Lq4runner

So I got my swap running. Runs good off idle but will not idle. I took the computer to F-body central in Baltimore to have vats deleted and a baseline tune done. I have a little handheld scanner that can show me some live data. Here's what I got

Fresh rebuilt Lq4 pretty much stock except 215 cam
Home built harness following lt1swap.com

55lbs of fuel pressure
New injectors
On my second MAF and is reading about right in the scanner
Both O2s are new and reading
IAC seems to work, moves when the key is first turned on and hunts for a high idle sometimes
ECT sensor is good
TPS is good
Stock pcv setup
Fixed the only vacuum leak I could find now I'm closer to getting it to idle

The lowest the rpm will go is right around 1000-1200 with the throttle proped open at 8% if I go to 7% it dies.

I'm thinking possibly
IAC
MAP
PCV > catch can
Tune

I'd like to get it to idle so is can drive it to get it tuned. Any ideas?

1970camaroRS

iTrader: (8)

What is the base timing? It should idle fine with even a stock tune on the computer.

Lq4runner

I dont know what base timing is but the handheld shows 20-23 around 1200 and up to 40 when I give it throttle

1970camaroRS

iTrader: (8)

That's odd. Should be more near 27 or 28 at idle.

Lq4runner

Ran the engine again last night. tried capping all vacuum ports. ran the same. tried unplugging the MAF = ran worse. plugged MAF back in and unplugged the MAP = ran worse and smelled very rich.

throttle at 9%
1000-1100rpm
MAP - 37-39 kPa running / 101 kPa koeo
seems like 18.5-19 in.Hg vacuum
MAF - ~14g/s
ignition timing - 27.5
fuel trims
bank 1
st - 0%
lt - 0%
bank 2
st - 0%
lt - 0%
bank 3
st - -24%
lt - -64%
bank 4
st - +10%
lt - +51%

Hart_Rod

iTrader: (3)

Do you have your exhaust hooked up? Did you change the injector data in the tune to match your injectors?

1970camaroRS

iTrader: (8)

Why are you getting readings for bank 3/4 and not 1/2?

Adam123

iTrader: (1)

Shouldn't it be idling between 55-75 kpa. A 5.3 ive been working on idles between 55 and 65 depending on idle speed. It has a Tsp 224/228 cam. I haven't started tuning it to far yet but it idles really good. It even started up with factory tune. Had to adjust the throttle butterfly. I have to close it down now because iac is down to 0 at idle. Are the injectors factory sized or larger. If they're larger and its not tuned for it, the engine will run rich. Maybe the base idle airflow table is off.

mountainman

you build your own harness?

tonypaul

iTrader: (2)

double check you IAC and throttle blade position... pull out the IAC and give it a good cleaning migh be something to try...

Lq4runner

I thought that was funny too. Swapped the pins at the PCM to read bank 1/2 but then I was getting fault codes for no b1s1 and no b2s1 readings. So I swapped the pins back and the fault went away. It's a launch scanner from matco. I think it's just displaying the banks backwards.

I have about 3ft of tube after the header with the o2s 1ft down them. Yea 30lbs from the from the big blocks. I told the tuner that I have 30lb and he said he adjusted it to them.

The butterfly is completely closed. The shop I went to for the baseline is good and reputable.

Yep. One thing I'm wondering is if I accidentally got the pins backwards for the IAC. Would that cause the IAC to move in the wrong direction?

Cleaned the IAC. Didn't help. I pushed the IAC all the way in and left it unplugged and idled really high and fine. I'm going to replace the IAC tomorrow. But if that doesn't work could my wiring be backwards for it?

1970camaroRS

iTrader: (8)

It's got to be those O2 sensors. Something's just not right there.

Lq4runner

Latest update. Yesterday, I got a new IAC and put it in. truck started and idled fine without me messing with it. I could rev it up a little bit and it would come right back to idle. no issues. Had about 5min of idle time. Turned the truck off to run brake lines. Tried to start it again for a buddy and right back to the same issue. I tried unplugging both O2s, same issue.

gagliano7

I have a 5.3 with a lunati 212/218 cam and my map is 39-40 kpa at idle.

Is your setup a cable throttle setup? If so your tps should be 0% at idle. Can your tool tell you the iac count?
Did the tuner turn off the rear 02's and cot (cat over temp protection)?

Lq4runner

I have cable throttle. With the throttle closed Im getting 0% throttle. My scan tool cant read IAC count. Im pretty sure the tuner said he turned off the rear O2s. I dont know about COT.

Yesterday I checked the wires for the IAC. all 4 have continuity and are going to the right pins in the harness. They arent shorted to ground or positive.

76 -> B
77 -> A
78 -> C
79 -> D

What I have that is known good:
New Delphi IAC
Good wiring
Good ECT signal
Good TPS signal
Good MAP signal
seems like a good MAF

Now more on the O2s
I have what I believe is a case grounded O2s. Theyre the flat 4pin connectors.
I have them wired

B1S1
A - Tan/white -> 29 blue
B - Purple/wht -> 69 blue
C - Black -> ground
D - Pink -> switched 12+

B2S1
A - Tan -> 26 blue
B - Purple -> 66 blue
C - Black -> ground
D - Pink -> switched 12+

Does this look right?