1994 pontiac bonneville ssei detonation at low IAC temps

[Kade lubensky]

here I am with another odd problem, i want to drop a pulley size from 2.8 down to 2.55, but I'm having trouble with KR, mods are as follows.
-accel #30 injectors
-custom FWI goes through headlight housing into front bumper
-zzp 10.5mm wires
-zzp 180* tstat
-3 bar fuel pressure regulator from the 92 ssei
-cat delete
-ngk tr55 plugs gapped at .50"



before these mods I had 1-2 degres of kr when initially stepping on the throttle, then it would die down to 0. this was when it was 80+ degrees out. fast forward a couple months later when fall had begun and outside temps are dropping. me and my friends went out to test it again its 30 degrees outside now, we do a pull and I had 5 degrees of kr. and it was also Audiable this time sounded like the clicking of a geiger counter.


after I put the injectors and tstat it completely killed it, i have none when stepping on the gas, and none throughout the pull. I tested this in the 90 degree heat of summer. engine was fully heat soaked. I thought I killed it, i decided I'd wait to drop a pulley till I tested it again when it's cold to see if I have that same problem, sure enough it's a year later from the last time I tested,its 30 degrees out and i still have that same 5 degrees of kr, it does go away after a couple seconds, but you can just feel the power being sucked away as the pcm retards timing. then it slowly pick back up after it adds timing back and it's gone, it doesn't come back not even one degree until you do the next pull, and the cycle repeats.
so I though it test it over a couple days, my buddy was nice enough to let me have his scanner for the week, and i found out the only time I get any kr is in between 27-32 degrees outside, anything higher or lower than that and I have absolutely none. ive tried 3 different gas stations ( first 2 had 91 and the third had 93), re gapping my plugs, seafoam in the oil, gas, and vacuum tree on the sc, and I still get that same 5 degrees of kr.
any help would be much appreciated.

[J Wikoff]

I don't have an answer, other than having seen similar behavior. I'm watching to see who does, though, while I think about this one.

[95naSTA]

Are your LTFT/BLMs hovering around 128?

You should get an aftermarket wideband O2 on there so you actually know what's going on fueling wise WOT. Narrow band O2 voltages don't really tell you much.

My initial thought is the fuel can't keep up as much with the colder, more dense air. Even though it should compensate with the IAT sensor. Or its compensating more now in closed loop at a colder temp, running rich overall, which can pull fuel in open loop.

[J Wikoff]

I'm trying to remember what the stock injector flow rate is. There was a time I had Accel injectors, maybe 24 or 27 pounds, mistakingly thinking they were "bigger" than stock and it caused some audible clicky pinging.

I have similar mods to you. My difference being a 92 pcm with hypertech chip, S2 L67 injectors and fpr. I've got a 94/95 sc, tb, MAF, 92 pulley.

[95naSTA]

I believe its 29lb/hr @3.0 bar and 32lb/hr @3.5 bar for S1 L67 injectors.

[Kade lubensky]

sorry for such late reply guys, i haven't really been able to scan this week, were in a heat wave right now temps haven't dropped below 60 for the whole week, yaay Minnesota weather. here a couple other things, i was reading a forum on here about dropping a pulley on the series 1 l67's' and it mentioned fuel pressure, i have pillar pods and one of them is fuel pressure. I think the forum said it should be 47 psi key on engine off, and 37psi minimum with key on engine on and should jump to 41psi with the vacuum line pulled off the fuel pressure regulator I have 38psi with key on engine off, and 27psi with key on engine on. it jumps up to 38psi with the vacuum line pulled off the fuel pressure regulator. 38psi at wot, and when I shut the car off it will slowly go up to 40psi. think it could possibly be a fuel pump? or a regulator, ive noticed my pump has been whining a lot louder then when I first bought it.

[95naSTA]

With your 3 bar regulator you should see 43.5 max. Those numbers sound like a weak pump and/or a clogged fuel filter.

You should still install a wideband if the situation improves or not since you don't know where your WOT fueling is. S1L67 ring lands car pop too.