1990 Throttle hesistation

[XfireZ51]

Chuck,

Reading what you've done by incrementally moving the throttle is this:
As you approach 1.6-1.9%TPS(just off idle) the ECM transitions from idle to run. What's happening is that it goes from using a static SA for closed throttle to SA in the spark tables. When tuning, you try to flatten that area so that you don't get surging that seems to be happening. May need to look at that table. At the same time you are also transitioning from single to double injector spraying since the ECM is transitioning from a Closed Port VE table to an Open Port Throttle VE table. OTOH, I doubt that your throttle movements are so fine that you are always are always at that point. In the stock calibration, there is a slight delay built into the turn on of the secondary injectors, most likely to give the secondary throttle plates time to open. Also, acceleration enrichment may need a bit more fuel to enhance tip-in response.

[Schrade]

Where do I buy a DIS 'checker'?

TPS is not new.

How do I examine the 'tables'?

[XfireZ51]

Originally Posted by Schrade

Where do I buy a DIS 'checker'?

TPS is not new.

How do I examine the 'tables'?

Are you datalogging any of this?

[Schrade]

Originally Posted by XfireZ51

Are you datalogging any of this?

I just replaced the OEM throttle stop screw, with another bolt, to be able to make FINE, MINUTE and PRECISE incremental increases in throttle, FOR DM recording, to attempt to see the 'offender' in action.

From post 79:

I need some way of MECHANICALLY increasing the throttle, in TINY increments, to get to 'the factor's threshhold'. The idle stop screw would be perfect, but it's too difficult to access, with all the components in place...

Today's exercise was just a dry-trial of the precision of the new bolt's movement.

NOW...perhaps we can find something in DM.

[Franke]

Schrade, as an FYI from The Datamaster files:

TPS Percent
This shows the calculated Load Value the PCM is using at the current instant. Roughly corresponds to the throttle position, but takes into account many other items as well. This value will not necessarily track the TPS volts value

TPS Volts
This shows the voltage measured from the Throttle Position Sensor. Will generally range from 0.5 Volts (throttle closed) to 4.5 Volts (throttle fully open).

[Tyler Townsley]

Originally Posted by XfireZ51

Chuck,

transitioning from single to double injector spraying since the ECM is transitioning from a Closed Port VE table to an Open Port Throttle VE table. .

I did not think we were talking about going into the PE mode here. I assumed we were talking about normal throttle operation?

Tyler

[XfireZ51]

Originally Posted by Tyler Townsley

I did not think we were talking about going into the PE mode here. I assumed we were talking about normal throttle operation?

Tyler

Tyler,

No, you're correct. Chuck has eliminated his secondaries and installed a Haibeck chip that brings on the secondary injectors above idle.

[Schrade]

Originally Posted by Franke

Schrade, as an FYI from The Datamaster files:

TPS Percent
This shows the calculated Load Value the PCM is using at the current instant. Roughly corresponds to the throttle position, but takes into account many other items as well. This value will not necessarily track the TPS volts value

TPS Volts
This shows the voltage measured from the Throttle Position Sensor. Will generally range from 0.5 Volts (throttle closed) to 4.5 Volts (throttle fully open).

I'm still only on p. 16 (of 92) of DM manual there Franke; long way to go, to another 51 page - 8khits thread, but no better scratchpad than the boards here, and maybe someone else might get something as I go ...

Mods are EASY. Tune is NOT...........

Next will be additional static TPS voltage test, with voltmeter backprobe to TPS, to compare DM TPS volt readout, with actual voltmeter readout.

Should have done that with post 100 test.....

[Tyler Townsley]

Originally Posted by Schrade

Where do I buy a DIS 'checker'?

I use a OTC 3575 ignition system simulator also known as a PRI ISS Ignition System Simulator. I bought it off ebay years ago for $130. It checks Ford, Chev and Chry dis ignition systems. What I like about it is you do not have to have the car running to check it out, you do need a scope to look at the different signal forms which is how I saw the fact that the dis was falling apart.

Tyler

[Tyler Townsley]

Originally Posted by XfireZ51

Tyler,

No, you're correct. Chuck has eliminated his secondaries and installed a Haibeck chip that brings on the secondary injectors above idle.

OK I have the same mod but I thought when Tod (I assume Marc is using Tods hack to accomplish the turn on) did the mod it turned on both injectors on start.

Tod are you out there?

If he is turning on both injectors is he using the constant that controls the initial flow of the injector then calculating how much to cut from one injector and applying that to the second injector on turn on so that the flow rate is the same? That % calculation is a constant in the table and can be adjusted.


Tyler