88 orangepeel notch

Hmmm, an AFR of 16.8-17.0 shouldn't cause a stall. It's a little lean, but at idle still OK yet.

What was the noise you heard before it stalled out ? That's what I'd be concerned with. Was it a pop, fizz, bang type noise and then motor dies instantly ? Or was it ferp, ding, doeing, then motor slowly drops rpm and gently stalls out.

yurizx6r

I don't remember to be quite honestly. It happened so fast and the exhaust is kind of loud. All I remember is I was starring at the wide band when it was at 16's then 17.0, sudden noise, and stall. I very well could have accidentally hit the kill switch because I noticed when I pulled it over the switch was 20% pushed in and it was sunset so I flipped my lights on around that point. It could have just been just enough to ground it out and mess with the spark that caused sputter and stall.

When I drove it home it didn't' make any weird noises. The drive home was about 5 miles and if I didn't have the wide band I would never know anything was wrong.

At this point I'm wondering why the hell it leaned out. I first started this motor with it running rich and a surging idle. I found vacuum leaks, swapped the fuel pressure regulator and it got better. I finally got the base idle right and it drove pretty decent, but was coasting at around 13.8. Finally yesterday, I plug up the cruise control vacuum line and put a new a/c vacuum line on (very very small leak when you wiggled it), and swapped the tune to street mode, and it ran perfect until after doing all the pulls. Why does it keep getting better and better and then finally too lean yesterday? Could it be the computer overcompensating and trying to find balance from all the WOT pulls? So weird.

88 orangepeel notch

Your coasting AFRs will go up as the fuel is cut off at idle. That's perfectly normal. As is your idle #'s. The motor isn't working so it just needs enough fuel to stay running. I think your #'s are spot on for your set up.

Your WOT #'s being the most important.

yurizx6r

What about under normal acceleration? What numbers are good, bad, and "SHUT IT OFF!!! SHUT IT OFF!!"

So you are also saying that 15-16 coasting in in 3rd+ gear is normal? With my old setup it was always around 14.5-14.7.

88 orangepeel notch

Here's the #'s I've been going by. Now take this for what it's worth as I'm no tuning guru. And I'm just a backyard mechanic that gets most of info from Google and YouTube lol.

Steady rpm cruising..... My wideband reads 14.8 - 15.5
WOT pulls............................................. ............12.3 - 12.8
Part throttle, say 1/4 to 1/2 ............................13.5 - 14.5
Cold start............................................. ..............11.0 - 12.0
Warm idle.............................................. ............15.8 - 17.0

And say coming off a freeway ramp, I let off completely, gauge will read off the scale lean for 2-4 seconds, then slowly come down to normal idle levels.

yurizx6r

So if it's at 15-17 on partial throttle, will that do any damage or will damage only be done in WOT?

mjr46

stop watching the damn meter.....if the car is running fine turn the meter off......you're falling into the same trap many of my customers do when they put every kind of meter and gauge they can think of on the car to monitor stuff........I took my wideband off unless at the track......you become a worry wart!! if you constantly stare at the gauge......drive the car and enjoy it...hammer it hard right now....no sense to baby it........it'll go or blow if not assembled/built properly.........no amount of break-in stops bad engine assembly/machine work.

yurizx6r

I'm sure you're right. I'm probably over thinking it like I do everything else. I just don't want to hurt my new motor. I've worked very, very hard on building this car for the last three years and I finally put the cherry on top that I've waited for since I was 16 (I'm now 28) when I was still driving my 1st car, a 93 LX 2.3L with AOD.

Ok so let me ask you this then, say I stop watching the gauge and if it's running too lean what do I watch and listen for? What are signs that the motor is running too lean before damage is done?

mjr46

drive it for the first few weeks normal to see how it runs and the most damage that'll occur from leanness will often be a wide open throttle...not at idle or cruise....so do a few WOT pulls and watch a/f there....that's the main concern....it a/f okay at WOT......AT IDLE AND CRUISE based on how much you push on the pedal the wideband can be all over the place.......I run a fast dual wideband and at idle it'll read really scary lean....19-21 on my s/c car and there are no vac leaks.

yurizx6r

Ok, are there any signs or symptoms I should keep an eye out for?