Put my 93' ta on the dyno yesterday, I had a feeling it was running lean. "alot of what seems like lean surging". And the ps ceramic coated LT's were running 500 degrees at the base of the headers according to my thermal gun. "my gto has the same headers, and the headers only run 350 at the base". So I figured it was running lean. Put it on the dyno w/ af. I told the dyno operator there that It might be pretty lean and to cut off the pull if it did go. So he stopped after about 3 secs after going wot. The car was tuned by Ed Wright last yr. from the prev. owner."I sold the car to a girl 2 yrs. ago, after I built it and then I bought it back about 3mo. ago. I believe the car was not running right when he tuned it. I got the car back to good running shape.I put in A Walbro 255 pump about 4 yrs. ago.and A kirbin adj. fp reg. and according to the elec. fp gauge in the car, the fuel press. does not drop when I go wot. Idle about 38lbs. and about 42-44 at wot. So I don't think the pump is getting weak. It fires right up and never stalls out. Could the tune be that bad on it to make it go to 19+ on the a/f ? According to the Girl I bought the car back from, when she took it to Ed. He did no drivability of the car when he tuned it, just did two dyno pulls made 2 changes on the chip, and then hit her up for I believe 600.00 bucks. I never heard of that before, but that is what I was told. Could the pump be getting actually weak? I have a new fuel filter on it. Any other ideas?
Im leaning towards the pump."but not dropping pressure". or the tune? I guess I might be heading to st.louis alittle sooner then I thought to get the tune right, before the engine goes boom. but I could use any ideas... :thumbup:
Some history of the car. ported stock heads/bigger valves. cc306 cam. 58mm. t.b. full exhaust,accel 30lb. inj. ported intake,cai. stalled,gears. so I built it pretty good. Car has 160-180 compression across the boards. 1yr. old msd opti. new wire/plugs. Car is not throwing any codes on my scanner. 02's are switching good. and going into closed loop. so Im at a loss. Im figuring it must be the tune now.
I haven't made it to the other dyno yet. "I got tied up w/halloween last sat". but anyways I noticed something. I jumped into the car the other day and happen to push on the brake while the car was not running, and noticed a whistling sound everytime I pumped the brakes, like the booster is leaking. could that be causing the car to also run lean? and maybe surging/slight stuttering problems at lower rpm's?
just thought I would ask....
You need to post some sort of log or have a quick eye on the scanner to let us know what is happening.
Being that its a 93' you are speed density so there are a few things to look at. If it runs fairly smooth that is no bad miss fires.
What does the block learn look like is it way higher then 128? Is your MAP over 90kpa at WOT, and is the TPS at least of 4.4v? Does it go into open loop at WOT?
Unless the tune is WAAAAAAAAAAAAY off, you've got a few more problems other than that. 237/260 out of your setup is extremely low.
You also need to try to find someone with a wideband so you can verify your A/F on the street, when the car has a full load on it.
these numbers were only from about a 3 second pull. then he stopped. because it went lean. I bet he didn't even hit 4,000rpm's.
Im going to pick up a wideband next week. and check out the af's then.
You need to post some sort of log or have a quick eye on the scanner to let us know what is happening.
Being that its a 93' you are speed density so there are a few things to look at. If it runs fairly smooth that is no bad miss fires.
What does the block learn look like is it way higher then 128? Is your MAP over 90kpa at WOT, and is the TPS at least of 4.4v? Does it go into open loop at WOT?
I have a autoxray for it, I'll run a scan and get some numbers for you. I had some written up off the scanner, I'll see if I can find them or I'll run another log and let you know.Thanks...
Okay my son has the ta at school, so I pulled out the autoxray scanner and looked at the log. at idle the :
map 2.58v.
tps. .54v
manifold air temp. 92.8
left ox. sens was switching
right ox. sens was switching.
Left block learn value 159
right block learn value 143
blk learn cell 16
left intergrator value 128 and hanging around there
right integrator value 132 and hanging around 128 both were going from 114-138 fluctuating.
ccp duty cycle 0.0%
idle air mtr. pos 85steps. this is after I put in a new iac the day before.
spark adv. 25*
idle hanging around 975 but loping and flux. from the cam.
when I went wot, I would only hit 1-3 degrees of knock for very short burst.
learned idle pos. 55 steps
tcc not locked
ccp purge off.
learn control enabled.
closed loop.
I'll try to get some new logs when runing and driving.
Its possible the Wb was broken. I've had them act like that before, where they would read fine until you got on it then they would go super high even though the car wasn't actually lean. A simple plug reading on a NEW plug will confirm or deny
__________________ 1993 Formula T-trim @ 13.5 psi! 2008 G8GT Tuned! 317RWHP 338rwtq Dynojet 2007 Trailblazer SS 7.81 @ 92mph 2001 Z06 494rwhp of stock bottom end, NA, and emmissions legal power!!!
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.
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.
My LT1 is running extremely lean. need help. 
torquer 2 cam,ported intake/t.b,vararam cai,PS LT's,no cats,magnaflow catback. sd tune,monster clutch. 423/403. 12.0 at 114mph. 1.7 60ft. 
