John Speake

Hi Tony
We are looking into this now.

Do you have the actual resistance figures you measured ?

Louie928

You can also put a switch in the NB O2 lead to the LH and open the switch when you want to go open loop.

IcemanG17

I just checked my tempII sensor....and interestingly enough the EZK side of the sender is DEAD...no resistance...but the LH side reads in the correct ranges....from what I understand the LH side defaults to a rich condition or COLD start......but the widow was VERY difficult to start until it was warm??? Once warm it ran just fine and started quickly...but when cold you have to crank that thing FOREVER to get it to start....so my guess is the failure mode of the EZK temp sensor is to default to hot running conditions..& apparently that effects cold start?? I dunno

AO

I did not have force non-cat mode enabled. As soon as I did, the O2 adjustment went to zero.

So now I get to re-do my STing with in in non-cat mode. Will report after I have done that.

Oh forgot to look at the Temp II, but I did manage to adjust my new throttle cable so now I really have WOT (it was only going about 2/3 upon 1st crude install.) You really can feel the difference between 7.5 and 9.X pounds of boost! That car is a rocket ship!

John Speake

Andrew, I don't subscribe to switching to forcing non-cat mode. It's easy to forget to swiitch it back on :-)

Just go to the Parameters screen and defeat adaptation. Do all your Sharktuning and leave it defeated while SharkTuning.

However, when you come to SharkPlotting, and are collecting data logs, you need to disable the O2 loop, either by inserting a switch in the NBO2 lead as Louie mentioned, or by using the ST "force non-cat mode"

John Speake

We have identified an error in the Temp 2 readings. The sensors are read in different ways from LH to EZK. We thought we had it right.

I have tested some modified software and the match is much better. We will issue a software update when Niklas recovers from the 'flu :-)

I measured the Temp 2 on my car, and found the match between the two elements was better than 2%. So it appears that although the absolute resistance has a wide tolerance, as per the WSM, the matching is close tolerance. If anyone else can measure their temp 2 sensors and post the values, that would be a good cross check of that theory.

bd0nalds0n

Hi John,

Can you describe what are the conditions that trigger Acceleration Enrichment on the Fuel Parameters page?

Also, I noticed that WOT on my TPS is only activated at the very limits of the accelerator pedal travel, not ~2/3 travel. I have adjusted the TPS so that it clicks off idle to cruise when the throttle body is opened the tiniest fraction, so I don't think I can adjust the positioning of the TPS in a way that makes WOT tripped any sooner. Can the TPS be disassembled and a connector bent so as to trip WOT sooner? Or should I juse replace the TPS? It's a fairly new unit...

dprantl

My TPS is a few months old and it behaves the same way as yours. I have mine set to click off the idle switch with a minute touch of the pedal, and full throttle is where the throttle butterfly is completely open. My WOT switch activates when the throttle is almost completely open.

It would not be so easy to modify the TPS the way you describe. Imagine a half-circle contact board, and a needle that touches the board which is connected to the throttle. When the throttle moves, so does the needle. The position of the needle on the contact board determines whether you are at idle, cruise or WOT.

Dan
'91 928GT S/C 475hp/460lb.ft

Louie928

Brian,
The TPS switch is two parts. The idle switch is a click action microswitch and it's activation point can be precisly set. The WOT switch is a leaf switch with open contacts similar to a relay contact set. The leaf switch is activated by a cam, but the activation point is not independently settable from the idle switch. Sometimes the WOT contacts get oily, dirty, or even bent and that will change the point at which the contacts close. Sometimes they don't close at all. The fix is either a new switch, or you can carefully saw off the cover and fix the WOT switch inside, then glue the cover back on.

I always tune both LH and EZ-K maps with the WOT enrichment zeroed out and the ST EZ-K option to not use the WOT switch checked. Recently, I tuned a GT where I couldn't get the mixture rich enough with zeros in the WOT map and had to resort to putting values in a couple cells in the mid range so the LH WOT switch operation may have some value. The LH goes to open loop above 3700 RPM without regard to the WOT switch

John Speake

Hi Brian,
Basically, the LH detects sudden increases in MAF voltage which is recalculated to increase in load.

It will then add enrichment of an amount that can be editted in ST, for a certain number of engine cycles, also editatble.

All the TPS I have measured on the bench activate around 60deg. But it appears that the throttle linkage of the S4 and later translate that into later degree of movement of the total throttle travel.

It is quite difficult to disassemble the TPS switch, but you may be handier with the Dremel that I am. The WOT moving contact is activated but a cam, so not easy to modifiy that. On the example I have the fixed WOT contact could perhaps be bent closer to the movable one to get WOT activation earlier. Not sure is the fairly large gap is because of vibration concerns.

The picture I posted in the old WOT thread isn't too good, but it shows the large gap
https://rennlist.com/forums/928-foru...le-switch.html

In that picture the cam is just startying to engage with the "kink" in the moveable contact...

bd0nalds0n

Louie addressed the concern I had, which was: If I'm not getting the WOT signal, does the LH continue to seek stoich at higher RPMs/higher loads, thus counteracting any of the SharkPlotter's attempts to richen the mixture in those cells in the base fuel map.

If the LH goes open loop > 3700 RPMs, then it's a moot point--the richer cells at high RPM/Load will be honored and not compensated leaner by the LH.

Thanks!

John Speake

It wasn't obvious from your original question that this was your concern....

AO

You guys do know that you can adjust the length of the throttle cable - which would have an affect on where you hit WOT. There are two areas to look at:
1. At the fire wall, there is a 13mm hexagonal adjuster. If you screw it "in" toward the fire wall, you will lengthen the pedal travel and thus the length of actuation.
2. The connector that attaches to the throttle quadrant can be screwed in or out to fine-tune the throttle adjustment (okay this really doesn't adjust the length of travel)

Bill Ball

I'm not sure I follow Andrew's idea on the firewall adjustment. I do the opposite - take as much slack out of the throttle cable as possible by screwing that adjuster out, as long as you still get the idle click reliably and the throttle seats fully when you release it. That will make the WOT come on as early as it can w/o screwing up the idle.

bd0nalds0n

I agree with Bill--my problem isn't that the throttle isn't opening all the way, but that the WOT switch doesn't get tripped until the throttle is almost all the way open. From what I understand, the WOT switch is supposed to be tripped at around 2/3 throttle.

In any event, it's not really a problem for me. I just wanted to be sure the car wasn't staying closed loop at high RPMs/Loads due to the fact that the WOT switch wasn't tripped, and it seems that the LH goes open loop above 3700 RPMs.