value into the pullup resistor, and this should line up with the voltages I had measured. Eventually I got this table out of it by using 210ohms as the pullup resistor. 180C 0.232V - Predicted 175C 0.254V - Predicted 170C 0.278V - Predicted 165C 0.305V - Predicted 160C 0.336V - Predicted 155C 0.369V - Predicted 150C 0.407V - Predicted 145C 0.448V - Predicted 140C 0.494V - Predicted 135C 0.545V - Predicted 130C 0.603V - Predicted 125C 0.668V - Predicted 120C 0.740V - Predicted 115C 0.817V - Predicted 110C 0.914V - Predicted 105C 1.023V - Predicted 100C 1.15V 90C 1.42V - Predicted 85C 1.59V 80C 1.74V 75C 1.94V 70C 2.10V 65C 2.33V 60C 2.56V 58C 2.68V 57C 2.70V 56C 2.74V 55C 2.78V 54C 2.80V 50C 2.98V 49C 3.06V 47C 3.18V 45C 3.23V 43C 3.36V 40C 3.51V 37C 3.67V 35C 3.75V 30C 4.00V As before, the formula in HPTuners is here: https://www.hptuners.com/documentation/files/VCM-Scanner/Content/vcm_scanner/defining_a_transform.htm?Highlight=defining a transform Specifically: In my case I used 50C and 150C, given the sensor is supposedly for that. Input 1 = 2.98V Output 1 = 50C Input 2 = 0.407V Output 2 = 150C (0.407-2.98) / (150-50) -2.573/100 = -0.02573 2.98/-0.02573 + 47.045 = 50 So the corresponding formula should be: (Input / -0.02573) + 47.045 = Output.   If someone can confirm my math it'd be great. Supposedly you can pick any two pairs of the data to make this formula.
×
×
  • Create New...