ok.. 350 TBI

runs like crap.. I hooked up the laptop and we tried it out..

- first off tps shows -4.1 % on idle.. mine shows 1.7%


the other thing is the engine light comes on everytime he floors it.. gives code 43.. and it's not picking up any knocks at all..

he had already replaced the knock sensor .. so I doubt it's that.. we check the connection from knock to esc and it's a good connection(ohmeter)..

anything else that we should check? that's the only code coming up.. could it be the esc itself? or is it ground somewhere?

thanks

 

not enough timing...

If you knew the **** i had to go through back in the days when this question wouldnt be answered.. lets just say i lived the horrors of that. Big cam, big single plane... wants alot more timing down low for some reason the 43 is set because the computer advances the timing like 20 degrees when you go into wot just for a split second to detect knock... te point is to trigger the knock sensor. Youre timing is so retarded that its not even triggering knock and hence running like crap. After that light goes on the ecm pulls a bunch of advance (alll of the retard programmed in the chip) and will run even crappier.


AIM me sometime i can probably help you out with this one
AIM sn is TopfuelTBI

just set it up like a mechanical advance and vacuum can hooked to manifold vacuum.. make a table that looks like that in other words. there are some other tricks and things to watch out for because the computer plays some games with the timing i can give you all the addresses if you wish (for the 7747)
ie, like the spark slope adder
0 out the two coolant bias's
set the init. constant to what you hvae at the distributor
0 out p/e table

and what i mean by mechanical advance table
just find a decent mechanical advance curve chart
and copy that across the board onto your spark table start off with something like 33 or so total timing
then add on top of that chart what a vacuum can would add... say your standard generic deal would throw in like 12 degrees of advance at 18 inches of vacuum. Vacuum cans are totally vacuum dependent so youd just add 12 degrees of timing up and down the corresponding ve table to what 18 inches would be (30 kpa??) and then just slope that down to 0 at 100 kpa
The table wont look all fancy and it will surely be "wrong" by all the prom gurus standards... but its what your buddy would likely run if he wussed out and went carb with mechanical dist and lots of guys do and are quite happy with the results. You can tweak it after that of course for better mileage and response.. etc.


like i said, AIM me sometime.

 

btw about his tps
did you back out the screw with the engine running? or in the on position? thats the only thing i can see explaining the deal with that.. id clear the ecm, like unplug the battery and wait a few seconds and id bet it would reset to 0%

 

thanks for the info pablo.. I don't think it's a timing being not advanced issue.. because when he get's on it you can hear the ping but knock still shows 0 count.

 

well damn
i was under the impression it wasnt knocking
scratch what i said then.. btw if you hear the ping and still get 0 counts its surely failing the timing advance test might wanna look into that

 

I'm in the same boat right now because my stupid timing tab isn't where it should be (between 4 and 16 degrees off). I retarded the timing to show 6 degrees, car ran like crap (might just be the eprom) but set a code 43 with no knock counts. Happened when I would push the pedal down and the car would actually slow down. Not enough timing so car was running too rich (BLMs pegged at the 108 wall). I pulled over, got out the dissy wrench (didn't have the timing gun) and moved the dissy like 10 degrees advance. Still having problems but it's getting better. Now that I'm done with finals I'm going to sit down and mess around with my timing. I think I figured out a good way to get max power/torque. Just keep tuning the VE tables until the BLM peaks at 128, no higher, no lower, might even want to use the INT and have the BLM locked. Anyways, then I'll just start advancing the timing until I notice the BLMs go above 128 (engine wants more fuel) and from what I understand, as long as the engine is wanting more fuel it means there is more power at that rpm/map cell. Oh well, I'm just having fun with this, hopefully get my damn pointer aligned within the weak. Just have to remove the cap, look at the rotor, know remove plug, pen in the hole, find TDC, mark it on the balancer, done.
Pablo, now that I've got this 8 in 1 eprom thing, I'm going to set up a few to have typical mechanical timing slopes. The booklet that came with the crate motor gives some specs so I'll try that out.