Finally getting around to tuning my URD kit and I'm noticing that when my rig first starts and is cold that it stays in Open Loop for a few minutes then switches to Closed Loop. Sounds good right? Well the weird thing in that when I have it at WOT it just stays in Closed Loop. I just pulled a big hill and had it at 7psi floored and no open loop.

I'm using the OBD Diagnostics tool that URD sells and running just the fuel trim and Open/Closed loop scanning (3 Lines). One thing to note is that when I select the TPS monitor it only reads 70% at WOT. I've verified that the butterfly is opening all the way at WOT.

Do you think:

A: The OBD scanner is giving me bad info, maybe too slow to refresh??

B: TPS calibration issue?

C: Gremlins?

Any thought would be appreciated. I'm not into my open loop tuning phase yet (still getting the closed loop tweaked) but I want to get this figured out before I get there.


Thanks!

 

That's what I think. Weasy?

 

TPS Calibration wont affect the open/closed loops as its ecu controled.

What i would do is have someone else go into the engine bay and while in park have him/her quickly snap the throttle to full open to see if the ecu goes into open loop, if it does then you got a problem still in your gas pedel connection.

Are you holding the Threottle open long enough for the software to refresh? Also do you have a wideband sensor at all? Or even a AFR gauge (dancing light gauge)

 

I held it at WOT for a good 4-5 sec. about 5 times. Any more and I would've been asking for a ticket. I do have a wideband, but I do not have it hooked up yet. The bung is in place, I just have to do some wiring. I'll give you "have someone hold it open" tirck when I get a chance and see what happens.

 

the reason why i ask about the wideband is because using the wideband unit you can see the AFR...and tell if its in open/closed loop.

 

What exaclty would tell you that? Will there be an obvious break from Stoich? I've never seen one in action but I assume that in closed loop the AFR should read 14.7 pretty consistantly right?

 

Normaly the ecu will go between 14-15afr while in closed loop as soon as it jumps into open it will go to a much richer (normaly) mixture and you will notice it right away

 

The AFR be changed to approx 13:1 in open loop (with no fuel upgrade kit). Is there a way to alter the close loop set up in the standard ECU?

 

Do you mean aler the time it comes on or the afr in open loop?

Its yes in both cases anyway