rich

hears the problem. #5 cyl. is real lean on hp. I did an injector balance test all good. I removed the intake no crack or physical signs of a vaccum leak intake port also looks good. I adjusted the valves found a couple tight ones (crane 1.8 ratio) still lean. can the tuning effect just one cyl? any ideas will help thanks rich

HumpinSS

iTrader: (1)

check your injectors. swap them ans see if it moves around

Ragtop 99

iTrader: (7)

How do you know that only cyl #5 is lean? The O2 sensors measure the entire bank.

Are you using any coolant? compression good in that cyl?

rich

I know it is lean the plug shows heat but is white as a ghost. I swapped the injector before the balance test. with the balance test rail pressure held at 52 psi and dropped to 39 with the test on each injector. left banks o2 is showing lean compared to the right bank max is 750 to 800 mv at idle on the left and the right is 800 to 875 mv max. compression is same in all the cylinders leak down is 5 to 8% across the board. 422 cuin ls1 heads 2.06/1.60 287cfm 237 cfm 67cc chambers 11.2:1 compression .600/.630 236/242 @.50 113.5 ls ls6 intake stock tb ported flp long tubes cometic head gaskets total seal gappless top rings. is there away to lean an individal cylinder? I know nothing about tuning these I can just build them.

Team ZR-1

At idle the O2 average should be around 450-500 mVolts so if they are reading as high as 800-875 mVolts that would be super rich for idle , not lean.
Use an Ohm meter on the coil, the two outer male pins of coil should be around 70,000 Ohms as a norm.
Not sure of your test method but why was rail pressure only 52 PSI when it should be more like 60 ?

HumpinSS

iTrader: (1)

Even with that healthy of a cam and some overlap

Team ZR-1

Yes if tuned correctly I see about normal reading, it has to so it can pass smog testing.

HumpinSS

iTrader: (1)

So what can you do to get them in line. Increase timing?

rich

I will agree it seems to be rich but the right bank is even more rich and #5 is still white. I took it out for a highway blast to watch the o2's under load. They leveled out about 850 ish upon the initial hit of the throttle it was up around 950 with a cloud of smoke out the exhaust. on deceleration the right bank is between 300's and 500's the left bank is at 090's to 100's. At idle it is at 26degrees and cruising it was at 33.6 the knock retard seems to be stuck at .48 and don't move a bit also the pcm is not giving me a mph on the scanner but the speedo works fine. the car has what people told me is the cruise effect when in gear it will want to idle at 1600 rpm and do about 45 mph on level ground. I will ohm out the coils tomarrow night and also check the plugs to see what they look like after the highway pass. I think I got a generic tune done and will try and get it corrected asap. I have svo 41# injector I know they are more than enough and I was going to get some 36# but I was told they could tune around the size of the injector I assume by decressing the duty cycle. Thanks Rich When i ran the test i didn't have all the injectors unpluged the pressure was about 60 but when the pump stopped it was down to 52. the tester is an otc injector drop test hooks up to the battey and one injector turn the key on the pressure holds you press the test button and the injector you have plugged in pulses for a few sec. and the pressure drops do all the injectors an record the drops if there is more than a 2# difference up or down they are cosidered bad all mine dropped to 39#s on the head the box also ohms out the injectors and does a coil test to se if it will fail when it gets hot.

Team ZR-1

An SVO 40 is rated at the 43 PSI rail pressure so in a LS1 thats more like a 50 lb injector so a basic tune will not be close.
PCM likes an average 3 mSec pulse width at part throttle
When using the Ohm meter measure the male pins of injectors, they must be between 11 and 14 Ohms, and no injector should be off by 3% of the average resistance of the 8 injectors.
I assume this is a six speed trannie so why is idle timing up around 26 degrees when the norm is like 18 degrees ?
With that much timing it would want to race the RPMs. Sounds like VE table might be off

rich

no. This is an a4 with a 3200 stall. injectors all ohmed out at high 14 low 15 ohms. I know the injectors are too big but when I tried to buy smaller ones they told me that they could tune for the larger injectors and it wouldn't be a problem. I agree for 422 inches wirh 26degress of timing at idle I would think it should idle at like 15 and be about 26 or 28 at full load I have a timing tuner for the N2O retards and timers but it is at zero til I get this mess straightend out. I am going to go through the valves again do another compression test leak it down again. I have been calling the shop but the owner isn't returning my calls I am going to e mail him now. Is it possible to compensate for the big injectors or should I get smaller ones?

Team ZR-1

I use the same injectors that the C5R, SC3800 and G.N use, they are about 44 lbs but at our 60 PSI rail pressure.
As long as you can best case tune the fuel tables so that on a average in part throttle the ON pulse time is around 3 mSecs you are fine so it is how you tune the PCM.
Going too large or an injector and then having to drive the PCM commanding of pulse width smaller then PCM does not have as good control on fuel as with 3 mSecs for the shorter the ON time is the more computer clock time of the PCM has to keep commanding and leaving less clock time for other functions.
I'd say you have to deal with the higher timing at idle.
High 14, low 15 Ohms, must be another brand of injector for stock LSx injectors are like 12 Ohms.

rich

they are svo injectors.thanks

rich

I installed a fresh set of plugs and it shows lean in #5 still but so lean that is not even getting heat in the plug (all the plugs show heat about 3 threads from the edge but #5 is only 1 thread if lucky). You can hear, feel and see the difference on the scanner when you drop 5 injector. I am lost. I emailed you zr1 thanks

Pro Stock John

iTrader: (34)

Maybe make sure the injector harness is not messed up.

CRAWLIN

iTrader: (6)

This is what my coil packs checked out at 70.x, 67.x, 63.x, 60.x, 65.x, 65.x, 64.x, 69.x on the ohm meter...do they look ok Im trying to lock down a missing problem....

Thanks
Tony