[PaulStud]

Hello, new to the forum. Joined specifically to ask Decipha about a high idle, which he already responded to. Will try his mechanical idle.

Few unasnwered questions I've had I'm hoping I can get info on.

Been tuning the A9L on an 89 Fox with a Tweecer RT since the year they came out ('03?). Car is pretty much a race car at this point, having a few issues with my latest engine combo. Dart based 363, N/A, 11:1, .700 lift solid roller, old 80mm C&L, Accufab 90mm TB, and all the rest of the crap needed to run low 10's.

Tune is pretty well finished, just a few odds and ends. Stable, fuel dialed in.

As I said, idle is high and won't settle down to desired for anything. I'm figuring this has most to do with my calculated TB Air Flow being over the 1.99 max of the Neutral Idle AirFlow PPM. Will try mechanical.

But a couple things have always persisted with this engine I'd like to get info on.

The HEGO's will not heat up in my stainless long tubes, even with various modifcations to exhaust pulse delay, they will constantly read wrong at idle compared to my wideband and in closed loop will lean the thing to 20 to 1 at idle. I've changed both sensors, and threw a new wideband in it with the same results. I've been forcing open loop for some time, and this seems to work allright, but I'd prefer to let it get into closed loop at some point. No way to get the narrow bands to work with large headers?

This cam has a significant amount of overlap. How skewed can my A/F be because of that?

Lastly, I've been conservatively limiting my RPM to under 7800 becauses I've heard the EEC IV will only go so high. How high will an A9L go? There is more left in it.

Thanks

[85GT]

Sounds a little contradicting. If the eec is leaning it out with them, then it must think it's rich from them. For them to be rich, they must have heated up.
Any chance you have left and right connectors swapped?

[PaulStud]

Sounds a little contradicting. If the eec is leaning it out with them, then it must think it's rich from them. For them to be rich, they must have heated up.
Any chance you have left and right connectors swapped?

Your logic is sound, I was under the impression they were reading rich due to cold. Perhaps another problem somewhere concerning them. At any rate, they don't come close to switching at 14.7.

[85GT]

That's more or less a steady state behavior. The delay could have a lot to do with too. I'm sure those with long tubes will have more insight to add.
Decipha also has his own forum with might get you to him quicker in case you didn't know.

[decipha]

if both o2s are trimming i would believe them over the wideband

how does it idle at this 20:1 AFR ?

[PaulStud]

if both o2s are trimming i would believe them over the wideband

how does it idle at this 20:1 AFR ?

They HEGO's do not match at all, not remotely close.

It idles like total balls.

[decipha]

how much do they not match if they both trim 20% ?

do you have an x pipe?

[PaulStud]

how much do they not match if they both trim 20% ?

do you have an x pipe?

Collector extensions. No H or X.