Been trying too tune my 82z crossfire, with 7747 ecm and prominator for two years,-------help i give up. and put stock ecm back in.---WHO WANTS TOO LOOK AT MY BIN.-------some of my problems are off gas surge and light throtle surge, and BLM;S are hard too get in line. one min thier in the range of 124-----130 and then 30 min later thier any where from 115---too 150, --lots of off gas surge and gurgle thru exaust.- and cant get rid of knock counts. im sure it not timing.---------WHO WANTS TOO CHECK MY BIN.-- IVE HAD IT.-- leaving stock ecm in for now, and 18 psi fuel pressure as too not run lean under load, as for the mods ive done.---P.S. Ive noticed the stock 5550 ecm, operates the AIS motors different.---NO throtle follower in stock one ?? ---with the 7747 ecm and asdu bin they have follower action. [retract too follow throtle] ????

 

Help us help you:

- What engine is in the car? Stock? Minor mods? Major mods?
- Being an '82, if you're re-using any stock parts (or everything is stock), are you certain that you've got all of the mechanical issues worked out? You must absolutely get rid of the mechanical issues before you try to tune, otherwise you'll just be masking problems that may or may not be intermittent. Wild goose chases are no fun, as you've discovered.
- What have you done to tackle these problems to date?

By the way: it's "to" not "too." "Who wants to look at my bin?" "retract to follow throttle.", etc. "Too" expresses extent, such as "Too much."

Sorry, couldn't help it.

 

Its 355 eng, --pro topline pro lightning cast heads [2.02 valve] approx, 9.3 compression,-- comp cam,[not sure of specs 480 lift ?], ---1.5 roller tip molley rockers,--eldebrock tubulars,--3'' exaust, into flow master,--[cat is visually there],--ported crossfire intake,-- open element air cleaner,-- 343 rear gears, with automatic turbo 350. Hope this helps, - Ive ruled out any mchanical issues.---Orig when engine was done and i ran 82 vett ecm and chip, and 350 vett injectors, with stock fuel pressure , i got high B.L.M readings in winaldl.--So then i decided too go to the 7747 ecm with prominator, as for what i did to eng. and was tuning and running it with 20 psi fuel pressure.---As of now im back to the 5550 ecm with vett chip, and kept the fuel at 18 psi, and did a quick check of B.L.M readings and they were more in line.----Veh runs pretty good now, but i lost a little of the lower end power,[0 to 40] I miss my timing i had set up in the bin i was using.---Hope this helps some. ---sorry for all the toooooo;s

 

What chamber size and piston type? If your pro toplines are 64cc with flat tops then you're at about 10:1, and you may benefit from taking out some spark (which would explain your knock). I've got the lightnings on my TA and find that ~40 degrees in the main table works well. Your milage may vary, of course, since I'm running TPI and a different intake, etc.

What size "350 vette" injectors? Was it from a TPI vette? If so, you may be drastically under injector'ed.

-M

 

no thier the 82 350 vett crossfire injectors. [stock],---the heads are 72 cc chamber. --and im running hyper pistons, [flat top]

 

i would suggest you double check for vac leaks. check hoses and all. also check for an exhaust leak at header flange or at the collector to ext pipe that effects NB02. that being said start from scratch with a stock 7747 .bin for manual transmission.

i am certain the BPC is calculated correct for 18 lbs FP right?

i am running now max timing of 36 deg and had KC this morning. not sure if mechanical knock. i was heavy on throttle getting on xway. I would set your SA tables with no more than 35 deg to start. i have idle 19 deg and surround my idle cell 800-40 map with 19 deg so if it wanders it sees 19.

i would run OL at idle.

i would run synch. disable asynch.

my BLMs wander as the intake gets fully heated or cools(heated 02) and i am pulling air under hood not cold air.

 

YES i calculated the B.P.W. , when i ran 7747 and prominator and ASDU BIN, using ben 's spead sheet.---with stock ecm and chip, i left it at 18 psi fuel for now.----why try the manual tran bin ??---As for exaust leak or intake leak ? i will triple check again, but seems i would have drivabilty problem with the stock ecm, and i dont.-----[Fill me in on the synch and asynch.] ----- I want too try to find a bin and def file on LT 1 THAT USED VORTEC HEADS, as they are close to the heads im using. and try thier timing tables. [ i use tuner pro ]

 

The Iron Head LT1 had heads that are virtually identical to the Cast Iron L30/L31/L35 Vortec heads. I've got a B-car LT1 timing table. I also have a timing table from a 1997 G1500 with a 5.7 Vortec.

 

So the first one is the B car, table and the second is the 97 g1500 ?-------What about setting the -P.E., knock retard, and- P.E. Air fuel ratio and coolant table, and what about warm and cold spark bias ??? -------And ronney you said start over with a standard trans bin, --is ASDZ FOR STANDARD OR WHAT OTHER IS RECOMMENDED--------I CURRENTLY just put my 7747 back in and is using the ASDU BIN,-- I then calculated my B.P.W, AND SET to 100, with my 20 PSI fuel.

 

HEY, FAST355, I see your first timing bin is very close to what im already at.---thanks.--- i currently have 7747 ecm back in and BPW set, --found and fixed my spark knock.---But off gas surge is back and no high idle when cold.--same old problems and stating over.

 

Perhaps I can help - I just tuned my crossfire on the weekend using a 7747 and prominator.
My engine is mostly stock with the exception of the cam

Caveat - I am a long time lurker, this is my first post.

Part 1 – please read the posts at the top
Part 2 – I too (two for Mangus) thought the stock ecm was doing a good job
Part 3 – once you get started correctly the 7747 will be a dream come true

Set your timing to 0 on the distributor, us a stock plug wire to get the timing light to work.
Start with a fresh stock bin that is close to your car (use a 5.7l truck bin)
Set your bpw based on the actual numbers.

Warning #1 – your stock injectors may not be enouph, try to get some 350 injectors
Warning #2 – you are changing too may a thing at once
Warning #3 – we need your cam and engine specs
Warning #4 – warn your car up first
Warning #5 – ensure your sensors are all working correctly.
Warning #6 – take your time
Warning #7 – “give it what it wants” – Grumpy

Do this first and then post in the morning

The reward is as follows – My car has never run this good in the entire 8 years that I have owned it. Surging, hesitation, all of it has been eliminated.

My set backs this weekend were:
O2 was not working correctly – replace and start again
Used bin from unknown source – start with fresh stock bin
Car ran very rich with stock truck bin – within 3 hours I had the fuel just slightly rich
Timing was way off – used timing from a known source

In the end (2 days) I am within 1-2% on my fuel and timing is getting very close.