aggravation

Well I'm back on the road with a new seal in the blower. No other problems from my blowing it out while pressurizing the intake looking for air leaks.

Please check my logic on this theory:

I think my sporadic lean conditions during cruise can not be fuel supply related, as in fuel pump weak or filter partially clogged, because if I give it heavy throttle at any time the car responds properly and the AF ratio goes toward rich right away and never seems to go lean as long as I'm accelerating.

Does that make sense?

David L. Lutz

Glad to hear your back on the road with no further problems.

Your theory sounds correct to me.

How lean does it go during Cruise? (what are the numbers)

Also, during WOT how rich does yours go?

I ask this because I just got my LC-1 installed and during cruise mine is running between 14 - 15 but at WOT it "seems" to lean out to around 12 - 13. I am a little surprized at the WOT numbers because at the same time my ARM-1 reads rich at WOT?

I say "seems" because I really haven't had it where I can really watch the meter and keep it at WOT very long. (no good place to let it stretch its legs near my house)

Kevin Michael

David 12-13 at wot is rich, but could be richer. For ex. my car idles at 14.7-15. At cruise it is around the same, punch it and it stays steady 11.7-12.1.
Pretty damn safe in my book.

AO

I don't recall... DO you have the 044 pump?

aggravation

Mine is running like that except during cruise it will swing suddenly from the 14-15 range up to 18-19...then back down again. Hitting the lean ratio maybe once or twice a minute and when it does go there it stays at the lean peak for about one second.....

aggravation

I've never looked at my pump and doubt it is anything but stock, possibly original. If I should be running that pump with the stage3 kit anyway I think I'll go ahead and put it in and that new filter sitting on my bench just to get it done and eliminate the pump and filter as a source of my trouble.

David L. Lutz

I had asked Tim about the pumps and he said that the stage III is good to go with the stock pump.

But my pump went out so I went ahead and installed the 044 per Andrew's write up.

dprantl

During cruise the car should be running in closed-loop mode. The air/fuel meter should be varying from 12 - 18 constantly (once per minute is definitely not enough; it should be more like once per second or so). When you floor the car, the WOT switch should be activated and the car should go to rich and stay there. If you do not see this air/fuel variation at cruise, your O2 sensor may be failing.

That said, I notice that my supercharged car makes "ticking" or "popping" noises at ~2/3 throttle. The WOT switch is not activated yet, and the air/fuel meter still varies so that means it is still on the cruise map. Since at this throttle opening I'm already making ~4psi of boost, it seems like an unsafe situation. So I just modified my driving habits to either cruise and not go substantially into boost, or floor it when I want the power. I'm not sure if the sharktuner could modify the mixture much during closed-loop cruise since the LH decides this from the O2 sensor feedback. Or can it?

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

David L. Lutz

Thanks for the numbers. I just thought it would go a little richer, but then again I really haven't spent that much time at WOT ... yet!

David L. Lutz

Dan makes a good point. If you will remember I also had some idle issues and just rough running after the install. And one of the last items I have replaced is the O2 sensor.

Since I replaced the O2 and have at least re-set the LH (disconnected the battery) 4 or 5 times my car is really showing improvement.

(I replaced my O2 because when I unplugged it the car idled much smoother!)

Kevin Michael

The 044 pump really isn't neccessary at anything below 500 whp. I have one with very low miles I will sell you for 175.00 though, if you really want one.
Kevin

AO

So stock pump. Could be an issue, but not at cruise.

How are you reading the lean condition? Through logworks or the Sharktuner?

123quattro

Kevin, if you want to sell that pump let me know. I'll take it at that price...

Dave, 12:1 at WOT should be rich enough. 11.5 is safer, but is leaving power on the table. In the 10s is just bad control. Peak power is at 12.5:1 A/F.

aggravation

Just last night I was just watching the XD-16 gauge but I've seen the conditions in SharkTuner logs I've done recently.
I'll go log it today in both LogWorks and SharkTuner at the same time and look for differences.

Since this started I've done:
O2 sensor - new
Throttle Position Switch - new
Idle Stabilizer Valve - new
Flappy rebuilt
Intake R&R
Vacuum lines

AO

Ok, since you read this through the XD-16 gauge, this is the digital feed from the WBO2, so no ground offset issues.

This is your own custom chip, right? Can you email me the bin file? You can send it to andrewmolson AT yahoo.com.