Something is ****ed. There’s no way your map should be 65-70 idling. Then it hits90?? Your map sensor calibration is jacked or its bad. Maybe bad grounding i dont know. Something doesnt seem right
CK5
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LSX454 swapped 95 BASS burb.
- Thread starter shady
- Start date
Little lower, little cooler, bigger sounds.
Old engine had better idle vacuum, but didn't change this.
At that same time that the vacuum is heading to 90, the IAC is cranking open to 50 or better. So the vacuum WOULD drop.
As was mentioned above, there's definitely a cause and effect going on, and I think it's going to take some very fine line looking at times in a data log to see which thing is happening first.
I was starting to do that with the logs I took last year when my plugged in laptop started getting pissy about a dead battery.
So I put it away for now and looked up a new battery that I have to order today.
At that same time that the vacuum is heading to 90, the IAC is cranking open to 50 or better. So the vacuum WOULD drop.
As was mentioned above, there's definitely a cause and effect going on, and I think it's going to take some very fine line looking at times in a data log to see which thing is happening first.
I was starting to do that with the logs I took last year when my plugged in laptop started getting pissy about a dead battery.
So I put it away for now and looked up a new battery that I have to order today.
I think vacuum is approaching atmospheric because the throttle is opening while the engine is stalling. At 0RPM it will be ~95. I don't think the AFR reading really means anything in this condition. If it's misfiring, that extra oxygen will show as rich. Even a WBO2 doesn't measure AFR. It measures how much oxygen is needed to get a stoich reading from the cell. You could look at the injector pulsewidth to see if the amount of fuel is actually changing.
Didn't we establish that this thing doesn't have an IAC valve, it's doing it with the TBW? It means something that you have to keep messing with the throttle stop.
Didn't we establish that this thing doesn't have an IAC valve, it's doing it with the TBW? It means something that you have to keep messing with the throttle stop.
It's DBC. So does have an IAC.
Theres a clear impression of the bottom of the adjustment screw on the pad it stops against.
So I think that part is just settling in.
Like mentioned, even when it's set to 8-10% IAC as they suggest, it still does it.
I went through a period with the last engine where I was pissed at the IAC and just opened my TB blade far enough that it idled about 1050ish, and the IAC was doing basically nothing. And it still died out coming to stops.
That time frame was where I first investigated the idea of the TC not unlocking. And went through the steps to verify that wasn't it.
One thing that HAS changed for the better and it came from changing the idle spark settings, was that it used to die 50-60% of the time, just putting it in gear at an idle.
I did get it to quit doing that.
Theres a clear impression of the bottom of the adjustment screw on the pad it stops against.
So I think that part is just settling in.
Like mentioned, even when it's set to 8-10% IAC as they suggest, it still does it.
I went through a period with the last engine where I was pissed at the IAC and just opened my TB blade far enough that it idled about 1050ish, and the IAC was doing basically nothing. And it still died out coming to stops.
That time frame was where I first investigated the idea of the TC not unlocking. And went through the steps to verify that wasn't it.
One thing that HAS changed for the better and it came from changing the idle spark settings, was that it used to die 50-60% of the time, just putting it in gear at an idle.
I did get it to quit doing that.
Toyed with a small change.
I kinda think it looks good. But I can't commit.
It had just barely enough sticky left to hang there for a second.
I think it looks good, and balances the shiny red of the tail lights out back.
But....
Even if I wanted to I wouldn't do it for months yet.
I kinda think it looks good. But I can't commit.
It had just barely enough sticky left to hang there for a second.
I think it looks good, and balances the shiny red of the tail lights out back.
But....
Even if I wanted to I wouldn't do it for months yet.
I like it.
Haven't gotten to that since I have to replace the window.
The cowl pieces aren't screwed down either .
I have some thin magnet material thats like you'd use for fridge magnets.
I think I'm going to make these badges magnets, and try them for a bit, and see what I think.
If I like it for sure I'll buy new ones to put on.
I think I'm going to make these badges magnets, and try them for a bit, and see what I think.
If I like it for sure I'll buy new ones to put on.
Did I hear the fans just turn on when it happened?
Are you sure there isn't something going on with the alternator load with your dual alternators and that camshaft having more overlap?
It may be a combination of changing loads and your idle tune not being ideal and that camshaft has more overlap so the idle is not going to be as strong and then the load changes suddenly and it sometimes can't compensate fast enough, that time it did but barely.
Not sure.
I know it's unhappy as hell if I turn the subwoofer alt on while it's idling lol.
If it set for on when I start it, it seems completely normal.
But if I pop the breaker beating bass, then reset it while idling, it surges up and down for a bit to catch its level.
But... What would do that on the last second and of a stop? My brake lights are on long before it does it. And the fans don't kick on every time I come to a stop....
Not sure what the overlap was on the howards cam with the last engine. But it was exactly the same as this.
Like basically no different.
The first version of the last engine had more trouble with dieing going into gear than at stop signs.
For the most part, it seems to do ok going into and out of gear now. Just does that die out at stops and random idling...
I know it's unhappy as hell if I turn the subwoofer alt on while it's idling lol.
If it set for on when I start it, it seems completely normal.
But if I pop the breaker beating bass, then reset it while idling, it surges up and down for a bit to catch its level.
But... What would do that on the last second and of a stop? My brake lights are on long before it does it. And the fans don't kick on every time I come to a stop....
Not sure what the overlap was on the howards cam with the last engine. But it was exactly the same as this.
Like basically no different.
The first version of the last engine had more trouble with dieing going into gear than at stop signs.
For the most part, it seems to do ok going into and out of gear now. Just does that die out at stops and random idling...
Something is really weird with what you got going on.
The most accurate way to explain it in my opinion is kind of as heath was saying.
It acts like it's the weakest engine on the planet at idle.
Push the brakes a little hard, fan kicks in, alt pulls harder, etc.
Any little extra effort needed at idle about kills it.
I've moved timing and fuel both directions in the area it idles, and it does the best where it's at.
It acts like it's the weakest engine on the planet at idle.
Push the brakes a little hard, fan kicks in, alt pulls harder, etc.
Any little extra effort needed at idle about kills it.
I've moved timing and fuel both directions in the area it idles, and it does the best where it's at.
I can retighten the header gaskets. They were good last I checked em.
The bung and O2 are in the header collector about 5-6" back from the flange.
Has a band clamp,
Like this one just a different brand.
If the header bolts are tight, I can't imagine there'd be enough suck between pulses to pull air through what tiny gap there may be and that far back up the pipe. But it's possible
I did buy a different clamp for that spot that has an inner sleeve and is supposed to seal better.
Haven't put it in yet.
The bung and O2 are in the header collector about 5-6" back from the flange.
Has a band clamp,
Like this one just a different brand.
If the header bolts are tight, I can't imagine there'd be enough suck between pulses to pull air through what tiny gap there may be and that far back up the pipe. But it's possible
I did buy a different clamp for that spot that has an inner sleeve and is supposed to seal better.
Haven't put it in yet.
When questioning that stuff back to basics, the plugs tell you what's really happening whether the 02 is right or not, due to an exhaust leak, overlap, etc.
I've had to shut off self learning below a certain RPM before because of overlap, I would think your factory LSX454 cam would be OK though.
The plugs would tell you if its way off. Or just turn off self learning and see what it likes manually.
I've had to shut off self learning below a certain RPM before because of overlap, I would think your factory LSX454 cam would be OK though.
The plugs would tell you if its way off. Or just turn off self learning and see what it likes manually.
That's a good point, that self-learning could skew things off at idle (especially if something else is amiss with the system). I am used to setting idle as open loop because some engines are more stable idling at 13.5-14.0 than they are under closed loop seeking 14.7:1 at all times. For reading the plugs, I would think that's more of an average over the whole operating time, vs. the few seconds the engine is dying.
There's an old trick to fine tune the spark table so that the desired idle speed sits in kind of a trough. When the engine tries to slow down, the increased timing pushes the PRM back up to where it should be. AFR can be similar. It's only kind of good, IMO, and I don't know if that's possible with this system. I just know that not stalling is better than stalling.
I think old school logic still applies, that fine-tuning the engine to achieve maximum vacuum for a given idle speed would still help. However, it may not be related to fuel or spark at all, but a weak signal or interference on CPS, MAF, etc. It's possible the system voltage is just too low and causing errors.
