Need help, 93' ta is running really lean.

[importkiller]

Okay figured I would put this on here. I have a 93' LT1 ta that I bought built myself about 4 yrs. ago. sold it 2 yrs. ago and then just bought it back 3 months ago for my son. Car has a cc306 cam,crane gold 1.6rr's. hardened pr's. stalled,built tranny,3800 fuddle stall,373's. LT's,flowmaster catback,no cats. holley 58mm.t.b., ported intake, ported stock heads,bigger valves. accel 300ign. msd opti. So pretty much the works. Anyways when I got it back, it has a bad surging to it, kinda like a lean surge, so I take it on the dyno, and as soon as he went wot, it maxed out the dyno on the leaness so he shut it down after about 3 seconds. Here is the sheet. Some people said it was the dyno acting up, but I do believe the car is really lean and I cant figure out the problem, It did have bad header gaskets leaking on it, and I fixed them with some dead soft alum. gaskets. Car doesn't miss, just surges pretty bad. I have a elec. fp gauge in the car, and a walbro in the tank. "4 yrs old". holds pressure at 38lbs. idle and 42-43psi. at wot. I have accel 30bl. injectors.


here are some closed loop idling scans I took of the car yesterday if anybody can see something wrong. thanks for any help.

Okay pulled some numbers yesterday while the car was warmed up in closed loop. Fuel pressure was around 38lbs.

Idle. engine warmed up.
map- 2.54-2.66v. fluctuating. "car has a big cam".
map- 4.68v Not running,key on, wot.

tps-.54v idling. 4.68v. wot,key on not running.
closed loop.
Left oxy. sens.- idling. switching volts.
Left oxy. sens.-key on not running open loop-92mv.

right oxy. sens.-idling. switching volts.I also noticed that the I believe the pass. 02' would not switch as fast at the left one. it would hang around 300's-400's for about 10sec. sometimes before it would start switching to more higher and lower numbers.

right oxy. sens..-key on not running open loop-484mv.dropping.

Left. block learn. 148-154 closed loop/open loop-150
rght. block learn. 142-147 closed loop/open loop-144

left integrator value-124-142 switching.
rght integrator value-114-146.switching.

Iac position. 70-80 steps. switching.
Iac valve and plug. 3 weeks old.

spark adv. 25-26'
idle- 900-950.
Learned idle position-34 steps.

If you need anymore info, I will try to get it for you. thanks. I noticed that if I shut the car off and then turned it on 1 min. later it would be in open loop and take about 2 min. idling to go back in closed loop.

I put in heated 02's and did the wire conversion about 4 yrs. ago.

Again thanks for any help

[JSK333]

I assume the 25-26* timing is at idle? The cc306 will need a lot more, and I imagine the main timing tables are similar in your existing tune, which means it wouldn't run optimally there either.

Since it appears the O2 sensors are working properly, it likely just needs the VE tables completely retuned, because those BLMs are pretty high. Since one side is not significantly different than the other, I'd doubt an exhaust leak or a bad sensor.

Like I told you in the other thread, if it was tuned when you had an exhaust leak, I'm sure the VE tables are way off. I'm sure a good tune would solve most of the issues, especially since you can do data-logging, you'd be able to get it dialed in pretty closely. And then once all the part-throttle stuff is done, you could finish on the dyno.

Speed density is not as forgiving as a MAF car, and with the rest of your story above, I'd say it's mostly or all a tuning issue.

If you're interested in getting it fine-tuned, let me know (PM/email), I've done several cc306s with great results.

[importkiller]

Originally Posted by JSK333

I assume the 25-26* timing is at idle? The cc306 will need a lot more, and I imagine the main timing tables are similar in your existing tune, which means it wouldn't run optimally there either.

Since it appears the O2 sensors are working properly, it likely just needs the VE tables completely retuned, because those BLMs are pretty high. Since one side is not significantly different than the other, I'd doubt an exhaust leak or a bad sensor.

Like I told you in the other thread, if it was tuned when you had an exhaust leak, I'm sure the VE tables are way off. I'm sure a good tune would solve most of the issues, especially since you can do data-logging, you'd be able to get it dialed in pretty closely. And then once all the part-throttle stuff is done, you could finish on the dyno.



Speed density is not as forgiving as a MAF car, and with the rest of your story above, I'd say it's mostly or all a tuning issue.

If you're interested in getting it fine-tuned, let me know (PM/email), I've done several cc306s with great results.

Yes that is at idle, I couldn't find the other thread I was going to delete it. It's nice to know that it should be the tune. I would have you tune it if you were closer to kc. I just don't have time to make the trip... "damn working overnights and 100mi. roundtrip driver everynight to work".

[JSK333]

I don't need to be there to do it. It sounds like you already have an ALDL cable. If you don't have a chip burner too, then I can send you a tuned chip. Then you can take a good long data-log with it, email it to me, and I can send you an updated chip. We can do that a few times until it's pretty close.

If you have or got yourself a chip burner ($85 for the BURN2 from www.moates.net) then it would go a lot quicker, as I could email you updated .bin files and you could burn them onto a chip yourself.

PM or email me if you're interested in this kind of option!

[importkiller]

Well I don't have a ALDL cable, all Im running is a autoxray scanner. Iv'e seen the chip burner before. I really don't have a way to data-log the car. I wish I could, I'll get some overtime in on the holiday's and I'll pick up aldl cable,burner, and I need to get a laptop. and then I'll get the software, and get some datalog's going. I'll get ahold of you after I get some equip. thanks.I'll start looking into it.

[JSK333]

No worries. Once you get the laptop, let me know, as my Cable Loan Power Tune would work perfect for you. I loan you the ALDL cable and software to data-log, then I send you new chips based on those logs. So you wouldn't need to buy anything other than the laptop, my tuning package would cover everything.

[importkiller]

I'll let you know. Someone pm'd me and said it might be the injectors, but there accel 30lb. about 4 yrs. old. I put my steth on them, and there all clicking good. they all sound the same.