mark kibort

We are working on the petty machine and the 6 liter street car and we got into the computers. the coding plug is right for the ricky machine (stock US auto) but on the 6 liter, its set for US , manual, with cat. then, i went to the race car and noticed the same pin out should i run the the two cars with the ROW setting wtih out CAT and manual???

what does the coding plug do . I thought we did that wihen i first had the holbert car, from day one! but its set at US , manual , with cat. (pins 1-2-3-4- 7) with out the cat, it should be 1-2-3-4-6

should i change it??

BTW, the 6 liter didnt even have the plug attached to the back of the ECU holder. it was keyed with a spare key, set for 4 pins which is basically auto, US . i wonder what that does?? anyway its keyed correct, but he doesnt have a cat, so we have the same questions for him as i do for my race car. no cat, change the pinout? performance gain??

thanks

Mark

Speedtoys

Any gain would just be in shifted fuel timing maps (cat or no cat, and possible fuel type)...which is better done with a sharktuner anyhow.

SO..yes..but..meh..should be sharktuning anyhow.

mark kibort

has anyone measured the differnces with and without the cat setting? wonder what the cat setting would alter.

Speedtoys

Maybe I wasnt clear.

It shifts timing and fuel maps...cats burn up with the wrong settings, timing on better octane gas outside the US can be used too.

The coding plug isnt a tuning plug.

Cheburator

Mark, if set up to run as a US cat equipped car, but has no lambda input, the ECU defaults to a sort of limp home mode, which runs a bit leaner than if the lambda was plugged in. Great for gas mileage, but sucks for power... That's all I know from messing around with coding plugs and lambda sensors

mark kibort

oh, well, thats what i was looking for. i do use the o2 sensor, so i guess its set up correctly.
thanks

i will try the GT computer next time at the the dyno to see if it has any gains too!

Mark

Speedtoys

Uhh...all of these 'gains' will have clear tradeoffs as well.

Any reason you are shying away from just using a sharktuner?

AO

Guys, the coding plug allows your to switch between one of three maps that are loaded into the LH and EZK. The factory US maps are stup as follows:

- 98 Octane (Cat) - Default
- 98 Octane (Non-Cat)
- 91 Octane

I don't believe there is much if any difference between the two 98 octane maps, and I'm pretty sure it has no functional control over the O2 sensor despite it claiming to be cat/non-cat. If you SharkTuned the car, and then subsequently switched the coding plug, you quite possible would be going back to a "stock" map which might be really bad for your motor. I guess the point I'm trying to make is that this is not some secret power-enhancing switch that the factory forgot to tell us about.

That said, I think you could use th coding plug to your advantage if done correctly.

KillaV (Mike V) runs a rear mount turbo outfitted a switch to toggle between the three coding plug options. The switch allows the driver to select between the three maps. BTW, you can do this on the fly! He has it set up for 5psi, 10psi with methanol inj, and then I think a valet mode.

Mark, if you Shark Tune the car, you might want to set one up for your best tune, then you might want one that has a little timing pulled for really hot days, and then one that has a little advance and maybe a bit more timing for really cool days. Just a suggestion. Or maybe based on elevation? Your call.

But the key is that swapping the coding plug, by itself will not help. The only way to really take advantage of it is via a shark tuner.

Oh and becaus a stroker, Sced, or turbo car have vastly different tunes from stock, I usually advocate that the base tune be copied and pasted into the two other maps in case the coding plug gets messed up. That way, there is no chance of a harmful tune getting inadvertantly selected.

jcorenman

Andrew, silly boy-- this is a Kibort thread, no Sharktuning here. He is talking about stock maps.

But really good info, and will be helpful for other folks. For stock maps, you are correct that there is little difference between the various maps-- except the EZK's 91-oct "Valet map". (Those octane numbers are RON by the way, subtract about 5 points for US numbers).

The only correction is that the coding-plug jumper for the LH Cat/No-cat selection also controls whether the NBO2 sensor and CO-Pot are used. This can have a big effect if not set up correctly-- and may what bit Cheburator when he tried it, above.

At the risk of cluttering up Mark's thread with technical details, here is the skinny on the coding plug, as far as I have worked it out:

• Pin-1 is ground, and is used to jumper other pins to ground.
• Pin-2: always grounded (LH, function unknown)
• Pin-3: Tranny selection-- jumper to ground for manual, open for auto (EZK- controls timing retard during shifting)
• Pin-4: always grounded (LH, function unknown)
• Pin-5: ground for 91-oct, open otherwise (EZK- selects 91-oct RON map)
• Pin-6: ground for No-cat, open for Cat (LH: Selects no-cat map, enables CO-pot, disables NBO2 sensor)
• Pin-7: ground for Cat, open for No-cat (EZK: selects Cat-map)
• Pin 8: either connects to 12v and left open (earlier cars, 87-88) or to the CO-Pot connection (later cars, 90-95-- see note below).

CO-Pot: ROW cars which were not fitted with Cats at the factory were jumpered for No-cat mode (pin-6 grounded, pin-7 open). This selects the No-cat map for both EZK and LH, and for the LH also disables the NBO2-sensor input, and enables the CO-Pot input for idle-mixture adjustment. When jumpered for Cat mode, then the NBO2-sensor is active and the CO-Pot is ignored.

Later (90-95) cars that were configured with cats and a relay to cut off fuel to one bank if the ignition failed, were also equipped with a 150-ohm resistor from pin-8 to ground, as a substitute CO-Pot. Earlier cars had pin-8 wired to 12v for unknown reasons, and if the later coding-plug is swapped to an earlier car then the resistor goes up in smoke. Without the ignition relay I believe there is no reason for the 150 ohm resistor.

If the LH is jumpered for Cat mode, but no NBO2-sensor is fitted (or it is disconnected, or broken) then the open-circuit is detected by the LH and the NBO2-input is ignored, but the Cat map is still used. So, for tuning, a switch can be added in series with the NBO2 signal-wire (black) to force open-loop operation for tuning, while staying on the cat map. Use shielded wire if the switch is remotely located.

If the LH's No-cat mode is selected (Pin-6 grounded) then a CO-pot must be fitted and used to set idle mixture, OR the Sharktuner option to "Disable CO-pot in no-cat mode" must be selected-- and the maps adjusted with Sharktuner.

Note: the CO-pot is called an idle adjustment-- and adjusted for proper AFR at idle-- but it has an effect over a wide range of light/moderate load, diminishing as load increases-- just like an idle-mixture adjustment on a carb.

The EZK and LH do indeed read the coding plug "on the fly", which means switches can be used to select EZK maps as Andrew describes. Temperature, octane, and altitude all change what the optimum ignition timing should be, and how much advance you can get away with. We've had our GT set up as Andrew suggests for some time-- SPDT toggle connected to pins 5 & 7 of the coding plug, to ground. (A second switch toggles the LH cat/no-cat maps, and a third disconnects the NBO2 sensor for tuning).

For the LH, there is little reason to change fuel maps, but might be useful for a street-driven track car-- with NBO2 disabled and a slightly richer map for the track.

Cheers,

mark kibort

you must have forgotten what we already have done there.

AO

Jim-

That's some great info right there. I wasn't sure if the coding plug did or did not control the use of the NBO2. Good to know.